Base pressure behaviour in a suddenly expanded duct at supersonic mach number regimes using Taguchi design of experiments
Experimental investigations are carried out to study the control of base pressure without and with the use of micro-jets through suddenly expanded axi-symmetric passage in the supersonic regime. Four micro jets having an orifice diameter of 1mm were located at 90◦ intervals. In the base area, act...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English English |
| Published: |
Technical University of Lodz
2018
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| Subjects: | |
| Online Access: | http://irep.iium.edu.my/71236/ http://irep.iium.edu.my/71236/ http://irep.iium.edu.my/71236/1/71236_Base%20Pressure%20Behaviour%20in%20a%20Suddenly.pdf http://irep.iium.edu.my/71236/7/71236_Base%20pressure%20behaviour%20in%20a%20suddenly%20expanded%20_scopus.pdf |
| Summary: | Experimental investigations are carried out to study the control of base pressure without
and with the use of micro-jets through suddenly expanded axi-symmetric passage in the
supersonic regime. Four micro jets having an orifice diameter of 1mm were located
at 90◦ intervals. In the base area, active controls jets have been placed on a pitch
of a circle diameter that is 1.3 times the exit diameter of the nozzle. The jets were
dispensed abruptly into the axi-symmetric tube maintained at a cross-sectional area
of 4.84 times the exit nozzle area. The variation of base pressure as a function of
flow control parameters namely Mach number, nozzle pressure ratio (NPR) and length
to diameter) ratio (L/D) are evaluated experimentally. This study also assesses the
impact of flow control variables on base pressure for two cases viz. with control and
without control respectively. An L9 orthogonal array of Taguchi and the analysis of
variance were employed to investigate the percentage of contribution of these parameters
and their interactions affecting the base pressure. The correlations between the various
factors affecting the base pressure were obtained by using multiple linear regression
equations. Confirmation tests were conducted in order to test the developed linear
regression equations for their practical significance. Both the regression models were
found to be significant and reliable with a percentage deviation lying in the range of
−6.12% to 10.26% for base pressure without control and −13.92% to 6.58% for base
pressure with control. Analysis of variance was also performed in order to determine
the statistical significance of each parameter on the total variability of base pressure.
The study concluded that Mach number is the most influential parameter affecting base
pressure followed by NPR and L/D. |
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