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-   -   Need Urgent Help!! (https://www.cfd-online.com/Forums/fluent/47922-need-urgent-help.html)

oulri April 15, 2008 10:33

Need Urgent Help!!
 
Hello everybody, I am a PHD student at the moment and I need to make a program in FLUENT very fast, but I don't really know the UDF-s. Here is my 2D problem: there is a plane plaque with a length of 150mm and 1mm in thickness; the initial conditions are: - Plaque temperature: Tp (e.g.: 300K) - Fluid temperature: Tfe (e.g.: 295K) - Initial fluid speed: v=0m/s.

In order to make a cycle, I have to accomplish 4 stages:

- t=1: the temperature of the plaque increases uniformly in the whole plaque with 2K (e.g.: Tp = Tpinitial +2K = 302K);

- t=2: the fluid flows from left to right for a certain period of time t (e.g.: t=1s) with a speed v=0.2m/s. There is a temperature gradient that appears both in the fluid and in the material. The temperature of the fluid at the right end of the plaque is Tf = Tfs

- t=3: the fluid has again a speed v=0m/s and the plaque has her temperature diminished uniformly by 2K (the temperature gradient is preserved)

- t=4: the fluid flows along the plaque from right to left this time, with a temperature at the entry point Tfs (the same temperature as the ending point in stage 2) " end of cycle.

I thought of doing all these above, but the problem is I don't know the functions I should use:

In the case of the material:

- to record the temperatures of each cell of the domain after each passage of the liquid

- to select only the cells (C) that interest me (the plaque in this particular case)

- to increase/ decrease the temperature of cells (C)

- to initialize then the temperature of the plaque with the newly established values of the cells (C)

- to reverse the fluid direction

- and to restart all the operations for n cycles

In the case of the fluid:

- to enter a speed profile for the fluid

- to store the thermal data at the end of each passage of the fluid, like in the case of the plaque, in order to be able to initialize the limit conditions with the new values determined

I know it's a little bit complicated, but I am really blocked at the moment. I am thanking you in advance for your help.



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