Executive Summary : | India's hypersonic arms race necessitates the development of a scramjet engine, which requires understanding and optimizing the injection of liquid fuel into a supersonic flow. The scramjet engine requires fuel to be injected, atomised, mixed, and evaporated in a short time, making penetration and evaporation crucial for its operation. Penetration depends on the liquid jet staying intact against air momentum, which can be increased by increasing the momentum flux ratio. Small droplet sizes evaporate quickly, but larger ones carry by the flow easily, limiting fuel injection penetration and engine size. In a scramjet engine, shocks and expansions have not been well understood, affecting the atomisation process. This project aims to study the breakup of liquid jets injected into M2.0 cross flow with and without an oblique shock or expansion fan crossing the jet path. Four jet configurations will be studied: single jet, two jets in tandem, two jets impinging, and single pulsed jet. The rationale behind these injection strategies is that when a single jet is split into two tandem jets, the front jet shields the one behind it, achieving better penetration. Impinging jets can increase penetration due to their impinging momentum, and pulsed jets have higher penetration than steady counterparts. These studies will help design new strategies for future scramjets that require quick atomisation with good penetration and mixing. The deliverables will include understanding the breakup process and new strategies for liquid injection in supersonic flow. |