Static pressure differences between 2 identical pipe
 

Hi,

I'm relatively new in using Ansys Fluent. I'm analyzing a Blast Furnace cooling element (copper stave) and I found a problem regarding the static pressure behavior along the cooling pipe. The geometry consist in a copper slab with 4 elliptical ducts, so I chose to analyze just half stave (only 2 channels). The boundary conditions are mass flow inlet (3.6 Kg/s) and pressure outlet (896000 Pa) for each channel. For stave hot wall (Blast furnace side) and cold wall (external air side) the boundary conditions are heat flux (350 kW/m^2) and convection (h=10 Wm^-2C^-1 Tfreestream= 318,15 K), respectively. The fluid is liquid water (Tinlet=318.15 K) with pincewise linear properties. When I obtain the results I notice that the static pressure is quite different within the 2 channel (about 0.2 bar on 9 bar) without physical relations with other properties like temperature. I tried to do a lot of changes in the set up but the problem is still there. Can anyone help me, please?
Thanks