[ali akbar salehi]

Hello. I want to calculate friction factor through air heater with a jet plate between bottom plate and absorber. What I calculated as pressure loss in test section is about 65 Pascals according to air as working fluid and Reynods number of 3500.I used f=deltap*D/2*ro*l*v2squared and I used RNG k-epsilon method. My problem is that I don't know what should I use as v and how to calculate deltap in test section(in simple air heater case I could validate my answers with assumption of velocity inlet as v and pressure loss between test section inlet and test section outlet).
Thanks in advance.

[ali akbar salehi]

And this is my geometry if it could help you besides average Nu no that I calculated is correct. I think I should use another way to calculate pressure loss or velocity in this geometry.