||April 10, 2012 22:43
Compressor Blade Analysis in Ansys CFX
Hey, I am modeling a compressor blade (just one blade) in Ansys CFX. I still haven't decided all of the specifications (air velocity, density, temperature, etc.) and I wanted your input. I was thinking about doing a jet compressor blade, in this case I would have low air density and temp and high inlet velocity (like 150-200 m/s). I could do conditions for a gas turbine on the ground with air at room temp and 1 atm. Would I want to assume an inlet velocity of zero in this case? In any case AND HERE IS MY BIGGEST QUESTION, I cannot model the compressor blade as going around in a circle because I don't have the computing power, time, or experience to run that kind of simulation. I was going to simply have air flow perpendicular to the compressor blade inlet. So if you can imagine, instead of flow caused by the blade traveling through the air, I am having the air travel over the blade, probably about 530 m/s (that's a blade with an average radius of 25 inches going at 8000 RPMs). IS THIS AN ACCEPTABLE MODEL?!?!? I'm worried about things getting tricky around supersonic flow for starters. Also I'm not sure if, because of this modeling, the temperature of the air will go up or down. As you know, if air adiabatically comes to a stop, it's temperature increases, which would be the case here. However, in real life, the compressor blade is accelerating a static fluid, so will my fluid decrease in temperature instead? I'm pretty sure that fluid temperature actually increases as it travels across a compressor blade towards the turbine. I just want to make sure this is an okay simulation set up. Also what results do you think I should expect? I'm thinking that on the side of the compressor blade closer to the turbine, the fluid should have higher density, pressure, and temperature, and lower velocity than the blade side closer to the diffuser/fan. Thanks for all of your help!