管道保温计算数学模型研究

采用有限差分法和焓降法相结合的方法数值模拟三维方管保温温度场，研究提高保温计算精度的途径和方法。研究结果表明：管内空气出口温度测试结果与考虑保温层热导率随温度变化及管内壁传热热阻时的数值模拟结果误差〈2．1％；保温材料热导率随温度变化和管内壁传热热阻对短管管内介质出口温度的影响可以忽略；管长〉2．35km时管内介质出口温度计算要考虑保温层热导率随温度变化；忽略保温层热导率随温度变化的管外壁散热损失误差〉11％，表明管外壁散热损失和长管管内介质出口温度计算必须考虑保温层热导率随温度变化，但可忽略管内壁综合表面传热热阻。

Research on Mathematic Model of Calculation for Pipeline Insulation

Based on the finite difference and the enthalpy drop method, a three-dimensional temperature field of square-pipe insulation is simulated and accurate calculation method is improved. Studies show the outlet temperature error of media inside the pipe between the calculation from considering the thermal conductivity change with temperature and the thermal resistance of pipe inner surface and the test is less than 2.1%; the effect of thermal conductivity change and thermal resistance on the outlet temperature of media in the short pipe can be neglected; the thermal conductivity change need be considered to the outlet temperature calculation of media when the pipe length is more than 2.35 km; the heat loss error of outside surface of pipe from neglecting thermal conductivity change is more than 11%. It is necessary to consider thermal conductivity change for the heat loss and outlet temperature calculation of media in the long pipe, but thermal resistance of pipe inner surface can be neglected.