scholarly journals Effect of Gas Volume Fraction on the Gas-Phase Distribution in the Passage and Blade Surface of the Axial Flow Screw-Type Oil-Gas Multiphase Pump

Processes ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 760
Author(s):  
Guangtai Shi ◽  
Sijia Tao ◽  
Xiaobing Liu ◽  
Haigang Wen ◽  
Zekui Shu
Keyword(s):  
Gas Phase ◽  
Volume Fraction ◽  
Phase Distribution ◽  
Axial Flow ◽  
Distribution Area ◽  
Phase Volume ◽  
Multiphase Pump ◽  
Gas Volume Fraction ◽  
Gas Volume ◽  
Oil Gas

The axial flow screw-type oil-gas multiphase pump is mainly applied to oil and gas transport in the deep sea. In the process of transporting the multiphase medium, the gas volume fraction (GVF) on the gas phase changes from time-to-time, resulting in the performance of the oil-gas multiphase pump being greatly influenced by the gas phase. This paper presents a detailed analysis of the gas-phase distribution law and the vortex distribution in the flow passages within the oil-gas multiphase pump by means of numerical calculations, supplemented by experimental verification. The results show that the gas phase is mainly concentrated in the diffuser at different GVFs, and the gas phase gathering in the diffuser becomes more significant with the increase in the GVF. The gas-phase volume fraction increases gradually from rim to hub, that is, the gas-phase gathering degree increases. The maximum gas-phase volume distribution area is mainly concentrated in the area near the hub of the diffuser inlet and the middle blade height area at the outlet of the diffuser. The flow in the impeller is relatively stable under the different GVFs, while there is a large vortex near the inlet of the diffuser near the hub, and there is a backflow phenomenon between the outlet of the diffuser and the tip clearance of the impeller. The volume fraction of the gas phase near the rim fluctuates more than that near the hub because the gas phase is squeezed by the liquid phase more violently. The research results can provide theoretical guidance for the optimal design of oil-gas multiphase pump blades.

scholarly journals Effect of Gas Volume Fraction on the Energy Loss Characteristics of Multiphase Pumps at Each Cavitation Stage

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2293
Author(s):  
Jianwei Shi ◽  
Sijia Tao ◽  
Guangtai Shi ◽  
Wenwu Song
Keyword(s):  
Energy Loss ◽  
Volume Fraction ◽  
Axial Flow ◽  
Two Phase ◽  
Multiphase Pump ◽  
Cavitation Phenomenon ◽  
Flow Loss ◽  
Gas Volume Fraction ◽  
Critical Cavitation ◽  
Gas Volume

In the process of conveying a medium, when the inlet pressure is low, the cavitation phenomenon easily occurs in the pump, especially in the gas–liquid two-phase working condition. The occurrence of the cavitation phenomenon has a great impact on the performance of the multiphase pump. In this paper, the SST (sheard stress transport) k-ω turbulence model and ZGB (Zwart–Gerber–Belamri) cavitation model were used to simulate the helical axial flow multiphase pump (hereinafter referred to as the multiphase pump), and the experimental verification was carried out. The effect of gas volume fraction (GVF) on the energy loss characteristics in each cavitation stage of the multiphase pump is analyzed in detail. The study shows that the critical cavitation coefficient of the multiphase pump gradually decreases with the increase in GVF, which depresses the evolution of cavitation, and the cavitation performance of the multiphase hump is improved. The ratio of total loss and friction loss to total flow loss in the impeller fluid domain gradually increases with the development of cavitation, and the pressurization performance of the multiphase pump gradually decreases with the development of cavitation. The results of the study can provide theoretical guidance for the improvement of the performance of the multiphase pump.

scholarly journals Effect of Thickness Ratio Coefficient on the Mixture Transportation Characteristics of Helical–Axial Multiphase Pumps

2020 ◽  
Vol 10 (1) ◽  
pp. 345
Author(s):  
Wei Han ◽  
Xing Li ◽  
Youliang Su ◽  
Min Su ◽  
Rennian Li ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Oil And Gas ◽  
Volume Fraction ◽  
Thickness Ratio ◽  
Two Phase ◽  
Multiphase Pump ◽  
Gas Volume Fraction ◽  
Gas Volume ◽  
Oil Gas ◽  
Transportation Characteristics

With the decrease of oil and gas resources on land, increased attention has been paid to multiphase oil–gas exploitation and the transportation technology represented by oil–gas multiphase pumps. The helical–axial multiphase pump has become the focus of research on oil and gas mixed transmission technology due to its relatively high operating efficiency and adaptability to a wide range of gas volume fraction changes. In order to investigate the thickness variation in the air foil from the hub to the shroud of the blade on the mixture transportation characteristics of the gas–liquid two-phase flow in a helical–axial pump, the thickness ratio coefficient ξ was introduced, and the hydraulic performance of the single compression unit with different thickness ratio coefficients was investigated. A single compression unit including an impeller, diffuser, inlet section and outlet section of a helical–axial multiphase pump. The hydraulic performance including the hydraulic head and efficiency was investigated by numerical simulation with the Eulerian multiphase model and the shear stress transport (SST) k-w turbulence model. In order to demonstrate the validity of the numerical simulation approach, the hydraulic head and efficiency of the basic model was measured based on a gas–liquid two-phase flow pump performance test bench. The simulation results agreed well with the experimental results; the error between the simulation results and experimental results of different inlet gas volume fractions was within 10% at the design point, which indicated the numerical simulation method can be used in the research. The thickness ratio coefficient ξ, which was taken as a variable, and the aggregation degree λ of the gas were introduced to analyze the gas–liquid mixture transportation characteristics of the pump. The thickness ratio coefficient was selected in a range from 0.8 to 1.8. The results showed that, for the same hub thickness, the head coefficient and efficiency increase, and the aggregation degree of gas decreases with the decreasing of the thickness ratio coefficient. The head coefficient of the modification multiphase pump was 5.8% higher in comparison to the base pump while the efficiency was 3.1% higher than that of the base pump, the aggregation degree of this model was the lowest, which was 30.3%; the optimal model in the research was the model of scheme 1 with ξ = 0.8. The accumulation of gas in the flow passage of the impeller could be delayed to the trailing edge of the blade by adjusting the thickness ratio coefficient, which produced a super-separated airfoil for helical–axial multiphase pumps and effectively ensured reliable operation under high gas volume fraction conditions. The accumulation area of gas was consistent with the area in which the gradient of turbulent kinetic energy was large.

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.

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.

Performance Test of a 5-Stage Helico-Axial Multiphase Pump

2011 ◽  
Vol 52-54 ◽  
pp. 399-404 ◽  
Author(s):  
Jin Ya Zhang ◽  
Hong Wu Zhu ◽  
Huan Wei ◽  
Jing Ying Peng
Keyword(s):  
Performance Test ◽  
Volume Fraction ◽  
Differential Pressure ◽  
Future Application ◽  
Multiphase Pump ◽  
The Future ◽  
Gas Volume Fraction ◽  
Gas Volume ◽  
Test Result

A 5-stage helico-axial multiphase pump was tested for studying its performance. The multiphase pump was tested on the conditions of different speed and different gas volume fraction (GVF). According to the test result, performances of the pump were analyzed. And the effects of speed and GVF to differential pressure and efficiency as well as to power of the pump were analyzed at the same time, so some conclusions were made basing of the above research and some of them are very helpful for the future application on the oilfield.

Qualification of a New Multiphase Pump. the Setting of a New Standard

2021 ◽  
Author(s):  
Åge Hofstad ◽  
Tarje Olderheim ◽  
Magnus Almgren ◽  
Marianna Rondon ◽  
Edouard Thibaut ◽  
...  
Keyword(s):  
High Speed ◽  
Oil And Gas ◽  
Volume Fraction ◽  
Two Phase ◽  
Specific Product ◽  
Multiphase Pump ◽  
Gas Volume Fraction ◽  
Gas Market ◽  
Gas Volume ◽  
Winding Insulation

Abstract The recent trend in the oil industry is to save CAPEX and exploit every offshore field to increase production and maximize reserves. Also, deeper water and longer step-out is a challenge for new fields. The most adapted technology to unlock these reserves is the use of subsea boosting like a multiphase pump on the seafloor. Subsea boosting has been used for decades with well proven results, but up to now, some limitations in power and lift pressure exist. This new multiphase pump development has increased the potential pressure generation manyfold from the typical ΔP of 50 bar (725 psi) at the beginning of the project. Developing such a powerful two-phase pump driven by a liquid-filled motor requires a unique combination of expertise in machinery engineering, electrical engineering, fluid mechanics and rotor dynamics. The objective of the co-authors is to share this experience by bringing some insights on what it takes to develop, test, and qualify such specific product. Outlines of the methodology will be described, key results will be detailed, and lessons learnt will be presented. The new design was fully tested first component-wise and then for a full-size prototype. A wide process envelope was mapped during the final qualification program with 3,000 points tested in the range 2,000-6,000 RPM and 0 - 100% GVF (Gas Volume Fraction). Qualification tests concluded with more than 2,000 cumulative hours. The main challenges in this program were the development of an innovative multiphase impeller and the qualification of the first MPP (MultiPhase Pump) with a back-to-back configuration. Concerning the motor, the development includes a high speed 6,000 RPM, 6 MW liquid-filled induction motor and a new stator winding insulation cable. With this new product, the pump market is ready to overcome challenges to produce deeper and further reservoirs in a constant evolutive oil and gas market.

scholarly journals 3D Blade Hydraulic Design Method of the Rotodynamic Multiphase Pump Impeller and Performance Research

2014 ◽  
Vol 6 ◽  
pp. 803972 ◽  
Author(s):  
Yongxue Zhang ◽  
Jinya Zhang ◽  
Hongwu Zhu ◽  
Shujie Cai
Keyword(s):  
Volume Fraction ◽  
Design Method ◽  
Three Dimensional ◽  
Bench Test ◽  
Pump Impeller ◽  
Multiphase Pump ◽  
Hydraulic Design ◽  
Gas Volume Fraction ◽  
And Performance ◽  
Gas Volume

A hydraulic design method of three-dimensional blade was presented to design the blades of the rotodynamic multiphase pump. Numerical simulations and bench test were conducted to investigate the performance of the example impeller designed by the presented method. The results obtained from the bench test were in good agreement with the simulation results, which indicated the reasonability of the simulation. The distributions of pressure and gas volume fraction were analyzed and the results showed that the designed impeller was good for the transportation of mixture composed of gas and liquid. In addition, the advantage of the impeller designed by the presented method was suitable for using in large volume rate conditions, which were reflected by the comparison of the head performance between this three-dimensional design method and another one.

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