Flotherm vs Flotherm XT vs FloEFD
 

Hello good people,
I would be greatful if anybody could calrify to me

what are the differences between those 3?

I used Flotherm and FloEFD so I know the basics like the way Flotherm captures geometry, or that I can do rotation in FloEFD and all the stuff from the tutorials. It looks to me that FlothermXT is an advanced version of Flotherm, but it would be surprising if Mentor would still work on Flotherm in case Flotherm XT was just better, so I am wondering if you could name any cases where flotherm can do better than Flotherm XT.
The same thing applies to FloEFD vs Flotherm (XT), is there something Flotherm XT can do that FloEFD (with i.e. electronics/led extension) cannot?

I could only think of interfaces between EDA software and Mentor - it looks like FloEFD wouldn't work so seamlessly with Altium, or Xpedition, am I right? Oh yah, and meshing is different in Flotherm, it is quicker I got used to it :)
So, why would anybody buy FLEXX license, which gives you Flotherm and Flotherm XT whereas Flotherm XT is just better? :confused:

Hello Pawel,

No Problem:

FloTHERM and FloEFD are two completely different products with different meshing technologies and different applications and capabilities in the ones they overlap.
FloTHERM is specifically for electronics cooling and also uses Cartesian mesh but has to create stair-steps for round geometry whereas FloEFD is a general purpose CFD tool that has some capabilities in electronics cooling but not as sophisticated as FloTHERM and uses a Cartesian mesh with a special meshing technology similar to the Immersed Boundary method to resolve the complex shaped surfaces without stair-steps as it is integrated in the CAD system and needs to treat the complex CAD model in detail.

Now FloTHERM XT is a hybrid of both tools with the meshing and fundamental solver technology of FloEFD but tuned to the application of electronics cooling with the capabilities and features of FloTHERM. It is still evolving as the current version is 2.3 so basically about 2 years old and more and more new features will go into XT, features that FloTHERM has but XT not yet but also features that FloTHERM does not have but FloEFD has.

So FloTHERM XT can capture complex geometry better than FloTHERM but will not be able to calculate cavitation in liquids or combustion and many other physics that FloEFD can calculate as it is not required in electronics cooling which FloTHERM XT is designed for.
With the capabilities of FloTHERM XT it is able to better plug into a Mechatronic environment where MCAD geometry is getting complex and ECAD (EDA) information is of course important for good electronics cooling simulations.

FloTHERM is very fast and ideal for everything more square shaped like big server racks or anything boxy. FloTHERM XT is handling complex geometry better, so everything where design in the MCAD geometry comes more into focus such as a nice shaped Xbox housing etc. It is simply easier to work with such geometries then.

FloEFD is ideal for those who don't want to leave their Catia, ProE/Creo or Siemens NX environment and don't need detailed electronics cooling but are happy with a heat source on a block as FloEFD does not have detailed electronics modeling such as Delphi models, it only goes up to 2-Resistor models as probably only a few MCAD designer really do e-cooling simulations in high detailed electronics modeling.

Yes, Meshing in FloTHERM is there from the second you place a component because it uses the boundaries of that component to create the mesh and since it are only Cartesian cells in their simpliest form they are described in an instant compared to the partial cell technology that contains either solid and fluid regions or multiple solid regions of different properties. They have to be generated by Boolean operations which are done during the meshing operation and is therefore a separate step in the model setup before the solver runs.

Let's consider a traditional computer vendor/manufacturer that has boxy desktops but also nicely shaped notebooks or even WLAN routers with more complex housings like Dell with their 19" rack units and projectors or tablets and desktops as well as other electronic equipment or HP with similar products. FloTHERM is ideal and super fast for racks and boxy desktops but has more issues with design objects.
Just as an example, which one would you rather use with FloEFD meshing technology that FloTHERM XT has or FloTHERM meshing technology from your experience in these options:

http://www.bestbuy.com/site/sony-3d-...&skuId=6359019

http://www.bestbuy.com/site/viewsoni...&skuId=8848612

Or this example:
http://www.bestbuy.com/site/netgear-...&skuId=8998506

http://www.bestbuy.com/site/belkin-n...&skuId=2089307

Or consider curved TVs vs. regular TVs

Or these two desktops:
http://www.bestbuy.com/site/hp-pavil...&skuId=3311063

http://www.bestbuy.com/site/hp-pavil...&skuId=7117105

I hope this helps,
Boris

Thank you very much for the answer Boris, yet I'd like to know more :)
-Is it really impossible to incorporate Delphi models into FloEFD? It looks like a great disadvantage to me, since 2-resistor models might be inaccurate.
2-FloEFD has this extensions like LED cooling package, or electronics coling package, or advanced modelling package. It looks like LED package covers radiation phenomena pretty well, which is a plus in aerospace industry wchich the company I work for is doing, so do you know if Flotherm XT or Flotherm is capable of modelling radiation like FloEFD (LED extension), wouldn't FloEFD electronics cooling extension cover delphi models, heat pipes, fans, TECs, heatsinks and all the smartparts we have in Flotherm?
3- FloEFD can also do phase changes (evaporiation, condensation, freezing?) can Flotherm XT do that?
4- I'm not sure if I would need to consider cavitation, rather heat transfer due to boiling. I guess FloeFD incorporates heat of evaporization but I am not sure if the model it uses allows doing sophisticated stuff or it is just there to check if cavitation/boiling occurs, what do you think?
5- can i create a heat exchanger in Flotherm XT? It requires velocity/flow rate inlet/outlet boundaries, good modelling of fluid flow, Flotherm has this fixed flow smartpart, can I use it as an inlet boundary? :P

Thanks,
Zdunol

Hi Zdunol,

1. No, of course it is not impossible but FloEFD is not planned to become a FloTHERM competition, there is a cut at some point where you will have to go to FloTHERM to do more detailed e-cooling simulations.
It is like with every product, Porsche also builds Panamera and Cayenne and both are sports cars and have 4 doors still there is a difference. HP builds Workstations and weaker Desktops because there is a difference in the user requirements.

2. Yes, the LED Module but it is not just for LEDs but also for lighting in general and is used in the automotive lighting industry extensively because of the Monte Carlo radiation model and the condensation model. It also has the E-Cooling Module with some features such as heat pipe, a simple PCB model, the 2-R model and joule heating etc. The Advanced Module has combustion, hypersonic flow and some other features which only few users need with some more advanced physics requirements.
The most advanced radiation model (Monte Carlo) is only in FloEFD as it is extremely important for the lighting industry or in applications where the focusing of radiation either by a reflector or a lens is important. FloTHERM and FloTHERM XT have radiation models but in electronics cooling there usually is no absorption in semi-transparent solids or focusing to a hotspot or wavelength dependency like the Monte Carlo is capable of. FloTHERM XT has the DTRM model and FloTHERM either the same or similar one like the Surface-to-Surface, I'm not sure and would have to look it up. These models are enough for regular heat radiation as it appears in electronics cooling applications.
Not all of what you mentioned. FloEFD's E-Cooling Module has 2-R models, heat pipes, fans curves (do exist in the basic version but there is an additional database in the E-Cooling Module with fan curves), TECs (also in the basic version but again an extended database in the module), there is a black box model for a heat sink with fan as a kind of smart part but no specific heat sink model or smart part where geometry is created automatically or something like that. FloEFD is based on Geometry in the CAD system whereas FloTHERM is based a lot on Smart Parts you can simply place somewhere by some basic definitions in the feature menu.

3. No, FloTHERM XT cannot do that.

4. The condensation/evaporation model is a film model so you can define a film thickness as an initial condition in a transient simulation and the evaporation energy is considered in the simulation but it is a film model so the film thickness is to be much smaller than a cell size. The cavitation can handle isothermal but also for water specifically the full temperature range as the properties for water are well known over the temperature compared to some industry liquids such as oils or fuels. There is also the real gas "Water" which partially can work in that range but all of them do not distinguish the different boiling methods which have a significant influence on the heat transfer. If you have any more detailed task definition I can give more information if that falls within the range of capabilities of FloEFD. FloTHERM and FloTHERM XT cannot do that at all.

5. I'm not 100% sure but it should basically be possible as liquid cooling of power electronics is of course an important factor and an air side should be possible too. I just cannot tell about the specific boundary condition types.
But if heat exchangers get more detailed with louvers etc. a special porous media type in FloEFD is way more better suited than resolving such structures with cells in the whole model. This is used for example in automotive oil-water cooler or oil-air or water-air cooler like for intercooler of charged air etc.

I hope this helps,
Boris

PS: I wasn't quite accurate about the FloTHERM stair-step meshing as it uses a special approach for the cells FloEFD calls partial cells, where the cell is partially fluid and partially solid. Just to be correct here :-)

Thank you very much Boris, it really looks like you know a lot about Mentor's products.

I really need to take a look at Flotherm XT because detailed ICs modelling is a must for us. Do you happen to know if Flotherm XT covers variation of material absorptivity with respect to wave length, or material temperature, or maybe even angle of incident (im not sure if the third one is physically correct or if I will ever need to include it in simulation - it's been a while since my last physics class :) )

It's hard to choose a proper software since we need it to cover robust CFD solver (for doing heat exchangers), EDA features and radiation since we will do space stuff. I guess I will have to do a compromise somewhere :(
It would be great if Flotherm XT could handle flows like FloEFD does.


Btw do you happen to know if any of theese can incorporate radiative heat transfer from and into fluid?

Regards,
Zdunol

FloEFD is capable of handling such radiation cases in detail but lacks the Delphi model for chips. FloTHERM can do the Delphi but does not take into account the wavelength dependency.

What do you need the wavelength dependency in the absorption for? Do you have glass (semi-transparent) solids in your assembly?

What exactly do you want to do with the radiative heat transfer from and into fluid?
And what fluid do you want to consider?

Boris

Yes, there will be some lenses, filters and windows and it would be great if we could use one software to do electronics, conjugate heat transfer, phase changes and radiation phenomena, and do it fast with concurrent approach :)
But I guess FloEFD's LED extension is there for thermal analysis and it won't be possible to check if for example our housing will suffice in protection against gamma rays right?

I was just wondering if radiation from fluid is somehow included in CFD in general. It just
occured to me that all the solvers concern subdividing solids into surfaces but I have never seen anybody mentioning fluids (liquids). I guess it would be important in space cooling applications, where there is no convection outside the assembly.

Lack of delphi models in FloEFD seems to exclude it from consideration unfortunately :(

Btw, as a customer I would love to be able to easily access more technical documents describing each product in general. Materials Mentor distributes is impressive I have to admit - great marketing, but remember that CFD does not stand for Colors For Directors (only) :)

Thank you very much for the help Boris.

Since gamma rays pass through opaque solids they are not really considered in FloEFD as radiation in opaque solids are only interacting with the solids surface (reflection or emission). Transmission and absorption are handled as a volume property and only for absorptive (semi-transparent) solids. So I doubt it will help with gamma radiation.

Yes, the reason is often because it depends especially in gasses on the pressure of the gas and especially in combustion cases it is of interest and here you also have tiny sooth particles which make out a large amount of the radiation emitted in the gas.

The only way to go around the delphi model is with a detailed modeling of the chip and applying the material properties but that requires of course detailed knowledge of the chip and its materials.

There is at least a detailed document that comes with FloEFD that describes all the features and physics of FloEFD such as the radiation models etc. There are also some white papers on certain capabilities online and worst case, always contact the support if you have a more detailed question about a capability that you need and let them help you with the answer if FloEFD or one of the other products is capable of it.

Boris

Boris, thank you for your explanation.

My company is in the business of Electronics cooling of Power electronics. Some of our large power enclosures have a lot of parts and complex shapes and we use SW for their mechanical design. We've been using SWFS for more than 7 years and are happy with its integration with SW, user friendliness, stability and reasonable accuracy.

My questions are as follows:
1. What are the features present in FloEFD but not in SWFS (related/needed in Electronics cooling)?
2. I understood that Flowtherm XT uses the meshing algorithm and the solver of FloEFD. In that case what advantage would XT bring to electronics cooling people who already have SWFS.

Hi CFDfan,

there is no difference between SWFS and FloEFD with regards to electronics cooling at the moment.
Yes, FloTHERM XT is based on the meshing and solver of FloEFD but uses the electronics cooling know-how of FloTHERM.
FloTHERM is the electronics cooling market leader and has waaaaay more electronics cooling capabilities than FloEFD has. It is specifically built to the electronics cooling applications whereas FloEFD is a general purpose CFD code and has some but nearly as many functionalities for electronics cooling as FloTHERM and FloTHERM XT has.
The good thing with FloTHERM XT is you can use the SW models directly in FloTHERM XT as is is based on the SW modeler and therefore all parametric data of the SW model is available and the geometry can be adjusted just like in SW.
In FloTHERM XT you can use EDA import in which you will get not only the PCB data from a simple block to a detailed PCB with single traces from ODB++ data (detailed Copper nets) as well as automatically getting all the EDA information about heat generation rate of the imported ICs and other components in that comes from the EDA tool. So if you import a PCB you can filter components by size as well as dissipated power and also select which detail you want to have them, as a block, 2R or more detailed like a DELPHI model etc. from FloTHERM Pack (www.flothermpack.com) where you can generate detail chip models or also use them from most major vendors. You can also capture power modes of components
And FloTHERM XT has just like FloTHERM a smart part library so if you need a heat sink you can basically drag and drop it out of a library with just a few definitions about the size and fin height etc. The same goes for many other components.

So if you are working strongly in the electronics cooling application FloTHERM or FloTHERM XT would be the best solution from Mentor Graphics. If you like the meshing and the direct use of your SW models then FloTHERM XT is the strongest electronics cooling solution you can get that even uses the FloEFD/SWFS meshing and solver technology.
If you are interested then you can always have a try of it by contacting one of the Mentor offices or resellers, depending on where you are based. It is like test driving a car. You don't have to buy it but if it helps to do you job more accurate and better then it is worth a try.

Boris

Thank you Boris for your explanations.

I talked about XT among my colleagues and it turned out one of them has evaluated it for about a month.
He confirmed its suitability for electronic cooling application , the smart part library and the tight integration with Solidworks (SW), which was great. The things he didn't like was that:
1. XT couldn't read native SW files created by later versions of SW (than the one XT was integrated with).
2. The meshing in XT he said was somewhat different than in SWFS. He run the model he had with the 3 different meshing levels in XT and got quite different results. This was not so prominent in SWFS, where the difference in the results when running (the same) model with mesh resolution factor of 3 and say 8 was just a couple of %. To get the same results in XT he had to run his model with the finest level of meshing there, but then the number of cells was about 30% higher than in SWFS' model and the simulation run slower.
In summary he had mixed feelings about XT - very good idea but not refined yet.

Hi CFDfan,

Yes, XT is always a little behind the SW version as SW releases it first and the next release of XT usually gets the next SW version as well.
The same is with FloEFD and SW. FloEFD releases new capabilities and they are not or not all of them in SWFS at the same time.

The meshing technology to be precise is the same but the way to mesh the models is different as it is tuned to the way FloTHERM meshes and that is based on smart parts. So each smart part will have a local mesh setting available and of course the way to specify the mesh by the look of the GUI is different. It simply has a different menu but the mesh technology is the same.

It depends on when he tested it. There has been some changes since the very first release. As in every product, the first release is the first release and never the best as the next is always better. It is always a convergence case. The older a product grows the more optimized it is.
As for the mesh settings I cannot tell what he did. Maybe he was used to the SWFS meshing and did it the same way in XT and here it simple has to be done differently. In such case it is best to talk with the engineers of the reseller or Mentor Graphics directly to get their input.
I've seen users of traditional CFD tools start using FloEFD and they tried to create meshes as they know it from the other tools. You had to teach them that this is not necessary as the technology is different. It's like learning to drive stick if you are used to automatic :-) (or the other way around in terms of automatic meshing)
Often you have to learn things new in a new product and forget about the old way of doing it. It will always frustrate you because you'll say "But I'm used to do it this way." You don't call your new girlfriend by the name of the old one because you are used to using that name for your girlfriends, right :-)

I mean you can certainly try it on your own to see how it is and make your own opinion of it.

Boris

Boris a continuation of this interesting topic.
I read a promotional material about the SmartCels in Floefd that allow for good accuracy with less cells and shorter calculation time. This sounds like a very good idea and my question is:


1. Starting from which version of Floefd will/are these "smartcells" be available?

2. Will the SWFS module in Solidworks 2017 be supporting the smartcells and if not are there plans to introduce them in SWFS as well and when?

Hi CFDfan,

It's a marketing decision, they just changed the name :)

Hi CFDfan,

The SmartCells are the combining technology of the formerly called partial cells and the solver technology that makes them work with FloEFD’s meshing technology, i.e. working without body fitted meshes and still get that good results.
The white paper you read eaxplains the technology a little better than the meshing and turbulence paper you can find on the Mentor Graphics website.

But it is nice to see that this technology seems to be so exciting that you want to have it in SWFS as well :-)
However, you have been using it already all the time, this just shows how goodthe technology is :-)

Boris

Hi Cengizhan,

Not quite true, it was a technical decision to give the "partial cells" a technical terminology that is better understood than its previous name and with that the need for a better explanation of the technology was required. But since it is not just the mesh but also the solver technology that make it work (the combination of both), this had to be shown and so the name SmartCells was given that describes the combined technology. Partial Cells were only the cells at the fluid/solid boundary called.

Regards,
Boris

Hi Boris,

What i was trying to say is that instead of smart cell, it could be intelligent or clever or wise or "geometry and solution adaptive, helping the solver with boundary layer treatment 'two-scales wall functions model' with just mesh number at boundary layer and whether it could be laminar-turbulence-transient flow; newtonian non-newtonian fluid or not etc.., you don't have to worry about the type of it because FloEFD only uses cartesian based, includes boundary layer" mesh. Well, maybe the last one is a little bit longer :) :)

But of course you are right, it's very different from other meshing technology like cut cell although they like similar to each other and like you said not just meshing, it's combined technology with FloEFD solver. Maybe solver needs a special name either :)

Regards,
Cengizhan

Hi Cengizhan,

Yes, exactly the long term was the reason for a good short name that basically summarizes the technology.
And SmartCell includes the solver technology that applies for those cells that make them work. The rest of the solver to the far field is not much different to other solvers, just the way to handle the boundary layer and the type of mesh the way it is and provide good results is what is the big difference and that is part of the SmartCell naming.

Happy holidays to everyone,
Boris

FloTHERM vs FloEFD comment
 

Don't know if this thread is still monitored due to being started in 2016. I use both XT and EFD and have used FloTHERM "classic" for many years.
FloTHERM XT vs FloEFd. ECAD import in XT automatically produces PCB Smart Part with three level options of detail. FloEFD does not. Changing level of PCB detail in EFD is a manual operation. XT has more bells and whistles for specialty electronic functions. Though on that note I would say that EFD is more receptive to improving product features where XT appears to be more stagnant in this area.
There are many idfference too many to go into open ended. FloTHERM classic does not import CAD geometry (tries to but way insufficient). XT does.
History......Classic and EFD separate products. EFD and classic (Flomerics Inc.) bought by Mentor Graphics. XT is porting of Classic functionality to EFD solver and geometry processor with new XT GUI. EFD accepts CAD data and meshes it completely differently than FT Classic by use of advanced partial cell technology. EFD has Electronic Module which is subset of XT and Classic funtionality. EFD was originally a flow solver and has evolved over time. They are currently still separate branches of now Siemens whom bought Mentor Graphics. Over time I suspect they will merge but until EFD raises to the level of XT and Classic FT it cannot replace them in terms of electronic modeling functionality. EFD has many nice features but also many productivity shortcomings when it comes to Electronics modeling.
Hope that helps if you're still listening.

Hi DB,

Yes, this is partially correct.
FloEFD has also the EDA Bridge Module which is about the same as in FloTHERM with which you can import also three levels of detail from the EDA data such as ODB++ files.
But you are correct, FloEFD doesn't create smart parts. It's aligned with the CAD modeling approach as it is designed for CAD users originally. So a feature-based modeling approach.

Where in electronics you usually pick and place existing components and therefore a Smart Part approach with a good library is key, in CAD modeling most of the models are totally new and maybe use standard parts such as screws and washers etc. but those are in libraries of the CAD system already. So the smart part approach is not the typical approach for thermal simulation.

In terms of capabilities, it purely depends if you need specific features or not. Often it is a lot of user preference as well in the way to handle the simulation setup. Some might need a specific capability others are not, some might like the handling of the software, others might not.
Therefore I suggest always to try the tools as it needs to fit your preference as well as needs to provide the capabilities you require to solve your problem.

Yes, FloEFD does not have a pure focus on electronics cooling as it is a multi-purpose CFD tool and therefore has many features that need enhancements. In V18 we got new radiation capabilities, new electronics cooling capabilities, brand new battery cooling models etc. So a wide spectrum of enhancements whereas application or industry-specific software like FloTHERM can focus on electronics cooling focused features purely and have therefore more capabilities to these applications.
FloEFD will get more electronics cooling capabilities as well of course but it won't be the focus such as with FloTHERM. In V18, for example, we released also the calibration capabilities that uses the T3Ster measurements to build better thermal models of semiconductors which was already available in FloTHERM for 2 years or so. And the same the other way around. FloTHERM XT received sliding mesh after it was in FloEFD for 1-2 years already. Often the features have to be validated in the field first as well as the GUI adopted as they are not the same and some features will probably never come to the other tool as they are simply not needed or never requested by the users.

Regards,
Boris

Smart Part, electronics
 

Boris,
You are correct about electronic component smart parts. I was referring to the PCB smart part. FloEFD 17.3.1 does not create this automatically as FloTHERM XT 3.2, 3.1 does. Instead EFD creates individual materials for each layer and puts them in the project. This is extraneous bookkeeping for the analyst. A single layer material is unique and not useful for any other pwb so it isn't necessary to have the part in the engineering library or project. Just creates extra work when switching the PCB type from compact, detailed or explicit. Additionally if you start with a detailed pwb (layers each with lumped bulk properties) and switch to compact pwb (single 1 layer lumped parameter body) you have no pwb component. Have to make one. Then with two versions of the pwb SolidWorks mates become problematic and have to be adjusted as well. The approach I use is after importing immediately take the %Cu for each layer and create a smart part PWB with it. The %Cu is in the name of the material after importing the EDA file.

I use both XT 3.2 and EFD 17.3.1 because of the model and user preferences and needs as Boris mentions. One limitation is even though both standalone versions use SolidWorks they are not compatible. XT uses SW 2017. After EFD V17.1 EFD uses SW 2018. Not backwardly compatible. So if you make or change the model in EFD 17.2+ you can no longer use it in XT. If you need to use both XT and EFD have to stay with EFD 17.1 (in which the parametric processor has useability glitches, fixed in later versions)

Another used asked about differences in the EDA. Although they are all called FloEDA Bridge they have differences. FloTHERM classic's EDA Bridge can plot power density (power versus area of a component). Neither XT or EFD do that. A very useful feature for an initial survey of critical components.

Another difference. The mesher in FT classic is different and has localized grids that behave differently than XT and EFD. They cannot touch each other. On a part such as an inclined block this takes up a lot of real estate and causes modeling difficulties for high packaging density. Say in a 2U-24 disk drive server for instance. Both XT and EFD have capability to have mesh refinement directly adjacent.

Even though XT and EFD are based on the same engine the meshing is different. in XT a 2 x 3 inch 12 layer pwb, using thermal territory explicit for a couple of BGA's, didn't finish geometry transfer after 18 hours....didn't even get to meshing stage and it was only using 1 core. This is with Dual XEON Gold 3+GHz processors on turbo (24 cores), 256Gb RDIMM memory using all channels, and hyper threading turned off. EFD mesher is better. Import geometry checker is better also.
DB

P.S.
Difference: Classic and XT sums all applied powers. EFD doesn't. Leaves out 2-R parts and network assemblies. Have to add them up manually.

Hi DB

You emphasized the differences between XT and EFD and you obviously prefer to work with both of them. Not many people/companies can afford that, so if you have to select only one of them for your application (servers if I got it correctly) which one would you choose?

FloTHERM, XT, EFD, which one for servers.
 

Aahh,

That's a complicated question. Some time has passed since my initial post. FloEFD has since implemented a smart PCB I believe. I think it was initially in beta some time ago. I have not used it yet. I recall also a new addition of some sort of network reduction of a local area. ie: resistance network replacement of cells. I do not recall the details of this either, only the notice about the new feature. Maybe Boris can enlighten us on this and save me trying to find the email or notice on it.
If the new feature smart pcb has the same features as XT, which are providing the option to switch back and forth easily from compact to detailed, and providing the calculated bulk Kxy and Kz (useable for other manual PCBs) for this feature it would be a toss up. As it stand now EFD generates a material for every layer. This is difficult to suppress and unsuppress. Too much bookkeepping within a project and between projects, and the materials database. The materials are only associated with the geometry the first initial import of the EDA. After that it is up to you to manage it. Time consuming.
Another thing to consider. In XT I have not yet had a successful mesh generated in an explicit PCB model, nor with only the "thermal territory" feature. The mesher runs differently in XT than EFD (better). On a simple 2" x 3" 12 layer PCB the XT mesher ran for 16 hours and didn't get anywhere (Dual Xeon Gold, 256Gb main memory). I think it never got to the mesher, geometry translator too slow is my guess.


***********************
Without considering the above if you can live with compact and detailed I prefer XT for PCB work. I can do them pretty fast in XT. Most of the time is spent working up the PCB component details. If you do your PCB's first and alone, and only do main components at the system level, then this isn't an issue. That might change if the Smart PCB upgrade in EFD has the features of XT's Smart PCB. EFD has some more bells and whistles available to the user for fans and things but at times it slows things down.....too many dialog box options, used infrequently, is adverse to being fast at it. I also do not like having to add up the thermals manually in eFD. Prone to errors in a fast paced environent and not convenient for quick checks during quick turn around power level what-ifs.
***********************



I might have mentioned it earlier but in my version the Electronics Module in EFD does not have a Smart Heat Sink Part. That alone is enough to make me us XT for electronic work. Even some housing heat sink work. You can make a parametric heat sink in Solidworks (Mentor's suggestion) but it's a pain to debug it and get the parametric scenarios to work correctly, especially if it's not a textbook simple heat sink configuration.

If there are narrow channels to consider FlotHERM Classic is to cumbersome in meshing to mesh them quickly. It takes a lot of manual follow up meshing. Both XT and EFD to a nice quick job on narrow channels.

For compact you also should know that in order to insure three cells through the PCB, especially if it is not aligned with the orthogonal mesh you need to add a "1/3 PCB". This is easy. It is a copy of the original PCB outline, cut down to one third the thickness, mated so as to be at the center of the main PCB, overlapping it geometrically, and beneath it in the model tree so it overwrites the main PCB. This should ensure keypoints of the mesh are generated at the 1/3 and 2/3 through plane points so as to force three cells through the PCB. This is unnecessary with Detailed PCB.
It also depends on the overall size of your server system. If you're aware of the mesh cell ration limit then in my experience sometimes XT has difficulty resolving small/thin geometry if the domain is large. Even when local meshes are applied. Some mesh settings in XT are built in and hidden in attempts to make it easier for a CAD person to run an analysis. EFD gives you more mesh controls. If it is a single rack not a problem. If it is a whole cabinet this situation might arise, especially if you use contact resistances, model thin PCB perimeter EMI strips (0.05mm thick) or such small features. The quick solution is to increase mesh density of the domain (smallest resolvable feature is hence reduced in size) and live with the longer run time.

Sorry for the long text. Guess I"m a little over tired at this hour (2:45 am).

supplement
 

XT Smart PCB: bulk Kxy, Kz and density and Cp also.
It also shows the stack up in a separate window for screen shot capturing.

supplement
 

I work on more than just servers. Consider that for electronics, that is what XT was built and specialized for. Many of the features of Classic were incorporated into XT. So for electronics in my opinion and use XT is more thorough and faster model building than EFD. EFD has more versatility outside of that. Don' recall but I think the included electronics component starter pack library is much more complete in XT. Preloaded with 2R models in the library for a lot of packages. Would have to check tomorrow at work.
XT is less expensive. "XT Ultra" includes EDA bridge. With EFD you have to add the electronics module and the EDA module to the price. The EFD electronics module does not get you up to snuff with XT.

I work in electronic cooling area as well and have used solidworks flow simulation (SWFS), that is Floefd embedded in solidworks, for a very long time. Was happy with it till a very large enclosure with a lot of details came along and SWFS simply refused to simulate it (with 128gB of RAM). After a lot of research we bought scStream. It was considerably more expensive than SWFS but very powerful and stable and we have never looked back. Some people in this forum were advocating for 6sigmaDC because of its accuracy. It is another code designed explicitly for electronic cooling. I have no opinion about its capabilities, knowing only that its price tag is the highest.

Both XT and EFD and most likely SWFS use only one core for geometry transfer. This is the bottleneck I see. With 24 cores it only uses 4% of CPU as shown in Resource Monitor or Task Manager - Performance tab. The mesher, once it gets to it is somewhat better because I think MS windows is getting it to use multiple cores. the mesher itself is not multi-threaded last I heard.
How many cells do you expect it might be? I could try meshing it in XT or EFD if it wasn't proprietary in nature and the SW version was compatible. Or how big is a .stp file?
In XT there is a green progress bar in the lower left corner of GUI. If it doesn't get past 25% (rough number) it's not in the mesher yet, it's still in the geometry transfer/translator stage.
Maybe try reducing the domain mesh to very light just to see what happens. No narrow channels, no fluid to solid refinement, no solid refinement, no fluid refinement. Does SWFS have these options available?

I'm not familiar with scStream but tried out the PICL demo version, ok for quick idea, what it is.

as I said SWFS is Floefd embedded in Solidworks, so whatever Floefd has SWFS has it as well (including the options you listed)

below is a brochure of all Cradles's products including scStream. Scstream has a module that is dedicated to electronics called HeatDesigner, but i prefer the full blown scstream because it has more features.
Very briefly - structured mesh, a lot of freedom for mesh adjustment, excellent handling of the memory - with 128gB of ram one can simulate 100-150 milion of cells (volumes), so very large and complex models can be simulated on a single PC. Excellent post-processing of the results, much more advanced than EFD or XT. Has a module called HeatPathView showing the path of the thermal flux between components and one can get an idea what is heating what and to what extend and how the heat dissipation within a component is distributed and if something can be done to reduce the hot spot temperatures
Very stable if the aspect ratio of the cells is kept below a threshold, yet that ratio is known after the meshing and before the solving, so one can refine/remesh the areas with bad aspect ratios (using so called multiblocks which are basically local meshes). The meshing is very fast, no more than a couple of minutes for say 100mil of cells. Tolerates overlapping of solids, the same way EFD does but in addition generates a message which parts are overlapping, so one can fix that if necessary. It is a standalone code that imports the geometry in Parasolid format. The geometry import doesn't take more than a minute.

Has much more sophisticated fan models (than EFD). Also has a lot of turbulence models (compared with the single one of EFD and XT), so one can get an idea how realistic the results are (by running with different turbulence models). Relatively fast solver that uses the CPU resources efficiently (if one has a license for all the cores).
Widely used by the electronic companies in Japan, Korea and China (scstream is a Japanese product bought by MSC Inc and then by Hexagon).
Excellent product support - updates are available every month and the bugs get fixed very quickly.

After these positive words I have to say that I don't have any association with scstream. I am just an user who worked in electronic cooling area for a very long time using a few CFD codes. The only thing I don't like about scstream is its price (but you get what you paid for).

https://media.mscsoftware.com/cdn/fa...e_a4_email.pdf

I just recalled something. Several years ago I was on a project doing stress analysis. The thermal-fluid person was using SWFS. He ran a complicated cabinet/rack simulation model ok. I was surprised how quickly he turned around one re-sim after changing fans and fan curves. It had some bends in the inlet to the cabinet, a distribution plenum, and several racks. Based on the geometry and detail I saw it would have been in the many millions of mesh cells. Maybe in the tens of millions I seem to recall.

I was running femap/Nastran stress and vibration sims. To take a shortcut on one minor aspect of the project with some simpler geometry I tried to run it in SW simulation instead of exporting/importing a stp/x_t file. It ran ok until I added contact. Then with a minimal amount of contact surfaces it never finished pre-processing. Had to go back to Nastran for it. I seem to recall something about SW contact "manager" being the problem.

These two issues suggest to me a Solidworks issue in implementing simulations of either type. SW may be set up for only simpler jobs. At the time I think SW used the Cosmos stress solver which was pretty good. So I wouldn't blame EFD in SWFS for your long time issues.

Unlike Ansys and others EFD and XT doesn't limit how many cores you use. You can use as many as you like. This keeps cost down compared to programs that charge for core usage. That makes large models too expensive and prohibitive.

I sense a sales pitch here. I think that is an inappropriate use of a technical forum, and quite frankly wasting my time where I am trying to help another analyst on my personal time. Somewhat of a bait and switch gambit too. For what it's worth the PICL demo was extremely limited in it's features and somewhat short sighted for PCB analysis. Only a simple not very useful case except for an inexperienced Engineer. Anyone familiar with Steinbergor a few years of PCB experience would't need PICL for the simple things it did. No component case, TIM, to housing capability. Hope the stream isn't the same way.

You mentioned cost. How much does a comparable stream program cost, as long as you're selling?
Pardon my boldness if I am in error.


PS. Since EFD can do supersonic and Mach 20 with plasma dissociation and recombination it must have a decent turbulence capability. If I have it correct it also can use a shear at the wall approach to handle the boundary layer appropriately. You can get the powerpoint explanation from the EFD Product Manager.


Electronic cooling isn't aerodynamics. Since the geometry details are usually abbreviated, say for several packaged components on a PWB, that are block models wthout pins or legs, extra detail in the flow solution is fantasy. For electronics cooling Spaulding developed what was needed for the typical characteristic dimensions. Since the manufacturers thermal data is mostly fantasy as well reading too much into it is more fantasy. ie: Theta_jc, Theta_jb, Delphi models are commonly poorly derived. Some of the thermal reports I've received from IC manufacturers don't even apply or get the JEDEC definitions right!

I"ve found that the physics capability of EFD is superb and the scientific code developers are first rate.

Well, if you think that of EFD(and I agree with you), read about the founders of 6SigmaDC - graduates from the 3 best technical universities of USA, UK and Russia.

I believe the Japanese scientists are world class too, we just know too little about them

Don't get me wrong - I used SWFS for more than 20 years when it was still a part of the German's NIKA (before Flomerics, Mentor and now Siemens) and was very familiar with it. I knew one of the developers too and used to get first rate suggestions from him when facing an issue (the local technical support wasn't of much help). It was and is excellent software and that's the reason I stuck to it for so long. It is just that I found scstream to be better.

I was afraid I would sound as a salesmen and that's why I made the statement, but believe it or not I have nothing to do with scStream.
The only thing I could tell you about its price is that it was about 2.5x the price of SWFS, bit less expensive than 6sigma. In addition, as you probably know, the prices of the CFD codes can vary significantly from user to user, so these figures may not be the market prices.

I agree completely that "Electronic cooling isn't aerodynamics" and what you said after that. I would just add that EFD originated in Russia and was developed by Russian scientists in aerodynamics, so it wasn't targeting too much the electronic cooling. In addition handling Mach 20 and the natural convection cooling with a single (or two) turbulent model, regardless how good it is, doesn't seem to come without limitations but I may be wrong about that.
Look, I don't want to spent more time on this discussion. I was expressing my personal opinion and you can agree or disagree. Again, EFD is an excellent CFD code and does an excellent job in vast majority of electronic cooling applications.

FloTHERM XT sample project
 

I've heard of 6Sigma and looked it's brochures over but not ever been with company that had it.


The attached should suffice to confirm capabilities. Whoops file is too big. I can send it if you like. You might search the web for it. It is a Siemens unrestricted presentation.


Liquid Cooling System for a 17kW Artificial Intelligence Module-Ver2.0.pdf


It's 17.6 kW on a single wafer ~ 20cm with 84 cores on it. Largest chip ever built known to the public. There are several layers of complicated inlet manifolds to give impingement cooling on each core.


I'm not the author or analyst of the project.

Presented at Realize Live (Siemens)

physics programming smarts is good and necessary. It's the user GUI experience that also counts big time and doesn't take a physics genius. Something that is unfortunately in these days left to the wayside over continuously adding more features to the programs.

Wow, one week away and there is a blast of posts 

Ok, here’s an update and some information on what has happened with Simcenter FLOEFD (as it is called now) but short FLOEFD for my hands sake  and to shorten the post at least a little.

Yes, you are right, an explicit PCB import and then getting it to the meshing can take quite a while to mesh as it is creating the full detail of the PCB geometry. So it depends on the amount of copper traces and the through connects etc. that needs to be created and then handled by the mesher. But as smart as the FLOEFD developers are (and this is a unique feature to FLOEFD only at the moment), they developed the SmartPCB. This has nothing to do with smart parts or libraries in any way. It is a thermal network assembly model of a PCB. With that, the PCB becomes mesh independent as the PCB is solved with a thermal network model and does not need a fine mesh to resolve the traces etc. The components on the PCB are excluded from this model, this only is for the PCB itself. The accuracy of the PCB representation can easily be defined in nodes which can be visualized similar to a pixelated image of the PCBs copper traces. It is extremely fast with very little accuracy loss from this approach.
This way, your meshing should not take 16 hours anymore for a complex PCB as the mesh is completely irrelevant for the PCB. ;-)

Yes, smart parts are a nice thing and that’s the foundation XT and Flotherm are based on, while FLOEFD is a CAD and feature based tool. So geometry typically comes from CAD designs. As you said, such libraries can be created inside the CAD system and I have done that in the past and with some scripting work you can get them nice and easy to use, this is all part of the XT and Flotherm package for their purpose of course.

As for the modules and things, there is the new “Electronics Cooling Center” module which brings a whole load of new electronics cooling features into FLOEFD in a single package. It combines several modules (which you can still get separately if you don’t need all of them):

- Electronics Cooling Center Module
---- EDA Bridge Module
---- Electronics cooling Module
---- T3STER Automatic Calibration Module
---- BCI-ROM + Package Creator Module
- Power Electrification Module
- LED Module
- HVAC Module
- Extended Design Exploration Module
- Advanced Module

With the Electronics Cooling Module it is about equally powered as XT Ultra with the usual differences such as smart parts etc. It received a lot of the electronics cooling knowhow and technology of Flotherm, but is still meant for CAD designers as a core user focus, hence the UI.
And no, Flotherm will not go away, it has a different user focus. If you consider that automotive companies also don’t just have one car model that suits all.

The CAD system is the bottleneck as it is not parallelized. Once the geometry is exported for the mesher, the mesher is parallelized just like the solver. The mesher is parallelized since version 10 or 11 I think, I can’t remember exactly but that’s almost 10 years now.

Yes, SWFS has the basic functions of FLOEFD mostly with some minor differences, the bigger differences come from the modules as SWFS only has the HVAC and Electronics cooling module.

By the way, FLOEFD also has the heat path viewer.

SWFS and SW Simulation are completely separate and have nothing to do with each other. Except using pressure and temperature loads being possible.
I cannot tell about the structural tools but know that FLOEFD for example can export to other structural tools, this is one of the basic version differences that SWFS cannot do.

Actually FLOEFD can do up to Mach 30 


This all is not meant as a sales pitch, after all it’s up to you if you buy or not. I just saw the messages and thought I’ll add my 2 cent on some of the things mentioned to avoid any misunderstanding or just to update on the latest news.

Regards,
Boris