Simulation of a Hydraulic Pulsation Dampener Used for Pulsation Reduction Induced by Vibrations in a Hydraulic System

To reduce vibration-induced pulsations, various devices have been developed, including diaphragm chamber system or gas bladder, non-intrusive fluid wave actuator and fluid filled also known as reflection-type dampeners. However, they are not suitable used in a hydraulic system powered by a triplet piston pump. For example, pulsation dampeners incorporating gas bladders are effective, but there are a number of drawbacks. Loss of gas charge, incorrect gas charge or volume/mass ratio, elastomeric rupture, narrow range of pressure operation and pump speeds, routine maintenance, ineffective location and branch connection instead of in-line configuration are all integrity issues which the industry faces. In addition to having a structural integrity issue, branch connected devices do not perform as efficiently as in-line devices. If a pulsation dampener is responsible for safeguarding critical equipment or systems, premature rupture of a gas bladder can be catastrophic.

This paper introduces a dynamic model and mathematical formulations of a spherical liquidpulsation dampener (U.S. patent number 3731709) that is commonly used to reduce harmful pulsations induced by a triplet piston pump source in fluid power systems. Based on the mathematically proven formulations, computer simulations and optimization procedures were developed in MATLAB to validate the model. Simulation results were then compared with field testing data to numerically verify the model and formulations. For the sake of simplicity, in this paper the pulsation dampener is in conjunction with a three-piston horizontal pump referred to as a triplex pump. The foundation of the simulation is based on a transfer function developed by electrohydraulic analogy resulting in a resistance-impedance-based model. This model takes into consideration all the components of the pulsation dampener and allows for a detailed relationship to its primary function of reducing magnitude spikes. After nonlinear impedances were linearized, MATLAB codes were able to recreate pressure pulsations before and after the pulsation dampener was applied to the system. This allowed for a comparison with field testing data, including mean pressures and range of pressure changes. The mean pressure values examined included 5 MPa, 15 MPa and 30 MPa. The key characteristics to properly analyze the comparison. The wave representing the pressure change over time via MATLAB and that of the field testing were consistent in pulsation reduction. With the validity of the transfer function confirmed, a meta-heuristic approach was utilized to find optimized dimensions of the pulsation dampener while maintaining the desired magnitude reduction. This method can be used to hone the precise dimensions for a variety of functions and even further reduce pulsations