HomePage
 




 


 

ISSN 2083-6473
ISSN 2083-6481 (electronic version)
 

 

 

Editor-in-Chief

Associate Editor
Prof. Tomasz Neumann
 

Published by
TransNav, Faculty of Navigation
Gdynia Maritime University
3, John Paul II Avenue
81-345 Gdynia, POLAND
www http://www.transnav.eu
e-mail transnav@umg.edu.pl
Study of Inline-slot Ejector Diffuser Under Varying Ambient Conditions: A Passive Infrared Suppression Device for Ships
ABSTRACT: Passive infrared (IR) suppression device, commonly known as ejector diffuser, is an integral part of the defence system of a ship. The definitive role of passive IR suppressor to counter the IR tracking and locking of the ship has made them indispensable for any combat marine. The gas turbine exhaust gases are the leading heat source on a ship. The exhaust temperature of the gases ranges between 650K-850K. At such temperatures, the ship can be easily detected by the enemy through IR imaging. The role of the ejector diffuser is to (i) lower the gas turbine exhaust gases temperature to the limits (< 450K) such that the IR locking of the marine can be avoided, and (ii) recover static pressure such that the engine performance of the gas turbine is not affected. Ejector diffuser has the ability to entrain ambient air and allow mixing it with the exhaust gases thereby, lowering the temperature of the exhaust gases. However, the mixed exhaust gases temperature depends on the ambient air temperature which under extreme conditions can fluctuate from 273K to 323K. This temperature range can affect the temperature characteristics of an ejector diffuser. The present study undertakes the effect of ambient temperature on the performance of inline-slot ejector diffuser. The ambient temperature (T0) has been varied in the range 273K ≤ T0 ≤ 323K in the step of 10K. It has been found that the mass entrainment increases (≈ 8%) as the ambient temperature decreases. The core temperature at the exit decreases, from 457.58 K to 417.75K, with a decrease in the ambient temperature. However, no significant changes in static pressure recovery.
REFERENCES
AM Birk and D VanDam. Marine gas turbine infrared signature suppression: Aerothermal design considerations. International Gas Turbine and Aeroengine Congress and Exposition, pages V002T03A009–V002T03A009–10, 1989.
Arvind Gangoli Rao. Infrared Signature Modeling and Analysis of Aircraft Plume. International Journal of Turbo and Jet Engines, 28:187, 2011. - doi:10.1515/tjj.2011.023
Saibal Sen. Studies on Flow Characteristics of a Stepped Conical Diffuser with Passive Suction. PhD thesis, Department of Applied Mechanics, Indian Institute of Technology Delhi, 2008.
Parminder Singh, S N Singh, and V Seshadri. Experimental Investigations on Non-Circular Ejector Air Diffusers. 39th AIAA Fluid Dynamics Conference, page 4213, 2009. - doi:10.2514/6.2009-4213
Parminder Singh, Sidh Nath Singh, and V Seshadri. Effect of number of slots and overlap on the performance of non-circular ejector air diffuser. In 43rd AIAA Fluid Dynamics Conference, page 2729, 2013. - doi:10.2514/6.2013-2729
Qi Chen. Performance of air-air ejectors with multi-ring entraining diffusers. PhD thesis, Department of Mechanical and Materials Engineering, Queen’s University, 2008.
L Singh, SN Singh, and SS Sinha. Effect of slot-guidance and slot-area on air entrainment in a conical ejector diffuser for infrared suppression. Journal of Applied Fluid Mechanics, 12(4):1303–1318, 2019. - doi:10.29252/jafm.12.04.29326
L Singh, SN Singh, and SS Sinha. Effect of standoff distance and area ratio on the performance of circular exhaust ejector using computational fluid dynamics. Proc. IMechE, Part G: Journal of Aerospace Engineering, 232(15):2821–2832, 2018. - doi:10.1177/0954410017717287
A Maqsood. A study of subsonic air-air ejector with short bent mixing tube. PhD thesis, Department of Mechanical and Materials Engineering, Queen’s University at Kingston, Canada, 2008.
Florian R Menter. Two-equation eddy- viscosity turbulence models for engineering applications. Journal of AIAA, 32(8):1598-1605, 1994. - doi:10.2514/3.12149
Simone Crippa. Improvement of unstructured computational fluid dynamics simulations through novel mesh generation methodologies. Journal of Aircraft, 48(3):1036–1044, 2011. - doi:10.2514/1.C031219
W. B. Nicoll and B. R. Ramaprian. Performance of conical diffusers with annular injection at inlet. Journal of Fluids Engineering, 92(4):827–835, 1970. - doi:10.1115/1.3425153
Citation note:
Singh L., Singh S.N., Sinha S.S.: Study of Inline-slot Ejector Diffuser Under Varying Ambient Conditions: A Passive Infrared Suppression Device for Ships. TransNav, the International Journal on Marine Navigation and Safety of Sea Transportation, Vol. 14, No. 2, doi:10.12716/1001.14.02.28, pp. 477-482, 2020

Other publications of authors:


File downloaded 128 times








Important: TransNav.eu cookie usage
The TransNav.eu website uses certain cookies. A cookie is a text-only string of information that the TransNav.EU website transfers to the cookie file of the browser on your computer. Cookies allow the TransNav.eu website to perform properly and remember your browsing history. Cookies also help a website to arrange content to match your preferred interests more quickly. Cookies alone cannot be used to identify you.
Akceptuję pliki cookies z tej strony