Effect of nozzle pressure ratio and control jets location to control base pressure in suddenly expanded flows

Pathan, Khizer Ahmed and Dabeer, Prakash S and Khan, Sher Afghan (2019) Effect of nozzle pressure ratio and control jets location to control base pressure in suddenly expanded flows. Journal of Applied Fluid Mechanics, 12 (4). pp. 1127-1135. ISSN 1735-3572 E-ISSN 1735-3645

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Abstract

In this paper, computational fluid dynamic (CFD) analysis and experiments have been carried out to study the effect of nozzle pressure ratio, i.e. the ratio of inlet pressure to atmospheric pressure, and the pitch circle diameter of the control jets to regulate the base pressure. The variables considered for the analysis as well as the experiments are the nozzle pressure ratio (NPR), the Mach number (M) and the pitch circle diameter (PCD) of the control jets. The area ratio considered for the study is kept constant at 4.84 while the length to diameter (L/D) ratio of an enlarged duct is set constant at 5. The inertia parameter considered for the study is the Mach number. The Mach numbers considered for the study are 1.5, 2.0, and 2.5. The nozzle pressure ratio considered for the study is 2, 5 and 8. Three different pitch circle diameters of control jets considered for the study are 13.1 mm, 16.2 mm and 19.3 mm. From the numerical simulations and the results of the experimental tests, it is found that the control jets are very beneficial to increase the base pressure at higher NPR when the jets issuing from the nozzles are under-expanded. The control jets were able to increase the base pressure value from 160% to 400% at a nozzle pressure ratio 8. It is concluded that the parameter D3 is the most effective pitch circle diameter of the control jets to increase the base pressure.

Item Type:	Article (Journal)
Additional Information:	7395/72736
Uncontrolled Keywords:	Base pressure; Mach number; PCD of control jets; Nozzle pressure ratio
Subjects:	T Technology > TL Motor vehicles. Aeronautics. Astronautics > TL780 Rockets
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button):	Kulliyyah of Engineering Kulliyyah of Engineering > Department of Mechanical Engineering
Depositing User:	Prof. Dr. Sher Afghan Khan
Date Deposited:	20 Jun 2019 08:27
Last Modified:	02 Apr 2020 23:12
URI:	http://irep.iium.edu.my/id/eprint/72736

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