Control of Unstart Phenomenon in a Hydrogen Fuelled Scramjet Engine

The present work aims at numerical methodology development for modeling supersonic combustion using 8 species, 13 reaction hydrogen-air reaction model. The governing equations of continuity, momentum, energy, and species conservation have been solved using the commercial code of Fluent®. The developed method is then used for modelling the unstart phenomenon in scramjet engine. The unstart is initiated as a result of heat released due to combustion of fuel. An automatic control system to mitigate unstart by leaking high-pressure fluid from the slots designed on the lower wall of the scramjet has been suggested and its efficacy has been tested. It is seen that slots of size 6mm on the lower wall are able to prevent inlet choking. The physics behind the unstart phenomenon and its control has been explained with the help of boundary layer bleeding and shock theory.