Fluidic Thrust Vectoring & Combustion Instability Research Facility

Fluidic Thrust Vectoring & Combustion Instability Research Facility

 F-1 Fluidic Thrust Vectoring Test Facility

Thrust vectoring is an important feature in combat air vehicle design.  There are various methods of achieving thrust vectoring.  One of the conventional methods is by using complex mechanical actuation systems.  These are usually very expensive, heavy, sluggish and difficult to integrate and maintain. They are also aerodynamically inefficient and as stealth requirements become even more important, the need for a reduction in the radar- cross section (RCS) and infra-red radiation (IRR) signatures of military aircraft becomes a huge challenge.  Another method of achieving thrust vectoring is by using fluidics.   “Fluidics” is the technology of employing general fluid phenomena of wall attachment and stream interaction in specially designed devices to perform the functions of sensing, logic and control.  Fluidic thrust vector control involves the use of no moving parts.  It increases structural rigidity and decreases weight.  It has great flexibility, rapid response and is inexpensive.  With careful design, it could lead to a reduction in the overall radar cross section of the aircraft.  Research in this area has been carried out to demonstrate the fludic thrust vectoring technique in a rectangular nozzle.

 


Fluidic Thrust Vectoring Test rig

 


Schlieren images showing vectored jet and location of secondary jets being injected

 

Fluidic thrust vectoring concepts

F2- Combustion Instability Research Facility


Combustion instabilities are caused by coupling between acoustic waves and the unsteady heat release. It is considered to be one of the major problems faced in the development of afterburners. Although this problem has been increasingly studied for over the past five decades, no accepted theoretical general rules have yet been established for designing stable afterburner systems; the complexity of the problem has prevented the achievement of a purely analytical solution.  This test rig that has been set up under the GATET initiative of GTRE, DRDO to carry out research activities on the mitigation of combustion instabilities in a research afterburner under simulated inlet conditions in terms of pressure and temperature.  Predetermined screech frequency can be generated on demand in a controlled and sustained manner to conduct mitigation studies using passive devices like the anti-screech liners. 
 

Afterburner test rig and typical screech frequency simulated in the test rig

Flow visualization

A complete understanding and control of high frequency screech combustion instabilities constitute the central problem in the development of high performance afterburners. To study the underlying high-speed flow-physics related to the crucial thermo-acoustic coupling, flow visualization tools are used effectively.  Flow past V-gutter flame stabilizer during smooth combustion and during screech combustion gives an idea of the flow field in the flame stabilizer zones.  Conventional method using spherical mirrors and special flow visualization techniques using retro-reflective screen method has also been developed to capture the flow field in the critical zones of flame stabilization. This method will help to understand the complex acoustic wave motion during the phase of combustion instability in an afterburner. 

High-speed shadowgraph flow visualization studies (Spherical mirror method)

 

Flow visualisation studies in a model afterburner

F-3 Pulsejet engine Test Facility


With the recent interest in the MAV development, various possible propulsion methods are being used for flying the MAV.  Presently used brushless motors connected to the propellers are being imported and the batteries used to power the motors have limited life and needs to be recharged before re-use.  In this direction, to develop an indigenous propulsive device valved and valveless pulsejet engines were built and experimental research to understand the flow physics behind its operation were conducted.  Chemical tracers were used to increase the luminosity of the hydrogen flame to understand the flame front movement in fully transparent quartz glass engine models.  Specially developed twin-beam shadowgraph technique revealed the couple unsteady combustion flow in a pulsejet engine.  Successful flight test was possible using valved pulsejet engine on a micro air vehicle of 1.5 m wingspan.

Studies on pulsejet engines

Valved PulseJet engine flight test

 

 

 

 

Name

Designation

Facility

C Rajashekar

Joint Head, Propulsion Division

F1, F2, F3

Shambhoo

Scientist

F1, F2,F3

H S Raghu Kumar

Technical Assistant

F1, F2, F3

Fakruddin Agadi

Technician-1

F1, F2 ,F3

 

F1: Fluidic Thrust Vectoring Test Facility (FTV)

F2: Combustion Instabilities Research Facility (CIRF)

F3: Pulsejet Engine Test facility


Last updated on : 04-02-2020 04:18:56pm