城市地下综合管廊通风缩尺模型的相似性分析

Similarity Analysis on the Ventilating Reduced-scale Model of Urban Underground Utility Tunnel

缩尺模型与实际原型的相似性对于缩尺模型实验结果在原型上的推广和应用有着重要作用。为了验证相似理论可靠性,以某综合管廊电力舱为实际原型作为研究对象,按5∶1的几何缩尺比例建立缩尺模型;运用相似理论,推导出相似准则数,在忽略格拉晓夫数Gr的条件下,得到了实际原型与缩尺模型各边界条件物理参数的比例关系;通过Fluent软件分别对原型和模型进行不同工况下的数值计算;对原型与模型计算结果中的热力和动力相似敏感性进行了分析,结果表明,各工况原型与模型的温度、热流密度、速度和阻力系数均符合理论推导的比例关系,各参数误差均在工程允许的10%范围内,为后续指导实验进行通风优化研究以及实际工程的推广应用提供了理论依据。

The similarity between the reduced-scale model and the original model plays an important role in the generalization and application of the reduced-scale model experimental results on the original model. To verify the reliability of similar theory,a ventilating reduced-scale model,based on the original model of an electric-power cabin of utility tunnel,was established with the geometric scale ratio of 5: 1. By using similarity principle,the similar criteria numbers were derived and the proportional relations of boundary conditions between original model and reduced-scale model were deduced in the condition of ignoring Gr. The calculations of original model and reducedscale model were done by software Fluent in different conditions. And the similarity susceptibility of thermal and power characteristics were analyzed. The results show that temperature,heat flux,velocity and resistance coefficient meet the proportional relations deduced by the similarity principle,whose errors are under 10%. This provides a theoretical basis for the further study of ventilation optimization and the extension of the application.