针对燃爆压裂过程中压挡液柱受冲击运动机理的复杂性,假设火药燃气与压挡液柱存在完全气液接触界面,采用拉格朗日的微元分析方法,建立了由连续性方程、动量守恒方程、能量守恒方程组成的压挡液柱运动规律动力学模型,并给出了该模型与火药燃爆模型的耦合数值解法。经程序编制和实例计算表明,在综合考虑火药燃气对液柱的宏观推动作用、冲击压缩作用、液柱自身的动能分布及管壁对其摩擦阻力的影响后,火药燃烧过程中气液界面上升高度有限(实例计算不足0.1m),可起到很好的持压作用;但全过程中最高液柱位移较大(18.9m),水力振荡增效作用明显。研究成果对提高燃爆压裂的数值模拟精度具有一定促进作用。
According to the kinematical mechanism complexity of the impacted pressurized liquid column in the high energy gas fracturing process,we assumes that the completely contacted gas liquid interface exits.Then by using a Lagrange analytical method for studying a random liquid across-section,a dynamic model of the pressurized liquid column movement law is set up,which comprises continuity equation,momentum conservative equation and energy conservative equation.Based on the pressure and volume conservation during the process of powder conflagration and pressurized liquid column movement,a coupling numerical method for describing the gas-liquid interface movement law is established.Example calculations show that when considering the macroscopical propel and impact compression on the pressurized liquid column caused by deflagration,dynamic energy distribution of the liquid distribution and pipe column friction resistance,the interface ascending height is limited(less than 0.1 m in the example conditions).This illustrates that pressurized liquid column has a good function of backing pressure.But in fact,in the fracturing process,the interface can reach a higher position(18.9 m),which shows that in the later process,hydraulic oscillation produces an obvious synergistic effect.