Leakage Loss Study of a Synchronal Rotary Multiphase Pump With a Full Range of Inlet Gas Volume Fractions

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Xu Yang ◽  
Yao Qin ◽  
Zongchang Qu
Keyword(s):  
Flow Rate ◽  
Flow Model ◽  
Full Range ◽  
Volumetric Flow Rate ◽  
Radial Clearance ◽  
Leakage Flow ◽  
Leakage Loss ◽  
Multiphase Pump ◽  
Volume Fractions ◽  
Gas Volume

The working performance of the synchronal rotary multiphase pump (SRMP), alike other types of positive-displacement multiphase pumps, is strongly affected by leakage loss. In this paper, the leakage loss in the SRMP with a full range of inlet gas volume fractions (GVFs) was theoretically and experimentally investigated. The leakage flows in the SRMP were modeled as the one-dimensional gas–liquid flows through narrow gaps. Two types of leakage flow models, homogeneous leakage flow model (HLFM) and separated leakage flow model (SLFM), were developed. The experimental work was conducted to measure the volumetric flow rate of the SRMP using the mixtures of air and N32 oil as working fluids under various inlet GVFs and differential pressures. Comparisons between the simulated and experimental pump flow rates showed that both the accuracies of the HLFM and SLFM related to the inlet GVF. In addition to the differential pressure, the leakage loss of the SRMP was affected by the inlet GVF. The leakage flow rate increased with the inlet GVF due to the changes in physical properties of the gas–liquid leakage flow. Parametric analysis showed that leakage loss in the SRMP can be effectively reduced by reducing the rotor radial clearance without much effect on its mechanical efficiency, whereas the optimum geometric parameters of the rotor and cylinder must be calculated by means of the optimization study with consideration of both the leakage loss and friction loss.

scholarly journals Effect of the Gas Volume Fraction on the Pressure Load of the Multiphase Pump Blade

Processes ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 650
Author(s):  
Guangtai Shi ◽  
Dandan Yan ◽  
Xiaobing Liu ◽  
Yexiang Xiao ◽  
Zekui Shu
Keyword(s):  
Flow Rate ◽  
Static Pressure ◽  
Volume Fraction ◽  
Pump Impeller ◽  
Impeller Blade ◽  
Multiphase Pump ◽  
Pressure Load ◽  
Gas Volume Fraction ◽  
Power Capability ◽  
Gas Volume

The gas volume fraction (GVF) often changes from time to time in a multiphase pump, causing the power capability of the pump to be increasingly affected. In the purpose of revealing the pressure load characteristics of the multiphase pump impeller blade with the gas-liquid two-phase case, firstly, a numerical simulation which uses the SST k-ω turbulence model is verified with an experiment. Then, the computational fluid dynamics (CFD) software is employed to investigate the variation characteristics of static pressure and pressure load of the multiphase pump impeller blade under the diverse inlet gas volume fractions (IGVFs) and flow rates. The results show that the effect of IGVF on the head and hydraulic efficiency at a small flow rate is obviously less than that at design and large flow rates. The static pressure on the blade pressure side (PS) is scarcely affected by the IGVF. However, the IGVF has an evident effect on the static pressure on the impeller blade suction side (SS). Moreover, the pump power capability is descended by degrees as the IGVF increases, and it is also descended with the increase of the flow rate at the impeller inlet. Simultaneously, under the same IGVF, with the increase of the flow rate, the peak value of the pressure load begins to gradually move toward the outlet and its value from hub to shroud is increased. The research results have important theoretical significance for improving the power capability of the multiphase pump impeller.

A 3D Transient Model for the Multiphase Flow in a Progressing-Cavity Pump

SPE Journal ◽  
2016 ◽  
Vol 21 (04) ◽  
pp. 1458-1469 ◽  
Author(s):  
Victor W. de Azevedo ◽  
João A. de Lima ◽  
Emilio E. Paladino
Keyword(s):  
Multiphase Flow ◽  
Flow Rate ◽  
Homogeneous Model ◽  
Volumetric Flow Rate ◽  
Volumetric Efficiency ◽  
Two Phase ◽  
Transient Model ◽  
Viscous Losses ◽  
Constant Displacement ◽  
Gas Volume

Summary This paper presents the development of a computational-fluid-dynamics (CFD) model for the 3D transient two-phase flow within a progressing-cavity pump (PCP). The model implementation was only possible because of the meticulous mesh-generation and mesh-motion algorithm, previously published by the authors, which is briefly described herein. In this algorithm, a structured mesh was generated by defining all nodes’ positions and connectivities, for each rotor position by means of FORTRAN subroutines, which were embodied into ANSYS CFX software. The model is capable of predicting accurately the volumetric efficiency and the viscous losses, and it provides detailed information of pressure and velocity fields and void distribution along the pump. Such information could be of fundamental importance for product development and/or optimization for field operation. In field applications, the common situation is that in which the oil comes into the pump accompanied with free gas, which characterizes a multiphase flow. Simplified models on the basis of the calculation of the backflow or “slippage,” which is subtracted from the displaced flow rate, fail to characterize the PCP performance under multiphase conditions because the slip is variable along the pump. In this model, the governing equations were solved with an element-based finite-volume method in a moving mesh. The Eulerian-Eulerian approach, considering the homogeneous model, is used to model the flow of the gas/liquid mixture. The compressibility of the gas is taken into account, which is one of the main shortcomings in positive/constant displacement pumps. The effects of the different gas-volume fractions (GVFs) in pump volumetric efficiency, pressure distribution, power, slippage flow rate, and volumetric flow rate were analyzed, and some new insights are presented about the slippage in PCPs operating in multiphase conditions. The results show that the developed model is capable of reproducing pump dynamic behavior under multiphase-flow conditions performed early in experimental works.

Estimation of Leakage Mass Flow Rate through Labyrinth Seal Using CFD Techniques

2017 ◽  
Vol 3 (02) ◽  
Author(s):  
M Neeharika ◽  
Prabhat Kumar Hensh
Keyword(s):  
Numerical Simulation ◽  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Flow Behavior ◽  
Labyrinth Seal ◽  
Empirical Correlation ◽  
Radial Clearance ◽  
Leakage Flow ◽  
Simulation Results

Seal design is an essential part for turbo machinery. Seal consisting of fins is placed in a gap between stationary and rotating component to minimize the leakage flow. Seal leakage flow has been considered as an inevitable loss factor that highly affects the efficiency of any machine. During operation of the equipment, thermal expansion/contraction of components take place, which causes variation of the gap between stationary and rotating component. Importance of the study is to understand the flow behavior due to variation of the gap. The variation of gap leads to change of radial clearance between fin to metal component and subsequent change of flow pattern. The main focus of the paper is to estimate the leakage flow through a labyrinth seal placed between rotor and casing of a typical steam turbine. Numerical techniques using 3D CFD tool are used for this purpose. Three different seal configurations are proposed in the study. The variables of the three seal configurations are radial clearance, number of fins in the flow passage and pressure drop across the seal passages. As an alternative methodology, an empirical correlation is formulated based on numerical simulation results for one set of radial clearance to estimate mass flow rate through the seal. In order to validate the formulated correlation, mass flow rate is determined for another set of radial clearance and compared with numerical simulation results. It is observed that flow rate estimated from 3D CFD study is around 20% lower compared to empirical correlation.

A Simple Leakage Flow Model Including Viscous Effect

2011 ◽  
Author(s):  
Yuping Qian ◽  
Jian Cui ◽  
Chaoqing Chen ◽  
Yifang Gong ◽  
Qiushi Li
Keyword(s):  
Flow Rate ◽  
Flow Model ◽  
Leakage Flow ◽  
Viscous Effect ◽  
Tip Leakage Flow ◽  
Stall Margin ◽  
Factors Affecting ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Leakage Flow Rate

The tip leakage flow rate can be directly linked to the loss and stall margin. In this paper, key factors affecting the tip leakage flow rate are explained based on a simple leakage flow model including viscous effect. Based on the numerical results, the flow model is verified in a low speed compressor rotor, and finally a simplified one-dimensional tip blockage model is established based on the Khalid’s model, which may be helpful in the design of compressor.

scholarly journals Transport Performance Improvement of a Multiphase Pump for Gas–Liquid Mixture Based on the Orthogonal Test Method

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1402
Author(s):  
Guangtai Shi ◽  
Helin Li ◽  
Xiaobing Liu ◽  
Zongku Liu ◽  
Binxin Wang
Keyword(s):  
Flow Rate ◽  
Volume Fraction ◽  
Liquid Mixture ◽  
Suction Side ◽  
Orthogonal Test ◽  
Test Method ◽  
Trailing Edge ◽  
Multiphase Pump ◽  
Gas Volume Fraction ◽  
Gas Volume

To improve the transport performance of a rotodynamic multiphase pump for a gas–liquid mixture, we took the head and efficiency index at rated flow rate with 15% inlet gas volume fraction as the indices, and used the orthogonal test design method and CFD technology to optimize. We selected the blade shroud angles at the leading edge and trailing edge, and axial length of the impeller, as well as the inlet incidence angle and blade number of the diffuser, and a total of five factors were used for the orthogonal test. The weight function was used to determine the final trial protocol. The results showed that the blade shroud angle at the trailing edge had the greatest influence on the head and efficiency indices. Under the rated flow rate with a 15% inlet gas volume fraction, the head and efficiency of the optimized pump were increased by 2.81 m and 5.6%, respectively, in comparison to the base pump. After the optimization, the partial fast-speed regions at the inlet of the impeller passage and the partial low-pressure regions on the blade suction side of the impeller disappeared, the accumulation of the gas phase on the blade suction side at the impeller outlet was suppressed, and the pumping performance of the impeller using the gas–liquid mixture was improved greatly. This study provides an important theoretical basis for the optimization and design of a multiphase pump.

Evaluation of a Twin Screw Pump for Use in High Gas Volume Fraction Flows

2012 ◽  
Author(s):  
Gerald L. Morrison ◽  
Abhay Patil ◽  
Daniel Cihak
Keyword(s):  
Volume Fraction ◽  
Pressure Rise ◽  
Maintenance Cost ◽  
Pure Liquid ◽  
Pump Efficiency ◽  
Screw Pump ◽  
Multiphase Pump ◽  
Volume Fractions ◽  
Twin Screw ◽  
Gas Volume

The use of multiphase pumps on gas and oil wells which have Gas Volume Fractions (GVF) between 50 and 100% have been shown to have practical applications[1]. A single multiphase pump can replace a separation system, gas compressor, and liquid pump. This can significantly reduce installation cost, maintenance cost, and the space occupied by the system. By reducing the well head pressure, additional production can also be obtained. This work investigates the ability of a 200 hp, 635 gpm twin screw pump designed for use as a multiphase pump to operate over a range of gas volume fractions, inlet pressure, pressure rise, and operating speed. GVF’s from 50% to 100% are considered with inlet pressures from 15 to 100 psig. The pump pressure rise is varied from 50 to 300 psig for operating speeds of 900, 1350, and 1800 rpm. The working fluids for this evaluation are air and water. Each are separately measured prior to injection into the pump inlet. Electrical power consumed along with pressure and temperature measurements across the pump allow the evaluation of pump efficiency, hydraulic performance, volumetric efficiency, and effectiveness (reduction in hydraulic efficiency from pure liquid performance).

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