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采用有限体积法数值求解控制二维绕流的雷诺平均Navier-Stokes(RANS)方程组,计算了光滑和粗糙NACA0012翼型以及圆柱表面的局部表面传热系数.分析了近壁面网格间距、湍流模式和表面粗糙度模型对数值计算结果的影响.结果表明:切应力输运(SST)湍流模型能够区分层流和湍流边界层的对流传热特性,并能预测转捩的发生;采用Spalart-Allmaras(S-A)扩展模型能够计算粗糙壁面的对流传热系数,但采用忽略转捩函数的S-A模型不能有效计算层流边界层的传热系数.当近壁面网格间距接近10-5量级的黏性子层时,在光滑和粗糙壁面都能得到准确的传热系数分布.结合合适的近壁面网格间距,湍流模式和表面粗糙度模型可以得到与实验数据十分接近的表面传热系数曲线.通过与求解不可压缩RANS方程得到的结果比较后发现,不可压缩RANS方程主要忽略了压缩和黏性耗散效应,这种效应可以通过绝热升温项的形式并入总体热分析.
The finite volume method is used to solve the Reynolds-average Navier-Stokes (RANS) equations governing the two-dimensional flow around the surface, and the local surface heat transfer coefficients of smooth and rough NACA0012 airfoils and cylindrical surfaces are calculated. The results show that the SST turbulence model can distinguish the convective heat transfer characteristics of laminar and turbulent boundary layers and predict the occurrence of turbulent transitions. Spalart The -Allmaras (SA) extended model can calculate the convective heat transfer coefficient of the rough wall, but the SA model ignoring the transition function can not effectively calculate the heat transfer coefficient of the laminar boundary layer.When the near-surface grid spacing is close to 10-5 , The accurate heat transfer coefficient distribution can be obtained on both smooth and rough walls.Considering the appropriate near-surface lattice spacing, turbulence model and surface roughness model, we can get the surface heat transfer coefficient curve that is very close to the experimental data By comparing with the result obtained by solving the incompressible RANS equation, we find that the incompressible RANS equation mainly neglects the compression and viscous dissipation effects, The adiabatic warming term is incorporated into the overall thermal analysis.