对流和辐射条件下变热特性参数的肋片传热性能

Heat transfer performance of convective-radiative fin with variable thermal characteristic parameters

采用谱配置法对导热系数、表面对流换热系数和表面发射率均为温度函数的对流-辐射肋片的传热性能进行研究。在求解过程中,肋片温度通过谱配置点和拉格朗日插值多项式离散,从而将微分形式的能量方程转化为矩阵形式的代数方程。与文献中的解析解相比较发现:谱配置法对肋片的非线性传热问题具有很好的计算精度和计算效率;计算精度随着配置点的增加近乎呈指数上升。同时发现:随着导热系数变化率和表面对流换热系数变化率的增加,以及表面发射率变化率的减少,肋片温度随之升高;随着对流与导热耦合参数和辐射与导热耦合参数的减少,肋效率随之提高。

Spectral collocation method （SCM）is used to analyze the heat transfer performance of convective-radiative fin with tem-perature dependent thermal conductivity,heat transfer coefficient and surface emissivity.In the solution procedure of SCM,the distribution of temperature in the fin is discretized by spectral collocation points and Lagrange interpolating polynomials.Thus the differential form of energy equation is transformed to the matrix form of algebraic equation.Compared with the analytical solution in literature,SCM has good computational accuracy and computational efficiency in solving nonlinear heat transfer problem in the fin.The accuracy of SCM almost increases exponentially with the increasing collocation points.In addition,with the increasing gradient of thermal conductivity and heat transfer coefficient,and the decreasing gradient of surface emissivity,the temperature distribution in the fin increases;with the decreasing convective-conductive parameter and radiative-conductive parameter,the fin efficiency also increases.