2. PRINCIPLE OF RAMJET ENGINE
THE FUNCTION OF A SUPERSONIC AND
SUBSONIC DIFFUSER IS TO CONVERT THE
KINETIC ENERGY OF THE ENTERING AIR INTO A
PRESSURE RISE CALLED RAM PRESSURE.
3. RAMJET BASIC OPERATION
Ramjet has no moving parts
Achieves compression of intake air by forward speed of vehicle
Fuel
injectors
4. RAMJET BASIC OPERATION
Air entering the intake of a supersonic aircraft is slowed by
aerodynamic diffusion created by the inlet and diffuser to low velocities.
Expansion of hot gases after fuel injection and combustion accelerates
exhaust air to a velocity higher than that at inlet and creates positive
thrust
6. HyFly RAMJET CONCEPT
HyFly program was initiated in 2002 by DARPA (Defense
Advanced Research Projects Agency) and U.S. Navy's ONR
(Office of Naval Research)
to develop and test a demonstrator for a hypersonic Mach 6+
ramjet-powered cruise missile
Prime contractor for HyFly missile is Boeing, Aero jet builds
sustainer engine
Air-launched from F-15E and accelerated to ramjet ignition speed
by solid-propellant rocket booster
7. •Engine runs on conventional liquid hydrocarbon fuel (JP-10)
•Much easier to handle than cryogenic fuels (LH2) used on other hypersonic
scramjet vehicles
• Sustainer engine of HyFly is a dual-combustion ramjet (DCR) (very complex)
•Two different air inlet systems
•Operate as a "conventional" ramjet with subsonic combustion
•Operate at hypersonic speeds as a scramjet
•First scramjet engine (hybrid or otherwise) to demonstrate operability
with LH2 fuel
11. SUMMARY
Ramjet develops no static thrust
Relies on ‘ram’ compression of air
Requires high speed flight
Performance depends on increase in stagnation temperature across burner
(combustor)
Efficiencies (thermal, propulsive, and overall) increase with increasing flight
Mach number
Next step: We desire an engine that develops static thrust
Put in a device to mechanically compress air (compressor)
Put in a device to power compressor (turbine)
Solution: Turbojet engine
13. DISADVANTAGES
THERE WE HAVING ALTITUDE LIMITATION.
LOW THERMAL EFFICIENCY.
HIGH TSFC.
EROSION OCCURS AT THE NOZZLE DUE HIGH
TEMPERATURE OF GAS COMING OUT FROM THE
NOZZLE.