Ming Liu, Shan Cao and Shuliang Cao
The modeling of interphase forces plays a significant role in the numerical simulation of gas–liquid flow in a rotodynamic multiphase pump, which deserves detailed study.
Abstract
Purpose
The modeling of interphase forces plays a significant role in the numerical simulation of gas–liquid flow in a rotodynamic multiphase pump, which deserves detailed study.
Design/methodology/approach
Numerical analysis is conducted to estimate the influence of interphase forces, including drag force, lift force, virtual mass force, wall lubrication force and turbulent dispersion force.
Findings
The results show that the magnitude of the interphase forces can be sorted by: drag force > virtual mass force > lift force > turbulent dispersion force > wall lubrication force. The relations between interphase forces and velocity difference of gas–liquid flow and also the interphase forces and gas volume fraction are revealed. The distribution characteristics of interphase forces in the passages from impeller inlet to diffuser outlet are illustrated and analyzed. According to the results, apart from the drag force, the virtual mass force, lift force and turbulent dispersion force are required, whereas wall lubrication force can be neglected for numerical simulation of gas–liquid flow in a rotodynamic multiphase pump. Compared with the conventional numerical method which considers drag force only, the relative errors of predicted pressure rise and efficiency based on the proposed numerical method in account of four major forces can be reduced by 4.95 per cent and 3.00 per cent, respectively.
Originality value
The numerical analysis reveals the magnitude and distribution of interphase forces inside multiphase pump, which is meaningful for the simulation and design of multiphase pump.
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Ming Liu, Lei Tan, Yabin Liu, Yun Xu and Shuliang Cao
This paper aims to investigate the effect of three-dimensional (3D) inlet guide vanes (IGVs) on performance of a centrifugal pump.
Abstract
Purpose
This paper aims to investigate the effect of three-dimensional (3D) inlet guide vanes (IGVs) on performance of a centrifugal pump.
Design/methodology/approach
A design method for 3D IGVs is proposed based on the controllable velocity moment, which is determined by a fourth-order dimensionless function. Numerical simulation of the centrifugal pump with IGVs is carried out by solving the Reynolds-averaged Navier–Stokes equations. The method of frozen rotor is applied to couple the stationary and rotational domain.
Findings
The efficiency of pump with 3D IGVs is higher than that with 2D IGVs for most prewhirl angles, which validate the advancement of 3D IGVs on prewhirl regulation. The effect of prewhirl regulation at small flow rate is more significant than that at large flow rate.
Originality/value
A prediction model of velocity moment based on the Oseen vortex is proposed to describe the flow pattern downstream the IGVs.
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Zhiyi Yu, Baoshan Zhu and Shuliang Cao
Interphase forces between the gas and liquid phases determine many phenomena in bubbly flow. For the interphase forces in a multiphase rotodynamic pump, the magnitude analysis was…
Abstract
Purpose
Interphase forces between the gas and liquid phases determine many phenomena in bubbly flow. For the interphase forces in a multiphase rotodynamic pump, the magnitude analysis was carried out within the framework of two-fluid model. The purpose of this paper is to clarify the relative importance of various interphase forces on the mixed transport process, and the findings herein will be a base for the future study on the mechanism of the gas blockage phenomenon, which is the most challenging issue for such pumps.
Design/methodology/approach
Four types of interphase forces, i.e. drag force, lift force, virtual mass force and turbulent dispersion force (TDF) were taken into account. By comparing with the experiment in the respect of the head performance, the effectiveness of the numerical model was validated. In conditions of different inlet gas void fractions, bubble diameters and rotational speeds, the magnitude analyses were made for the interphase forces.
Findings
The results demonstrate that the TDF can be neglected in the running of the multiphase rotodynamic pump; the drag force is dominant in the impeller region and the outlet extended region. The sensitivity analyses of the bubble diameter and the rotational speed were also performed. It is found that larger bubble size is accompanied by smaller predicted drag but larger predicted lift and virtual mass, while the increase of the rotational speed can raise all the interphase forces mentioned above.
Originality/value
This paper has revealed the magnitude information and the relative importance of the interphase forces in a multiphase rotodynamic pump.
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Keywords
WANSHI QU, lei tan, Shuliang CAO, YUCHUAN WANG and YUN XU
The paper aims to investigate the clocking effect on a centrifugal pump with inlet guide vanes (IGVs).
Abstract
Purpose
The paper aims to investigate the clocking effect on a centrifugal pump with inlet guide vanes (IGVs).
Design/methodology/approach
The paper uses a computation fluid dynamics (CFD) framework to solve the unsteady flows in a centrifugal pump with inlet guide vanes. The relative position between the stationary vanes and the stationary volute tongue is defined as the clocking position when IGVs inside the suction pipe rotate along the circumferential direction.
Findings
The results show that clocking positions have little effect on the pump head and efficiency, however their influences are obvious for the pressure fluctuation and flow field in the centrifugal pump. The maximum difference of pressure amplitude at dominant frequency reach up to 28% on the monitoring point V8 at different clocking positions under design flow rate. For the large flow rate, the clocking effect on flow field and pressure fluctuation in centrifugal pump is similar to that of design flow rate. However, the clocking effect is nearly negligible at partial flow rate, because there are reverse flows around the tongue tip and obvious vortexes forming and developing in the impeller. Those complex phenomena interacting in the centrifugal pump make the clocking effect less evident.
Originality/value
The numerical investigation reveals the clocking effect on a centrifugal pump with inlet guide vanes, which also valuable for the stable operation and optimal design of centrifugal pumps.
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
Keywords
Shuliang Zhao and Jinshuang Li
With the development of regional economy, innovation network plays an increasingly prominent role in reducing regional innovation cost and enabling information, knowledge and…
Abstract
Purpose
With the development of regional economy, innovation network plays an increasingly prominent role in reducing regional innovation cost and enabling information, knowledge and capital flow and diffusion. Building an efficient innovation network has become a feasible way to improve regional innovation capabilities and performance. Thus, under the background of Chinese special triple helix structure, the specific mechanism of innovation network characteristics on regional innovation performance is still an issue that needs to be studied urgently.
Design/methodology/approach
This study conducts a multi-level regression analysis regional innovation panel data of China from the past four years to explore how the three dimensions of innovation network characteristics (i.e. network density, openness and strength) affect regional innovation performance.
Findings
The results show that there is an inverted-U relationship exists between network density and regional innovation performance. The network openness and regional innovation performance show a significantly positive relationship and a U-shaped relationship exists between network strength and regional innovation performance.
Research limitations/implications
First, this study examines the relationship between network density, openness, strength and innovation ability in the network variable structure. However, this study does not analyze how absorptive capacity impacts the network structure and innovation performance of regional innovators. Second, innovation network intensity largely varies according to different types of enterprises or industries. Therefore, future studies can attempt to analyze the relationship between innovation network and innovation performance on the basis of the industry or the enterprise itself. Fourth, this study does not consider the change in the influence of innovation network structure on innovation ability.
Practical implications
The results of this study provide insights for the formulation of the regional innovation policy. First, enterprises must maintain good contact with research institutes, universities and technology intermediaries and promote resource, information and money flow between networks through formal and informal interactions. Enterprises can currently only interact with a limited number of innovative subjects due to their limited resources. Therefore, we should continue implementing the open policy of foreign capital utilization and absorb the technology, knowledge, management, ideas, talent and other resource advantages in the world. The investment environment in the central and western regions should be improved as soon as possible to guide foreign direct investments to the middle and the west part of China, thereby promoting the coordinated development of regional innovation ability and economy.
Social implications
In 2015, the Chinese Government proposed “public entrepreneurship and innovation,” including technological, institutional, management and mode innovations. This study suggests that innovation subjects in the region should establish an interactive and dynamic innovation network among innovators.
Originality/value
The innovation of this study lies in the analysis of the characteristics of innovation network that significantly affect regional innovation performance, the exploration of different stages of innovation network construction path and provide theoretical guidance for the construction of innovation network.
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Shuliang Li, Ke Gong, Bo Zeng, Wenhao Zhou, Zhouyi Zhang, Aixing Li and Li Zhang
The purpose of this paper is to overcome the weakness of the traditional model, in which the grey action quantity is a real number and thus leads to a “unique solution” and to…
Abstract
Purpose
The purpose of this paper is to overcome the weakness of the traditional model, in which the grey action quantity is a real number and thus leads to a “unique solution” and to build the model with a trapezoidal possibility degree function.
Design/methodology/approach
Using the system input and output block diagram of the model, the interval grey action quantity is restored under the condition of insufficient system influencing factors, and the trapezoidal possibility degree function is formed. Based on that, a new model able to output non-unique solutions is constructed.
Findings
The model satisfies the non-unique solution principle of the grey theory under the condition of insufficient information. The model is compatible with the traditional model in structure and modelling results. The validity and practicability of the new model are verified by applying it in simulating the ecological environment water consumption in the Yangtze River basin.
Practical implications
In this study, the interval grey number form of grey action quantity is restored under the condition of insufficient system influencing factors, and the unique solution to the problem of the traditional model is solved. It is of great value in enriching the theoretical system of grey prediction models.
Social implications
Taking power consumption as an example, the accurate prediction of the future power consumption level is related to the utilization efficiency of the power infrastructure investment. If the prediction of the power consumption level is too low, it will lead to the insufficient construction of the power infrastructure and the frequent occurrence of “power shortage” in the power industry. If the prediction is too high, it will lead to excessive investment in the power infrastructure. As a result, the overall surplus of power supply will lead to relatively low operation efficiency. Therefore, building an appropriate model for the correct interval prediction is a better way to solve such problems. The model proposed in this study is an effective one to solve such problems.
Originality/value
A new grey prediction model with its interval grey action quantity based on the trapezoidal possibility degree function is proposed for the first time.
Details
Keywords
Renwen Wang, Shuliang Zhao, Wei Song, Luca Cacciolatti, Xinyue Zhang, Chris Sausman and Yelin Fu
The purpose of this paper is to investigate the effects of product substitutability on sales performance of integrated and decentralised supply chains. The authors model supply…
Abstract
Purpose
The purpose of this paper is to investigate the effects of product substitutability on sales performance of integrated and decentralised supply chains. The authors model supply chain performance effects by applying a Cournot equation to a combination of different industry configurations. The study aims to extend existing equilibria models in different supply chains by including the effects of product substitutability on supply chain performance. By extending existing equilibria models, the authors explore the relationship between the degree of product substitutability, chain structure and chain performance when some actors of the supply chain behave as Stackelberg leaders in a duopoly.
Design/methodology/approach
The paper models a supply chain performance by applying a Cournot equation to different supply chain structures in a duopoly.
Findings
The findings indicate that, for each specific-supply chain structures in different market configurations, when product substitutability reaches a certain threshold decentralised supply chains outperform integrated chains, in disagreement with common belief in current existing literature.
Research limitations/implications
The study is limited to the application of differential equations in a competitive market configured as a duopoly. Future studies might extend the same model to a competitive market characterised by more than two actors. The findings imply that current tendency of lean implementations through integrated supply chains does not always favour supply chain performance.
Practical implications
The paper includes implications for the development of a stronger differentiation strategy based on consumer value when markets are characterised by high-product substitutability.
Originality/value
These findings highlight the importance of differentiation and consumer-value generation in markets that follow Nash equilibria as opposed to the current focus on price competition.
Details
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Shuliang Zhao and Junchen Wang
Proximity is a crucial factor influencing innovation collaboration and performance. Most existing studies have primarily focused on the organizational level and been static in…
Abstract
Purpose
Proximity is a crucial factor influencing innovation collaboration and performance. Most existing studies have primarily focused on the organizational level and been static in nature. Therefore, a further study on how proximity affects innovation performance is needed. This paper aims to fill this gap by highlighting the organizational, cognitive and geographical proximity in China’s open regional innovation system.
Design/methodology/approach
This paper analyzes the data from 2010 to 2015 through path analysis.
Findings
The results reveal that geographical proximity has a direct positive effect on regional innovation performance in China’s regional innovation system. It also shows that organizational proximity exerts a negative impact on absorptive capacity, and through it adversely affects regional innovation performance. In contrast, cognitive proximity is found to have a positive effect on absorptive capacity, enhancing regional innovation performance.
Originality/value
Based on these findings, this paper contributes to a better understanding of the role of proximity in innovation collaboration and performance. By highlighting the importance of different proximity types, it provides insights for policymakers and practitioners seeking to foster regional innovation.
Details
Keywords
Shuliang Zhao and Li Liu
The impact of environmental regulations on ecological innovation is a contested issue in current research. However, there is no uniform consensus on existing conclusions. It is…
Abstract
Purpose
The impact of environmental regulations on ecological innovation is a contested issue in current research. However, there is no uniform consensus on existing conclusions. It is commonly accepted among scholars that external environment and organizational characteristics are key factors affecting ecological innovation. However, these are often analyzed in isolation, without consideration of the interaction between leadership and external environment. So this study aims to explore the impact of environmental regulation on ecological innovation by combining internal and external factors.
Design/methodology/approach
Based on institutional theory and leadership theory, this paper takes environmental regulation as the independent variable, environmental leadership as the intermediary variable and intellectual property protection level as the regulating variable to explore the impact mechanism of environmental regulation on ecological innovation.
Findings
The findings indicate an inverted U-shaped relationship between environmental regulation and ecological innovation. Additionally, there is a positive correlation between environmental leadership and intellectual property protection level with ecological innovation. Furthermore, environmental leadership partially mediates the relationship between environmental regulation and ecological innovation. However, the level of intellectual property protection does not have a significant moderating effect on the relationship between environmental leadership and ecological innovation.
Originality/value
This paper proposes suggestions for regional ecological innovation based on the current policy and research situation to promote its development.