• Journal of the Korean Society of Propulsion Engineers
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• v.7 no.2
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• pp.23-35
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• 2003

"Backhole" is a new geometric parameter and is defined as an extra empty volume which is located behind the tangential entries at the rear part of the vortex chamber in the swirl injector. Backhole makes a difference to the spray characteristics of swirl injectors such as the spray angle, SMD, the mixing characteristics and so on. To find its characteristics, experiments are conducted by using a stroboscopic photography, a PDPA apparatus and a mechanical patternator. With the backhole, the mass flow rate of the swirl injector is increased and the center region of the injected flow has more large volume than that of without the backhole. Also the cone angle can be controlled by the backhole, so that the mixing efficiencies of swirl injectors are changed. Based on cold-flow tests, the swirl injector with the backhole may improve its performance.rformance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.8
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• pp.79-86
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• 2006

Swirl injector with adjustable backhole length was analyzed to suppress high-frequency combustion instability in Liquid Rocket Engines. In order to analyze the effect of variable backhole injector as an acoustic absorber, backhole injector was regarded as a quarter-wave resonator. As a result of theoretical approaches and acoustic tests, backhole injector with adjustable length could decrease the unstable modes of combustion chamber. And the damping efficiency was estimated by measuring damping rates experimentally.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.153-156
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• 2003

Backhole, which is one of geometric parameters in swirl coaxial injectors, is found to affect the inner flow motion and the acoustic characteristics of the swirl injector. In order to analyze the effect of the backhole as a damping device such as acoustic cavities of the combustion chamber, it was regarded as a Helmholtz or Quarter-wave resonator. As a result, it is known that the swirl coaxial injector with the backhole may produce the resonant frequency coincided with the frequency of the combustion chamber.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.224-228
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• 2005

Dynamic control tests for Backhole as a dynamic damper were performed. For the forced oscillation generated by pressure drop in the feed line and internal wave analysis of swirl injector, hydrodynamic pulsator and 1D visualization model injector was produced, respectively We focus on effect of Backhole as a dynamic damper instead of a acoustic one. So, the breakup length and film thickness of liquid sheet on the steady state and the forced oscillation state have been measured and compared.

• Proceedings of the KSME Conference
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• 2002.08a
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• pp.287-290
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• 2002

'Backhole' is an extra empty volume where is located behind the tangential entries at the rear par of the vortex chamber in the swirl coaxial injector. With the backhole, there are three major hydraulic characteristics. First, mass flow rate is increased about $15{\%}$ compared with the case without the backhole. Second, with the backhole, the center region of the injected flow has more large volume than that of without the backhole. The last, some range of the cone angle can be controlled by the backhole Experiments are conducted by using a PDPA apparatus, a mechanical patternator, stroboscopic photography and etc. With the backhole, based on cold-flow tests, the model swirl injector has some Improvement in its performance.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.251-255
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• 2005

By using liquid film thickness measurement the spray characteristics of swirl injector according to the geometric parameters were investigated in this paper. A specially designed injector having a variable backhole length, swirl chamber length, orifice length was used to measure the liquid film thickness. The spray characteristics of the injector were represented by mass flow rate according to the injection pressure, liquid film thickness in the lower orifice, spray cone angle.

• Journal of ILASS-Korea
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• v.11 no.3
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• pp.147-154
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• 2006

A specially designed injector using electric conductivity was used to measure the liquid film thickness accurately. The measurement conducted through the precise calibration, accuracy is demonstrated in comparison with the previous theory and the results using other measurement method. The tendency of liquid film thickness for geometric parameters was examined by the precise measurement. The variation of air core and stability are examined through the visualization of the formation of air core in swirl chamber and the variation of liquid film thickness by the time.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.2
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• pp.70-77
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• 2006

A specially designed in;ector using electric conductivity was used to measure the liquid film thickness exactly, The measurement conducted through the precise calibration, accuracy is demonstrated in comparison with the previous theory and the results using other measurement method. The variation of internal flow and stability are examined through the variation of liquid film thickness by the time. The tendency of liquid film thickness for geometric parameters was examined by the precise measurement.