摘要
利用三维计算流体力学软件对燃料棒棒束通道内有污垢沉积的结构进行了汽液相变数值模拟研究。建立了四分之一通道的简化模型,研究了污垢导热率对相变换热特性的影响,得到了相同污垢厚度,不同污垢导热率下通道的含气率曲线和壁温分布,并采用壁面局部努塞数分析了通道的换热性能。研究结果表明,在污垢覆盖段,污垢厚度最大值为1.55mm时导致壁面最高温度值比污垢厚度为0.45mm的壁面温度升高约120K,污垢导热率减小会大幅度降低换热性能。
Numerical simulations were conducted to study the flow and concentration fields in the canyon with different background wind speed, when there are upstream buildings. The results show that the increasing extent of wind speed and turbulence intensity in the canyon are less than the increasing extent of background wind speed, while the change of background wind speed almost has no influence on the flow pattern and distribution law. Under the impact of wind speed and turbulence intensity, the decreasing extent of pollutant concentration is larger than the increasing extent of wind speed. Thus, the urban traffic management can be adjusted with the different wind speed for the current street canyon.
出处
《建筑热能通风空调》
2017年第6期44-47,54,共5页
Building Energy & Environment
关键词
污垢
棒束通道
相变
换热特性
background wind speed, upstream buildings, street canyon, flow field, pollutant concentration
