• The KSFM Journal of Fluid Machinery
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• v.17 no.5
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• pp.72-77
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• 2014

Because of overload working condition of sintering cooler, the cooler fan often suffers the break or damage of rotor blade and fixing shaft. Therefore, internal flow characteristics of a steelworks sintering cooler fan by the duct shape of the cooler fan outlet, such as duct outlet opening ratio, duct height and dividing wall shape on the duct outlet flow pattern are examined in detail. The results show that relatively short duct wall height and attachment of dividing wall shape improves flow patterns considerably.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.1
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• pp.89-94
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• 2016

This study investigates the durability of the radiator and cooler of a laptop through a thermal analysis. In the result of this study, the maximum deformation happened at the part holding up the support stand at the radiator and cooler. The maximum thermal stress of the cooler was 60.939 Mpa, as low as that of the radiator. In addition, the safety factor of the cooler was 1.64 times as high as that of the radiator. The radiator of the laptop was less durable than the cooler. The result of this study could help with designing a laptop model with a durable radiator and cooler.

• Transactions of the Korean Society of Automotive Engineers
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• v.11 no.6
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• pp.44-50
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• 2003

Cooled EGR is an effective method for the reduction of NOx from a diesel engine and an EGR Cooler is the key component of the system. High efficiency, low pressure loss and compactness are required for the EGR Cooler. To meet these requirements, new geometric tube must be developed. In this paper, a full size EGR cooler test bench has been developed to validate the CFD flow and heat transfer models. Fluid temperature and pressure drop measurements are provided. fillet temperature is $200^{\circ}C$ and $300^{\circ}C$, and flow rates vary from 0.008 kg/sec to 0.019 kg/sec. The gas flow and heat transfer in a single tube cooler have been studied using computational fluid dynamics(CFD). Analysis has been carried out in a single tube with a plain tube and six spirally enhanced tubes of varying pitch to depth ratio(p/e).

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2609-2614
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• 2007

Shell & Tube type Oil Cooler is widely used for hydraulic presses, die casting machines, generation equipments, machine tools and construction heavy machinery. Temperature of oil in the hydraulic system changes viscosity and thickness of oil film. They have a bad effect to performance and lubrication of hydraulic machinery, so it is important to know exactly the heat exchanging efficiency of oil cooler for controlling oil temperature. But most Korean manufacturers do not have test equipment for oil cooler, so they cannot carry out the efficiency test of oil cooler and it is impossible to verify its performance. This paper includes information of construction of necessary utilities for oil cooler test and design and manufacture of test equipment. One can select the optimum product by obtaining performance data through tests of various kinds of oil coolers. And also the paper developed a program which can be easily used for design of 2D and 3D drawings of oil cooler.

• Journal of Power System Engineering
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• v.15 no.3
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• pp.25-30
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• 2011

A shell-and-tube oil cooler with plate fins was suggested to improve the defect of the conventional shell-and-tube oil cooler. Experiments were conducted to evaluate the heat transfer performance on the shell side of shell-and-plate finned tube oil cooler with three different tube numbers(9, 13 and 19). Oil flowing on the shell side was cooled by cold water flowing inside the tubes. A shell-and-tube heat exchanger of an oil cooler consisted of one shell pass and two tube passes with the inner tube diameter of 8.82 mm and the tube length of 575 mm. From the experiment of shell-and-tube oil cooler, it was found that the heat transfer coefficient of oil cooler with 9 tubes, as oil flow rate was increased, was approximately 140% and 250% higher than that of 13 and 19 tubes, respectively. The heat transfer coefficient at the water flow rate of $3m^3/h$, also was 120% and 140% higher than that of 2.4 and $1.8m^3/h$, respectively.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.3
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• pp.60-65
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• 2008

A typical louvered-fin oil cooler can be easily contaminated under dusty environment hence resulting in poor performance of a heat exchanger. Thus, in this study, a dust-proof oil cooler has been studied with a unique shape of a 3-dimensional wavy fin since non-louvered fins could have better performance under dusty environment compared to louvered fins. Recently, they have been introduced to commercial and constructional vehicles in Japan. At first numerical analysis has been done to optimize the angle of the wavy fin so that the oil cooler developed can satisfy the target performance. The wavy fin has been then made with roll-forming and roll-pitch stands, and a prototype of an oil cooler with the wavy fin has been finally built with brazing. The performance test showed that the heat release rate of the oil cooler was well beyond the target, 4.94kW and the air-side pressure drop was below the criterion, 0.19kPa. In addition, the results showed that the numerical prediction was effective enough to design the dust-proof oil cooler that satisfies the performance criteria.

• Progress in Superconductivity and Cryogenics
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• v.24 no.1
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• pp.23-28
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• 2022

A sorption cooler, which utilizes helium-4 as a working fluid, was previously developed and tested in KAIST. The cooler consists of a sorption pump and a thermosyphon. The developed sorption cooler aims to pre-cool a certain amount of the magnetic refrigerant of an adiabatic demagnetization refrigerator (ADR) from 4.5 K to 2.5 K. To simulate the high heat capacitance of the magnetic refrigerant, liquid helium was utilized not only as a refrigerant for the sorption cooling but also as a thermal capacitor. The previous experiment, however, showed that the lowest temperature of 2.7 K which was slightly higher than the target temperature (2.5 K) was achieved due to the radiation heat leak. This excessive heat leak would not occur when the sorption cooler is completely integrated with the ADR. Thus, based on the experimentally obtained pumping speed, the prediction model for the sorption cooler is developed in this study. The presented model in this paper assumes the sorption cooler is integrated with the ADR and the heat leak is negligible. The model predicts the amount of the liquid helium and the required time for the sorption cooling process. Furthermore, it is confirmed that the performance of the sorption cooler is enhanced by reducing the volume of the thermosiphon. The detailed results and discussions are summarized.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.11
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• pp.432-436
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• 2016

The cooler, which is the main part in a Thermal Observation Device (TOD), makes the TOD function by reducing the temperature. As the cooler is imported, overseas enterprises presented 20,000 hours as the operation time and the military have used the cooler as presented. However, failures have occurred occasionally after mass production stage. Therefore, we need to analyze the MTBF of the TOD cooler. So, military and defense industry companies collected the failure data of the TOD cooler. We analyze the MTBF of the TOD cooler using survival probability function and failure data. We find the optimal distribution by applying parametric method and estimate parameters. We determine that the Log-logistic distribution is the most appropriate for this data. Also, we analyze the reliability per hour of the TOD cooler. The result of MTBF of the TOD cooler was higher than that of presented by oversee enterprises.

• Journal of Advanced Marine Engineering and Technology
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• v.34 no.1
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• pp.30-36
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• 2010

The heat flowrate and pressure drop of $CO_2$ in a multi-tube-in-tube helical coil type gas cooler were investigated experimentally. The mass flowrate of $CO_2$ and coolant were varied from 0.06 to 0.075 [kg/s], respectively and the cooling pressure of gas cooler were from 8 to 10 [MPa]. The heat flowrate of $CO_2$ in the test section is increased with the increase in mass flowrate of coolant, the cooling pressure and mass flowrate of $CO_2$. The pressure drop of $CO_2$ is decreased with the decrease in mass flowrate of coolant and $CO_2$, but decreased with increase in cooling pressure of $CO_2$. The heat flowrate of $CO_2$ in the multi-tube-in-tube helical coil type gas cooler is greatly higher than that of $CO_2$ in the double pipe type gas cooler, while the pressure drop of $CO_2$ in the multi-tube-in-tube helical coil type gas cooler is greatly lower than that of $CO_2$ in the double pipe type gas cooler. Therefore, in case of the application of $CO_2$ at the multi-tube-in-tube helical coil type gas cooler, it is expected to carry out the high-efficiency, high-performance and compactness of gas cooler.

• Proceedings of the KSME Conference
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• 2003.04a
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• pp.1518-1523
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• 2003

The objective of the present work is to investigate an effect on the solution crystallization temperature difference and the cooling capacity of the absorption chiller by a solution cooler in the absorber. The cooling capacity of the absorption chiller can be higher, with the enhanced performance of the solution heat exchangers. But, because the solution crystallization temperature difference becomes smaller at the absorber inlet, the heat capacity of the solution heat exchangers might be limited by the danger of crystallization, which can cause the serious damages. In this paper, the heat capacity ratio of the solution cooler is defined as the ratio of the heat capacity of the solution cooler to that of the absorber. If it becomes larger in the additional type solution cooler, the solution crystallization temperature difference is augmented and the cooling capacity is also increased.