An innovative simulation method for the estimation of the nozzle pressure pulsation attenuation

Abstract

Pressure pulsations in volumetric compressor manifolds have a high impact on compression power requirement and the reliability of manifold operation. These pulsations induce vibrations, noise, and in some cases, mechanical failure of piping or compressor valves. For pressure pulsation attenuation, different types of mufflers are applied using a design based upon the Helmholtz resonator approach. This design is particularly effective for constant revolution speed compressors. For contemporary applications of variable revolution speed compressors, other pressure pulsation attenuation methods are needed. It is known that different shapes of nozzles can attenuate pressure pulsations, however, they unfortunately increase the compressor power at the same time. The main criterion for nozzle selection is achieving pressure pulsation attenuation that is as high as possible whilst having the lowest possible effect on compressor power. In this paper, innovative computational fluid dynamics (CFD) simulation methodology is applied for the optimisation of nozzle shape and size. The steady flow simulation results correspond with compressor power consumption and impulse flow simulation results are related to pressure pulsation attenuation. This method has been validated on the basis of the experimental results for three different nozzle geometries. For experimental validation, nozzles have been mounted in the variable speed screw compressor discharge manifold.