Experimental and modeled response of hydraulic motors under pulsating flow

Abstract

This study investigates the dynamic response and performance of a hydraulic motor operating under controlled pulsating flow conditions. An experimental setup was developed incorporating a variable frequency pulse generator within an electro-hydraulic control circuit. Tests were conducted at inlet pressures of 20, 40, and 60 bar and pulsation frequencies of 2, 4, and 6 Hz. The results revealed that increasing flow pulsation frequency from 0 to 6 Hz significantly enhanced motor performance. At 60 bar, the motor speed increased from 71 RPM at 2 Hz to 114 RPM at 6 Hz, while torque rose from 6.11 kNm to 7.07 kNm. Similarly, increasing inlet pressure from 20 to 60 bar at 6 Hz improved speed from 67 to 114 RPM and torque from 3.65 to 7.07 kNm. At lower operating conditions (20 bar and 2 Hz), speed and pressure decreased by 60.74 % and 15 %, respectively, confirming the high sensitivity of motor output to pulsation parameters. Simulation results using Automation Studio closely matched the experimental findings, particularly at moderate frequencies and pressures with less than 4 % error. The developed empirical correlations accurately predicted motor speed and torque, with maximum deviations of ±10.49 %. The results demonstrate that controlling pulsation frequency provides an effective means of optimizing hydraulic motor performance, enhancing energy efficiency, and enabling dynamic regulation of speed and torque.