Effect of heated wall position on heat transfer and entropy generation of Cu-water nanofluid flow in an open cavity

摘要

This paper reports the numerical results of the mixed convection and entropy generation of Cu-water nanofluid flow in an open cavity heated from different sides with non-uniform temperature distribution. The finite volume method is used to solve the governing equations. The analysis is carried out by a range of Richardson numbers, 0.01 <= Ri <= 10, at a nanoparticle volume fraction of 0 <= phi <= 0.1, and Reynolds number Re = 200, with a cavity aspect ratio of L/H = 2. Three heating modes are considered: (A) the left wall is heated (inflow side, assisting flow); (B) the horizontal bottom wall is heated; and (C) the right wall is heated (outflow side, opposing flow). The results show that the heat transfer and the entropy generation increase with increasing Richardson number and nanoparticle volume fraction. The highest heat transfer and entropy generation are obtained with heating mode C (opposing flow). The contribution of heat transfer and fluid friction irreversibilities in the entropy generation depends on Richardson number and the heater position. The present investigation shows that the configuration with non-isothermal heater located at the bottom wall (B) has the highest performance in terms of heat transfer enhancement with minimum entropy generation.