• Journal of the Korean Society of Propulsion Engineers
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• v.10 no.4
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• pp.85-92
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• 2006

A design program has been developed to predict film cooling performance of a liquid rocket engine. A thermal protecting effect of low mixture ratio gas layer has been analysed by CFD. A one-dimensional film cooling model based on the CFD results has been implemented to the previously developed design program of regenerative cooling. Satisfactory agreement has been achieved by comparing the predicted maximum heat flux at the throat of a subscale chamber and the average measured value, and the predicted nozzle average heat flux and the measured value for a full scale chamber with film cooling. It is ascertained that the film cooling is effective to reduce the throat heat flux in rocket engine chamber.

• The KSFM Journal of Fluid Machinery
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• v.18 no.1
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• pp.37-43
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• 2015

A Beta-type Stirling engine is developed and tested on the operation stability and cycle performance. The flow rate for cooling water ranges from 300 to 1500 ml/min, while the temperature of heat source changes from 300 to $500^{\circ}C$. The internal pressure, working temperatures, and operation speed are measured and the engine performance is estimated from them. In the experiment, the rise in the temperature of heat source reduces internal pressure but increases operation speed, and overall, enhances the power output. The faster coolant flow rate contributes to the high temperature limit for stable operation, the cycle efficiency due to the alleviated thermal expansion of power piston, and the heat input to the engine, respectively. The experimental Stirling engine showed the maximum power output of 12.1 W and the cycle efficiency of 3.0 % when the cooling flow is 900 ml/min and the heat source temperature is $500^{\circ}C$.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2006.05a
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• pp.161-164
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• 2006

A design program has been developed to predict film cooling performance in a liquid rocket engine combustion chamber. A thermal protecting effect of low mixture ratio gas has been analysed by CFD. A one-dimensional film cooling model based on the CFD results has been implemented in the previously developed design program of regenerative cooling. The predicted heat flux at the nozzle throat ranges from -16% to +28% when it is compared to the published measured data. The throat heat flux reduces by 36% when film cooling of 10% of fuel mass flow rate is applied.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.341-344
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• 2006

In this analytical study on the engine coolant flow of a heavy-duty diesel engine with 4 valves and linear-type 8 liter 6 cylinders, the characteristics of pressure drop and engine cooling performance with the additional coolant passages between cylinder blocks have been investigated. Since the most part of pressure drop is caused by the coolant flow passages inside a cylinder head and cylinder blocks for this type of heavy-duty diesel engines, the advantage of pressure drop is just 2.6% and the characteristics of heat transfer and the distribution of coolant velocities in the head part show little differences in case of additional coolant passages. Thus the coolant flow passages between cylinder blocks make little contribution on the cooling performance of heavy-duty diesel engines

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.148-154
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.3
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• pp.24-29
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• 2013

An automotive cooling system is designed sufficiently large enough to endure the excessive heat load. In general driving condition, the cooling systems are too large to operate optimally. An experimental study was performed to evaluate a novel automotive cooling strategy using the latent heat of a phase change material (PCM). The strategy is expected to reduce the cooling system size up to around 35% and the engine warm-up time around 60%. The strategy will help improve fuel economy and emissions characteristics of vehicles as a result of reduced total body weight and shortened engine warm-up time by a smaller radiator, as well as more stable combustion mode due to constantly maintained coolant temperature.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.6
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• pp.71-75
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• 2005

An experimental study was carried out to investigate the effect of film cooling in the lab-scale dump-cooled liquid rocket engine using LOX and kerosene as propellants. The nozzle of the rocket engine was film cooled with water as coolant. A special film cooling adapter was fabricated to introduce the film-coolant into the thrust chamber. The flow rates of film coolant was approximately 15~19 percent of the total propellant. The nozzle heat flux was determined from the measured temperature rise and flow rate of the coolant(water). Large reductions in the nozzle heat flux was resulted when film cooling adapter located directly upstream of the nozzle.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.170-173
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• 2007

Cooling characteristics of a liner were investigated by a film cooling method using a gas nitrogen in a rocket engine. High temperature gas of this test was made by mixing liquid nitrogen with combustion gas of a liquid rocket. A supply system of gas nitrogen was additionally constructed to the existing test facility of liquid rocket engine, and a new test section consisted of a liner and a gas injection ring was manufactured. A 10 second firing test for finding cooling characteristics of the liner was successfully conducted and liner surface temperatures and hot gas temperature was obtained.

• Aerospace Engineering and Technology
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• v.8 no.2
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• pp.133-139
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• 2009

An analysis has been performed on the specific impulse for a liquid rocket engine of gas generator cycle. The present analysis method has been validated through the comparison of the optimal specific impulse for the 300t thrust conceptual engine against the published data. The engine specific impulse can be increased by applying film coolant decreasing the fuel pump head for regenerative cooling despite the decrease of specific impulse of the combustion chamber when the film coolant participates combustion more than the critical amount. The improved condition shows that higher combustion chamber pressure is achieved with less fuel pump head rise by additional film cooling.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.1
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• pp.79-87
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• 2015

In a gas engine, the exhaust and the engine cooling water are generated. The engine cooling water temperature is $100^{\circ}C$ and the exhaust temperature is $500^{\circ}C$. The amount of heat of engine cooling water is 43 kW and the amount of heat of exhaust is 21 kW. Eight different hybrid organic Rankine cycle (ORC) system configurations which considering different amount and temperature of waste heat are proposed for two gas engine tri-generation system and are thermodynamically analyzed. Simple system which concentrating two different waste heat on relatively low temperature engine cooling water shows highest thermal efficiency of 7.84% with pressure ratio of 3.67 and shaft power of 5.17 kW.