Numerical study on void fraction wave of reciprocating multiphase pumps with high gas rates based on real gas models

Abstract

Instantaneous gas-liquid flow and distribution have an important influence on the performance of a multiphase pump, especially under the high gas content conditions. How to accurately simulate the complete working cycle of a multiphase pump and reflect the transient oil-gas flow inside the pump cavity are the main difficulties of the study. A three-dimensional whole-cycle numerical simulation has been conducted to predict the void fraction waves of the reciprocating multiphase pumps under the high gas rates and to evaluate the effects of multi-case parameters on its pulsation characteristics. The instantaneous two-phase distribution and fluctuation characteristic accompanying the movement of the piston and the valves during each process of the multiphase pump are innovatively obtained under the high gas rates. Five different ideal gas model and real gas models used in this simulation are compared and optimized first, and then validated by the experimental results. Void fraction wave signals in the time and frequency domains are obtained from multiple working cycles of the multiphase pump, and the pulsation rates, propagation speeds, amplitudes, and power spectral densities are analyzed in great detail under different inlet gas contents, pressure ratios, crank speeds, and stroke lengths.

Simulation on two-phase refrigerant compression in the cylinder of rotary compressors using CFD method

“…It can be found from Fig. 19a that most of the liquid during the compression process is accumulated under the discharge port, which leads to the higher pressure under the discharge port than that of (13) Figure 20 shows the variations of the pressure in the cylinder of the rotary compressor and the reciprocating compressor with crank angle under the same operating conditions.…”

“…The results showed that liquid presence in the cylinder may cause up to five times the normal pressure on the compressor. Ma 13 simulated the transient liquid distribution and pressure fluctuation in the cylinder of reciprocating multiphase pump with different gas models and gas fractions. Through the calculations and experimental analysis, the impacts of liquid slugging on the reciprocating compressor can be predicted.…”

Studies on Flow Characteristics of Gas–Liquid Multiphase Pumps Applied in Petroleum Transportation Engineering—A Review

“…The turbulence model is the key factor that affects the accuracy of CFD simulation for multiphase pumps, but there is no unified model [52,53]. At present, the two-equation models are usually adopted to predict the gas-liquid flow in the pump, which includes k-ε [25,[54][55][56], RNG k-ε [57][58][59] and SST k-ω [27,[60][61][62][63] models. The information on these three turbulence models and their application to the flow prediction in the multiphase pump are summarized in Table 3 [64].…”

Research on Cavitation of the Rotating-Sleeve Distributing Flow System Considering Different Cam Groove Profiles

“…Hydraulic pump is the core component of hydraulic equipment, known as the "heart" of the hydraulic system, and according to statistics, the pump industry consumes about 20 percent of electrical energy, is the second-largest electromechanical industry in the world [4][5][6][7]. Reciprocating piston pump (RPP) has the characteristics of large power density and ultimate high pressure, at first mainly used in large ships, water conservancy and hydropower and oil, mining fields [8,9]. With the aggravation of energy and environmental problems, RPPs are increasingly widely used in automobiles, engineering machinery, mobile machinery and stationary machinery.…”