空心屋面热工性能的三维数值研究

Research on the 3D Numerical Thermal Performance of Hollow Roofs

采用基于有限容积法的三维自编程序对嵌入4种不同外形尺寸箱体的空心屋面进行了热工性能的数值模拟。为了提高屋面的保温性能,在空心箱体中设置不同数量的隔板,以抑制其中的对流和辐射换热量。模拟结果表明:垂直于热流方向的水平隔板可以有效降低屋面的当量导热系数,随着隔板数量的增加,屋面当量导热系数降低的程度变缓,这种作用对于空心率高的屋面更加明显。平行于热流方向的竖直隔板对屋面的当量导热系数基本没有影响。模拟结果为实际工程中的空心屋面设计与选型提供了参考依据。

The thermal performance of the hollow roofs embedded with four box fillers of different sizes was simulated numerically by 3D self-made code based on the finite volume method,which could deal with complicated heat transfer efficiently. In order to enhance the insulating performance of the roofs,different numbers of partitions were put in the hollow box fillers to suppress the convection and radiation. The numerical results indicate that the horizontal partitions vertical to heat flux could reduce the equivalent thermal conductivity of the hollow roofs efficiently. With the increase of the number of partitions,the equivalent thermal conductivity decreased slowly. For the hollow roofs with higher void fraction,this effect was more significant. However,the vertical partitions parallel to heat flux had little effect on the equivalent thermal conductivity of the hollow roofs. The simulated results could serve as references for the design and selection of hollow roofs in practical engineering.