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Article
Publication date: 2 October 2017

Hui Quan, Baiheng Fu, Rennian Li, Guangxian Li, Zhengjie Zhang and Jin Li

To analyze the work principle and capacity of energy conversion in each segment of profile lines, the energy transfer from impeller to transmission medium is separated…

Abstract

Purpose

To analyze the work principle and capacity of energy conversion in each segment of profile lines, the energy transfer from impeller to transmission medium is separated into head coefficient and load coefficient to analyze the energy transfer process. The concepts of airfoil lift coefficient and drag coefficient are used; the third manifestation of the Euler equations is used as well.

Design/methodology/approach

The numerical simulation of energy conversion mechanism based on load criteria of vane airfoil has been established in screw centrifugal pump to explain its energy conversion mechanism in an impeller. Upon this basis, the velocity and pressure along the entire blade are investigated through the numerical simulation of internal solid–liquid flow in the pump. The energy conversion process under load criteria in the blade airfoil has also been obtained.

Findings

The research suggests that the mathematical model of energy conversion mechanism based on the load criteria of the vane airfoil is reliable in the screw centrifugal pump. The screw centrifugal blade has twice or even several times the wrap angle than the ordinary centrifugal blade. It is a large wrap angle that forms the unique flow channel which lays the foundation for solid particles to pass smoothly and for soft energy conversion. At the same time, load distribution along the profile line on the long-screw centrifugal blade is an important factor affecting the energy conversion efficiency of the impeller.

Originality/value

The quantitative analysis method of energy in the screw centrifugal pump can help the pump designer improve certain features of the pump and shorten the research cycle.

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Article
Publication date: 1 November 1937

Frank Nixon

THE past two years have seen a notable increase in the number of services on aircraft for which some form of power is required. First, retractable undercarriages, followed…

Abstract

THE past two years have seen a notable increase in the number of services on aircraft for which some form of power is required. First, retractable undercarriages, followed by wing flaps, gun turrets, and automatic pilots, have demanded a light and compact source of power, capable of being transmitted to remote points on the machine. As suitable power units have become available, so have other applications presented themselves, with the consequent freeing of the pilot and crew from irksome manual effort.

Details

Aircraft Engineering and Aerospace Technology, vol. 9 no. 11
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 25 June 2019

Chunlei Shao, Aixia He, Zhongyuan Zhang and Jianfeng Zhou

The purpose of this paper is to study the transition process from the crystalline particles appearing before the pump inlet to the stable operation of the pump.

Abstract

Purpose

The purpose of this paper is to study the transition process from the crystalline particles appearing before the pump inlet to the stable operation of the pump.

Design/methodology/approach

Firstly, a modeling test method was put forward for the high-temperature molten salt pump. Then, according to a modeling test scheme, the experiment of the solid–liquid two-phase flow was carried out by using a model pump similar to the prototype pump. Meanwhile, the numerical method to simulate the transition process of a molten salt pump was studied, and the correctness of the numerical model was verified by the experimental results. Finally, the transition process of the molten salt pump was studied by the verified numerical model in detail.

Findings

In the simulation of the transition process, it is more accurate to judge the end of the transition process based on the unchanged particle volume fraction (PVF) at the pump outlet than on the periodic fluctuation of the outlet pressure. The outlet pressure is closely related to the PVF in the pump. The variation of the outlet pressure is slightly prior to that of the PVF at the pump outlet and mainly affected by the PVF in the impeller and volute. After 0.63 s, the PVF at each monitoring point changes periodically, and the time-averaged value does not change with time.

Practical implications

This study is of great significance to further improve the design method of molten salt pump and predict the abrasion characteristic of the pump due to interactions with solid particles.

Originality/value

A numerical method is established to simulate the transition process of a molten salt pump, and a method is proposed to verify the numerical model of two-phase flow by modeling test.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 29 no. 9
Type: Research Article
ISSN: 0961-5539

Keywords

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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: 3 August 2015

Lei Tan, Baoshan Zhu, Yuchuan Wang, Shuliang CAO and Shaobo Gui

– The purpose of this paper is to elucidate the detailed flow field and cavitation effect in the centrifugal pump volute at partial load condition.

Abstract

Purpose

The purpose of this paper is to elucidate the detailed flow field and cavitation effect in the centrifugal pump volute at partial load condition.

Design/methodology/approach

Unsteady flows in a centrifugal pump volute at non-cavitation and cavitation conditions are investigated by using a computation fluid dynamics framework combining the re-normalization group k-e turbulence model and the mass transport cavitation model.

Findings

The flow field in pump volute is very complicated at part load condition with large pressure gradient and intensive vortex movement. Under cavitation conditions, the dominant frequency for most of the monitoring points in volute transit from the blade passing frequency to a lower frequency. Generally, the maximum amplitudes of pressure fluctuations in volute at serious cavitation condition is twice than that at non-cavitation condition because of the violent disturbances caused by cavitation shedding and explosion.

Originality/value

The detailed flow field and cavitation effect in the centrifugal pump volute at partial load condition are revealed and analysed.

Details

Engineering Computations, vol. 32 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

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Article
Publication date: 1 August 1942

THE B.M.W.801 is an air‐cooled, 14‐cylinder, 4‐strokc, 2‐row radial, fuel‐injection engine with reduction gear and engine‐driven cooling‐fan. Supercharging is by a…

Abstract

THE B.M.W.801 is an air‐cooled, 14‐cylinder, 4‐strokc, 2‐row radial, fuel‐injection engine with reduction gear and engine‐driven cooling‐fan. Supercharging is by a single‐stage centrifugal blower with two automatic speed changes (Figs. 1 and 2).

Details

Aircraft Engineering and Aerospace Technology, vol. 14 no. 8
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 1 November 1953

WITH record attendances during the first days of the Motor Show this year, Exhibitors are asking if it would not be possible to have certain times, or days, reserved for…

Abstract

WITH record attendances during the first days of the Motor Show this year, Exhibitors are asking if it would not be possible to have certain times, or days, reserved for trade buyers. The promoters are obviously concerned with any possible loss of gate money, but it is very true that at times, when stands are crowded with mere sight‐seers it is very difficult for genuine potential buyers and trade personnel to see what they want in the short time that may be at their disposal. These record attendances may not be repeated always; this year is the first time for a long time that anyone can order any car with a reasonable delivery date, and most cars with only a few weeks wait.

Details

Industrial Lubrication and Tribology, vol. 5 no. 11
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 October 1938

THE Rotol airscrew is the modern development of the Gloster‐Hele‐Shaw Beecham unit originally designed by Dr. Hele‐Shaw, developed by the Gloster Aircraft Company, and…

Abstract

THE Rotol airscrew is the modern development of the Gloster‐Hele‐Shaw Beecham unit originally designed by Dr. Hele‐Shaw, developed by the Gloster Aircraft Company, and test flown in various aeroplanes some years ago. It is interesting to recall that this early British airscrew anticipated the present demand for constant‐speed control. The first models, which were arranged either for hydraulic or electric operation, had welded hollow steel or forged aluminium alloy blades; the current types, the constant speed and fully feathering hydraulic models, may be fitted with wooden blades. Unfortunately there are restrictions upon the publication of a description of the feathering airscrew, owing to a number of novel features in connexion with its design and construction, but it has been fully flight‐tested and will soon be on the Open List. However, the following description of the hydraulically operated constant‐speed model covers the latest details available for publication.

Details

Aircraft Engineering and Aerospace Technology, vol. 10 no. 10
Type: Research Article
ISSN: 0002-2667

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Article
Publication date: 15 December 2017

Hui Jiang, Jianjun Yi, Xiaomin Zhu and Zhao Li

This paper aims to develop methods for generating disassembly tasks for selective disassembly. The disassembly task contains the disassembly information, namely…

Abstract

Purpose

This paper aims to develop methods for generating disassembly tasks for selective disassembly. The disassembly task contains the disassembly information, namely, disassembly direction, disassembly tool and selective disassembly sequence.

Design/methodology/approach

Ontology is adopted to represent the product, and ontology rules are used to represent the disassembly knowledge. A product ontology model (POM) is introduced on the basis of material, connection matrix and interference matrix. Two types of disassembly knowledge are taken into account, one is the disassembly knowledge of disassembly tool selection and the other is the disassembly knowledge of special connections. Based on the POM and the disassembly knowledge, decision support methods are designed to generate disassembly tasks.

Findings

A centrifugal pump is used to demonstrate the proposed methods, and the result shows that the methods work well.

Research limitations/implications

The methods developed in this study are fundamental approaches. The ontology and the ontology rules can be extended with more disassembly knowledge.

Originality/value

The main contribution of this research is the development of methods for representing disassembly knowledge based on ontology rules and the decision support methods for generating disassembly tasks.

Details

Assembly Automation, vol. 38 no. 2
Type: Research Article
ISSN: 0144-5154

Keywords

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Article
Publication date: 1 October 1943

BMW 801A/1 The engine is a radial, air‐cooled, fourteen‐cylindcr, double‐bank motor of 42 litres capacity, 6–5/1 compression ratio and 156 mm. bore and stroke.

Abstract

BMW 801A/1 The engine is a radial, air‐cooled, fourteen‐cylindcr, double‐bank motor of 42 litres capacity, 6–5/1 compression ratio and 156 mm. bore and stroke.

Details

Aircraft Engineering and Aerospace Technology, vol. 15 no. 10
Type: Research Article
ISSN: 0002-2667

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