Control of Nozzle Flow Using Microjets at Supersonic Mach Regime

Document Type : Original Article

Authors

1 Department of Mechanical Engineering, Bearys Institute of Technology, Mangalore, Karnataka, India

2 Department of Mechanical Engineering, Faculty of Engineering, IIUM, Kuala Lumpur, Malaysia

Abstract

This article reports the active control of base flows using the experimental procedure. Active control of base pressure helps in reducing the base drag in aerodynamic devices having suddenly expanded flows. Active control in the form of microjets having 0.5 mm radius placed at forty-five degrees apart is employed to control the base pressure. The Mach numbers of the present analysis are 1.7, 2.3, and 2.7. The length to diameter (L/D) ratio is varied from 10 to 1 and the nozzle pressure ratio (NPR) being changed from 1 to 10 in steps of 1 for base pressure measurements. The area ratio for the entire analysis is fixed at 2.56. Wall pressure distribution along the enlarged duct is also recorded. No change in base pressure increase/decrease is thoroughly analysed as well. From the experimental investigation, it is found that control plays an important in modifying the base pressure without disturbing the wall pressure distribution. The base pressure variation is entirely different at L/D = 1 compared to a higher L/D ratio due to change in reattachment length and the requirement of the duct length at higher inertia levels. The quality of the flow in the duct in the presence and absence of control remained the same.

Keywords



1. Khan, S.A. and Rathakrishnan, E., "Active control of suddenly
expanded flows from overexpanded nozzles", International
Journal of Turbo and Jet Engines,  Vol. 19, No. 1-2, (2002),
119-126.
2. Khan, S.A. and Rathakrishnan, E., "Control of suddenly
expanded flows with micro-jets", International Journal of
Turbo and Jet Engines,  Vol. 20, No. 1, (2003), 63-82.
3. Khan, S.A. and Rathakrishnan, E., "Control of suddenly
expanded flows from correctly expanded nozzles", International
Journal of Turbo and Jet Engines,  Vol. 21, No. 4, (2004),
255-278.
4. Khan, S.A. and Rathakrishnan, E., "Active control of suddenly
expanded flows from underexpanded nozzles", International
Journal of Turbo and Jet Engines,  Vol. 21, No. 4, (2004),
233-254.
5. Khan, S.A. and Rathakrishnan, E., "Active control of suddenly
expanded flows from underexpanded nozzles-part ii",
International Journal of Turbo and Jet Engines,  Vol. 22, No.
3, (2005), 163-184.
6. Khan, S.A. and Rathakrishnan, E., "Nozzle expansion level
effect on suddenly expanded flow", International Journal of
Turbo and Jet Engines,  Vol. 23, No. 4, (2006), 233-258.
7. Khan, S.A. and Rathakrishnan, E., "Active control of base
pressure in supersonic regime", Journal of Aerospace
Engineering, Institution of Engineers, India,  Vol. 87, (2006),
1-8.
8. Khan, S.A. and Rathakrishnan, E., "Control of suddenly
expanded flow", Aircraft Engineering and Aerospace
Technology,  Vol. 78, No. 4, (2006), 293-309.
9. Rathakrishnan, E., "Effect of ribs on suddenly expanded flows",
AIAA journal,  Vol. 39, No. 7, (2001), 1402-1404.
10. Srikanth, R. and Rathakrishnan, E., "Flow through pipes with
sudden enlargement", Mechanics Research Communications,
Vol. 18, No. 4, (1991), 199-206.
11. Rathakrishnan, E., Ramanaraju, O. and Padmanaban, K.,
"Influence of cavities on suddenly expanded flow field",
Mechanics Research Communications,  Vol. 16, No. 3, (1989),
139-146.
12. Viswanath, P., "Passive devices for axisymmetric base drag
reduction at transonic speeds", Journal of aircraft,  Vol. 25, No.
3, (1988), 258-262.
13. Rehman, S. and Khan, S.A., "Control of base pressure with
micro-jets: Part i", Aircraft Engineering and Aerospace
Technology,  Vol. 80, No. 2, (2008), 158-164.
14. Khan, S.A. and Mohammed, A., "Passive control of base drag in
compressible subsonic flow using multiple cavity", Iternational
Journal of Mechanical and Production Engineering Research
and Development,  Vol. 8, (2018), 39-44.
15. Khan, S., Chaudhary, Z.I. and Shinde, V.B., "Base pressure
control by supersonic micro jets in a suddenly expanded nozzle",
International Journal of Mechanical and Mechatronics
Engineering,  Vol. 18, No. 4, (2018), 101-113.
16. Khan, S.A., Asadullah, M. and Sadhiq, J., "Passive control of
base drag employing dimple in subsonic suddenly expanded
flow", International Journal of Mechanical and Mechatronics
Engineering,  Vol. 18, No. 03, (2018), 69-74.
17. Asadullah, M., Khan, S.A., Asrar, W. and Sulaeman, E.,
"Passive control of base pressure with static cylinder at
supersonic flow", in IOP Conference Series: Materials Science
and Engineering, IOP Publishing. Vol. 370, (2018), 012050.
18. Asadullah, M., Khan, S.A., Asrar, W. and Sulaeman, E., "Lowcost
base
drag

reduction technique", International Journal on
Mechanical Engineering and Robotics,  Vol. 7, No. 4, (2018),
428-432.
19. Alrobaian, A.A., Khan, S. And Asadullah, M., "A new approach
to low-cost open-typed subsonic compressible flow wind tunnel
for academic purpose",  Vol. 8, No. 6, (2018), 383-394
20. Vikramaditya, N., Viji, M., Verma, S., Ali, N. and Thakur, D.,
"Base pressure fluctuations on typical missile configuration in
presence of base cavity", Journal of Spacecraft and Rockets,
Vol. 55, No. 2, (2017), 335-345.