渗透壁面竖直平板Blasius流熵产特性  

Characteristics of entropy generation of Blasius flow over permeable wall vertical flat plate

作　　者：赵国昌[1,2] 单龙[1] 宋丽萍[3] 孔敬儒 赵恒[1] 刘宇[1] 毛晓东[1] 

机构地区：[1]沈阳航空航天大学航空航天工程学部(院),沈阳110136 [2]沈阳航空航天大学航空航天工程学部(院)辽宁省航空推进系统先进测试技术重点实验室,沈阳110136 [3]沈阳航空航天大学科学技术协会,沈阳110136

出　　处：《航空动力学报》2015年第6期1281-1292,共12页Journal of Aerospace Power

基　　金：航空科学基金(20131954004);辽宁省攀登学者研究基金(20132015)

摘　　要：对渗透壁面竖直平板Blasius流层流边界层流动熵产及传热熵产与总熵产的比值（Bejan数）进行了深入研究,将耦合的动量与能量偏微分方程组通过相似变换转换为非线性常微分方程组,用Runge-Kutta法求解获得了无量纲流函数与无量纲温度的相似解,进而研究了无量纲参数对熵产及Bejan数的影响.结果表明：吸入时最大熵产位于壁面处,吸入速度越大最大熵产越大,熵产随相似变量的增加单调下降;喷注速度越大壁面处熵产越小;近壁面处熵产随变黏度参数增大而增大,远离壁面处随喷注/吸入参数或变黏度参数的增大而减小;远离壁面处Bejan数随喷注/吸入参数或变黏度参数的增大而增大,近壁面处与此相反;熵产和Bejan数随着辐射参数和Reynolds数增大而减小,随着Biot数增大而增大;Biot数在0~2范围内对传热熵产的影响很剧烈,Biot数较小时总熵产由流动熵产控制,Biot数较大时总熵产由传热熵产控制;熵产随滑移参数的减小而增大,Bejan数随滑移参数的增大而增大;Grashof数对熵产的影响较大,在较大的Grashof数条件下熵产随相似变量的变化较剧烈;滑移参数越大,流动熵产越小,Bejan数越大.The entropy generation in the Blasius flow boundary layer over permeable wall vertical flat plate and the ratio of entropy generation due to heat transfer and total entropy generation（Bejan number）were investigated in detail.The coupled momentum and energy partial differential equations（PDEs）were transformed into nonlinear ordinary differential equations（ODEs）using similarity transformation,which were then solved numerically using the Runge-Kutta method and the similarity solutions of the dimensionless flow function anddimensionless temperature were obtained.The effects of dimensionless parameters on the entropy generation and Bejan number were investigated.The results are as follows：for suction,the maximum entropy generation appears on the wall and entropy generation decreases monotonically with the increase of similarity variables,the greater suction speed means the greater entropy generation.For injection,the greater injection speed at the wall means the smaller entropy generation.Near the wall,entropy generation increases with the variable viscosity parameter increases.However this effect away from the wall is reversed.Increases in either the injection/suction parameter or the variable viscosity parameter will increase the Bejan number when it’s away from the wall and decrease the Bejan number when near the wall.Increases in either the radiation parameter or Reynolds number will decrease entropy generation and Bejan number,while increases in the Biot number will increase entropy generation and Bejan number.The entropy generation due to heat transfer changes with Biot number dramatically when Biot number is within the range of 0to 2.The total entropy generation is dominated by the entropy generation due to flow when Biot number is small,and dominated by the entropy generation due to heat transfer when Biot number is large.The entropy generation will increase as the slip parameter increases,while the Bejan number decreases.The effect of Grashof number on entropy generation is relatively large,an

关 键 词：渗透壁面 Blasius流 熵产 滑移边界 辐射 相似变换 Bejan数 

分 类 号：V231[航空宇航科学与技术—航空宇航推进理论与工程] TG156.99[金属学及工艺—热处理]