方形与圆形冻结管单管冻结温度场数值对比分析

Numerical Comparison of Temperature Fields Formed by Square-and Circular-shaped Freezing Pipes in Frozen Ground

为解决现有冻结管单管冻结能力不强致使增加循环冷媒介质用量和施工机械能耗的问题,可将传统圆形截面设计成方形截面。对方形冻结管的截面形式和施工工艺作一简单介绍,运用有限元软件对方形冻结管单管冻结时的温度场发展规律进行研究,主要得出:与传统圆形冻结管相比,方形冻结管可在不增加工程量的前提下大大提高单管冻结能力;虽然方形冻结管为非圆形截面,但其冻土帷幕温度场也是以冻结管中心为圆心呈同心圆分布;在靠近冻结管200mm内,方形冻结管比圆形冻结管制冷效果好;在距冻结管300mm以外,两种冻结管降温过程基本一致。

In order to mitigate the consumption of energy and circulating refrigerant caused by the existing single freezing pipe method, which usually has a low freezing capacity, the traditional circular-shaped freezing pipes can be designed as square-shaped. In this paper, the shape configuration and construction procedures of square-shape freezing pipes are introduced. The temperature field formed by the square-shaped freezing pipes is simulated by finite element method. It has been found that the square-shaped pipe has a larger surface area than that of a circular-shaped pipe ; thus, under the same construction procedures, a square shape pipe can improve the freezing capacity significantly. Although the shape is not circular, the temperature filed formed by a square-shaped pipe is still a circular shape. Numerical analysis shows that, within 200 mm from its centre, a square-shaped pipe performances better than a circular-shaped pipe in ground freezing; beyond 300 mm, the temperature fields of both type of pipes were approximately the same.