论文部分内容阅读
利用牛顿冷却方程和圆筒传热公式推导出了保温材料管道保温的热流损失数学模型,并基于该模型推导出了热流损失随保温层厚度增减变化的临界半径的理论计算公式.假定保温材料外表面与周围环境之间的对流传热系数为常数时,临界半径与保温材料导热系数成正比,而与保温材料外表面与周围环境之间的对流传热系数成反比.当管道裸管半径大于临界半径时,管道热流损失随着保温层厚度的增加而减小;当管道裸管半径小于临界半径,且裸管半径与保温材料厚度之和小于临界半径时,管道热流损失随着保温层厚度的增加而增加;而当裸管半径与保温材料厚度之和大于或等于临界半径时,管道热流损失随着保温层厚度的增加而减小.最后,对保温材料导热系数、保温材料外表面与周围环境之间的对流传热系数对管道热流损失的影响也进行了计算和分析.图5,表1,参8.
Based on Newton’s cooling equation and cylinder heat transfer formula, the mathematical model of heat flow loss of heat preservation pipe was deduced. Based on this model, the theoretical formula of the critical radius of heat flow loss with the increase or decrease of heat preservation thickness was deduced. When the convective heat transfer coefficient between the outer surface and the surrounding environment is constant, the critical radius is proportional to the thermal conductivity of the thermal insulation material and inversely proportional to the convective heat transfer coefficient between the outer surface of the thermal insulation material and the surrounding environment. When the radius of the bare pipe is less than the critical radius, and the sum of the bare pipe radius and the thickness of the thermal insulation material is less than the critical radius, the heat flux loss of the pipe decreases with the thickness of the thermal insulation layer While the sum of the bare tube radius and the thickness of the insulation material is greater than or equal to the critical radius, the heat flux loss decreases with the thickness of the insulation layer.Finally, the thermal conductivity of the insulation material, the outer surface of the insulation material And the surrounding environment on the heat transfer coefficient of convection heat loss is also calculated and analyzed.Figure 5, Table 1, reference 8.