Context:
Recently, the Defence Research & Development Laboratory (DRDL) developed long-duration Supersonic Combustion Ramjet or scramjet-powered Hypersonic technology and demonstrated an Active-Cooled Scramjet Compressor ground test for 120 seconds for the first time in India.
- The DRDL in Hyderabad, part of DRDO, is developing hypersonic technology using a long-duration Supersonic Combustion Ramjet (Scramjet) engine.
- The successful ground test represents a key achievement in developing next-generation hypersonic missiles.
- Hypersonic missiles are a class of advanced weaponry that travel at speeds greater than Mach 5 i.e., five times the speed of sound or more than 5,400 km/hr.
- India is the fourth country after the USA, Russia, and China actively pursuing Hypersonic technology.
- Scramjets are air-breathing engines that sustain combustion at supersonic speeds without any moving parts, making them key to hypersonic vehicles.
Ground Test of Scramjet Combustor:
- Demonstrated key achievements, including successful ignition and stable combustion.
- Flame Stabilization: An innovative technique that ensures continuous flame inside the combustor at airspeeds above 1.5 km/s, even under extreme conditions.
- Advanced Computational Fluid Dynamics Tools: Used for evaluating and predicting the performance of novel ignition and flame-holding techniques.
Thermal Barrier Coating (TBC):
- Advanced Ceramic TBC: Developed with the Department of Science & Technology (DST), capable of withstanding extreme temperatures encountered during hypersonic flight.
- High Thermal Resistance: It can operate beyond the melting point of steel.
- Special Deposition Methods: Applied inside the Scramjet engine to enhance performance and longevity.
About Scramjet Engine
- A scramjet engine (supersonic combusting ramjet) uses a vehicle’s forward motion to compress incoming air without needing a compressor.
- It is an evolution of the ramjet, using internal combustion at supersonic speeds, which avoids energy loss from breaking the incoming airflow.
- It is different because it cannot generate thrust at low speeds.
- It needs a rocket to help them reach high speeds before they start working.
- It is most efficient at speeds between Mach 3 and Mach 6 (three to six times the speed of sound).
- It uses air’s oxygen as the Fuel (oxidizer) and releases air at supersonic speeds (faster than the speed of sound).
Ramjet VS Scramjet
- Both ramjet and scramjet engines use atmospheric oxygen as oxidizer.
- While exit flow from the inlet of a ramjet engine is subsonic that from a scramjet engine is supersonic.
- Ramjet works best at supersonic speed, but Scramjet works best at Hypersonic speed.
- Ramjet Uses subsonic combustion, whereas, Scramjet uses supersonic combustion.