Experimental and numerical heat transfer investigation of reverse jet impingement

Ahmed, Abdallah (2023) Experimental and numerical heat transfer investigation of reverse jet impingement. PhD thesis, University of Nottingham.

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Abstract

This project aimed to study heat transfer and flow in double wall aerofoil cooling using two primary studies: a novel jet impingement cooling geometry and a typical film cooling arrangement. Experimental testing with thermochromic liquid crystal validated numerical work using ANSYS Fluent.

A novel ‘reverse’ jet impingement geometry was developed to enhance heat transfer performance, comprising of a ‘dimple’ target enclosed within a cylindrical ‘silo’. Experimental variations included Reynolds number range of 10,000 to 70,000, jet-to-target, crossflow condition, and an extended nozzle geometry. An overall enhancement of heat transfer was achieved with the novel geometry, with optimum jet to target spacing found at around 4 jet diameters, and some reduction in crossflow effects were observed.

A numerical investigation validated against experimental data for a novel 'reverse' jet impingement geometry was conducted. Optimizations in jet-to-jet and jet-to-target spacing were found, but no significant optimization of inlet condition was observed. The effect of outlet condition on discharge coefficient was significant, with an optimum nozzle length of 1 jet diameter for heat transfer enhancement. Staggered and inline dimples were shown to provide similar enhancements to heat transfer, significantly compared to a traditional flat plate target.

The study evaluated heat transfer and discharge coefficients in a scaled cylindrical film cooling channel with varied Reynolds number, entry sharpness, inclination, and rotation angle.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Yan, Yuying
Keywords: Heat Transfer; Jet Impingement; Transient Liquid Crystal
Subjects: T Technology > TL Motor vehicles. Aeronautics. Astronautics
Faculties/Schools: UK Campuses > Faculty of Engineering
Item ID: 74017
Depositing User: Ahmed, Abdallah
Date Deposited: 31 Dec 2023 04:40
Last Modified: 31 Dec 2023 04:40
URI: https://eprints.nottingham.ac.uk/id/eprint/74017

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