| Summary: | 碩士 === 國立成功大學 === 航空太空工程學系 === 104 === This study uses the numerical simulation software ANSYS FLUENT to conduct a numerical simulation of liquid-hydrocarbon fuel injected into a supersonic flow. With this numerical simulation we can investigate the detailed flow of the liquid jet into the supersonic flow, and observe the relationships among the Mach Number, flow rate of the liquid jet, recirculation zone and the shock waves. This study finds that when liquid kerosene is vertically injected into the supersonic flow, the free stream impacts the liquid column, and this produces a high- temperature, high-pressure shock wave. The flow forms a recirculation zone in front of the shock, and a separation shock results in the leading edge of the recirculation zone.
The results of using different injection flow rates show that increasing this will increase the strength of the bow shock, and also increase the angle of the bow shock. If the bow shock is enhanced then the length of the recirculation zone will increase, as will the height and strength of the separation shock. Moreover, the results of using different inlet Mach Numbers for the free stream show that enhancing the Mach Number will increase the strength of the bow shock and separation shock. However, due to the increase in inlet velocity, the flow has more momentum and thus makes the air flow downstream with greater intensity. Because of this, the angle of the bow shock will decrease, as will the length of the recirculation zone also decrease and the height of the separation shock. Moreover, when the Mach number of the free stream or the mass flow rate of injection increases, the interaction between the strength of bow shock and separation shock is strongly related to the strength of the bow shock.
Therefore, changing the momentum of injection can also change the strength of the shock, the length of the recirculation zone and the position of the interaction between the two shocks. The results of this simulation presented in this work can be used to further examine the impact of liquid jet into supersonic flow in future works.
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