Study of Instability Nature of Circular Liquid Jet at Critical Chamber Conditions

Direct Injection (DI) technology that is used in the IC engines has gained significant interest over the last few decades. In DI engines, the fuel is directly injected into the combustion chamber through an injector. The efficiency and the corresponding emission characteristics of DI, IC engines are dependent on the thermo-physical properties of the fuel and its corresponding spray dynamics and air/fuel mixing. Therefore, a comprehensive understanding of the process involving liquid injection, breakup and atomization, and combustion inside the engine environment is very essential. There are several theoretical and experimental studies carried out to understand the stability of the liquid jets, but there is not much literature available to understand the behavior of liquid jets near the injector at critical and supercritical conditions. This is largely due to the experimental and computational challenges associated with the process of high-pressure injection. The main objective of this paper is to study the instability nature on the liquid jet near the injector at critical conditions. Visualization using high-speed camera is used to capture the images of the disturbances to bring further insight into the jet dynamics at critical conditions. Experiments are carried out for different environmental pressures for both single component system and binary component system where the environment is a mixture of two fluids.