影响自激振荡脉冲射流性能的喷嘴结构参数研究

Study on the Nozzle Structure Parameters Affecting the Performance of Self-excited Oscillation Pulsed Jet

脉冲射流射孔增产技术可有效改善低渗气藏渗透率,提高产气量。自激振荡喷嘴作为射孔增产技术的核心装置,其结构参数直接决定射孔质量。为得到适用于此技术的最优喷嘴结构,根据流体力学、射流力学、边界层及大涡模拟计算理论,利用大涡模拟方法和PIV测试实验研究了不同后喷嘴和前喷嘴直径比、振荡腔长和前喷嘴直径比对脉冲射流的影响规律。将大涡模拟计算结果与PIV试验测试结果相结合,建立了适用于低渗气藏射孔增产的自激振荡喷嘴设计准则:前后喷嘴直径比(d2/d1)为1.2～1.3,腔径比(L/d1)为2.3～3.3。所得结论可作为脉冲射流发生装置的结构设计和优化依据。

Pulsed jet can be used to increase gas production,improve the permeability in low permeability gas reservoirs and enhance the yield of wells. According to fluid mechanics,jet mechanics,boundary layer and large-eddy simulation computational theory,the method of large-eddy simulation and the experiment of PIV were used to calculate the influence of ratio before and after nozzles diameter and ratio of oscillation chamber length with before nozzle diameter to the performance of pulsed jet. The design criterion of self-excited oscillation nozzle was established based on the stimulation of LES and PIV experimental results,which the diameter ratio（ d2/ d1） of anterior nozzle to posterior nozzle is 1. 2 ～ 1. 3 and the chamber length / diameter ratio（ L / d1） is 2. 3 ～3. 3. The conclusions can be used as a criterions in structure design and optimization of pulsed jet.