A technology that in situ removes dissolved oxygen [1] in jet fuel stabilizes jet fuel (JP8) at elevated temperatures up to 600K. This allows the fuel to be used as a heat sink and also opens up the possibility of flash atomization in aero-engine combustors. Superheated fluid dynamics was first studied in the nuclear power industry [2, 3], followed by the automotive industry [4, 5, 6], and more recently by the aerospace industry [7, 8] which looked into flash atomization in JP-8 fueled pulse detonation engine and vapor lock mitigation [9]. Previously, we showed that by adjusting or controlling the residence time with respect to the relaxation time of the superheated fluid [10], at the exit of the nozzle, the fluid can remain in the superheated state. Its further relaxation outside the nozzle, under the right conditions lead to the core breakup and formation of droplets via flash atomization rather then shear atomization [11]. This paper presents simulation of the spray pattern with all superheated fluid models implemented into a CFD code. These models describe the primary and secondary breakup of the superheated liquid fuel core, droplet size, initial velocity, and droplet evaporation rates. All models included the effects of detailed properties of superheated and subcooled JP8. These models were constructed upon the hypothesis that (1) there exists two concurrent and interacting physical processes that govern the primary and secondary superheated jet atomization: shear instability and the intrinsic relaxation of the superheated fluid (2) the rapid expansion of a superheated fluid imparts the momentum to the droplets formed in the flash atomization process; and (3) the evaporation rate of a superheated droplet is enhanced by the heat transfer from the interior to the liquid-vapor interface and that the liquid-vapor interface on the droplet surface is in the equilibrium condition.
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