一个横截面尺寸为200x300 mm 的二维导热物体，边界条件分别为：左边绝热；右边与接触的流体对流换热，表面传热系数为50 W/(m2·K)，流体温度为20°C；上边维持均匀的温度400°C；下边被常热流加热，热流密度为1500 W/m2。已知该物体的热导率为45 W/(m·K)。采用均匀网格，△y=△x=50mm，试用数值方法计算该物体的温度分布。(A two-dimensional heat conducting object with a cross-section size of 200 x 300 mm has the following boundary conditions: left adiabatic; right-side convective heat transfer with contact fluid, with a surface heat transfer coefficient of 50 W/(m2.K) and a fluid temperature of 20 C; the upper side maintains a uniform temperature of 400 C; and the lower side is heated by normal heat flow with a heat flux of 1500 W/m2. It is known that the thermal conductivity of the object is 45 W/ (M. K). Using uniform mesh and delta y= x=50mm, the temperature distribution of the object is calculated by numerical method.)