Analysis of the Influence of LPG Density on the Performance of a Centrifugal Pump-Impeller Through CFD Simulations

Abstract

Abstract This paper deals with the performance analysis of a centrifugal pump-impeller of diffuser type for transporting liquefied petroleum gas (LPG). The performance analysis is conducted here through numerical methods and computational fluid dynamic (CFD) simulations. The focus of the study is on the behavior of the centrifugal-pump as the diffuser-blade angles change. A methodology of dimensional analysis is employed here to combine both, real operating conditions and simulations with a commercial-grade CFD software. The analysis lakes into account the decrease in the density of the transported fluid, along with temperature increases due to the external environment. The monitoring of these two variables is necessary in practice to guarantee a constant flow-rate and it is done analytically since the corresponding experiments are deemed risky and difficult. To evaluate LPG pump-efficiency it is considered here that the range of densities is from 490 to 550 kg/m3. The CFD software SolidWorks is used here to conduct the simulations of a centrifugal impeller by varying the fluid density. Operating data from a real-life pump are further used to corroborate the simulations. The vast majority of LPG pumps being installed at industrial parks must hands the fluid as two-phase gas-liquid one. However, most studies elsewhere consider it as a homogeneous flow. In real operating conditions, when dealing with volatile liquids like LPG, pressures lower than the ones of vapor can be produced and this should be avoided to prevent cavitation. Unfortunately, the specialized literature in this topic does not include considerations on the varying physical properties of liquefied gas, such as density. These variations have been at the simulations reported in this paper. It is concluded here that these factors must be taken into account to avoid the poor performance of installed LPG pumps. Analysis of the influence of LPG Density on the Performance of a Centrifugal Pump-Impeller through CFD simulations.