Numerical analysis of entropy generation in laminar viscous fluid flow between parallel plates

Intrinsic irreversibilities associated within various process components lead to generation of entropy which destroys available energy and influences the performance of processes. In this study, entropy generation for fully developed laminar viscous flow is numerically investigated between parallel plates subjected to either constant wall temperature or constant heat flux. The governing partial differential equations representing the continuity, momentum and energy equations are solved numerically using a Chebyshev pseudospectral technique by taking into account the temperature dependence of the viscosity. The governing equations are transformed into stream function and vorticity formulations and solved by using a new technique for treating the boundary conditions of vorticity at the wall. Entropy generated from temperature and velocity fields is shown to depend upon Reynolds number, liquid type and inlet to wall temperature difference. The increase in the Reynolds number values shifts and extends the entropy generation profile downstream. The higher the liquid viscosity, the higher the entropy generation for the flowing fluid between the parallel plates. Further, the entropy generation from heat transfer effect is dominant compared to that from fluid friction effect. The study revealed that the constant viscosity assumption may yield a considerable amount of deviation in entropy generation from that of the variable viscosity case.; The obtained entropy generation profiles are an initial step to the design of fluid flow between parallel plates and to minimize entropy generation.