• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.2
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• pp.54-61
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• 2007

Propellant pressurization system in liquid rocket propulsion system plays a role supplying pressurant gas at a controlled pressure into the ullage space of propellant tanks. The most important design parameter for such propellant pressurization system is the temperature of pressurant gas fed from pressurant tank. Such pressurant is gaseous state, of which density is very sensitive to the temperature of pressurant. Generally for the propulsion system, which requires high thrust and is consisted of cryogenic propellant the pressurant is stored at high density and high pressure to reduce the weight of pressurant tanks, which are placed inside of cryogenic propellant tank. That is called cryogenic storage pressurization system. This study investigates the temperature variation of pressurant at the time when the pressurant is coming out of pressurant tank experimentally as well as numerically. Fluids used in this study are air and liquid oxygen as outer fluid and gaseous nitrogen and gaseous helium as pressurant respectively.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.38 no.12
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• pp.1202-1208
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• 2010

The prediction of the required pressurant mass for maintaining the pressure of propellant tanks during propellant feeding is an important issue in designing pressurization system. The temperature of pressurant fed into propellant tank is the critical factor in the required pressurant mass and is one of the most crucial design parameters in the development of pressurization system including designing the weight of pressurant tanks and the size of heat exchanger. Hence a series of propellant drainage tests by pressurizing propellant stored in a cryogenic propellant tank have been performed with measuring the temperature distribution inside ullage and the required pressurant mass according to the temperature condition of pressurant. Results shows that the required pressurant mass decreases as the temperature of pressurant increases. However, the rate of the actual pressurant mass to the ideal required pressurant mass increases.

• Journal of the Korean Society of Propulsion Engineers
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• v.20 no.1
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• pp.37-42
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• 2016

In this study, we examined the burning rate of the uncured propellant (with and without a curing agent application) in order to inspect the process of the HTPB solid propellant. The burning rate of the uncured propellant, that did not contain the curing agent, was approximately 9.7 mm/s at 1000 psi. In relation to the curing time, the burning rate was constant. The propellant, with the curing agent application, was approximately 8.1 mm/s showed a tendency of slowing as it burned. When the cure reaction rate was low, in accordance to the time, there were small changes in burn rate. However, when the cure reaction rate was high, the difference in burning rate was increased. The burning rate of a fully-cured propellant was approximately 6.8 mm/s, which appeared to be the lowest in order.

• Journal of the Korean Society of Propulsion Engineers
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• v.6 no.3
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• pp.9-17
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• 2002

This Study is to investigate 8 composite propellants including Butacene and ${Bi_2}{O_3}$ by Shotgun/RQ Bomb test. Burning rate and mechanical properity are known to be major factors in determining the deflagrability of propellant. Propellant including over 5.5% Butacene(Ferrocene grafted HTPB) burned out over 135 m/s of impact velocity during Shotgun/RQ Bomb test. It was blown that Butacene was very sensitive material under high velocity impact. In the test results, propellants under 25mm/s in burning rate at 1500 psia could meet the requirements for IM of UN Test Series 7c(ii). Propellant deflagrabillity depends on burning rate at performance in the results of the present.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.43 no.12
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• pp.1116-1123
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• 2015

The lifetime of a geostationary satellite depends on the residual propellant amount and therefore the precise residual propellant gauging is very important for the mitigation of economic loss arised from premature removal of satellite from its orbit, satellites replacement planning, slot management and so on. In this paper, the thermal mass method and its uncertainty are described. The residual propellant analysis of a geostationary satellite is simulated based on the KOREASAT data and the uncertainty of thermal mass method is calculated by using the Monte Carlo method. The results of this study show the importance parameter of estimation residual propellant using the thermal mass method.

• Journal of the Korean Society of Propulsion Engineers
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• v.19 no.5
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• pp.71-77
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• 2015

Internal ballistics is a phenomenon happened in tens of milliseconds during the gun firing. The configuration variables of the solid propellant are important factors which have influences on the performance of the gun system. In this study, the performance analysis of the 7-perforated propellant has been conducted using the numerical program for the interior ballistics. The effect of the configuration variables on the gun system performance has been analyzed. The propellant design has been conducted for the satisfaction of the performance requirements. As results, the relationship between the configuration variables and the performance has been obtained and the basic design concept of the multi-perforated propellant has been provided.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.207-210
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• 2009

The AP/HTPB composite propellant is a common choice for solid rocket propulsion. The externally heated rocket via fires, for instance, can cause the energetic substance to ignite, and this may lead to a thermal runaway event marked by a severe explosion. In order to develop preventive measures to reduce the possibility of such accidents in propulsion systems, we investigate the ignition and initiation properties of AP/HTPB propellant.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.11a
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• pp.279-282
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• 2008

The AP/HTPB composite propellant is a common choice for solid rocket propulsion. The externally heated rocket via fires, for instance, can cause the energetic substance to ignite, and this may lead to a thermal runaway event marked by a severe explosion. In order to develop preventive measures to reduce the possibility of such accidents in propulsion systems, we investigate the ignition and initiation properties of AP/HTPB propellant.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.5
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• pp.57-64
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• 2010

A performance test of inter propellant seal for a 75 ton class turbopump is conducted using water to evaluate leakage and endurance performance. Each part of fuel pump side and oxidizer pump side for a prototype inter propellant seal has been tested for verifying endurance performance during total accumulated test time 2,100 sec in water. The fuel pump side part with one-stage seal of carbon floating ring shows average leakage rate 13.7 gram/sec under average seal differential pressure 9.4 bar. On the other hand, the oxidizer pump side part with two-stage seal assembly of carbon floating rings shows average leakage rate 7.3 gram/sec under average seal differential pressure 9.5 bar. After the endurance performance test, the inter propellant seal shows good physical condition. A leakage performance test of the inter propellant seal for cryogenic environment will be performed using LN2 in the near future.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.47-53
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• 2010

A performance test of a 75 ton class turbopump inter propellant seal is conducted using water to evaluate leakage and endurance performance. Each fuel pump side part and oxidizer pump side part of a prototype inter propellant seal has been tested for verifying endurance performance during total accumulated test time 2,100 sec in water. The fuel pump side part with 1 stage carbon floating ring seal shows average leakage rate 13.7 gram/sec under average seal differential pressure 9.4 bar. On the other hand, the LOx pump side part with 2 stage carbon floating ring seal shows average leakage rate 7.3 gram/sec under average seal differential pressure 9.5 bar. After the endurance performance test, the inter propellant seal shows good physical condition. A cryogenic leakage performance test of the inter propellant seal will be performed using LN2 in the near future.