垃圾填埋气收集控制的CFD数值模拟应用研究

Application research on CFD numerical simulation of sanitary landfill gas control

基于多孔介质渗流理论,给出了填埋气在填埋场内流动控制方程组及其定解条件,但实际填埋场的不规则边界使其很难求得解析解。建立填埋场竖井抽气物理模型,采用计算流体力学数值模拟软件PHONEICS求得控制方程的数值解,并用相关文献的结论进行校验,结果与前人结论相吻合。将该方法应用于实际填埋场抽气系统的设计,通过PHONEICS软件编程接口二次开发计算负压抽气条件下流入抽气系统的外部空气量,由此引入抽气效率做为抽气效果的评价指标,模拟了传统等边三角形布置竖井抽气系统的运行效果,并根据模拟结果对传统竖井抽气系统进行优化。

Based on the theory of porous medium seepage,a set of equations to define the gas flow in landfills and there definite conditions were introduced, however, irregular boundary of landfills made it difficult to get the analytical solution. The physical model of vertical well extraction in landfills was established and then was simulated by the computational fluid dynamics tool PHONEICS to obtain its numerical results, which were checked with the known results of related literature to prove this method. Furthermore, the method was applied to gas extraction system design of practical sanitary landfill. Running effect of the traditional gas collection system with vertical wells in equilateral triangle arrangement was simulated and then optimized. In the process of this application research, index of extraction efficiency was introduced into evaluation of landfill gas exhaust effect by using a self-compiling program to calculate extra air flow which was pumped in system from upside of the landfill cover through programming interface of PHONEICS.