DRDO successfully conducts scramjet engine ground test for hypersonic missiles

The key to hypersonic vehicles is scramjets, which are variants of a category of jet engines called the air breathing engines. The ability of the engines to handle airflows at speeds in multiples of speed of sound without using any moving parts gives them the capability of operating at those speeds.

The MoD said the ground test of the scramjet combustor showcased several notable achievements, demonstrating its potential for operational use in hypersonic vehicles, like successful ignition and stable combustion. Officials said the 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 air speeds more than 1.5 km per second. Many novel and promising ignition and flame-holding techniques were studied by the DRDO scientists over multiple ground tests before arriving at the scramjet engine configuration. Advanced Computational Fluid Dynamics (CFD) simulation tools were used for their evaluation and performance prediction.

“The indigenous development of endothermic scramjet fuel, the first time in India, jointly by DRDL and industry partners is central to this breakthrough. The fuel offers dual benefits of significant cooling improvement and ease of ignition. The team developed a special manufacturing process to achieve stringent fuel requirements of DRDL at industrial scale,” the MoD said.

Another key achievement is the development of Thermal Barrier Coating (TBC), which is designed to withstand extreme temperatures encountered during hypersonic flight. A new advanced ceramic TBC having high thermal resistance and capable of operating beyond melting point of steel has been jointly developed by DRDL and Department of Science and Technology (DST) facilities. The coating is applied inside the scramjet engine using special deposition methods that enhance their performance and longevity.

“With demonstrated capabilities in stable combustion, enhanced performance and advanced thermal management, this breakthrough sets the stage for next generation hypersonic missiles. Raksha Mantri Rajnath Singh has complimented DRDO and the industry for the successful scramjet engine ground test,” the MoD said.

Earlier in September 2020, in another major milestone in India’s hypersonic technology development, the DRDO had successfully flight-tested the Hypersonic Technology Demonstrator Vehicle (HSTDV). In this test, the hypersonic cruise vehicle was launched using a solid rocket motor, which took it to an altitude of 30 km, where the aerodynamic heat shields were separated at hypersonic Mach number. The hypersonic combustion sustained and the cruise vehicle continued on its desired flight path at hypersonic speed for more than 20 seconds.