气井超声速激波雾化喷管的PSV试验研究

PSV Experimental Study on Supersonic Shock Atomization Nozzle for Gas Well

天然气在开采过程中存在"气井积液"现象,为了排除积水并保障生产的连续性,采用了超声速激波雾化技术,为了验证该技术中心喷管的雾化效果,利用粒子阴影图像测速技术(PSV),对比分析了拉瓦尔喷管和直孔喷管在不同进口压力条件下的雾化性能;利用数字图像处理算法,同步测量液滴粒径和液体速度,验证了拉瓦尔喷管雾化技术的有效性和可行性。研究结果表明:气相被喷管加速之后,可以促进液滴破碎为小液滴,从而起到雾化作用;利用PSV技术证实了拉瓦尔喷管的雾化性能要优于直孔喷管,液滴随着来流气相压力的增大获得了更大的动能,在与速度更高的气体碰撞之后,液滴平均粒径进一步减小;气相中应该添加另一种示踪粒子,使该粒子的跟随性好,且其粒子图像能与液滴的图像区分开,由此进一步获得气相和液相的流场分布。研究结果可以为低产气井的积液排除提供技术支撑。

"Liquid accumulation in gas well" could be observed in the natural gas well production. According to the principle of supersonic shock atomization technology, the particle shadow velocimetry(PSV) is used to compare and analyze the atomization performance of the Laval nozzle and the straight-hole nozzle under different inlet pressure conditions. By simultaneously measuring the droplet size and velocity using digital image processing algorithm, the effectiveness and feasibility of the Laval nozzle atomization technology is verified. The results show that after the gas phase is accelerated by the nozzle, it can promote the droplets to break into smaller droplets and thus enhance atomization. Using PSV technology, it is proved that the atomization performance of the Laval nozzle is better than that of the straight-hole nozzle. The droplets get more kinetic energy as the inlet gas phase pressure increases, and after colliding with the high-velocity gas, the droplets average size is further reduced. A tracer particle with great following performance and distinguished particle image should be added to the gas phase in order to attain the flow field distribution of the gas phase and the liquid phase. The study can provide technical support for the liquid accumulation elimination of low-production gas wells.