寒区工程离心模型试验地基表面换热特性及热边界设置方法研究

Research on heat transfer characteristics on ground surface and thermal boundary setting method in centrifugal tests for cold regions engineering

温度场的准确模拟是开展寒区工程离心模型试验的关键。目前大多数基于半导体换热装置的相关试验,忽视了热边界的参数设置,导致试验边界条件不清晰。为进一步提升试验的合理性和精确性,采用有限元CFD方法模拟了基于半导体制冷装置热交换场景的、超重力场下密闭夹层空间的换热过程;通过变换模型率、冷端初始温度、间隙间距等主要热边界条件,明晰了该场景下的换热特征及时空规律。在此基础上,结合设备特点与原型实际,提出采用空气冻结指数作为匹配原型环境温度的指标,用于反映地基表面的“冻结程度”,并指导试验中热边界条件的具体参数设置。

The accurate simulation of temperature field is the key to carry out geotechnical centrifugal tests for cold regions engineering.Neglecting the setting of thermal boundary conditions in most tests where using semiconductor refrigeration devices,which makes it difficult to ensure the accuracy of the test.In order to improve the rationality and accuracy of tests,the finite element CFD method was used to simulate the heat transfer process in the confined space under the super gravity field.By changing the main boundary conditions such as model scale(acceleration),output temperature and gap spacing,the heat transfer characteristics and their space-time laws based on semiconductor heat exchanger are clarified.On this basis,combined with the characteristics of the equipment and true conditions,the temperature boundary of the model is described by the air freezing index,as the optimal index for matching prototype temperature at geotechnical centrifugal tests for cold regions engineering,which specifying the heat boundary parameter settings.