• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.294-296
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• 2017

In this study heat transfer characteristics of kerosene at supercritical condition was predicted. And a sample heat transfer calculation was performed using this result. The prediction was done by assuming kerosene as a mixture of a number of pure substances, and combining the thermodynamic properties of them, using NIST SUPERTRAPP. A regeneratively cooled supersonic combustor will be desinged using the resultant thermophysical property data of supercritical kerosene. Comparing with the combustion test results of the regenerative cooling combustor, the predicted thermophysical property data will be verified.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.114-118
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• 2007

Design and fabrication of a 30-tonf-class full-scale regenerative cooling combustion chamber of a liquid rocket engine for a ground hot firing test are described. It has chamber pressure of 60 bar and nozzle expansion ration of 12 and manufactured to have a single welded structure of· the mixing head and the chamber. The material of the mixing head is STS316L which has excellent mechanical property in cryogenic condition. The chamber comprise of the cylinder, nozzle throat, and 1st/2nd nozzle parts. The material of the inner jacket is copper alloy/STS329J1/STS316L and that of the outer jacket is STS329J1. The components of· the combustor were manufactured by mechanical processing including lathing, milling, MCT, rolling and pressing. The machined components were integrated to a single body by means of general welding, electron beam welding(EBW), and brazing.

• Transactions of the Korean Society of Automotive Engineers
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• v.22 no.1
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• pp.59-64
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• 2014

Integrated Starter Generator (ISG) system improves the fuel economy of hybrid electric vehicles by using idle stop and go function, and regenerative braking system. To obtain the high performance and durability of ISG motor under continuously high load condition, the motor needs to properly design the cooling system (cooling fan and cooling structure). In this study, we suggested the enhanced design by modifying the thermal design of the ISG motor and then analyzed the improvement of the cooling performance under high-speed condition and generating mode by CFD simulation. The temperatures at the coil and the magnet of the enhanced model were decreased by about $4^{\circ}C$ and $6^{\circ}C$, respectively, compared to those of the conventional model. Therefore, we verified the cooling performance enhancement of the novel thermal design in the case of core loss increment due to the higher speed condition.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.120-127
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• 2013

Hybrid electric vehicles have applied electric parts for saving fuel consumption and reducing levels of environmental pollution. Electrification of automobiles is indispensable for entering into global market because of enhanced environment restriction. ISG (Integrated Starter & Generator) system is one of main electric parts and can improve fuel efficiency more than other components by using Idle Stop & Go function and regenerative braking system. However, if ISG motor and inverter work under the continuously high load condition, it will make them the decrease of performance and durability. So the ISG motor and inverter need to properly design the cooling system of them. In this study, we suggested the enhancement points by modifying the thermal design of ISG motor and then confirmed the improvement of the cooling performance.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.2
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• pp.106-111
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• 2006

Combustion test facility for liquid rocket engine using kerosene and liquid oxygen has been developed for the purpose of cooling and performance study. Test engine of thrust under 1.0 KN can be evaluated, and the real combustion test ensures a good operation of the combustion test facility. Combustion test facility will be modified to supply natural gas and liquefied natural gas as fuel and to give a regenerative cooling test.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.12-15
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• 2011

The most widely used kerosene-LOx liquid-propellant rocket engines in these days have a similar engine schematic to those of the past because of the development cost and the reliability. The efficiency of engines could be increased by the factors such as a cooling method, engine cycles, shape of cooling channels, additional coolant and so on. In this article, it is described that some design ideas for performance enhancement by exchange kerosene with LOx of a coolant.

• Progress in Superconductivity and Cryogenics
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• v.14 no.3
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• pp.60-64
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• 2012

In this paper, an investigation of a room temperature active magnetic regenerative refrigerator is carried out. Experimental apparatus includes two active magnetic regenerators containing 186 g of Gd spheres. Four E-type thermocouples are installed inside the Active magnetic regenerator(AMR) to observe the instantaneous temperature variation of AMR. Both warm and cold heat exchangers are designed for large temperature span. The cold heat exchanger, which separates the two AMRs, employs a copper tube with length of 80 mm and diameter of 6.35 mm. In order to minimize dead volume between the warm heat exchanger and AMRs, the warm heat exchangers are located close to the AMRs. The deionized water is used as a heat transfer fluid, and maximum 1.4 T magnetic field is supplied by Halbach array of permanent magnets. The AMR plate, which contains the warm and the cold heat exchangers and the AMRs, has reciprocating motion using a linear actuator and each AMR is alternatively magnetized and demagnetized by a Halbach array of permanent magnet. Since the gap of the Halbach array of permanent magnets is 25 mm and two warm heat exchangers have the motion through it, a compact printed circuit heat exchanger (PCHE) is used as a warm heat exchanger. A maximum no-load temperature span of 26.8 K and a maximum cooling power of 33 W are obtained from the fabricated Active Magnetic Regenerative Refrigerator (AMRR).

• Journal of the Korean Society of Propulsion Engineers
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• v.8 no.4
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• pp.36-42
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• 2004

The Properties of material, C18200 which is used for development of high performance liquid rocket engine combustor chamber were obtained by tension tests. The specimen for regenerative combustor was designed by structural analysis using that Properties. After the designed specimen was manufactured by the same manufacturing process of regenerative combustor. the yielding stress and yielding strain were obtained by strength tests. The properties of C18200 was degraded very much after brazing. The estimation of yielding pressure by structural analysis was almost same as that of strength test. The collector Part was yielded and failed previously than that of cooling channel part during strength test.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.32 no.3
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• pp.66-73
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• 2004

As a rocket propellent of hydrocarbon fuels, the characteristics of liquefied natural gas was evaluated with the viewpoint of the constituents and content, the cooling performance as a coolant, and characteristic velocity and specific impulse as parameters of the engine performance. Content of methane was a principal factor to determine the characteristics as a rocket propellant and more than 90% of it was needed as a fuel and coolant in the regenerative cooled liquid rocket engine. Some constituents of the liquefied natural gas can be frozen by the pre-cooling of the pipe lines, therefore they can be a factor disturbing the normal working of engine. In case the content of methane is around 90% in the liquefied natural gas, a normalized stoichiometric O/F mixture ratio of 0.75 is suggested for a nominal operation condition to get the maximum specific impulse and characteristic velocity.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.139-143
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• 2007

The overall results of combustion tests performed for a 30 tonf-class full-scale combustion chambers of a liquid rocket engine were described. The combustion chambers have chamber pressure of 53${\sim}$60 bar and propellant mass flow rate of 89 kg/so The combustion chamber is composed of mixing head, SUS baffle, baffle injector, ablative chamber, channel cooling chamber and regenerative cooling chamber. The test results show that the combustion characteristic velocity is in the range of 1673${\sim}$1730 m/sec and the specific impulse of the combustion chamber is in the range of 254${\sim}$263 sec. As the recess number of the injectors increases, the combustion characteristic velocity increases. And as the combustion characteristic velocity increases, the specific impulse of the combustion chamber also increases.