Performance Prediction of a Swash Plate Piston Pump Using 3D CFD Simulation

Abstract

Abstract Axial piston pumps are widely used for inlet fogging, wet compression and NOx reduction in gas turbines and also as a part of hydraulic systems in landing gears and brakes of aircraft. These pumps operate at high pressures and flow rates with greater efficiency due to their high power to weight ratio. The design of such high-pressure pumps is challenging as its performance is affected by cavitation/aeration and various leakages among the piston, cylinder block, valve plate, slippers and swash plate at high operating speed. Computational Fluid Dynamics (CFD) simulations provide detailed insights of the flow field and pressure for understanding the performance of a pump and assist in developing an efficient and reliable product in a shorter time. In the present work, the performance of a swash plate piston pump with 9 pistons is simulated at 100bar using 3-D CFD software Simerics-MP+. The rotation and deformation of the pumping chambers along with all the leakage gaps is modeled for accurate prediction of the pump performance. The change in piston displacement as it rotates based on swash plate angle is captured in the simulation. Conformal Adaptive Binary-tree (CAB) algorithm [1] is used to generate a high quality grid dominated by Cartesian cells and the mesh motion is captured through volume remeshing. The governing flow equations are solved using Finite Volume Method (FVM) in Simerics-MP+. The fluid compressibility and cavitation/aeration due to entrained and dissolved air is considered by solving the cavitation model developed by Singhal et al [2] to predict the fill speed accurately. The swash plate angle is varied to predict the change in flow rate at a fixed pump speed. The effect of leakage gaps on the volumetric efficiency of the pump is predicted at different pump speeds. The pump performance at different speeds along with leakage effects, cavitation effects, vapor/gas bubble locations are presented in detail in this study.