Richardson数对后台阶流动熵产的影响

后台阶流动是研究伴随有传热现象的分离流动的常用模型．虽然Richardson数的改变会明显影响分离流动的流动和传热特性，但是迄今为止关于Richardson数对后台阶流动熵产影响的研究依然很少．基于求解熵产方程，第一次系统研究Richardson数对后台阶流动熵产的影响．对于求解熵产方程所需的速度和温度等变量，通过格子Boltzmann方法来得到．通过上述工作可以发现，后台阶流动中熵产和Bejan数的分布随Richardson数变化显著．总熵产数是Richardson数的单调减函数而平均Bejan数是Richardson数的单调增函数．

Effect of Richardson Number on Entropy Generation Over a Backward Facing Step

Flow over a backward facing step (BFS) has been taken as a useful prototype to investigate characteristics of separated flow with heat transfer. However, to date the study on the effect of Richardson number on entropy generation over BFS is absent yet although the flow pattern and heat transfer characteristic both would receive significant influence caused by variation of Richardson number in many practical applications, for example in microelectromechanical systems and aerocrafts. The effect of Richardson number on entropy generation in BFS flow was reported for the first time. Results of entropy generation analysis was obtained by numerically solving the entropy generation equation. The values of velocity and temperature, which were the inputs of the entropy generation equation, were obtained by the lattice Boltzmann method.It is found that the distributions of local entropy generation number and Bejan number are significantly influenced by the variation of Richardson number. The total entropy generation number is a monotonic decreasing function of Richardson number whereas the average Bejan number is a monotonic increasing function of Richardson number.