边界元法在填埋场气体运移数值模拟中的应用

基于多孔介质流体动力学理论和边界元法原理,构建了填埋气运移边界元数值模型,进行填埋场内部填理气的运动规律研究;通过与理想条件下的解析解对比分析,检验了该边界元数值模型方法本身;进行了垂直抽气井设施的填埋场实例气体运动数值模拟,得到了填埋场内部填埋气体的压力分布情况,由此确定了集气井的影响范围.模型精度分析和模型验证结果表明,该模型与解析解的平均相对误差在3%以下,与实测数据的平均相对误差均在10%左右,具有较高的精度;抽气井模拟结果表明,该模型可应用于填埋场气体运移的模拟预测和现场分析,能够为填埋场释放气体控制系统设计和优化提供理论依据.

Application of boundary element method in numerical modeling of landfill gas migration

Based on the theory of fluid dynamics in porous media and the Boundary Element Method(BEM),a numerical model of BEM was established to investigate the mechanisms of Landfill Gas(LFG) migration within a landfill site.The model was validated through comparison of the resultant numerical solution with the analytical solution under ideal conditions.Numerical modeling of LFG migration with a vertical extraction well was conducted.Gas pressure distribution within the landfill site was obtained;subsequently,the radius of influence of the extraction well was determined.The results of accuracy analysis showed good accuracy for the model with average relative errors of less than 3% and approximately 10% compared with the analytical solution and in-situ monitored data,respectively.The good accuracy indicates that the model can be applied in prediction of in-situ LFGmigration and can provide a theoretical basis for landfill gas control system design and optimization.