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Article
Publication date: 31 July 2019

Hui Quan, Yi Chai, Rennian Li and Jianhui Guo

The special structure of the vortex pump contributes to its complex internal flow pattern. A type of horizontal 150WX-200-20 vortex pump is taken as a research subject to…

Abstract

Purpose

The special structure of the vortex pump contributes to its complex internal flow pattern. A type of horizontal 150WX-200-20 vortex pump is taken as a research subject to deeply study the progression and distribution of flow pattern in its channel. To explain the mechanism of flow in this pump, numerical analysis of the whole flow and experiment have been conducted.

Design/methodology/approach

The authors studied and analyzed the distribution and evolution of flow pattern under different flow, such as circulating-flow, through-flow and other forms. Finally, a model of flow pattern in the vortex pump has been built, which has more perfectly fit the reality.

Findings

They are through-flow affected by circulating-flow, main and subsidiary circulating-flow, vortices between vanes and other vortices (or liquid impingement) in volute. Entering the pump, part of the flow stays in vanes and turn into vortices while the other goes into the front chamber. The flow that runs into the front chamber will be divided into two parts. One part will be collected by viscosity into a vortex rope when it passing through the interface between the impeller and the vaneless chamber, which closely relates to the circulating-flow, and the rest directly goes out of the field through the diffuser. Besides, a fraction of circulating-flow joins the through-flow when it goes through the section V and leaves the pump.

Originality/value

The research results build a theoretical foundation for working out the flow mechanism of the vortex pump, improving its efficiency and optimizing its hydraulic design.

Details

Engineering Computations, vol. 36 no. 5
Type: Research Article
ISSN: 0264-4401

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Article
Publication date: 1 April 2014

Tihomir Mihalić, Zvonimir Guzović and Andrej Predin

Aging of the oil wells leads to a decrease in reservoir pressure and also to an increase in the water, gas and abrasive particles content. Therefore, there is a need for…

Abstract

Purpose

Aging of the oil wells leads to a decrease in reservoir pressure and also to an increase in the water, gas and abrasive particles content. Therefore, there is a need for the oil pumps exploitation characteristics improvements. This paper aims to generate a valuable numerical model which will provide a useful tool to study various cases.

Design/methodology/approach

Computational fluid dynamics (CFD) analysis of the generation of so-called coherent structures of eddies and turbulence in the peripheral area of the vortex rotor mounted at the back side of centrifugal rotor was undertaken. After detailed analysis of the influence of the used turbulence models on the results, a hybrid turbulent model Detached Eddies Simulation (DES) was chosen as the most suitable.

Findings

Numerical control volume method with unsteady solver and DES turbulence model was proven to be valuable tool for flow analysis in the centrifugal pumps. Having in mind that DES turbulence model consumes much less computational time than large eddies turbulence model, this is a very useful fact that resulted from this research.

Practical implications

The proven numerical model is robust and reliable enough to become a standard method in simulating flow and other physical phenomena occurring in centrifugal pumps and similar turbo machines. This makes it possible to easily research different factors that influence their performances.

Originality/value

Comprehensive experimental and CFD study was performed which made it possible to conduct detailed validation and verification of described CFD model.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 24 no. 3
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 27 August 2019

Hui Quan, Yi Chai, Rennian Li, Guo-Yi Peng and Ying Guo

Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However…

Abstract

Purpose

Having read previous literature about vortex pump, we noticed that mechanisms of circulating flow and its relationship with energy transition remain unclear yet. However, this mechanism, which should be clarified, significantly influences the pump’s efficiency. To comply with the aim of investigating it, the 150WX-200-20 type pump is selected as study object in our present work.

Design/methodology/approach

Numerical simulation is conducted to formulate interactions between flow rate and geometric parameters of circulating flow with certain types of blade while experiments on inner flow are served as a witness to provide experimental confirmation of numerical results. Based on these, we coupled some parameters with the pump’s external performance to study their internal connections.

Findings

It is concluded that separatrix between circulating flow and other turbulent forms is not that clear under low flow rate. With flow increases, hydraulic losses coming of it will be dominant within the front chamber. Besides, we analogized circulating flow to vortices so as to make a quantitative analysis on its progressive evolution with changing flow, and vortices speaking for circulating flow can be divided into two groups. One is called main circulating flow vortex (hereinafter referred to as MCFV), which occurs all the time while subsidiary circulating flow vortices (hereinafter referred to as SCFV) appear in certain conditions. This context discusses the primary phase of our work with intent to follow up further with circulating flow characterized by vortices (hereinafter referred to as CFV). We confirmed that MCFV Vortex 1 (Vor1) directly influences the efficiency while SCFVs only play helping. As the flow goes to the given working condition, fluids in this pump tend to be steady with the size of CFVs getting larger and their shape being regular. Meanwhile, for MCFV Vor2 and Vor4, their geometric parameters are the key factors for efficiency. When CFVs become steady, they absorb other vortices nearby, as they have higher viscosity with the efficiency reaching its maximum.

Originality/value

The research results explore a new way to measure the circulating flow and help work out the causation of this flow pattern, which may be used to improve the vortex pump’s efficiency.

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Article
Publication date: 7 August 2017

Wenjie Cheng, Boqin Gu and Chunlei Shao

This paper aims to figure out the steady flow status in the molten salt pump under various temperatures and blade number conditions, and give good insight on the structure…

Abstract

Purpose

This paper aims to figure out the steady flow status in the molten salt pump under various temperatures and blade number conditions, and give good insight on the structure and temperature-dependent efficiencies of all pump cases. Finally, the main objective of present work is to get best working condition and blade numbers for optimized hydraulic performance.

Design/methodology/approach

The steady flow in the molten salt pump was studied numerically based on the three-dimensional Reynolds-Averaged Navier–Stokes equations and the standard k-ε turbulence model. Under different temperature conditions, the internal flow fields in the pumps with different blade number were systematically simulated. Besides, a quantitative backflow analysis method was proposed for further investigation.

Findings

With the molten salt fluid temperature, sharply increasing from 160°C to 480°C, the static pressure decreases gently in all pump cases, and seven-blades pump has the least backflow under low flow rate condition. The efficiencies of all pump cases increase slowly at low temperature (about 160 to 320°C), but there is almost no variation at high temperature, and obviously seven-blades pump has the best efficiency and head in all pump cases over the wide range of temperatures. The seven-blades pump has the best performance in all selected pump cases.

Originality/value

The steady flow in molten salt pumps was systematically studied under various temperature and blade number conditions for the first time. A quantitative backflow analysis method was proposed first for further investigation on the local flow status in the molten salt pump. A definition about the low velocity region in molten salt pumps was built up to account for whether the studied pump gains most energy. This method can help us to know how to improve the efficiencies of molten salt pumps.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 8
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 11 January 2011

Francis Quail, Thomas Scanlon and Matthew Stickland

Regenerative pumps are the subject of increased interest in industry as these pumps are low‐cost, low‐specific speed, compact and able to deliver high heads with stable…

Abstract

Purpose

Regenerative pumps are the subject of increased interest in industry as these pumps are low‐cost, low‐specific speed, compact and able to deliver high heads with stable performance characteristics. However, these pumps have a low efficiency (35‐50 per cent). The complex flow field within the pumps represents a considerable challenge to detailed mathematical modelling. Better understanding of the flow field would result in improvement of the pump efficiency. The purpose of this paper is to consider a numerical and experimental analysis of a regenerative pump to simulate the flow field and math pump performance.

Design/methodology/approach

This paper outlines the use of a commercial computational fluid dynamics (CFD) code to simulate the flow field within the regenerative pump and compare the CFD results with new experimental data. A novel rapid manufacturing process is used to consider the effect of impeller geometry changes on the pump efficiency.

Findings

The CFD results demonstrate that it is possible to represent the helical flow field for the pump which has only been witnessed in experimental flow visualisation until now. The CFD performance results also demonstrate reasonable agreement with the experimental tests.

Research limitations/implications

The design optimisation only considers a number of blade geometry changes. The future work will consider a much broader spectrum of design modifications which have resulted in efficiency improvements in the past.

Practical implications

The ability to use CFD modelling in conjunction with rapid manufacturing techniques has meant that more complex geometry configurations can now be assessed with better understanding of the flow field effects and resulting efficiency.

Originality/value

This paper presents new flow field visualisation and better correlation to the matched performance than the current limited mathematical models. This paper also presents a novel method for rapid manufacturing of the pump impeller.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 21 no. 1
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 3 August 2010

Francis J. Quail, Thomas Scanlon and Matthew Strickland

The purpose of this paper is to present a method of rapid prototyping (RP) used in the development of a regenerative pump impeller. RP technology was used to create…

Abstract

Purpose

The purpose of this paper is to present a method of rapid prototyping (RP) used in the development of a regenerative pump impeller. RP technology was used to create complex impeller blade profiles for testing as part of a regenerative pump optimisation process. Regenerative pumps are the subject of increased interest in industry.

Design/methodology/approach

Ten modified impeller blade profiles, relative to the standard radial configuration, were evaluated with the use of computational fluid dynamics (CFD) and experimental testing. Prototype impellers were needed for experimental validation of the CFD results. The manufacture of the complex blade profiles using conventional milling techniques is a considerable challenge for skilled machinists.

Findings

The complexity of the modified blade profiles would normally necessitate the use of expensive computer numerically controlled machining with five‐axis capability. With an impeller less than 75 mm in diameter with a maximum blade thickness of 1.3 mm, a rapid manufacturing technique enabled production of complex blade profiles that are dimensionally accurate and structurally robust enough for testing.

Research limitations/implications

As more advanced RP machines become available in the study in the coming months, e.g. selective laser sintering, the strength of the parts particularly for higher speed testing will improve and the amount of post processing operations will reduce.

Practical implications

This technique offers the possibility to produce components of increased complexity whilst ensuring quality, strength, performance and speed of manufacture.

Originality/value

The ability to manufacture complex blade profiles that are robust enough for testing, in a rapid and cost effective manner is proving essential in the overall design optimisation process for the regenerative pump.

Details

Rapid Prototyping Journal, vol. 16 no. 5
Type: Research Article
ISSN: 1355-2546

Keywords

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Article
Publication date: 7 August 2017

Jafar Nejad, Alireza Riasi and Ahmad Nourbakhsh

Regenerative flow pump (RFP) is a rotodynamic turbomachine capable of developing high pressure rise at low flow rates. This paper aims to numerically investigate the…

Abstract

Purpose

Regenerative flow pump (RFP) is a rotodynamic turbomachine capable of developing high pressure rise at low flow rates. This paper aims to numerically investigate the performance of a regenerative pump considering the modification in blade and casing geometry.

Design/methodology/approach

The radial blade shape was changed to the bucket form and a core is added to flow path. A parametric study was performed to improve the performance of the pump. Thus, the effect of change in blade angle, chord, height, pitch to chord ratio and also inlet port on the performance of RFP was investigated.

Findings

Results showed that the modified blade angle to achieve the maximum efficiency is about 41 degree. Also, the most efficient point occurs close to pitch/chord = 0.4 and by reducing the axial chord, efficiency of the pump increases. It was found that better efficiency will be achieved by increasing the “Arc of admission”, but there are limitations of manufacturing. It was observed that the performance curves shifted towards lower flow coefficients by reducing height of blades.

Originality/value

To improve the characteristics of regenerative pump, the blade shape changed to the bucket form (airfoil blades with identical inlet and outlet angle) and a core is added to flow path. A parametric study has been accomplished to see the influence of some important parameters on the performance of the pump.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 8
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 1 January 1970

Five integral fuel tanks are carried in the fuselage. Port and starboard side tanks of 51½ gallons (234 litres) capacity each between the front engine nozzles and the…

Abstract

Five integral fuel tanks are carried in the fuselage. Port and starboard side tanks of 51½ gallons (234 litres) capacity each between the front engine nozzles and the engine air intakes, a further pair of side tanks of 39 gallons (178 litres) capacity each between the front and rear engine nozzles, and a central tank of 104 gallons (473 litres) capacity occupying the upper portion of the fuselage immediately aft of the wing.

Details

Aircraft Engineering and Aerospace Technology, vol. 42 no. 1
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 4 December 2017

Chunbao Liu, Weiyang Bu, Dong Xu, Yulong Lei and Xuesong Li

This paper aims to improve performance prediction and to acquire more detailed flow structures so as to analyze the turbulence in complex rotor-stator flow.

Abstract

Purpose

This paper aims to improve performance prediction and to acquire more detailed flow structures so as to analyze the turbulence in complex rotor-stator flow.

Design/methodology/approach

Hydraulic retarder as typical fluid machinery was numerically investigated by using hybrid Reynolds-averaged Navier–Stokes (RANS)/large eddy simulation (LES) models CIDDES Algebraic Wall-Modeled Large Eddy Simulation (LES) (WMLES) S-Ω and dynamic hybrid RANS/LES (DHRL). The prediction results were compared and analyzed with a RANS model shear stress transport (SST) k-omega which was a recommended choice in engineering.

Findings

The numerical results were verified by experiment and indicated that the predicted values for three hybrid turbulence models were more accurate. Then, the transient flow field was further analyzed visually in terms of turbulence statistics, Reynolds number, pressure-streamline, vortex structure and eddy viscosity ratio. The results indicated that HRL approaches could capture unsteady flow phenomena.

Practical implications

This study achieves both in performance prediction improvement and better flow mechanism understanding. The computational fluid dynamics (CFD) could be used instead of flow visualization to a certain extent. The improved CFD method, the fine computational grid and the reasonable simulation settings jointly enhance the application of CFD in the rotor-stator flow.

Originality/value

The improvement was quite encouraging compared with the reported literatures, contributing to the CFD playing a more important role in the flow machinery. DHRL provided the detailed explanation of flow transport between rotor and stator, which was not reported before. Through it, the flow mechanism can be better understood.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 12
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 9 March 2010

Zhengwei Wang, Guangjie Peng, Lingjiu Zhou and Deyi Hu

The pump of the Taipuhe Pump Station, larger flow discharge, lower head, is one of the largest 15° slanted axial‐flow pumps in the world. However, few studies have been…

Abstract

Purpose

The pump of the Taipuhe Pump Station, larger flow discharge, lower head, is one of the largest 15° slanted axial‐flow pumps in the world. However, few studies have been done for the larger slanted axial‐flow pump on safe operation. The purpose of this paper is to analyze the impeller elevation, unsteady flow, hydraulic thrust and the zero‐head flow characteristics of the pump.

Design/methodology/approach

The flow field in and through the pump was analyzed numerically during the initial stages of the pump design process, then the entire flow passage through the pump was analyzed to calculate the hydraulic thrust to prevent damage to the bearings and improve the operating stability. The zero‐head pump flow characteristics were analyzed to ensure that the pump will work reliably at much lower heads.

Findings

The calculated results are in good agreement with experimental data for the pump elevation effects, the performance curve, pressure oscillations, hydraulic thrust and zero‐head performance.

Research limitations/implications

Since it is assumed that there is no gap between blades and shroud, gap cavitations are beyond the scope of the paper.

Originality/value

The paper indicates the slanted axial‐flow pump characteristics including the characteristic curves, pressure fluctuations, hydraulic thrust and radial force for normal operating conditions and zero‐head conditions. It shows how to guarantee the pump safety operating by computational fluid dynamics.

Details

Engineering Computations, vol. 27 no. 2
Type: Research Article
ISSN: 0264-4401

Keywords

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