Hi, I have a duct with multiple inlets and one outlet. I know the maximum allowable airflow through the duct. What I would like to know is the pressure loss through the duct. I don't know the inlet flows or the outlet pressure. The inlets stick out into a room that is at atmospheric pressure.

I am using CFD2000 (now called Storm, I think). My choices of BCs are inlet: pressure, velocity, or mass flow; outlet: pressure, zero gradient, or mass flux.

Any ideas?

thanks, Bob

(1). The total pressure loss in a duct will be a function of the mass flow rate. So, you will have to measure it first. (2). The loss prediction is among one of the most difficult task to do. It also requires a relatively fine mesh so that the flow field can be computed correctly. (3). If you really need the loss number accurately, testing is the way to go.