【摘要】 本文采用摄动法求解不等温竖平板层流自然对流的换热问题。通过正则摄动将很难处理的偏微分方程组转化为常微分方程组,并对边界条件进行相应变换。采用四阶龙格——库塔方法进行数值计算。计算中采用 Nachtseim——Swigert及 Marquardt 方法进行选代以确保渐近边界条件的满足及其数值计算的收敛性。由此得到竖平板自然对流为层流流动时在任意壁面处的近似换热量,可把它应用于相应的工程换热问题的计算中。更多还原

【Abstract】 ——In this paper,the normal purturbation method is adopted to solve the nonlinear partial differential equations for laminar free convection heat transfer from a non—isothermal vertical plate.As the set of partial differential equations is hard to be solved by general methods,we trans- fered it into a set of ordinary differential equations by normal perturbation method so as to apply the fourth—order Runge—Kutta calculus to obtain the numerical solution.In the iteration ,Naehseim— Swigert and Marquardt methods are employed to deal with the approximate boundary conditions and ensure the convergence of the numerical calculation.By this method we can get the heat transfer quantity of laminar free convection from a non—isothermal vertical plate at any location and apply it for the heat transfer problems in engineering.更多还原