边界条件对椭球颗粒在超临界水中受力与传热特性影响的数值模拟  

Numerical investigation on the effect of boundary condition on momentum and heat transfer of spheroids in supercritical water

作　　者：熊勃 张浩 郭鹏越[1,2] 安希忠 Xiong Bo;Zhang Hao;Guo Pengyue;An Xizhong(Northeastern University School of Metallurgy,Shenyang 110819,China;Northeastern University Key Laboratory for Ecological Metallurgy of Multimetallic Mineral(Ministry of Education),Shenyang 110819,China)

机构地区：[1]东北大学冶金学院,沈阳110819 [2]东北大学教育部多金属矿山生态冶金重点实验室,沈阳110819

出　　处：《材料与冶金学报》2021年第4期297-303,共7页Journal of Materials and Metallurgy

基　　金：国家自然科学基金(12072071);国家重点研发计划资助项目(2016YFB0600101-4).

摘　　要：采用颗粒尺度直接数值模拟的方法进行超临界水中单个椭球颗粒强制对流模拟,在压强为23 MPa条件下,考虑了超临界水物性参数随温度变化特性,计算得到了不同工况下椭球颗粒在超临界水中的曳力系数和平均努赛尔数.在两种不同的边界条件下,即流化颗粒问题的固定墙边界和沉降颗粒问题的移动墙边界,比较和讨论了墙壁因子和颗粒纵横比对曳力系数和平均努赛尔数的影响.结果表明:曳力系数和平均努赛尔数随着墙壁因子和颗粒纵横比的增大而减小,与沉降颗粒相比,流化颗粒受墙壁因子的影响更大.超临界水中的曳力系数与平均努赛尔数和前人的经验公式计算值存在很大差距,因此提出了新的预测关联式.A comparative study on cold supercritical water(SCW)passing over a hot spheroid is carried out using the particle-resolved direct numerical simulation(PR-DNS)to examine the wall effects.Different working conditions are considered to obtain the drag coefficient and average Nusselt number of spheroids in SCW whose physical properties significantly change with temperature.The effects of wall factors on Cd and Nu under two different boundary conditions,namely a stationary one for the fluidized particle problem(FPP)and a moving one for the settling particle problem(SPP),are compared and discussed.Numerical results show that Cd and Nu decrease as the wall factor and Ar increase.Moreover,the numerical results for FPP are more affected by the wall factor than SPP.Finally,it is found that Cd and Nu of a spheroid in SCW cannot fit the previous correlations for conventional fluids well.Therefore,these correlations are improved for SCW which are good tools to understand the basic knowledge of SCW.

关 键 词：椭球颗粒 超临界水 平均努塞尔数 曳力系数 

分 类 号：TK91[动力工程及工程热物理]