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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: 15 May 2009

Junye Wang and Geoffrey H. Priestman

The purpose of this paper is to simulate the behaviour of the symmetrical turn‐up vortex amplifier (STuVA) to obtain insight into its maximum through‐flow operation within…

Abstract

Purpose

The purpose of this paper is to simulate the behaviour of the symmetrical turn‐up vortex amplifier (STuVA) to obtain insight into its maximum through‐flow operation within the eight‐port STuVA, and understand the relation between its design parameters and flow characteristics. Furthermore, it is to test the performance of different turbulent models and near‐wall models using the same grid, the same numerical methods and the same computational fluid dynamics code under multiple impingement conditions.

Design/methodology/approach

Three turbulence models, the standard k‐ε, the renormalization group (RNG) k‐ε model and the Reynolds stress model (RSM), and three near‐wall models have been used to simulate the confined incompressible turbulent flow in an eight‐port STuVA using unstructured meshes. The STuVA is a special symmetrical design of turn‐up vortex amplifier, and the simulation focused on its extreme operation in the maximum flow state with no swirling. The predictions were compared with basic pressure‐drop flow rate measurements made using air at ambient conditions. The effect of different combinations of turbulence and near‐wall models was evaluated.

Findings

The RSM gave predictions slightly closer to the experimental data than the other models, although the RNG k‐ε model predicted nearly as accurately as the RSM. They both improved errors by about 3 per cent compared to the standard k‐ε model but took a long time for convergence. The modelling of complex flows depends not only on the turbulence model but also on the near‐wall treatments and computational economy. In this study a good combination was the RSM, the two layer wall model and the higher order discretization scheme, which improved accuracy by more than 10 per cent compared to the standard k‐ε model, the standard wall function and first order upwind.

Research limitation/implications

The results of this paper are valid for the global pressure drop flow rate. It should be desirable to compare some local information with the experiment.

Originality/value

This paper provides insight into the maximum through‐flow operation within the eight‐port STuVA to understand the relation between its design parameters and flow characteristics and study the performance of turbulence and near wall models.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 19 no. 3/4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 22 May 2007

Deepthi Duddempudi, Yufeng Yao, David Edmondson, Jun Yao and Andy Curley

The paper seeks to perform a detailed numerical study of flow over a generic fan‐wing airfoil and also attempts to modify the geometry for the improvement of the…

Abstract

Purpose

The paper seeks to perform a detailed numerical study of flow over a generic fan‐wing airfoil and also attempts to modify the geometry for the improvement of the aerodynamic performance.

Design/methodology/approach

Advanced computational fluid dynamics (CFD) technique has been employed for evaluation of the aerodynamic performance (e.g. lift/drag ratio) of a model problem. Numerical investigation starts with sensitivity studies to minimize domain size influence and grid dependency, followed by time‐accurate transient calculations. A preliminary re‐design exercise has been performed by analyzing the results of a current design.

Findings

CFD predicted lift force agrees fairly well with the measurement data with about 6.55 per cent error, while drag force compares less favourably with about 12.59 per cent error. Both errors are generally acceptable for an engineering application of complex flow problems. Several key flow features observed previously by experiment have also been re‐produced by simulation, notably the eccentric vortex motions in the blade interior and the stream “jet” flow outside the blades near the exit. With the modified geometry, there is a considerable lift/drag ratio improvement of about 29.42 per cent. The possible reasons for such a significant improvement have been discussed.

Research limitations/implications

As it is the first step towards the detailed flow analysis of this type of model, a simpler blade shape rather than “real” one has been used.

Practical implications

The paper provides a very useful source of information and could be used as guidance for further industry practice of unmanned aerial vehicles design.

Originality/value

This paper is valuable for both academic researchers and industry engineers, especially those working in the area of high‐lift wing design. The works presented are original.

Details

Aircraft Engineering and Aerospace Technology, vol. 79 no. 3
Type: Research Article
ISSN: 0002-2667

Keywords

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Article
Publication date: 14 January 2021

Pavleen Soni

In an era of burgeoning activity in online retail in India, the role of web-store design is paramount. Web-store design elements such as website functionality, brand…

Abstract

Purpose

In an era of burgeoning activity in online retail in India, the role of web-store design is paramount. Web-store design elements such as website functionality, brand assortment and product quality are expected to generate customer loyalty.

Design/methodology/approach

Using data collected from 553 students from two universities in north India, the present study investigates the indirect effect of web-store dimensions (through website functionality, brand assortment and product quality) on online store loyalty via an enjoyment state (flow) and customer satisfaction. Serial mediation has been analysed through PROCESS macro developed by Hayes version 3.0. In addition to this, the moderating role of gender and purchase frequency has also been investigated.

Findings

The present study renders support to serial mediation between website functionality, flow, customer satisfaction and loyalty. However, the path between brand assortment and loyalty is more strongly mediated by customer satisfaction only. Males experience less flow as compared to females while handling brand assortment on websites. The three-way interaction between brand assortment, gender and purchase frequency is also statistically significant.

Originality/value

The study examines the manner in which online retailers can choose to build customer loyalty when they try to build retail image using web store functionality and /or product/brand assortments. The study offers insights to retailers about how and when to focus on hedonism versus customer satisfaction or both of them in conjunction to enhance customer loyalty. This study is important as it investigates the relationships in Indian scenario witnessing a high rate of growth in online retail which can tremendously affect these relationships.

Details

American Journal of Business, vol. 36 no. 1
Type: Research Article
ISSN: 1935-5181

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Article
Publication date: 2 May 2017

Lei Chen and Jiang Chen

This paper aims to conduct the optimization of the multi-stage gas turbine with the effect of the cooling air injection based on the adjoint method.

Abstract

Purpose

This paper aims to conduct the optimization of the multi-stage gas turbine with the effect of the cooling air injection based on the adjoint method.

Design/methodology/approach

Continuous adjoint method is combined with the S2 surface code.

Findings

The optimization of the stagger angles, stacking lines and the passage can improve the attack angles and restrain the development of the boundary, reducing the secondary flow loss caused by the cooling air injection.

Practical implications

The aerodynamic performance of the gas turbine can be improved via the optimization of blade and passage based on the adjoint method.

Originality/value

The results of the first study on the adjoint method applied to the S2 surface through flow calculation including the cooling air effect are presented.

Details

Aircraft Engineering and Aerospace Technology, vol. 89 no. 3
Type: Research Article
ISSN: 1748-8842

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: 1 June 2005

Suat Canbazoğlu and Fazıl Canbulut

The main objective of this study was to obtain the flow restricting capacity by determining their flow coefficients and to investigate the unsteady flow with low Reynolds…

Abstract

Purpose

The main objective of this study was to obtain the flow restricting capacity by determining their flow coefficients and to investigate the unsteady flow with low Reynolds number in the flow‐restricting devices such as orifices and capillary tubes having small diameters.

Design/methodology/approach

There is an enormous literature on the flow of Newtonian fluids through capillaries and orifices particularly in many application fields of the mechanical and chemical engineering. But most of the experimental results in literature are given for steady flows at moderate and high Reynolds numbers (Re>500). In this study, the unsteady flow at low Reynolds number (10<Re<650) through flow‐restricting devices such as orifices and capillary tubes having very small diameters between 0.35 and 0.70 mm were experimentally investigated.

Findings

The capillary tubes have much more capillarity property with respect to equal diameter orifices. Increasing the ratio of capillary tube length to tube diameter and decreasing the ratio of orifice diameter to pipe diameter before orifice increase the throttling or restricting property of the orifices and the capillary tubes. The orifices can be preferred to the capillary tubes having the same diameter at the same system pressure for the hydraulic systems or circuits requiring small velocity variations. The capillary tubes provide higher pressure losses and they can be also used as hydraulic accumulators in hydraulic control devices to attenuate flow‐induced vibrations because of their large pressure coefficients. An important feature of the results obtained for capillary tubes and small orifices is that as the d/D for orifices increases and the L/d reduces for capillary tubes, higher values C are obtained and the transition from viscous to inertia‐controlled flow appears to take place at lower Reynolds numbers. This may be explained by the fact that for small orifices with high d/D ratios and for capillary tubes with small L/d ratios, the losses due to viscous shear are small. Another important feature of the results is that the least variations in C for small orifices and the higher variations in C for capillary tubes occur when the d/D and L/d ratios are smallest. This has favourable implications in hydraulic control devices since a constant value for the C may be assumed even at relatively low values of Re.

Originality/value

To the authors' knowledge, there is not enough information in the literature about the flow coefficients of unsteady flows through capillary tubes and small orifices at low Reynolds numbers. This paper fulfils this gap.

Details

Industrial Lubrication and Tribology, vol. 57 no. 3
Type: Research Article
ISSN: 0036-8792

Keywords

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Article
Publication date: 1 February 2016

Chung-Hui Tseng and Tseng-Lung Huang

Based on narrative theory, emotional contagion theory, and anticipated emotions theory, the purpose of this paper is to adopt an experimental design intended to understand…

Abstract

Purpose

Based on narrative theory, emotional contagion theory, and anticipated emotions theory, the purpose of this paper is to adopt an experimental design intended to understand how narrative advertising video on internet, narrator flow and online audience characteristics influence the health communication effects and depression prevention messages of public service advertisements.

Design/methodology/approach

This study uses two experimental designs. The first contrasts the effectiveness of persuasion between narrative and argument advertising videos on internet, while the second contrasts the effectiveness of persuasion between narrators with high and low flow. This study employed partial least squares path modeling to validate the research structure hypothesis.

Findings

Empirical results indicate that internet narrative advertising video is not direct, but rather draws on flow and positive anticipated emotions to stimulate the production of online audience intention to adopt health risk-reducing behaviors. Compared with narrative advertising video, which influences intention to adopt health risk-reducing behaviors through flow and positive anticipated emotions, narrator advertising video with an emotionally invested high-flow narrator can strengthen online audience intention to adopt risk-reducing behaviors more directly and positively.

Practical implications

The study results can provide elements to assist in the design of online advertising video on depression prevention and health promotion.

Originality/value

In this study, the dialogue among narrative theory, emotional contagion theory, and anticipated emotions theory is constructed, and an integrated conceptual framework is developed for the relationship between internet advertising video type and the health communication.

Details

Internet Research, vol. 26 no. 1
Type: Research Article
ISSN: 1066-2243

Keywords

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Article
Publication date: 12 July 2018

Yanni Liu, Dongsheng Liu, Yufei Yuan and Norm Archer

The purpose of this paper is to investigate users’ continuous adoption behaviors on mobile game playing from the perspective of situational habit formation.

Abstract

Purpose

The purpose of this paper is to investigate users’ continuous adoption behaviors on mobile game playing from the perspective of situational habit formation.

Design/methodology/approach

Based on the literature research, a continuous adoption model for situational mobile game is proposed. And the research model is assessed based on data gathered from a sample of 226 mobile game players by employing the structural equation model methodology.

Findings

The results show that situational cues represented by availability, perceived ease of use and diversion lead to repeated performance that can be represented by flow experience and satisfaction in the situational mobile game playing context. But only flow experience and diversion influence continuous usage directly. Additionally diversion, as a critical situational variable, not only indirectly affects continuous usage intention through flow experience, but also directly affects continuous usage intention for situational mobile game playing.

Originality/value

Mobile game adoption has been studied from different perspectives, but most research is based on the technology acceptance model. They could not explain the common fact that young people tend to be highly motivated by mobile games and can be regarded as pro-active mobile game players, but many people play mobile games only when they are bored and need a diversion. So this study attempts to illustrate the phenomena to fill the gaps.

Details

Information Technology & People, vol. 31 no. 4
Type: Research Article
ISSN: 0959-3845

Keywords

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Article
Publication date: 1 June 2005

Yao Zheng, Liu Gao‐Lian and Wu Xiao‐Jiang

Provides two hybrid methods for the aerodynamic design of cascade profiles, of which the design constraints are the combination of aerodynamic and geometric conditions.

Abstract

Purpose

Provides two hybrid methods for the aerodynamic design of cascade profiles, of which the design constraints are the combination of aerodynamic and geometric conditions.

Design/methodology/approach

In the first method, the design constrain is composed of the velocity (or pressure) distribution on part of the blade surface and the geometry of the rest part. In the second method, the aerodynamic load distribution, i.e. the pressure difference between the suction and pressure surfaces, and the blade thickness distribution are employed as the design constrain. These constraints, together with all the other boundary conditions, are involved in the stationary conditions of a variational principle. The solution domain, i.e. the blade‐to‐blade passage, is transformed into a square in the image plane, while the blade contour is projected to a straight line; thus, the difficulty caused by the unknown geometry of profile is avoided. Finite element method is employed to produce the calculation code.

Findings

Applications show the accuracy and the flexibility of the two methods, which can satisfy the different needs from blade design. Finally, the possibility of combining the hybrid methods with the through‐flow method is discussed, which would develop the present methods to three‐dimensional design of cascades.

Research limitations/implications

The design methods are limited to frictionless flow.

Practical implications

A design software of cascade profiles based on this method has been developed, and will be provided to the engineering users for cascade design.

Originality/value

The hybrid methods developed in this paper can satisfy the demands from different aspects of engineering designs: aerodynamics, strength, manufacture, etc.

Details

Aircraft Engineering and Aerospace Technology, vol. 77 no. 3
Type: Research Article
ISSN: 0002-2667

Keywords

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