Combined effect of relief and level of expansion in a suddenly expanded flow

This paper presents the experimental results on the flow characteristics of a suddenly expanded flow from the convergent nozzle for subsonic, sonic and sonic under expanded flow. In the present study micro jets were used to investigate the effect of micro jets on base pressure flow field in the enla...

Full description

Bibliographic Details
Main Authors:	Syed, Syed Ashfaq, Khan, Sher Afgha
Format:	Article
Language:	English
Published:	International Organisation of Scientific Research (IOSR) 2015
Subjects:	TL500 Aeronautics TL780 Rockets TL787 Astronautics U Military Science (General)
Online Access:	http://irep.iium.edu.my/46634/ http://irep.iium.edu.my/46634/ http://irep.iium.edu.my/46634/ http://irep.iium.edu.my/46634/1/I012545259.pdf

id	iium-46634
recordtype	eprints
spelling	iium-466342015-12-29T08:25:37Z http://irep.iium.edu.my/46634/ Combined effect of relief and level of expansion in a suddenly expanded flow Syed, Syed Ashfaq Khan, Sher Afgha TL500 Aeronautics TL780 Rockets TL787 Astronautics U Military Science (General) This paper presents the experimental results on the flow characteristics of a suddenly expanded flow from the convergent nozzle for subsonic, sonic and sonic under expanded flow. In the present study micro jets were used to investigate the effect of micro jets on base pressure flow field in the enlarged duct. Accordingly an active control in the form of four micro jets of 1 mm orifice diameter located at 900 intervals along a pitch circle diameter of 1.3 times the nozzle exit diameter in the base region was employed. The NPRs of the present study are 1.5, 2.0, 2.5 and 3.0 and the area ratio (ratio of area of suddenly expanded duct to nozzle exit area) studied were 2.4, 3.61, 4.84, and 6.25. The length-to-diameter (i.e. L/D) ratio of the sudden expansion duct was varied from 10 to 1. From the results, it is seen that the flow in the base region is dominated by the waves, the general perception what we have that correctly expanded flow will be from waves is proved to be wrong; also, it is found that for L/D in the range L/D = 4, 3 and 2 the flow remains oscillatory mostly for NPRs 2.5 and 3.0. However, these oscillations are suppressed either with the increase in the L/D ratio in the range from 3 to 10 or with decrease in the level of expansion NPRs from 2.5 to 1.5. The present study explicitly reveals that, the base pressure in a suddenly expanded axi-symmetric duct can be controlled by employing micro jets under the influence of favorable pressure gradient. International Organisation of Scientific Research (IOSR) 2015-09 Article PeerReviewed application/pdf en http://irep.iium.edu.my/46634/1/I012545259.pdf Syed, Syed Ashfaq and Khan, Sher Afgha (2015) Combined effect of relief and level of expansion in a suddenly expanded flow. IOSR Journal , 12 (5). pp. 52-59. ISSN e-ISSN: 2279-0837, p-ISSN: 2279-0845. http://www.iosrjournals.org Doi :10.9790 /1684-12545259.
repository_type	Digital Repository
institution_category	Local University
institution	International Islamic University Malaysia
building	IIUM Repository
collection	Online Access
language	English
topic	TL500 Aeronautics TL780 Rockets TL787 Astronautics U Military Science (General)
spellingShingle	TL500 Aeronautics TL780 Rockets TL787 Astronautics U Military Science (General) Syed, Syed Ashfaq Khan, Sher Afgha Combined effect of relief and level of expansion in a suddenly expanded flow
description	This paper presents the experimental results on the flow characteristics of a suddenly expanded flow from the convergent nozzle for subsonic, sonic and sonic under expanded flow. In the present study micro jets were used to investigate the effect of micro jets on base pressure flow field in the enlarged duct. Accordingly an active control in the form of four micro jets of 1 mm orifice diameter located at 900 intervals along a pitch circle diameter of 1.3 times the nozzle exit diameter in the base region was employed. The NPRs of the present study are 1.5, 2.0, 2.5 and 3.0 and the area ratio (ratio of area of suddenly expanded duct to nozzle exit area) studied were 2.4, 3.61, 4.84, and 6.25. The length-to-diameter (i.e. L/D) ratio of the sudden expansion duct was varied from 10 to 1. From the results, it is seen that the flow in the base region is dominated by the waves, the general perception what we have that correctly expanded flow will be from waves is proved to be wrong; also, it is found that for L/D in the range L/D = 4, 3 and 2 the flow remains oscillatory mostly for NPRs 2.5 and 3.0. However, these oscillations are suppressed either with the increase in the L/D ratio in the range from 3 to 10 or with decrease in the level of expansion NPRs from 2.5 to 1.5. The present study explicitly reveals that, the base pressure in a suddenly expanded axi-symmetric duct can be controlled by employing micro jets under the influence of favorable pressure gradient.
format	Article
author	Syed, Syed Ashfaq Khan, Sher Afgha
author_facet	Syed, Syed Ashfaq Khan, Sher Afgha
author_sort	Syed, Syed Ashfaq
title	Combined effect of relief and level of expansion in a suddenly expanded flow
title_short	Combined effect of relief and level of expansion in a suddenly expanded flow
title_full	Combined effect of relief and level of expansion in a suddenly expanded flow
title_fullStr	Combined effect of relief and level of expansion in a suddenly expanded flow
title_full_unstemmed	Combined effect of relief and level of expansion in a suddenly expanded flow
title_sort	combined effect of relief and level of expansion in a suddenly expanded flow
publisher	International Organisation of Scientific Research (IOSR)
publishDate	2015
url	http://irep.iium.edu.my/46634/ http://irep.iium.edu.my/46634/ http://irep.iium.edu.my/46634/ http://irep.iium.edu.my/46634/1/I012545259.pdf
first_indexed	2023-09-18T21:06:23Z
last_indexed	2023-09-18T21:06:23Z
_version_	1777410960980443136

Combined effect of relief and level of expansion in a suddenly expanded flow

Similar Items