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Old   April 6, 2006, 17:43
Default KIVA DATA files
  #1
Sanaz
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Hello, Does anybody know, what kind of information for the injection properties(droplet distribution,..) is written in the output file DAT.INJECT of KIVA?

Thanks Sanaz

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Old   April 7, 2006, 02:24
Default Re: KIVA DATA files
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Ravi
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Hi Sanaz

dat.inject file consists of the data of amount of fuel injected into the cylinder by each nozle i.e. each hole of the injector w.r.t crank

and can I know what problem you are working on so that we can share the KIVA experience

and what type of errors have you encountered in simulation

I am using KIVA for diesel engine simulation

ok all the best Ravi Kiran
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Old   April 7, 2006, 03:42
Default Re: KIVA DATA files
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Sanaz
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Hi Ravi , Thank you for your reply,in dat.inject file there are more than one column for the crank angle consisting of this format: degrees grams grams grams Crank [0,.01] [.01,.5] [.5,1.5]

grams cm^3 cm^3 cm^3 cm^3 [1.5,~] [0,.01] [.01,.5] [.5,1.5] [1.5,~]

what does these values [0,.01], [.01,.5], ... mean? do they represent the size of injected droplets? if so in what unit? I try to model the spray in disel engines but I have different problems like when I see the formation of spray in tecplot,it seems most of the particle remains unburned and the combustion area is local and not well developed, the max pressure is not high enough, when I try to change the amount of fuel by changin , tnparc,tspmas, in most cases the code crashes. I've not find the reason for it yet. I'd be pleased if we can share our experience and work in KIVA with eachother. Regards, Sanaz
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Old   April 8, 2006, 01:18
Default Re: KIVA DATA files
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Ravi
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Hi Sanaz

I havent worked on checking of the spray formation in tecplot or any other post processor

But the collumns indicate the following

Suppose for your spray u have a nozzle with four holes then these four columns represent the mass injected from the four holes

and the values indicate the location of the holes wrt the axis at cylinder centre from the top of the cylinder

Can u tell me how to see the spray formation in tecplot It would be very useful for me

tspmas is a fixed value of the amount of fuel injected u calculate it wrt the engine speed tnparc u can give from code manuals

and othters parameters which u can check are the injection velocity to increase the pressure in the cylinder

also the Arrhenius rate parameters cf, ef can be varied for getting the expected result

tcut and tcute are the temperatures for start of combustion using kinetic reactions and equilibrium reactions in a cell

u first run the case upto 2 degrees before injection and use the restart file for numerical experimentation for the variation of above parameters during total injection and for combustion period say 20 degrees

any more help I am always available for help

all the best

Ravi Kiran
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Old   April 10, 2006, 22:46
Default Re: KIVA DATA files
  #5
sanaz
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Hi Ravi, Thank you so much for your help, actually the format of data in DAT.INJEC file is a bit different from what you said, in my case that I have only one nozzle, in the file there are four columns which I guess each column shows the amount of mass of droplets related to the specific range of stoimetry ratio(I'm not sure about it)and also there are four other columns with the unit of Cm^3 which some how denotes the volume corresponding to that specific stoimetric ratio.I should work on it more to find out what it exactly is. For visulazing spray in tecplot, KIVA3V takes care of it by constructing GMV files which also include the information of spray, when you open the tecplot in import section there is also a KIVA LOADER(in tecplot 10)which recognize GMV files and can open it. If you have more question please do not hesitate to ask, All the best, Sanaz
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Old   April 11, 2006, 17:17
Default Re: KIVA DATA files
  #6
Felix
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Hello:

I am using KIVA for diesel engine simulation. However, my results are not correct. The ignition is too late if I matched the TDC pressure, otherwise, the peak pressure is too high. Do you know what could be wrong with my simulations.

Thanks.

Felix
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