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Article
Publication date: 31 December 2021

Hakan Coşanay, Hakan F. Öztop, Muhammed Gür and Eda Bakır

The purpose of this study is to make a numerical analysis of a wall jet with a moving wall attached with a heated body. The hot body is cooled via impinging wall jet. Thus, a jet…

283

Abstract

Purpose

The purpose of this study is to make a numerical analysis of a wall jet with a moving wall attached with a heated body. The hot body is cooled via impinging wall jet. Thus, a jet cooling problem is modeled. The Reynolds number is taken in three different values between 5 × 103 ≤ Re ≤ 15 × 103. The h/H ratio for each value of the Re number was taken as 0.02, 0.04 and 0.0, respectively.

Design/methodology/approach

Two-dimensional impinged wall jet problem onto a moving body on a conveyor is numerically studied. The heated body is inserted onto an adiabatic moving wall, and it moves in +x direction with the wall. Governing equations for turbulent flow are solved by using the finite element method via analysis and system Fluent R2020. A dynamic mesh was produced to simulate the moving hot body.

Findings

The obtained results showed that the heat transfer (HT) is decreased with distance between the jet outlet and the jet inlet. The best HT occurred for the parameters of h/H = 0.02 and Re = 15 × 103. Also, HT can be controlled by changing the h/H ratio as a passive method.

Originality/value

Originality of this work is to make an analysis of turbulent flow and heat transfer for wall jet impinging onto a moving heated body.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 32 no. 9
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 30 January 2025

Muhammed Gur, Hakan Oztop, Nirmalendu Biswas and Fatih Selimefendigil

The purpose of this study is to investigate the impact of swirling jet flow on the cooling performance of a heated rectangular prism placed within a channel. The primary aim is to…

42

Abstract

Purpose

The purpose of this study is to investigate the impact of swirling jet flow on the cooling performance of a heated rectangular prism placed within a channel. The primary aim is to explore the influence of varying aspect ratios (AR) of the prism and different fluid Reynolds numbers (Re) on the cooling efficiency.

Design/methodology/approach

The numerical analysis is performed using a finite volume-based solver, which incorporates the large eddy simulations (LES) turbulence model. The setup consists of twin 45° swirling jets directed at isothermally heated bodies, with water used as the cooling medium. The rectangular prism is oriented perpendicularly to the channel flow direction, positioned one unit distance from the inlet. This study examines three distinct aspect ratios (AR = 0.5, 1 and 1.5) and a range of Reynolds numbers (6000 = Re = 20000).

Findings

The results indicate that cooling efficiency improves as the aspect ratio decreases and the Reynolds number increases. Higher Reynolds numbers enhance jet impingement and turbulent mixing, which are crucial for efficient heat transfer. Conversely, lower Reynolds numbers lead to diminished impingement and reduced cooling efficiency. Increasing the Reynolds number from 6000 to 20000 elevates the average Nusselt number by 35% (for AR = 0.5) and up to 45% (for AR = 1.5). It was observed that lower aspect ratios produce superior cooling effects due to intensified localized jet interactions.

Originality/value

This research significantly contributes to the fields of fluid dynamics and thermal engineering by elucidating the influence of swirling jet flows on the cooling of heated surfaces. The findings offer valuable insights for optimizing the design and performance of cooling systems across various industrial applications.

Details

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

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Article
Publication date: 3 July 2023

Hakan F. Oztop, Muhammed Gür, Fatih Selimefendigil and Hakan Coşanay

The purpose of this study is to do a numerical analysis of the jet to a body filled with phase change material (PCM). The melting of the PCM filled body was investigated by the…

174

Abstract

Purpose

The purpose of this study is to do a numerical analysis of the jet to a body filled with phase change material (PCM). The melting of the PCM filled body was investigated by the hot jet flow. Four different values of the Reynolds number were taken, ranging from 5 × 103 = Re = 12.5 103. Water, Al2O3 1%, Al2O3 2% and hybrid nanofluid (HNF; Al2O3–Ag mixture) were used as fluid types and the effects of fluid type on melting were investigated. At 60 °C, the jet stream was impinged on the PCM filled body at different Reynolds numbers.

Design/methodology/approach

Two-dimensional analysis of melting of PCM inserted A block via impinging turbulent slot jet is numerically studied. Governing equations for turbulent flow are solved by using the finite element method via analysis and system fluent R2020.

Findings

The obtained results showed that the best melting occurred when the Reynolds number increased and the HNF was used. However, the impacts of using alumina-water nanofluid were slight. At Re = 12,500, phase completion time was reduced by about 13.77% when HNF was used while this was only 3.93% with water + alumina nanofluid as compared to using only water at Re = 5,000. In future studies, HNF concentrations will change the type of nanoenhanced PCMs. In addition, the geometry and jet parameters of the PCM-filled cube can be changed.

Originality/value

Effects of impinging jet onto PCM filled block and control of melting via impinging hot jet of PCM. Thus, novelty of the work is to control of melting in a block by impinging hot jet and nanoparticles.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 33 no. 10
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 23 July 2024

Sadia Anwar and Ummi Naiemah Saraih

Establishing an effective educational system is directly tied to academic leadership, a multifaceted concept that differs from one environment to another. The purpose of this…

429

Abstract

Purpose

Establishing an effective educational system is directly tied to academic leadership, a multifaceted concept that differs from one environment to another. The purpose of this research is to investigate the role of digital leadership (DL) aspects in the enhancement of technical knowledge sharing (KS) and dealing with emotional intelligence (EI) among the teaching faculty of higher education institutions (HEIs).

Design/methodology/approach

Following a quantitative and cross-sectional research design, convenient sampling is employed for data collection via a self-administered questionnaire from 320 faculty members of private HEIs in Pakistan.

Findings

Structural equation model (SEM) is used for path analysis. The results reveal a positive and significant effect of DL, aspects like visionary leadership (VL), digital citizenship (DC), systematic improvement (SI), on knowledge sharing (KS), and emotional intelligence (EI).

Practical implications

This study has highlighted the significance of DL in private HEIs. The findings of the study imply that institutional heads of higher education institutions (HEIs) can successfully manage the knowledge assets that they have and those of their staff members, ensure the successful adoption of technology and foster product and process innovation that improves organizational performance and integrates successful strategies into the educational system by demonstrating DL aspects. The research also analyzes institutional heads' present leadership strategies to enhance response to technological change and innovations, which are considered fundamental pillars of organizational success. Ultimately, this will extend the literature on adopting DL techniques towards digital transformation in the education system.

Originality/value

This study empirically confirms the role of DL aspects such as VL, DC, and SI towards KS and EI. Most of the research demonstrates the direct impact of DL on EI, whereas the aspects of DL are not directly related to KS and EI. Studies have also shown how DL enhances its role in incorporating leadership in organizations, industries, and education, mainly in Western countries. This research addresses the gap in understanding the direct effects of DL aspects on KS and EI in non-Western countries, particularly within the education sector.

Details

International Journal of Educational Management, vol. 38 no. 6
Type: Research Article
ISSN: 0951-354X

Keywords

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