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为解决冻结法模型试验中冻结管作为冷源的相似转换问题,将管内流动盐水和管壁的换热过程按对流边界条件处理,根据相似模拟理论推导出原型和模型之间的相似判据。理论分析结果表明:要满足冻结器原型与模型传热过程的相似性,模型中对流换热系数相似比与几何相似比的乘积应等于冻土的导热系数相似比。试验测试-30℃盐水(雷诺数为533~2 143)强迫对流换热的特征关联式系数。相似模型试验结果表明:当冻结管内盐水为层流状态时,在进行冻结法相似模型试验时除了要对盐水的温度进行设定外,还应按照冷源相似准则对模型冻结器中盐水的流量进行设定。如果盐水流量高于(或低于)该设定值,则模型的温度场将产生偏差。
In order to solve the problem of the similarity conversion of the freezing pipe as the cold source in the freezing model test, the heat transfer process of the flowing brine and the pipe wall in the pipe is treated according to the convection boundary conditions. Based on the similarity simulation theory, the similarity criterion between the prototype and the model is deduced. The theoretical analysis shows that to meet the similarity of the heat transfer process between the prototype and the model, the product of the similarity ratio and the geometrical similarity ratio of the convective heat transfer coefficient in the model should be equal to the similarity coefficient of the thermal conductivity of the frozen soil. The test was conducted to test the characteristic correlation coefficients of forced convection heat transfer at -30 ° C (Reynolds number: 533 ~ 2,143). The results of similar model tests show that when the brine in the frozen pipe is in a laminar flow state, in addition to setting the temperature of the brine during the similar model test of the freezing method, the flow rate of brine in the model freezer should be in accordance with the similarity criterion of the cold source Make settings. If the brine flow is above (or below) the model’s temperature field, the flow will deviate.