J.J. Hwang, T.Y. Lia and S.H. Chen
Turbulent fluid flow and heat transfer characteristics are analyzed numerically for fluids flowing through a rotating periodical two‐pass square channel. The smooth walls of this…
Abstract
Turbulent fluid flow and heat transfer characteristics are analyzed numerically for fluids flowing through a rotating periodical two‐pass square channel. The smooth walls of this two‐pass channel are subject to a constant heat flux. A two‐equation k‐ε turbulence model with modified terms for Coriolis and rotational buoyancy is employed to resolve this elliptic problem. The duct through‐flow rate and rotating speed are fixed constantly; while the wall heat flux into the fluid is varied to examine the rotating buoyancy effect on the heat transfer and fluid flow characteristics. It is disclosed that the changes in local heat transfer due to the rotational buoyancy in the radially outward flow are more significant than those in the radially inward flow. However, the channel averaged heat transfer is altered slightly due to the rotational buoyancy in the both ducts. Whenever the buoyancy effects are sufficiently strong, the flow reversal appears over the leading face of the radially outward‐flow channel, and the radial distance for initiation of flow separation decreases with increasing the buoyancy parameter. A comparison of the present numerical results with the available experimental data by taking buoyancy into consideration is also presented.
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Seyyed Mostafa Hoseinalipour, Hamidreza Shahbazian and Bengt Ake Sunden
The study aims to focus on rotation effects on a ribbed channel of gas turbine blades for internal cooling. The combination and interaction between secondary flows generated by…
Abstract
Purpose
The study aims to focus on rotation effects on a ribbed channel of gas turbine blades for internal cooling. The combination and interaction between secondary flows generated by angled rib geometry and Coriolis forces in the rotating channel are studied numerically.
Design/methodology/approach
A radially outward flow passage as an internal cooling test model with and without ribs is used to perform the investigation. Aspect ratio of the passage is 1:1. Square ribs with e/Dh = 0.1, p/e = 10 and four various rib angles of 90°, 75°, 60° and 45° are configured on both the leading and trailing surfaces along the rotating duct. The study covers a Reynolds number of 10,000 and Rotation number in the range of 0-0.15.
Findings
Nusselt numbers in the ribbed duct are 2.5 to 3.5 times those of a smooth square duct, depending on the Rotation number and rib angle. The maximum value is attained for the 45° ribbed surface. The synergy angle between the velocity and temperature gradients is improved by the angled rib secondary flows and Coriolis vortex. The decrease of the synergy angle is 8.9, 13.4, 12.1 and 10.1 per cent for the 90°, 75°, 60° and 45° ribbed channels with rotation, respectively. Secondary flow intensity is increased by rotation in the 90° and 75° ribbed ducts and is decreased in 45° and 60° ribbed cases for which the rib-induced secondary flow dominates.
Originality/value
The primary motivation behind this work is to investigate the possibility of heat transfer enhancement by vortex flow with developing turbulence in the view point of the field synergy principle and secondary flow intensity.
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Zhiqi Zhao, Lei Luo, Dandan Qiu, Songtao Wang, Zhongqi Wang and Bengt Ake Sunden
This study aims to explore the 3 D separated flow fields and heat transfer characteristics at the end wall of a serpentine channel with various turn clearances using topological…
Abstract
Purpose
This study aims to explore the 3 D separated flow fields and heat transfer characteristics at the end wall of a serpentine channel with various turn clearances using topological analysis and critical points principles of three-dimensional vortex flow.
Design/methodology/approach
This aims to explore the 3 D separated flow fields and heat transfer characteristics at the end wall of a serpentine channel with various turn clearances using topological analysis as well as critical points principles of three-dimensional vortex flow.
Findings
The endwall heat transfer in the narrow spacing passage is significantly stronger than that in a wide spacing channel. As the gap clearance is kept at 0.87 times of the hydraulic diameter, the endwall heat transfer and thermal performance can be accordingly enhanced with low pressure drops, which is because a relatively strong concentrated impingement flow for the medium gap clearance helps to restrain the downstream fluid flow and enhance the shear effect of the secondary flow.
Practical implications
The numerical results can be applied in designing sharp turn of serpentine channel in heat exchangers, heat sinks, piping system, solar receiver and gas turbine blades.
Originality/value
The evolution mechanism of the vortices in the turning region under different gap clearance was analyzed, and thermal enhancement characteristics were predicted innovatively using topological analysis method.
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Andrew Powl and Martin Skitmore
It has been said that the effective performance of the Project Manager (PM) is the single most critical factor affecting successful project outcomes. Little is known, however, of…
Abstract
It has been said that the effective performance of the Project Manager (PM) is the single most critical factor affecting successful project outcomes. Little is known, however, of the nature and extent of the hindrances to PM effectiveness in the Construction Industry (CI). This paper reports on the results of a worldwide survey of PMs concerning these issues and shows that they have the potential to be more effective and more productive in their working. Associated with this is a need to be more aware of progress and developments in the CI generally, more aware of progress and developments in their own organization, more delegation of contract administration tasks and more general administrative support. Also highlighted is the lengthy working hours of PMs.
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Yaw A. Debrah and Ian G. Smith
Presents over sixty abstracts summarising the 1999 Employment Research Unit annual conference held at the University of Cardiff. Explores the multiple impacts of globalization on…
Abstract
Presents over sixty abstracts summarising the 1999 Employment Research Unit annual conference held at the University of Cardiff. Explores the multiple impacts of globalization on work and employment in contemporary organizations. Covers the human resource management implications of organizational responses to globalization. Examines the theoretical, methodological, empirical and comparative issues pertaining to competitiveness and the management of human resources, the impact of organisational strategies and international production on the workplace, the organization of labour markets, human resource development, cultural change in organisations, trade union responses, and trans‐national corporations. Cites many case studies showing how globalization has brought a lot of opportunities together with much change both to the employee and the employer. Considers the threats to existing cultures, structures and systems.
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Cheryl Leo, Rebekah Bennett and Charmine E.J. Härtel
This article compares consumer decision‐making styles between Singaporeans and Australians. Utilising Hofstede’s framework, the paper argues that cultural dimensions influence…
Abstract
This article compares consumer decision‐making styles between Singaporeans and Australians. Utilising Hofstede’s framework, the paper argues that cultural dimensions influence consumer decision making styles. It is essential that managers understand cross‐cultural consumer decision‐making styles to make strategic decisions or effectively handle members of these nationalities. Marked differences were found between the two populations for: brand consciousness, innovativeness and overchoice confusion. The results suggest that some consumer decision‐making styles differ due to consumers’ cultural values. Managerial implications and future research directions are discussed.
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This study aims to propose a method for monitoring bearing health in the time–frequency domain, termed the Lock-in spectrum, to track the evolution of bearing faults over time and…
Abstract
Purpose
This study aims to propose a method for monitoring bearing health in the time–frequency domain, termed the Lock-in spectrum, to track the evolution of bearing faults over time and frequency.
Design/methodology/approach
The Lock-in spectrum uses vibration signals captured by vibration sensors and uses a lock-in process to analyze specified frequency bands. It calculates the distribution of signal amplitudes around fault characteristic frequencies over short time intervals.
Findings
Experimental results demonstrate that the Lock-in spectrum effectively captures the degradation process of bearings from fault inception to complete failure. It provides time-varying information on fault frequencies and amplitudes, enabling early detection of fault growth, even in the initial stages when fault signals are weak. Compared to the benchmark short-time Fourier transform method, the Lock-in spectrum exhibits superior expressive ability, allowing for higher-resolution, long-term monitoring of bearing condition.
Originality/value
The proposed Lock-in spectrum offers a novel approach to bearing health monitoring by capturing the dynamic evolution of fault frequencies over time. It surpasses traditional methods by providing enhanced frequency resolution and early fault detection capabilities.
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Dr Chamila D.D. Ramanayaka and Associate Professor Monty Sutrisna
In a world where every competitive advantage must be fully exploited, productive diversity – utilising Australia’s linguistic and cultural diversity to economic benefit – offers a…
Abstract
In a world where every competitive advantage must be fully exploited, productive diversity – utilising Australia’s linguistic and cultural diversity to economic benefit – offers a practical resource, which no organisation, including government, can afford to ignore. Astute employers have begun to tap this resource – people who speak the language, understand the culture and often maintain business and personal contacts in countries where they want to do business. The respondents in this research tell the story of the potential bottom line value of this unique human resource, termed productive diversity (that has been coined to describe the use of our language, skills and cultural diversity for economic benefit). This is a resource‐based study focussing on cultural resources and links to the country of origin as a sustained competitive advantage and a strategy for success of the ethnic business operations in Australia. It presents case studies/stories of ethnic entrepreneurs who have succeeded in business through productive diversity.