hi

i am trying to simulate fan using pressure jump condition. I have pressure vs mass flow rate data with me. Now as per fluent help file I have created a linear equation of pressure and velocity. delta p = 407 - 23.12v

Now my doubt is how to put this equation into fluent fan panel window.

I will use only pressure jump condition only

Hi

I think you have to write a UDF for that.

Thanks, Shanti

hi thanks for replying.

there are many options available in fluent to use fan pressure jump, lets say i am in fan window panel of fluent. in pressure jump box there are polynomial, piecewise polynomial, piecewise linear. if i click on edit it again goes to another window where 1 to 8 coefficient can be given.

Now does coefficient 1 means 407 of my equation and coefficient 2 means -23.1

thanks

I agree with wilson check could you log on (hook) the fan model

hi sach

i am still confused, of the many options available which one is better. If u have worked on fan model sometime, can you tell me a well proven way of defining it. besides i didn't understand what you mean to say by hooking the fan model.

thanks

1) I worked on similar problems for ex. flow resistance problem similarly fan mod3els where the coefficients you need to put in the gui you get form the fan model this is said by wilson 2) there are many convergence issues you may come across when you initiate the fan model. i.e. hooking the model hooking the model I mean; these models are externaly created in the software and so the link is established once you apply these models in the main program (fluent) many times you may face these problem when the main program try to couple a fan model to the solver.

Pleasae try to do it and if problem comes let me know I have some remidies for the same

3) why dont you apply MRF for Fan?

hi

Actually my assignment is to compare the results of MRF and plane model. So i have already generated the P vs Q data thru MRF and now i am trying to compare it with fan plane model. only hurdle is which type to use. polynomial, piecewise polynomial or other types mentioned. And even what i am doing is correct or not?

thanks

[chaudhry_hashim]

Hi Wilson,
I am quite new to CFD i am trying to find out the fan curve. My fan diameter is 71mm and what did uptill now I made inlet duct 11 times of fan dia with pressure inlet (0.0 Pa), outlet duct 15 times of fan dia with pressure outlet (0.0 Pa) and I am giving fixed rpm to the rotating region in between. I am measuring pressure in inlet and outlet duct at a position 10 times of fan dia. but Still I didnt find the relevant pressure difference across the fan and also the solution is not converges. If i want to give the value of dynamic pressure at the inlet then how can i calculate this value as i know the flowrate.
Although I am working in the same way as hiras worked that I am using steady state solution, MRF, pressure-inlet/pressure outlet conditions, k-e standard.

I would be very grateful if you people help me out