Learning Forum

[Deus Ex Machina]

Hi everyone,n I need to quantify the energy variation between the inlet and outlet of a compressor (SST, constant temperature on walls, Mach < 0.4).n After reading the CFX manual, it's not clear to me. When I run:nareaInt(Heat Flux)@INLET + areaInt(Heat Flux)@OUTLETn I get a very different result from:nareaInt(Wall Heat Flux)@INLET + areaInt(Wall Heat Flux)@OUTLETn Why is this happening, I don't understand.n The CFX manual says more or less that they are the same but Heat Flux is calculated by the CFD-POST while Wall Heat Flux solver.n The intuition tells me that Wall Heat Flux is incorrect because the result is very small while Heat Flux has an order of magnitude of the energy introduced by the rotor (mechanical energy transformation by rotation).n Please, does anyone know what I'm doing wrong, could it be that Wall Heat Flux can only apply Wall border condition, not Inlet?n Thank you very much for any contribution.n

[Surya Deb]

Hello, nPlease use Heat Flux in preference to Wall Heat Flux. nHeat Flux is directly computed on the boundary vertices by CFD post using the convective energy data written out to the results file by CFX Solver.nWall Heat Flux on the other hand employs averaging techniques to get the vertex values from adjacent face values. So in essence Wall heat Flux tries to capture the contribution from adjacent boundaries. nI hope this helps.nRegards,nSDn