Context: The Defence Research and Development Organisation (DRDO) has successfully conducted a long-duration ground test of an Active Cooled Scramjet Subscale Combustor for over 1000 seconds. Earlier, DRDO had successfully conducted the ground test of the scramjet engine for 120 seconds. This marks a significant milestone in development of scramjet-powered hypersonic technology.
Relevance of the Topic: Prelims: Key facts about Hypersonic Missiles; Scramjet Engine.
What are Hypersonic Missiles?
- Hypersonic Missiles are a class of advanced weaponry that travel at speeds greater than Mach 5.
- Key Features:
- Speed: Over Mach 5 (five times speed of sound or more than 5,400 km/hr)
- Manoeuvrability: Hypersonic missiles can change course mid-air, making it very difficult for an interceptor to intercept it.
- Altitude: Travels at relatively lower altitudes than a conventional missile, thereby, evading detection by radar.
- Thus, they have the potential to bypass existing Air Defence Systems and deliver rapid and high-impact strikes.
- Engine: The key to hypersonic vehicles is Scramjets engines which are capable of sustaining combustion at supersonic speeds.
- Several nations including the USA, Russia, India and China are actively pursuing Hypersonic technology.
What is a Scramjet Engine?
- Scramjets are air-breathing engines capable of sustaining combustion at supersonic speeds without the need for any moving parts (functions without turbines or compressors).
- The Scramjet engine designed by ISRO uses Hydrogen as fuel and the Oxygen from the atmospheric air as the oxidiser.
- Working:
- A scramjet engine collects oxygen from the atmosphere (rather than carrying an oxidiser) as it is travelling, and mixes the oxygen with its hydrogen fuel.
- Combustion occurs at supersonic speed (exceeding Mach 1), needed for hypersonic travel of the missile.
Recent successful ground test by DRDO
The ground test of the scramjet combustor showcased several notable achievements like successful ignition and stable combustion.
- Stable combustion:
- Ignition in a scramjet engine is like ‘keeping a candle lit in a hurricane.’
- Scramjet combustor incorporates an innovative flame stabilisation technique that holds continuous flame inside the combustor with airspeed of over 1.5 km per second.
- Scramjet fuel: Endothermic scramjet fuel (central to this breakthrough) was developed for the first time in India jointly by Defence Research and Development Laboratory (DRDL), and industry.
- The fuel offers dual benefits of significant cooling improvement and ease of ignition.
- Advanced Computational Fluid Dynamics simulation tools were used for their evaluation and performance prediction.
- Thermal Barrier Coating: Thermal Barrier Coating was designed to withstand extreme temperatures encountered during hypersonic flight. The coating is applied inside the Scramjet engine using special deposition methods that enhance their performance and longevity.
Significance: The achievement is a crucial milestone in the development of next-generation hypersonic missions.