• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.238-244
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• 2003

An experimental study was performed to examine the heat transfer performance of individual rows of fin-tube heat exchangers. The heat transfer performance was measured using air-enthalpy type calorimeter. The examined heat exchangers consists of $7{\Phi}$ tube and fin patterns of them are slit and louver types. Equivalent fin spacing are 18 FPI for all samples, and the number of tube rows were 2. In order to confirm that thermal boundary condition on fins of each row are the same, physically separated between two rows as well as connected heat exchangers were used. The frontal air velocity varied from 0.7 to 2.5 m/s. Heat transfer performance for each row are measured. It was observed that the heat transfer coefficient of the 2nd row were smaller than that of the 1st row at low Reynolds number while larger at high Reynolds number.

• 설비공학논문집
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• 제15권8호
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• pp.667-673
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• 2003

Recent trends in the electronic equipment indicate that the power consumption and heat generation in a chip increase as the components are miniaturized and the computing speed becomes faster. Suitable heat dissipation is required to ensure the guaranteed performance and reliable operation of the electronic devices. The aim of the present study is to investigate the forced-convective thermal-hydraulic characteristics of a pin-fin heat exchanger as a candidate for cooling system of the electronic devices. The influence of the structure of the pin-fin assembly on heat transfer is investigated by porous medium model. The results are compared with the experimental data or correlations of several researchers for the heat transfer coefficients for the channel flow with pin-fin arrays. Finally, the effects of design parameters such as the pin-fin diameter and the spacing are examined.

• 설비공학논문집
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• 제2권4호
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• pp.288-294
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• 1990

A study has been conducted experimentally on heat transfer characteristics of louvered fin heat exchangers with various fin spacings in air. The experimental results are as follows; 1. Mean heat transfer coefficient is increased with increasing air velocity and the optimum fin spacing shows at S=5mm. 2. Pressure drop is increased with increasing air velocity and its maximum value shows at S=3.5mm and its minimum value shows at S=6mm. 3. $\bar{h}/{\Delta}P$ is decreased with increasing air velocity and its maximum value shows at S=5mm and its minimum value shows at S=3.5mm.

• 한국군사과학기술학회지
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• 제14권6호
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• pp.1178-1185
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• 2011

In the present study, a recuperator is suggested to improve the thermal efficiency of a micro gas turbine. Primary design parameters of the recuperator are determined from the ideal cycle analysis. The counter flow plate-fin heat exchanger with offset strip fins is chosen as the type of the recuperator. In order to satisfy the design constraints which are the minimum effectiveness and the maximum pressure drop, the optimization for the internal structure of the recuperator is performed with varying the fin spacing and the fin height of offset strip fins. Also the effects of the thermal conductivity of fins and separation plates and the longitudinal heat conduction on the thermal performance of the recuperator are investigated.

• 설비공학논문집
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• 제16권7호
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• pp.623-629
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• 2004

Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices, which result in more heat generation by the electronic system. Present cooling technology may not be adequate for the thermal management in the current state-of-the-art electronic equipment. Forced convective heat transfer in a channel filled with pin-fin array is studied experimentally in this paper as an alternative cool-ing scheme for a high heat-dissipating equipment. Various configurations of the pin-fin array are selected in order to find out the effect of spacing and diameter of the pin-fin on the heat transfer and pressure drop characteristics. In the low porosity region, interfacial heat transfer and pressure drop seem to show different trend compared to the conventional heat transfer process.

• 설비공학논문집
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• 제19권5호
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• pp.418-425
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• 2007

The power consumption and heat generation in a chip increase as the components are miniaturized and the computing speed becomes faster. Therefore, suitable heat dissipation has become one of the primary limiting factors to ensure the guaranteed performance and reliable operation of the electronic devices. A pin-fin array which may be considered as a porous medium could be used as an alterative cooling system of the electronic equipment. The aim of the present study is to investigate the forced-convective heat transfer characteristics of pin-fin heat exchangers. Convective heat transfer through the pin~fin array is analyzed experimentally based on porous medium approach. The influence of the structure of the pin-fin array including the pin-fin spacing, the pin diameter and plate length on heat transfer characteristic is investigated and compared with the Previous analytical results and existing correlation equations. Nowadays, electronic and mechanical devices become smaller and smaller. In this sense, the main purpose of this study is to decide the optimum pin-fin arrangement to get similar heat transfer performance when the length of the existing cooling system is reduced as a half.

• Journal of Mechanical Science and Technology
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• 제14권12호
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• pp.1421-1428
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• 2000

The characteristics of heat transfer and pressure drop for fully developed turbulent flow in a tube with circumferential fins and circular were experimentally studied. The various spacing and sizes of circumferential fins and circular disks were selected as design parameters, while the effects of these parameters on heat transfer enhancement and pressure drop were investigated. In order to quantify the effect of heat transfer enhancement and the increase of pressure drop due to the fins and disks in a tube, the Nusselt numbers and the friction factors for various configurations and operating conditions were compared to those for a corresponding smooth tube. The results showed that the heat transfer rate was significantly enhanced by increasing the height of circumferential fins and decreasing the pitch of circumferential fins. On the other hand, the influence of the disk size and the fin-disk spacing were not significant. Based on the experimental results, a correlation for estimating the Nusselt number was suggested.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.2408-2413
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• 2007

Since the heat generation in a chip increases as the components are miniaturized and the computing speed becomes faster, suitable heat dissipation has become one of the primary limiting factors to ensure the reliable operation of the electronic devices. A pin-fin array could be used as an alterative cooling system of the electronic equipment. In this study, convective heat transfer through the pin-fin array is analyzed experimentally based on porous medium approach. The influence of the structure of the pin-fin array including the pin-fin spacing, the pin diameter and plate length on heat transfer characteristics is investigated and compared with the previous analytical results and existing correlation equations. Nowadays, electronic and mechanical devices become smaller and smaller. In this sense, the main purpose of this study is to decide the optimum pin-fin arrangement to get similar heat transfer performance when the length of the existing cooling system is reduced as a half.

• 설비공학논문집
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• 제18권6호
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• pp.459-467
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• 2006

Rapid development of electronic technology requires small size, high density packaging and high power in the electronic devices, which results in more heat generation. Suitable heat dissipation is required to ensure the guaranteed performance and reliable operation of the current state-of-the-art electronic equipment. The aim of the present study is to find out the forced-convective thermal-hydraulic characteristics of a pin-fin heat exchanger as a candidate for cooling system of the electronic devices through the analysis and experiment. Various configuration of the pin-fin array is selected in order to find out the effect of spacing and diameter of the pin-fin on the heat transfer and pressure drop characteristics. Experimental results are compared with the analyses and correlations of several researchers. Finally, the design guide are provided for the required pressure drop and/or the heat transfer characteristics of the heat exchanger.

• International Journal of Air-Conditioning and Refrigeration
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• 제14권2호
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• pp.49-56
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• 2006

Heat transfer performances of individual row of two-row fin and tube heat exchangers are experimentally investigated. Tested are four heat exchangers which are geometrically identical with the exception of fin shape, slit or louver, and that the fins between the first row and the second row are connected or separated. The tube diameter and fin spacing of the heat exchangers examined are 7mm and 1.4mm, respectively. All thermal fluid measurements are made using a psychrometric calorimeter. In order to evaluate air-side heat transfer coefficients of individual rows, tube-side water flow rates of individual rows are independently controlled such that the water-side temperature drops in each row remain at $5^{\circ}C$. Frontal air velocity varies in the range from 0.7m/s to 2.5m/s. Heat transfer coefficients are presented in terms of Colburn ${\jmath}-factor$. The results show that the heat transfer coefficient of the upstream row is larger than that for the downstream row at low Reynolds numbers.