Thermal Poiseullli flow

Hello everyone,

I have been trying to write a code for thermal Poiseulli flow through a heated channel (both top and bottom wall heated) with pressure inlet and outlet boundary condition using LBM.
Length in x-direction: 40 times as length in y direction. However I am not getting the expected parabolic curve for the temperature profile which should be inverted parabola having some magnitude (Temperature) at the mid-Y plane. But my code is giving “Zero” value of temperature at the mid -Y plane.
Please I would be grateful if anyone can enlighten me !!!