单栋建筑室外热环境的模拟计算方法

NUMERICAL METHOD ON OUTDOOR THERMAL ENVIRONMENT OF SINGLE BUILDING

建筑室外热环境模拟计算是住区微气候研究的重要内容。本文提出了将求解建筑物和周围下垫面的热平衡方程组与室外空气场的CFD(Computational Fluid Dynamics)模拟计算相结合的方法,解决了空气场计算时间步长与建筑物以及下垫面计算时间步长不一致的问题。并提出将下垫面温度简化为逐时太阳直射区域温度和日影区域温度的方法,降低了CFD计算的复杂程度。该数值方法可以得到在自然条件作用下,建筑物表面和下垫面表面的逐时温度及空气温度与流动情况。计算结果与实验结果吻合较好,说明所提出的计算方法是有效的。

Simulation of outdoor thermal environment is an important part of residential microclimate study. The temperature distribution of outdoor air, building surfaces and near building ground surface was achieved by combining the CFD (computational fluid dynamics) calculation of the outdoor air and the energy balance equations of the surfaces. Response factor method was adopted to solve the energy balance equations of building and ground surfaces, and steady heat transfer between air and the surfaces was assumed at every time step. For every time step calculation, the temperatures of surfaces were simplified as sunshine field temperatures and shadow field temperatures, which decrease greatly the calculation time in simulation.