围压下自振空化射流冲蚀性能实验研究

自振空化射流是利用瞬态流和水声学原理调制而成的一种新型射流,为研究围压下自激振荡空化射流的冲蚀破碎规律,利用高压釜装置测量了1.0mm出口直径的风琴管自振空化喷嘴在各种射流参数情况下冲蚀铝试样的冲蚀质量,并与同等条件下锥形喷嘴冲蚀效率进行了对比。测量结果表明,冲蚀质量基本与射流压力成正比;存在最优喷距和围压,使得冲蚀效果最佳,在本实验条件,分别为喷嘴出口直径的5～7倍和2MPa左右;相同条件下,自振空化喷嘴冲蚀质量约为同等条件下锥形喷嘴冲蚀的1～2倍,这为自振空化射流提高钻井速度等实际应用提供了实验依据。

Experimental Study on Self-Oscillating Cavitating Jet Erosion Ability under Ambient Pressure

Self-resonant cavitating jet is a kind of modulated jet with significant impact pressure fluctuations and cavitation effects. For the purpose of understanding the relationship between the effects of parameters and the erosion quantities of aluminum specimen impinged by cavitating jet, which was produced by a self-oscillating organ pipe nozzle of 1.0 mm in diameter, experiments were conducted in the High Pressure Vessels. The effect of working parameters on the erosion performance of the self-oscillating cavitating jet under ambient pressure was investigated, such as, jet pressure, ambient pressure, stand-off distance and exposure time. The obtained data show that the erosion quantity is positive proportional to the pressure drop, and the optimal results can be got for the stand-off distance and ambient pressure, which are 5~7 times of nozzle diameter and 2 MPa under the present experiment condition. The erosion quantities of self-oscillating cavitating jet are 1~2 times of common round jets under the same conditions, which could provide necessary tools in practical application, such as increasing drilling footages and drilling speed etc.