The purpose of this paper is to investigate the thermal performance of the cooling plates with conventional straight channel and wavy channel designs.
Abstract
Purpose
The purpose of this paper is to investigate the thermal performance of the cooling plates with conventional straight channel and wavy channel designs.
Design/methodology/approach
A three-dimensional model involving coupled fluid flow and heat transfer processes is developed to study the thermal performance of the cooling plates. The effects of wavelength and amplitude on the cooling performance are also studied. In addition, two novel wavy channels with varying wavelength are proposed and investigated.
Findings
The simulated results are compared in terms of pressure drop, average temperature, maximum surface temperature, temperature difference between the maximum temperature and minimum temperature and surface temperature uniformity index. It is concluded that the cooling performance is significantly improved by the wavy channel.
Practical implications
The current study can improve the understanding of transport characterization of the cooling plates with wavy channel design and provide guidelines for the design of cooling plates.
Originality/value
The design of cooling plates with wavy channels can be used in proton exchange membrane fuel cells to improve the cooling performance.
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Keywords
Weiqiang Kong, Qiuwan Shen, Naibao Huang, Min Yan and Shian Li
The purpose of this study is to investigate the effect of catalyst distribution in the combustion catalytic layer on heat and mass transport characteristics of the auto-thermal…
Abstract
Purpose
The purpose of this study is to investigate the effect of catalyst distribution in the combustion catalytic layer on heat and mass transport characteristics of the auto-thermal methanol steam reforming microchannel reactor.
Design/methodology/approach
Computational fluid dynamics (CFD) method is used to study four different gradient designs. The corresponding distributions of temperature, species and chemical reaction rate are provided and compared.
Findings
The distributions of species, temperature and chemical reaction rate are significantly affected by the catalyst distribution in the combustion catalytic layer. A more uniform temperature distribution can be observed when the gradient design is used. Meanwhile, the methanol conversion rate is also improved.
Practical implications
This work reveals the effect of catalyst distribution in the combustion catalytic layer on heat and mass transport characteristics of the auto-thermal methanol steam reforming microchannel reactor and provides guidance for the design of reactors.
Originality/value
The temperature uniformity and hydrogen production performance can be improved by the gradient design in the combustion catalytic layer.
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Shian Li, Chongyang Wang, Qiuwan Shen, Yuanzhe Cheng, Chengdong Peng, Guogang Yang and Bengt Ake Sunden
The purpose of this study is to design a new type of cold plate to improve the thermal performance of liquid-cooled thermal management system of lithium-ion batteries.
Abstract
Purpose
The purpose of this study is to design a new type of cold plate to improve the thermal performance of liquid-cooled thermal management system of lithium-ion batteries.
Design/methodology/approach
A cold plate with leaf type channels is proposed to enhance the cooling performance. Effects of the leaf type channel parameters (i.e. channel angle 20°, 40°, 60°, 80°; coolant mass flow rate 0.25 × 10–3, 0.50 × 10–3, 0.75 × 10–3, 1.00 × 10–3, 1.25 × 10–3 kg·s−1; channel number 1, 3, 5, 7) on the performance are numerically investigated by using a 3D mathematical model.
Findings
Compared to the traditional I type channels, the leaf type channels have better cooling performance. It is found that the battery temperature variation and channel pressure drop are decreased with decreasing channel angle and increasing channel number. In addition, the cooling performance can be improved by increasing the coolant mass flow rate.
Practical implications
This study can provide guidance for the development of novel effective cold plates.
Originality/value
The design of cold plates with leaf type channels can be used in liquid-cooled thermal management system to reduce the battery temperature difference.
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Keywords
Shian Li, Yuanzhe Cheng, Qiuwan Shen, Chongyang Wang, Chengdong Peng and Guogang Yang
The purpose of this study is to improve the thermal management of lithium-ion batteries. The phase change material (PCM) cooling does not require additional equipment to consume…
Abstract
Purpose
The purpose of this study is to improve the thermal management of lithium-ion batteries. The phase change material (PCM) cooling does not require additional equipment to consume energy. To improve the heat dissipation capacity of batteries, fins are added in the PCM to enhance the heat transfer process.
Design/methodology/approach
Computational fluid dynamics method is used to study the influence of number of vertical fins and ring fins (i.e. 2, 4, 6 and 8 vertical fins, and 2, 3, 4 and 5 ring fins) and the combination of them on the cooling performance.
Findings
The battery maximum temperature can be decreased by the PCM with vertical or ring fins, and it can be further decreased by the combination of them. The PCM with eight vertical fins and five ring fins reduces the battery maximum temperature by 5.21 K. In addition, the temperature and liquid-phase distributions of the battery and PCM are affected by the design of the cooling system.
Practical implications
This work can provide guidelines for the development of new and efficient PCM cooling systems for lithium-ion batteries.
Originality/value
The combination of PCM and fins can be used to reduce the battery maximum temperature and temperature difference.
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Keywords
Shian Li, Zhi Yang, Yihui Liu, Qiuwan Shen, Guogang Yang and Bengt Ake Sunden
The purpose of this paper is to investigate the heat and mass transport characteristics in microchannel reactors with non-uniform catalyst distributions.
Abstract
Purpose
The purpose of this paper is to investigate the heat and mass transport characteristics in microchannel reactors with non-uniform catalyst distributions.
Design/methodology/approach
A two-dimensional model is developed to study the heat and mass transport characteristics in microchannel reactors. The heat and mass transport processes in the microchannel reactors with non-uniform catalyst distribution in the catalytic combustion channel are also studied.
Findings
The simulated results are compared in terms of the distributions of species mole fraction, temperature and reaction rate for the conventional and new designed reactors. It is found that the chemical reaction, heat and mass transport processes are significantly affected and the maximum temperature in the reactor is also greatly reduced when a non-uniform catalyst distribution is applied in the combustion catalyst layer.
Practical implications
This study can improve the understanding of the transportation characteristics in microchannel reactors with non-uniform catalyst distributions and provide guidance for the design of microchannel reactors.
Originality/value
The design of microchannel reactors with non-uniform catalyst distributions can be used in methane steam reforming to reduce the maximum temperature inside the reactor.
Details
Keywords
Shian Li, Gongnan Xie and Bengt Sunden
The employment of continuous ribs in a passage involves a noticeable pressure drop penalty, while other studies have shown that truncated ribs may provide a potential to reduce…
Abstract
Purpose
The employment of continuous ribs in a passage involves a noticeable pressure drop penalty, while other studies have shown that truncated ribs may provide a potential to reduce the pressure drop while keeping a significant heat transfer enhancement. The purpose of this paper is to perform computer-aided simulations of turbulent flow and heat transfer of a rectangular cooling passage with continuous or truncated 45-deg V-shaped ribs on opposite walls.
Design/methodology/approach
Computational fluid dynamics technique is used to study the fluid flow and heat transfer characteristics in a three-dimensional rectangular passage with continuous and truncated V-shaped ribs.
Findings
The inlet Reynolds number, based on the hydraulic diameter, is ranged from 12,000 to 60,000 and a low-Re k-e model is selected for the turbulent computations. The local flow structure and heat transfer in the internal cooling passages are presented and the thermal performances of the ribbed passages are compared. It is found that the passage with truncated V-shaped ribs on opposite walls provides nearly equivalent heat transfer enhancement with a lower (about 17 percent at high Reynolds number of 60,000) pressure loss compared to a passage with continuous V-shaped ribs or continuous transversal ribs.
Research limitations/implications
The fluid is incompressible with constant thermophysical properties and the flow is steady. The passage is stationary.
Practical implications
New and additional data will be helpful in the design of ribbed passages to achieve a good thermal performance.
Originality/value
The results imply that truncated V-shaped ribs are very effective in improving the thermal performance and thus are suggested to be applied in gas turbine blade internal cooling, especially at high velocity or Reynolds number.
Details
Keywords
Gongnan Xie, Shian Li, Bengt Sunden and Weihong Zhang
With the development of electronic devices, including the desires of integration, miniaturization, high performance and the output power, cooling requirement of chips have been…
Abstract
Purpose
With the development of electronic devices, including the desires of integration, miniaturization, high performance and the output power, cooling requirement of chips have been increased gradually. Water-cooled minichannel is an effective cooling technology for cooling of heat sinks. The minichannel flow geometry offers large surface area for heat transfer and a high convective heat transfer coefficient with only a moderate pressure loss. The purpose of this paper is to analyze a minichannel heat sink having the bottom size of 35 mm×35 mm numerically. Two kinds of chip arrangement are investigated: diagonal arrangement and parallel arrangement.
Design/methodology/approach
Computational fluid dynamics (CFD) technique is used to investigate the flow and thermal fields in forced convection in a three-dimensional minichannels heat sink with different chip arrangements. The standard k-e turbulence model is applied for the turbulence simulations on the minichannel heat sink.
Findings
The results show that the bottom surface of the heat sink with various chip arrangements will have different temperature distribution and thermal resistance. A suitable chip arrangement will achieve a good cooling performance for electronic devices.
Research limitations/implications
The fluid is incompressible and the thermophysical properties are constant.
Practical implications
New and additional data will be helpful as guidelines in the design of heat sinks to achieve a good thermal performance and a long lifetime in operation.
Originality/value
In real engineering situations, chips are always placed in various manners according to design conditions and constraints. In this case the assumption of uniform heat flux is acceptable for the surfaces of the chips rather than for the entire bottom surface of the heat sink.
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Hannah‐Hanh D. Nguyen and Jie Yang
The main research purposes of this paper are to: conceptualize Chinese conflict management behaviors as contingent on the hierarchical relations of conflict parties in an…
Abstract
Purpose
The main research purposes of this paper are to: conceptualize Chinese conflict management behaviors as contingent on the hierarchical relations of conflict parties in an organizational context; and investigate individual characteristics as moderators in this contingency framework.
Design/methodology/approach
This emic study consisted of two steps: using nine subject matter experts to develop conflict scenarios and conflict management strategies, and using this instrument to collect data from 704 actual employees across China. Multinomial logistic analysis was used to analyze respondents' choice of strategies.
Findings
The findings supported the hypotheses. Chinese role‐playing a supervisor in a conflict with their subordinate tended to use direct, assertive strategies to resolve the conflict, but the results depended on age, education, gender, region and work experience. As a subordinate in a conflict with their supervisor, Chinese chose indirect, harmony‐preserving strategies, particularly when they were older and more interaction adept. In a conflict with a peer, respondents used a broader spectrum of conflict management strategies, depending on their individual characteristics. No “best practices” were found or universal strategies adopted.
Research limitations/implications
The limitations include the lack of random sampling and a scenario‐based method. The emic evidence for a contingency perspective of conflict resolution framework was provided. The conflict scenarios may be used in organizational training of conflict management.
Originality/value
Conflict scenarios and management strategies developed by local subject matter experts were used to evaluate Chinese workers' choices of conflict management strategies. The findings call for the re‐conceptualization of conflict management strategies as a contingent and culture‐specific construct.
Details
Keywords
Yi‐Chan Chung, Chih‐Hung Tsai, Shiaw‐Wen Tien and Lin‐Yi Lin
Customer Support Knowledge of Customer Support Organization is one of the important assets of enterprises and “Customer Support Knowledge Management” is also the critical aspect…
Abstract
Customer Support Knowledge of Customer Support Organization is one of the important assets of enterprises and “Customer Support Knowledge Management” is also the critical aspect of Business Knowledge Management; however, the attributes of Customer Support Knowledge are complicated, diverse, renewed rapidly and difficult to be managed. Thus, in order to design a successful Customer Support Knowledge Management System, apart from the consideration of “human” and “information technology” aspects, the concerns of attributes and Customer Support Knowledge and industry characteristics should be involved for meeting the requirements of Customer Support Organization and allowing the organization to acquire the competitive advantage of “Differentiation Service”. This research used the “Customer Support Knowledge Management System” in a high‐tech industry as an example and treated the end users of medical instruments in different types of hospitals in Taiwan which have received the support service of our company in recent six months as the population. The end users were mostly the nursing executives or ultrasonic wave technical personnel in intensive care unit and they had similar educational background and incomes and adopted the medical instruments such as physical supervision system, ultrasonic wave system, heart start or ECG machine produced by our company; the research method was to randomly treat the investigation results of the telephone customers’ satisfaction from respective 30 end users in the population three months before and after this system execution as the samples and use hypotheses to validate if the end users’ customer satisfaction significantly improved in terms of “Remote Support,” “On‐site Support,” “Service Turn Around time,” “Technical Competence” and “Service Manner” in order to understand the influence and managerial significance of execution of “Customer Support Knowledge Management System” on Customer Support Organization.