• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.4
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• pp.76-81
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• 2003

To investigate the convective heat transfer phenomena inside the Lox/Kerosene liquid rocket combustion chamber, hot fire tests were performed by using a water-cooled calorimetric chamber. The calorimetric chamber consists of one cylindrical section and nozzle section with independent cooling passage. To measure the heat flux, thermocouples were installed inlet and outlet of cooling passage of each section. The investigated range of combustion chamber pressure is from 100 psi to 300psi at fixed O/F ratio of 2.0 and radiation heat transfer from the hot gas to the surface is not considered. The measured heat flux was almost linearly depended on the chamber pressure.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.78-81
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• 2009

A series of hydraulic tests of a fuel pump are performed using water at a room temperature. The pump is under development for 75-ton class liquid rocket engines of the open-loop gas generator type. According to the test results, the fuel pump satisfies its design requirement and its head and efficiency at the design flowrate are higher than the expected value by the computational analysis. Also, it is found that the pressure at the rear bearing outlet is higher than expected because the inlet of bypass pipe line is narrow. Furthermore, the flowrate of the secondary flow is estimated using the pressure difference of the elbow of the bypass pipe line.

• Journal of ILASS-Korea
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• v.1 no.3
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• pp.37-50
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• 1996

Computational fluid dynamics was used to optimize an A/C duct. Three dimensional flow analysis in an automotive A/C duct was performed computationally using various turbulence models and compared numerical predictions such as outlet flow split, surface pressure distribution along the duct to experimental data. Additionally, we studied the effect of location variation of 2nd branch on exit flow ratio and could find optimal location of 2nd branch. The design of an A/C duct was modeled and calculated to enhance the airflow distribution in each outlet using the STAR-CD computational fluid dynamics software. In results, modified $k-\varepsilon$ turbulence model allows a successful prediction of static pressure distribution particulary at around strong curvature but little improvement flow split. In the future, adoption of CFD to design an A/C duct with modified $k-\varepsilon$ model will bring benefits of producing more accurate prediction, and also give designers more detail information much more than now.

• Journal of the Korean Institute of Gas
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• v.10 no.4 s.33
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• pp.1-5
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• 2006

With the rapid increase in gas consumption, the role of pipelines as a transportation means of natural gas is increasing. In general, when natural gas is being transported in pipelines, some liquid mainly from formation of condensate is introduced and this phenomenon makes operational problems more complex in the gas industry. Thus, an appropriate method is necessary for predicting the effect of presence of gas condensate on operational efficiency. In this study, a statistical model was developed using an integrated single- and two-phase flows concept. Using this model, the effects of the incipient point of gas condensate and its quantity on outlet pressure were analyzed. Also, the effect of variations of flow regimes in two-phase region on outlet pressure after the incipient point was analyzed.

• Journal of ILASS-Korea
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• v.4 no.3
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• pp.32-41
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• 1999

In this research, internal-mixing twin-fluid atomizer using sonic energy is designed and manufactured. We are trying to intimate high efficiency twin-fluid atomizer to obtain good liquid atomization in the low pressure region. Define of geometric form of atomizer, characteristics of spray is influenced by position, depth and height variation of cavity resonator, variation of sound intensity and resonant sound frequency with liquid flow rate. The liquid atomization is promoted by multi-stage disintegration of mixing flow of gas with liquid and the optimum condition of position and depth of cavity resonator according to sonic energy is obtained from the condition at a=2.5mm and L=2mm. The velocity distribution of droplets shows negative value due to recirculation region at the center of axial, and as the radial direction distance is far, the velocity distribution of droplets decrease slowly after having a maximum value. However velocity and SMD show nearly uniform distribution at the down stream and as result compared to Nukiyama and Tanasawa's equation. atomization of mixing flow with air and liquid dispersing from the outlet of the nozzle is promoted by the effect of collision at the cavity resonator.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.34 no.3
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• pp.346-351
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• 1998

The purpose of this study is analyzing the performance of sea water cooling system under various refrigerant pipe length. In sea water cooling system, the increase of refrigerant pipe length cause increases of pressure drops. These pressure drops cause fresh gas in liquid pipe and increase specific volume in gas pipe outlet, so sea water cooling system capacity is decreased by decrease of refrigerant mass flow rate. Sea water cooling system capacity in refrigerant pipe length 70m is decreased more than 30% when compared with pipe length 10m and the decrease of the coefficient of performance is nearly 20%.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.34-37
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• 2007

Propellant filling and holding test was carried out using liquid oxygen as a working fluid. The feeding line system has a filter at propellant tank outlet. Vaporization of liquid oxygen during holding after completion of filling and effect of vaporization to recirculation performance in this system was observed. Filling rate and pressure of tank ullage had the effect on state of liquid oxygen in feeding line. There was no geysering in feeding line during holding because of the position of filter.

• Journal of Mechanical Science and Technology
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• v.20 no.10
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• pp.1765-1772
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• 2006

High-pressure die casting such as thixocasting and rheocasting is an effective process in the manufacturing automotive parts. Following the recent trend in the automotive manufacturing technologies, the product design subject to the die casting becomes more and more complex. Simultaneously the injection speed is also designed to be very high to establish a short cycletime. Thus, the requirement of the die design becomes more demanding than ever before. In some cases the product's shape can have multiple slender manifolds. In such cases, design of the inlet and outlet parts of the die is very important in the whole manufacturing process. The main issues required for the qualified products are to attain gentle and uniform flow of the molten liquid within the passages of the die. To satisfy such issues, the inlet cylinder ('bed cylinder' in this paper) must be as large as possible and simultaneously the outlet opening at the end of each passage must be as small as possible. However these in turn obviously bring additional manufacturing costs caused by re-melting of the bed cylinder and increased power due to the small outlet-openings. The purpose of this paper is to develop effective simulation methods of calculation for fluid flows in multiple columns, which mimic the actual complex design, and to get some useful information which can give some contributions to the die-casting industry. We have used a commercial code CFX in the numerical simulation. The primary parameter involved is the size of the bed cylinder. We will show how the very small opening of the outlet can be treated with the aid of the porous model provided in the code. To check the validity of the numerical results we have also conducted a simple experiment by using water.

• Journal of the Korean Society of Propulsion Engineers
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• v.22 no.5
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• pp.107-114
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• 2018

Korea Space Launch Vehicle (KSLV)-I flight test data and the modified 1-dimensional steady state modeling data from the critical design results of the KSLV-II liquid oxygen filling system operation are compared to validate the reliability of critical design modeling. A comparison of major flow rates and pressure values between test data and calculation results are conducted. The relative errors relative to maximum total flow rate for each cooling, filling, and replenishment mode are determined within 6.7%. Calculated pressure values at the outlet of the pump and the inlet of flow control valves are within 5.1%. The pressure at the inlet of the launch vehicle for each operation mode are within the measured pressure range.

• The KSFM Journal of Fluid Machinery
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• v.14 no.1
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• pp.61-65
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• 2011

A series of water tests of a fuel pump for liquid rocket engines are performed at a room temperature. According to the test results, the head coefficient of the pump follows the conventional similarity rule - unlike this, the pump shows better efficiency with higher rotational speed. Also, it is found that the pressure at the rear bearing outlet is higher than expected because the inlet of bypass pipe line is narrow. Furthermore, the cavitation performance of the fuel pump is found to be sufficient for the engine operation and is better at the lower flow ratio and higher rotational speed.