• Journal of the Korean Society of Propulsion Engineers
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• v.13 no.5
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• pp.21-28
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• 2009

This experimental study was performed to find the important design parameters and the starting characteristics of a supersonic exhaust diffuser. The experimental study was carried out on a scaled down model of straight cylindrical supersonic exhaust diffuser, in order to evaluate the effects of operating fluid(air, nitrogen), the diffuser inlet area over the primary nozzle throat area($A_d/A_t$), the inlet pressure of primary nozzle, diffuser length over diffuser inner diameter($L_d/D_d$) and existence or nonexistence of diffuser divergence. The test results showed that the starting pressure increased with decrease in diameter of primary nozzle, and the measured starting pressure of the diffuser had approximately 90~98% efficiency as compared with the predicted starting pressure. Also, the diffuser was started at all case, regardless of $L_d/D_d$ (above 8.4) and diffuser divergence. The result of this study can be used as an essential database for developing a simulated high-altitude facility for real-scale model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1148-1152
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• 2017

To simulate a high altitude for rocket at sea level, the test facility should provide a sufficiently low pressure environment. Center Body Diffuser(CBD) is those applied for high altitude simulation test facility. To elucidate the flow characteristics of center body diffuser with various the center body location, numerical analyses using ANSYS FLUENT were performed. The result of this study is deemed to be valuable as a data base for the operation of the Center Body Diffuser.

• Aerospace Engineering and Technology
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• v.11 no.2
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• pp.117-121
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• 2012

Upper stage propulsion system designed for operation in the upper atmosphere should be tested under nozzle full flow conditions to verify its performance on the ground. KARI has carried out high altitude simulation test of KSLV-I kick motor using cylindrical supersonic exhaust diffuser. Also cold and hot flow test for the sub-scaled diffuser have been conducted to verify the design of real scale diffuser and to study its operating characteristics. This paper deals with the results obtained from these high altitude simulation tests.