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A numerical study of mist-air film cooling on a 3-D flat plate

Srinivas M.V.V. (Department of Mechanical Engineering, Shiv Nadar (Institution of Eminence Deemed to be University)- Delhi NCR, India)
Mudragada Hari Surya (Department of Mechanical Engineering, Shiv Nadar (Institution of Eminence Deemed to be University)- Delhi NCR, India)
Devendra Pratap Singh (Department of Mechanical Engineering, Shiv Nadar (Institution of Eminence Deemed to be University)- Delhi NCR, India)
Pratibha Biswal (Department of Chemical Engineering, Indian Institute of Petroleum and Energy, Visakhapatnam, India)
Sathi Rajesh Reddy (Department of Mechanical Engineering, Shiv Nadar (Institution of Eminence Deemed to be University)- Delhi NCR, India)

International Journal of Numerical Methods for Heat & Fluid Flow

ISSN: 0961-5539

Article publication date: 5 December 2022

18

Abstract

Purpose

The purpose of this study is to explore the mist-air film cooling performance on a three-dimensional (3-D) flat plate. In mist-air film cooling technique, a small amount of water droplets is injected along with the coolant air. The objective is to study the influence of shape of the coolant hole and operating conditions on the cooling effectiveness.

Design/methodology/approach

In this study, 3-D numerical simulations are performed. To simulate the mist-air film cooling over a flat plate, air is considered as a continuous phase and mist is considered as a discrete phase. Turbulence in the flow is accounted using Reynolds averaged Navier–Stokes equation and is modeled using k–e model with enhanced wall treatment.

Findings

The results of this study show that, for cylindrical coolant hole, coolant with 5% mist concentration is not effective for mainstream temperatures above 600 K, whereas for fan-shaped hole, even 2% mist concentration has shown significant impact on cooling effectiveness for temperatures up to 1,000 K. For given mist-air coolant flow conditions, different trend in effectiveness is observed for cylindrical and fan-shaped coolant hole with respect to main stream temperature.

Research limitations/implications

This study is limited to a flat plate geometry with single coolant hole.

Practical implications

The motivation of this study comes from the requirement of high efficiency cooling techniques for cooling of gas turbine blades. This study aims to study the performance of mist-air film cooling at different geometric and operating conditions.

Originality/value

The originality of this study lies in studying the effect of parameters such as mist concentration, droplet size and blowing ratio on cooling performance, particularly at high mainstream temperatures. In addition, a systematic performance comparison is presented between the cylindrical and fan-shaped cooling hole geometries.

Keywords

Acknowledgements

Funding: No funding was received to assist with the preparation of this manuscript.

Conflicts of interest/Competing interests: The authors have no conflicts of interest to declare. All co-authors have seen and agree with the contents of the manuscript, and there is no financial interest to report. We certify that the submission is original work and is not under review at any other publication.

Availability of data and material: The authors confirm that the data supporting the findings of this study are available within the article [and/or] its supplementary materials.

Consent for publication: I give my consent for the publication of identifiable details, which can include photograph(s) and/or videos and/or case history and/or details within the text (“Material”) to be published in the Journal International Journal of Numerical Methods for Heat and Fluid Flow.

Citation

M.V.V., S., Hari Surya, M., Singh, D.P., Biswal, P. and Reddy, S.R. (2022), "A numerical study of mist-air film cooling on a 3-D flat plate", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. ahead-of-print No. ahead-of-print. https://doi.org/10.1108/HFF-06-2022-0328

Publisher

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Emerald Publishing Limited

Copyright © 2022, Emerald Publishing Limited

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