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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...

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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/46634/1/I012545259.pdf
http://irep.iium.edu.my/46634/
http://www.iosrjournals.org
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spelling my.iium.irep.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 REM 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.
institution Universiti Islam Antarabangsa Malaysia
building IIUM Library
collection Institutional Repository
continent Asia
country Malaysia
content_provider International Islamic University Malaysia
content_source IIUM Repository (IREP)
url_provider http://irep.iium.edu.my/
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/46634/1/I012545259.pdf
http://irep.iium.edu.my/46634/
http://www.iosrjournals.org
_version_ 1643613033462759424
score 13.211869

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