Abstract:  In order to solve the problem of soil interaction and missing heat transfer parameters, JKR surface energy, recovery coefficient, dynamic friction coefficient and static friction coefficient between soils were calibrated in the discrete element software. The soil accumulation angle was taken as the response value, and the regression model of soil accumulation angle was obtained by using the Behnken optimization method of Design—Expert software. The simulation parameter optimization experimentwas carried out with the measured accumulation angle as the optimization objective. The relative error between the simulation value of 38.5° and the measured value of 37.3° was 3.2%. The optimized parameter results were as follows: JKR surface energy was 0.4 J/m2, recovery coefficient was 0.363, static friction coefficient was 0.857, and dynamic friction coefficient was 0.36. After setting the optimized calibration parameters, the transient simulation of the heat transfer process of flame nozzle combustion in soil was carried out by DEM—CFD coupling. The experimental results show that the heat transfer temperature of smaller soil particles is higher than that of larger particles. The maximum surface temperature of soil is 915K and the maximum heat transfer depth is 17mm. The influence range of flame temperature on the surface of soil is approximately circular with a radius of 58 mm.

Key words: soil, stacking angle, parameter calibration, coupling, combustion heat transfer, nonpremixed combustion

摘要： 为解决土壤间作用以及传热参数缺失问题，对离散元软件中土壤之间的JKR表面能、恢复系数、动摩擦系数以及静摩擦系数进行标定，以土壤堆积角为响应值，使用Design—Expert软件Behnken优化方法获得土壤堆积角的回归模型，以实测堆积角为优化目标，进行仿真参数优化试验。仿真结果表明，堆积角的仿真试验值为38.5°，与实测值37.3°的相对误差为3.2%。优化后的参数结果为：JKR表面能0.4 J/m2，恢复系数0.363，静摩擦系数0.857，动摩擦系数0.36。设定优化后的标定参数并通过DEM—CFD耦合对火焰喷头燃烧在土壤中的传热过程进行瞬态仿真。试验表明，较小的土壤颗粒相比于较大的颗粒传热温度更高，土壤表面温度最高可达915 K，传热深度最大可达17 mm，火焰温度在土壤表层影响范围近似半径约为58 mm的圆形。

关键词: 土壤, 堆积角, 参数标定, 耦合, 燃烧传热, 非预混燃烧