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Jonas Pedro Caumo April 15, 2007 13:03

Wind tunnel of a turbine blade tests.
Im doing a simulation of a wind tunel cascade of turbine blades, i have a lot of variables from my project calculation and i know that teh results are right, because this turbine is operating in reality, but i want to improve its efficiency, so i decided to use CFX to simulate the flow in 3D. At first i try to validate the programa by calculating the cp (pressure coefficient), i have Mach=0.5, and Reynolds=4,5x100000. Im using hex mesh, aboutr 1,5 millions. My inlet region is 1.0(chord) from the blade and at exit i put 2.0(chord). I used a lot of configurations on CFX-Pre, i try to put pressure (total) at inlet and static pressure at exit (0 atm relative)(1). I put pressure (total) at inlet and mass flow at exit(2). I put mass flow at inlet and static pressure (0 atm relative) at the exit(3). I found a lot of diferent results. What do you think it is better (1), (2) or (3) ? I know that (1) have the better convergence. Im calculating cp (pressure coefficient) by exporting the results and using excel or tecplot to make the graphics in the middle of the blade height. I know that the maximum value of cp is 1.0, but im not achieving a good result. Is there anybody to help me. Thanks for the help.

Ermanno April 16, 2007 02:43

Re: Wind tunnel of a turbine blade tests.
In my simulations I use configuration # 1 with a convergence RMS < 10^-6, when it is possible : generally when I calculate the loss coefficient (I have some experimental values of that one) I find values a little higher than the experimental results, but they are acceptables. In your case what is the amount of the difference (about) between the value of a variable that you find (in configuration 1,2 or 3)and the value that you expected ? Are they much difference?


Jonas Pedro Caumo April 16, 2007 17:02

Re: Wind tunnel of a turbine blade tests.
Comparing one to each other they are in percentage 8%different, but comparing with the experimental results i found a little higher values than the experimental results. I use RMS = 10^-6, and for this configuration, when i put pressure (total) at inlet and static at exit i found the better convergence, but why im doing this im telling the program the loss in a inderectly. And about your elements, how many ? Thanks. Jonas.

maddy April 28, 2007 02:35

Re: Wind tunnel of a turbine blade tests.
Dear sir, i would like to join your group because i am doing the work on the same kind of project. we r having CFX-10 (at s.s.g.m.c.e. shegaon, maharastra.India)i will go in detail & discuss with u. bye bye

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