• Aerospace Engineering and Technology
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• v.5 no.2
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• pp.134-142
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• 2006

Sub-cooling of cryogenic propellant by helium injection is one of the most effective methods for suppressing bulk boiling and keeping sub-cooled liquid oxygen before rocket launch. In order to design the cooling system, understanding of the limitations of heat and mass transfer is required. In this paper, an analytical model for the helium injection system is presented. This model's main feature is the representation of bubbling system using finite-rate heat transfer and instantaneous mass transfer concept. With this simplified approach, the effect of helium injection to liquid oxygen system under several circumstances is examined. Experimental results along with simulations of single bubble rising in liquid oxygen and bubbling system are presented with various helium injection flow rates, and with change of oxygen chamber pressure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• v.y2005m4
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• pp.179-182
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• 2005

Test of liquid oxygen sub-cooling by helium injection, which is one of the method of temperature conditioning of cryogenic propellant in liquid propulsion rocket, is performed. The sub-cooling effect at different He injection flow rate with the same initial liquid oxygen mass is compared. Test results showed liquid oxygen temperature decrease of $5\sim6^{\circ}C$ under test condition. And the required time for cooling is inversely proportional to He injection flow rate.

• Aerospace Engineering and Technology
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• v.3 no.1
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• pp.205-212
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• 2004

In this paper, to satisfy the temperature requirement of turbopump-inlet condition, the cooling of cryogenic propellant is performed at the simulated suction-line of the Launch Vehicle. The cooling method is by using gas helium injection. This paper investigates the effect of helium injection on liquid nitrogen, which simulates the liquid oxygen. By using helium injection, subcooling of liquid nitrogen can be achieved and in the condition of v/vL≒0.8min-¹ approximately in four minutes subcooling temperature can be achieved.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2003.10a
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• pp.141-144
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• 2003

In this paper, to satisfy the temperature requirement of turbopump-inlet condition, the cooling of cryogenic propellant is performed at the simulated suction-line of the Launch Vehicle. The cooling method is by using Gas helium injection. This study investigates the effect of helium injection on the liquid nitrogen which simulates the liquid oxygen. By using helium injection, the subcooling of liquid nitrogen can be achieved within four minute when the ratio of gas volume flowrate to the volume of L$N_2$ is approximately v/v$_{L}$≒0.8min$^{-1}$ . .

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.2
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• pp.9-17
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• 2007

The performance test of recirculation line in propellant feeding system was carried out. Liquid oxygen was used as cryogenic propellant and helium was used as recirculation promotion gas. Tests were done in cases at atmospheric pressure and at pressure of 4 barg in the ullage space of propellant tank. Liquid oxygen recirculation flowrate with helium injection flowrate and temperature distribution along the line were measured. There was appropriate helium injection flowrate for gas-lift recirculation system. Test data were used to make calculation program by test data correlation method. In this paper the procedure of calculation was presented and the results were compared to test data.

• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.1-10
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• 2006

In this paper, a calculation method of the thermodynamic parameters of cryogenic propellant is proposed when a cryogenic propellant tank is pressurized by gaseous helium(GHe) bubbling. Temperature of cryogenic propellant and mass of dissolved GHe into propellant were analyzed at the various operation of pressurization of tile liquid oxygen(LOX) and hydrogen($LH_2$) tank using helium bubbling. It was evaluated how the GHe bubbling influences to the thermodynamic parameters of LOX and $LH_2$ with results of the analysis. With the proposed calculation method, It will be able to confirm the feasibility of GHe bubbling as a pressurization system of cryogenic propellant tank and to optimize the pressurization system using GHe bubbling.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.551-554
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• 2006

Inhibition of propellant temperature rising in liquid propulsion rocket using cryogenic fluid as a propellant is very important. Especially propellant temperature rising during stand-by after filling and pre-pressurization can bring into cavitation in turbo-pump. One of the method preventing propellant temperature rising in cryogenic feeding system is recirculating propellant through the loop composed of propellant tank, feed pipe, and recirculation pipe. The circulation of propellant is promoted through gas-lift effect by gas injection to lower position of recirculation pipe. In this experiment liquid oxygen and gas helium is used as propellant and injection gas. Under atmospheric and pressurized tank ullage condition, helium injection flow-rate is varied to observe the variation of recirculating flow-rate and propellant temperature in the feed pipe. There is appropriate helium injection flow-rate for gas-lift recirculation system.

• Journal of Plant Biotechnology
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• v.29 no.4
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• pp.223-228
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• 2002

We have developed a homemade particle inflow gun (PIG) system which has simple operation method, low price and high gene introduction efficiency into rice callus. Rice callus were inflowed with gold particles containing DNA of a plasmid, pIG121Hm, harboring intron GUS ($\beta$-glucuronidase) gene, NPTII gene and HPT gene. For optimal GUS transient expression, the effects of parameters on DNA delivery efficiency of the PIG system was investigated by scoring transient GUS expression. The highest number of blue spots was observed at 16 mM of spemidine and 1.5 M of calcium chloride, respectively. And the amount of gold particles required for the best GUD expression was 2 mg. Optimum GUS transient expression was observed at target distance of 12 cm and helium pressure of 3.5 bar (50 psi). Gene introduction efficiency of the PIG system was observed almost similar to that of the Biolistic Gun (Bio-Rad Company). Since PIG system is simple to operate and one doesn't need disposable accessaries, the PIG system can be easily applied to various replication experiments.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.11a
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• pp.319-322
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• 2006

Rapid mixing of air-fuel (<1 ms) is needed to accomplish supersonic combustion. In this experiment, helium was injected laterally in to the Mach 1.92 air flow. 2 kinds of model, flat plate/cavity, were used in this experiment and images were taken by schlieren visualization. Pressure was affected by shock structure in the supersonic duct, and penetration height was increased by increasing J. Penetration height was higher in the cavity model than flat plate model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1080-1083
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• 2017

In the design of KSLV-II, there is a scenario in which supercooled liquid oxygen is supplied to prevent a geysering phenomenon in the oxidizer pipe and a cavitation phenomenon at the pump inlet. To verify this condition in the engine development test phase, a system that supplies supercooled liquid oxygen to the engine was applied in the engine combustion test facility. In this system, supercooling methods using a vacuum ejector and using helium injection to the tank were appied. Both tests were carried out for about 17 minutes. Supercooling results of about 3.3K for the ejector test and about 2.2K for the helium injection test were obtained at the 50% level of the tank.