有热源巷道风流温度分布非稳定模型及数值计算

Unsteady model and numerical calculation on airflow temperature distribution in roadway with heat source

针对矿井有热源巷道中风流温度分布非稳定计算问题,通过通风巷道存在放热源-对流-扩散-热交换的非稳定温度传播方程,建立一维有限元数值模拟求解方法的数学模型,讨论按放热强度(2类热流量条件)的热源项处理算法,给出有热源通风巷道风流初始温度均匀分布与非均匀分布的定解条件,并编写计算机仿真程序进行求解计算。结果表明:在起点27℃-热源300 kW和起点32℃-热源100 kW的不同边界条件和热源强度下,有热源通风巷道中温度分布的非稳定传播过程;数值解收敛准则用Peclet数来衡量,取Pe<2作为收敛条件,程序中根据Peclet数自动加以判断,算例中剖分单元长度1.5 m,模拟时间步长取2 s不发生振荡。实现了巷道中风流各点的温度和温度分布随时间的变化过程的描述,为矿井系统多设备热源散热计算及热害防治设计提供基础算法。

Aiming at the problem of unsteady calculation on the airflow temperature distribution in the mine roadway with heat source,a mathematical model of one-dimensional finite element numerical simulation solution method was established by the unsteady temperature propagation equation of heat source-convection-diffusion-heat transfer existed in the ventilation roadway,and the processing algorithm of the heat source term for the heat source with the exothermal intensity(type-2 heat flow conditions)was discussed.The definite conditions for the uniform distribution and non-uniform distribution of the initial airflow temperature in the ventilation roadway with heat source were given,and the solution calculation was carried out through writing the computer simulation program.The results showed that under different boundary conditions and intensities of heat source as 27℃in the starting point with 300 kW heat source and 32℃in the starting point with 100 kW heat source,the temperature distribution in the ventilation roadway with heat source presented the unsteady propagation process.The convergence criterion of numerical solution could be measured by the Peclet number,and taking Pe less than 2 as the convergence condition,the automatic judgment according to the Peclet number was realized in the program.In the calculation case,the divided unit length was 1.5 m,and the oscillation would not occur when the simulation time step was 2 s.The description on the change processes of temperature and temperature distribution with time for each point of airflow in the roadway was achieved,and it provide the basic algorithm for the heat dissipation calculation and heat-harm prevention and control design of multi-equipment sources in the mine system.