液压卡紧对射流式液动锤性能的影响

Effects of hydraulic locking on performance of liquid-jet hammer

运用CFD动态数值模拟方法,计算新一代射流式液动锤试验样机的性能参数,并将其与实测结果进行对比。结果表明：若不考虑液压卡紧引起的摩擦力,射流式液动锤冲击频率、冲击末速度和冲击功计算值分别是实测值的1.853-1.898倍、2.024-2.107倍和4.097-4.439倍;将由液压卡紧效应引起的摩擦力考虑在内,冲击频率、冲击末速度和冲击功计算值分别是实测值的1.218-1.439倍、0.936-1.171倍和0.876-1.371倍,大幅度提高了数值计算结果与实测值之间的吻合程度。这说明液压卡紧引起的轴向摩擦力,大幅度增加了活塞运动阻力,减小了其加速度和速度,进而显著降低了冲击功和冲击频率等性能参数。设法减小甚至消除液压卡紧力的影响可望成为提高射流式液动锤冲击功和能量利用率的新途径。

The performance parameters of the prototype of a new generation of the liquid-jet hammer were calculated by means of CFD dynamic simulation. The simulated results were compared with those measured resuhs. The results show that if the friction caused by hydraulic locking was ignored, the calculated blow frequencies, impact velocities and blow energies were 1. 853 - 1. 898 times, 2. 024 -2. 107 times and 4. 097 -4. 439 times as great as the measured values respectively. While the friction caused by hydraulic locking was taken into account, the calculated blow frequencies, impact velocities and blow energies were 1. 218 - 1. 439 times, 0. 936 - 1. 171 times and 0. 876 - 1. 371 times as great as the measured values respectively, the simulated results were more highly consistent with the measured values. The friction caused by hydraulic locking can greatly increase the resistance to the movement of the piston, and reduce its acceleration and velocity, and thus decrease the blow energy and blow frequency of the hammer. The blow energy and energy efficiency might be increased by taking measures to eliminate the friction caused by hydraulic locking.