Date of Award

Fall 1996

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Mechanical & Aerospace Engineering

Program/Concentration

Mechanical Engineering

Committee Director

Ayodeji O. Demuren

Committee Member

Surendra N. Tiwari

Committee Member

Arthur C. Taylor III

Committee Member

Saied Emani

Call Number for Print

Special Collections; LD4331.E56 Y68

Abstract

The impetus of this technical document is to report results of aerothermodynamic cooling of a scramjet nozzle under favorable pressure gradients. The goals of film cooling are to protect the nozzle skin from the high enthalpy combustor flow, reduce regenerative cooling requirements, and decrease nozzle skin friction. A hypersonic nozzle configuration for which experimental data exists was selected as the basis of this numerical study. As a first step, the numerical results of film cooling along a flat plate are compared to previous literature to validate the numerical model. Subsequently, computations are performed to study the effects of varying the nozzle expansion angle, the nozzle wall temperature, and the injectant mass flux ratio. The simulated numerical results are used to compare the durability of film cooling under a favorable pressure gradient to those results obtained in the absence of pressure gradients, and to previous experimental data. Computed results are in excellent agreement with measured wall pressure and wall heat flux data. Film cooling is shown to be highly effective in reducing convective heat transfer to the nozzle surface and in reducing shear stress in a nozzle flowfield that involves a highly expanding flow with relatively low mixing of the film. Favorable pressure gradients, regardless of strength, have a beneficial effect on film cooling effectiveness in the region of the film injection, and more importantly, in the far downstream region.

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In Copyright. URI: http://rightsstatements.org/vocab/InC/1.0/ This Item is protected by copyright and/or related rights. You are free to use this Item in any way that is permitted by the copyright and related rights legislation that applies to your use. For other uses you need to obtain permission from the rights-holder(s).

DOI

10.25777/9mfk-n261

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