Effect of sucking the hot fluid film on the performance of flat plate solar energy collectors

An hydrodynamically developed but thermally developing laminar channel flow is considered. The flow prevails between an upper rigid plate and a lower porous heated plate, as is encountered in a new form of flat plate solar energy collector. Velocity and temperature profiles were computed in terms of the wall Reynolds number, Rew, at different axial locations, for various fluids. The results indicate that the convective losses at the upper wall, expressed by the Nusselt number, significantly decrease as a result of suction. Furthermore, the variation with Prandtl number was found to be negligible.