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Active control of suddenly expanded flows from overexpanded nozzles

Khan, Sher and Rathakrishnan, E. (2002) Active control of suddenly expanded flows from overexpanded nozzles. International Journal of Turbo & Jet-Engines, 19 (1-2). pp. 119-126. ISSN 0334-0082 E-ISSN 2191-0332

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An experimental investigation was carried out to study the effectiveness of micro-jets to control base pressure in suddenly expanded axi-symmetric ducts. Four micro-jets of 1 mm orifice diameter located at 90$^\circ$ interval along a pitch circle diameter of 1.3 times the nozzle exit diameter in the base region was employed as active controls. The Mach numbers of the suddenly expanded flows were studies 2.0, 2.5 and 3.0. The jets were expanded suddenly into an axi-symmetric tube with cross-sectional area 2.56, 3.24, 4.84, and 6.25 times that of nozzle exit diameter. The length-to-diameter ratio of the sudden expansion tube was varied from 10 to 1. The jets were operated at an over expansion level of Pe/Pa = 0.277. The wall pressure distribution in the suddenly enlarged duct was also measured. It is found that the micro-jets can serve as active controllers for base pressure. Also, the wall pressure distribution is not adversely influenced by the micro-jets. From the present investigation it is evident that for a given Mach number and nozzle pressure ratio one can identify the enlargement length to diameter ratio which will result in maximum increase/decrease of base pressure.

Item Type: Article (Journal)
Additional Information: 7395/46690
Uncontrolled Keywords: Microjets,pressure control,
Subjects: T Technology > TL Motor vehicles. Aeronautics. Astronautics
Kulliyyahs/Centres/Divisions/Institutes (Can select more than one option. Press CONTROL button): Kulliyyah of Engineering > Department of Mechanical Engineering
Depositing User: Prof. Dr. Sher Afghan Khan
Date Deposited: 16 Feb 2016 10:39
Last Modified: 15 Jul 2016 07:48
URI: http://irep.iium.edu.my/id/eprint/46690

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