Hi folks, I´m dealing with a valve in a duct, 0.05 meter of diameter and long enough to avoid reverse flow and to get a full developed flow. I have to use nitric acid and the mass flow is 15 liters/sec. The problem is that I have to simulate the valve when initiates the opening, so the velocity between the valve and the tube wall is increased very high. Wich models and settings in general are prefered for this kind of problems?

Thanks for your time.

H

Oh! I almost forget... The fluid is supossed to be incompresible. So what density model should I use? constant?

Thanks.