• 제목/요약/키워드: 밀집형 열교환기

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미소열교환기법에 의한 밀집형 열교환기의 성능 계산 : 핀을 통한 튜브간 전도의 영향 (Computation of Compact Heat Exchanger Performance by the Heat Exchangelet Method : Effect of Tube-to-tube Conduction along the Fin)

  • 성시경;송태호;최영철
    • 설비공학논문집
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    • 제12권5호
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    • pp.494-501
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    • 2000
  • Effectiveness of a 3-pass plate finned-tube heat exchanger is calculated using heat exchangelet method by changing the shape of fin and the arrangement of tubes. The alternative refrigerant R134a is taken in this study. Conduction between neighboring tubes along the fin is taken into account in addition to convection between the fin and the surrounding air. Governing equations are obtained by using energy balance in a small control volume containing a tube and fins. They are numerically solved following the tube. Effect of tube-to-tube conduction is investigated in single-phase and two-phase flows with various fin shapes and arrangements of tubes. Improvement of effectiveness by fin perforation is studied too. The results shows that perforating fins, increasing the number of tubes, and increasing the distance between neighboring tubes at the same fin area enhance the effectiveness.

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원형관 및 납작관-평판휜 형상의 밀집형 열교환기에 대한 대류열전달 상관관계식 (Convective Heat Transfer Correlations for the Compact Heat Exchanger with Circular Tubes and Flat Tubes-Plate Fins)

  • 모정하
    • 대한기계학회논문집B
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    • 제34권3호
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    • pp.291-299
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    • 2010
  • 본 연구에서는 열의 수가 세 개인 원형관 및 종횡비가 고려된 납작관-평판휜 형상의 밀집형 열교환기 내 공기의 유동 및 열전달 특성을 RNG $k-{\varepsilon}$ 난류모델을 적용하여 수치적으로 해석하였다. 수치조건의 범위는 원형관인 경우 1,000<$Re_D_h$<10,000이며, 납작관인 경우 1,000<$Re_{D_h}$<10,000 및 3.06$f\;=\;CRe^m_{D_h}$의 형태로, Colburn j 계수는 $j\;=\;CRe^m_{D_h}$ 형태로 상관관계식을 제시하였다. 이러한 상관관계식은 향후 원형관 및 납작관-평판휜 형상의 열교환기 설계시에 기본적인 자료로 충분히 활용될 수 있을 것으로 판단된다.

밀집형 열교환기 내 공기 측 대류열전달특성 (Analysis for Air-Side Convective Heat Transfer Characteristics in Compact Heat Exchangers)

  • 모정하;이상호
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2009년도 하계학술발표대회 논문집
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    • pp.1443-1448
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    • 2009
  • Numerical analysis has been carried out to investigate air-side convective heat transfer characteristics in compact heat exchangers with continuous plate fins. Simulation results such as air flow and temperature distributions are presented, and heat transfer characteristics are compared for various inlet conditions. Results from various turbulence models are also compared for applicability. There is large difference between the local heat transfer coefficient distributions along the cylinder wall for circular tubes. Colburn j factors from the calculated results of circular and flat tubes in the heat exchangers are compared for various Reynolds number. The predicted results in this study can be applied to the optimal design of air conditioning system. with compact heat exchanger.

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밀집형 열교환기에 사용하는 평판핀 성능에 관한 수치적 연구 (Numerical investigation of plate fin performance for a compact heat exchanger)

  • 유재욱;송태호
    • 설비공학논문집
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    • 제11권3호
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    • pp.292-300
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    • 1999
  • Fin conduction not only enhances heat transfer to the ambient air but also increases tube-to-tube conduction. The latter is known to deteriorate the heat exchanger performance. Heat conduction between neighboring tubes thorough the fin is numerically investigated for accurate performance analysis of plate finned-tube heat exchangers. Governing equations for arbitrary plate fin are solved and the temperature distribution is obtained using the principle of superposition. Analysis is made using finite element method by changing the shapes of fin, the arrangements of tubes and the fin parameter mD. It is found that tube-to-tube conduction is significant when mD is small or the distance between neighboring tubes is small.

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마이크로채널과 핀 튜브 열교환기를 적용한 가정용 에어컨디셔너의 성능 평가 (Evaluation of Performance of a Residential Air-Conditioning System Using Microchannel and Fin-and-Tube Heat Exchanger)

  • 윤린
    • 설비공학논문집
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    • 제19권1호
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    • pp.28-35
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    • 2007
  • In this study the seasonal performance of a residential air conditioning system having either a fin-and-tube condenser or a microchannel condenser is experimentally investigated. A commercially available 7 kW capacity residential air conditioning system having a fin-and-tube condenser served as the base system. The test results show that the system with a microchannel heat exchanger has a reduced refrigerant charge amount of 10%, the coefficient of performance is increased by 6% to 10%, and the SEER is increased by 7% as compared with those of the base system. Moreover, the condensing pressure of the system is decreased by 100 kPa and the pressure drop across the condenser is decreased by 84%. The microchannel heat exchanger enhances the SEER of the residential air conditioning system by providing better heat transfers at reduced pressure drops.

비대칭 엇갈림 배열로 구성된 납작관-평판휜 형상의 밀집형 열교환기에 대한 대류열전달 특성 해석 (Analysis of Convective Heat Transfer Characteristics for the Compact Heat Exchanger with Flat Tubes and Plate Fins Having a Non-symmetric Staggered Arrangements)

  • 모정하;이상호
    • 대한기계학회논문집B
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    • 제33권5호
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    • pp.318-325
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    • 2009
  • Numerical analysis has been carried out to investigate air-side convective heat transfer characteristics in compact heat exchanger with flat tubes and continuous plate fins having a symmetric and non-symm etric staggered arrangements. Simulation results such as air velocity and temperature distributions are presented, and heat transfer coefficients are compared with previous experimental results. In order to investigate the flow and heat transfer features by periodic boundary conditions, the three blocks were used. Predicted heat transfer coefficients between the three blocks are similar while there are relatively differences, compared with the experimental data. From the calculated results a correlation for Colburn j factor in the compact heat exchanger system is suggested. The predicted results in this study can be applied to the optimal design of air conditioning system.

종횡비에 따른 납작관-평판휜 형상의 밀집형 열교환기 내공기 측 대류열전달특성에 대한 수치해석 (Numerical Analysis for the Air-Side Convective Heat Transfer Characteristics in a Compact Heat Exchanger with Flat Tubes and Plate Fins According to the Aspect Ratio)

  • 모정하
    • 대한기계학회논문집B
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    • 제32권9호
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    • pp.695-703
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    • 2008
  • Numerical analysis has been carried out to investigate air-side convective heat transfer characteristics in a compact heat exchanger with flat tubes and continuous plate fins according to the aspect ratio. RNG k-$\varepsilon$ model is applied for turbulence analysis. Simulation results such as air velocity and temperature distributions are presented, and heat transfer coefficients are compared with previous correlations for circular tubes. The numerical conditions are considered for the aspect ratios ranging from 3.06 to 5.44 and Reynolds number ranging from 1000 to 10,000. The results showed that heat transfer coefficients decreased with the increase of aspect ratio. From the calculated results a correlation of Colburn j factor for the considered aspect ratio in the compact heat exchanger system is suggested. The predicted results in this study can be applied to the optimal design of air conditioning system.

원형관-평판휜 형상의 밀집형 열교환기 내 공기 측대류열전달특성에 대한 수치해석 (Numerical Analysis for the Air-Side Convective Heat Transfer Characteristics in a Compact Heat Exchanger with Circular Tubes and Continuous Plate Fins)

  • 모정하;이상호
    • 대한기계학회논문집B
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    • 제31권12호
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    • pp.994-1001
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    • 2007
  • Numerical analysis has been carried out to investigate air-side convective heat transfer characteristics in a compact heat exchanger with circular tubes and continuous plate fins. Simulation results such as air velocity and temperature distributions are presented, and heat transfer coefficients are compared with previous experimental correlations. Three models of standard and RNG $k-{\varepsilon}$, and Reynolds stress are applied for turbulence model applicability. Predicted heat transfer coefficient from the models of standard and RNG $k-{\varepsilon}$ are very close to those of the heat transfer correlations while there are relatively large difference, more than 17 percentage in the result from the Reynolds stress model. From the calculated results a correlation for Colburn j factor in the compact heat exchanger system is suggested.

발포금속을 삽입한 밀집형 열교환기 최적 설계 (Optimum Design of a Compact Heat Exchanger with Foam Metal Insertion)

  • 이대영;진재식;강병하
    • 설비공학논문집
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    • 제13권7호
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    • pp.612-620
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    • 2001
  • The optimum design of a heat exchanger with porous media insertion is studied in this paper. It is considered that the aluminum foam metal is inserted in a flat plate channel and air flows through it. The influence of the microstructure of the foam metal on the pressure drop and heat transfer is investigated utilizing previous analytical results and existing correlation equations. Design parameters are identified as the unit-cell size and the ligament thickness of the porous medium, and their effects are examined. The results show that there exists optimum microstructure of the porous media maximizing heat transfer with a constant pressure drop. When the increase in the pressure drop is within a practically acceptable range, the increase in the heat transfer is dominated by the increase in the heat transfer area due to the porous medium insertion. Consequently, among the porous media with a constant pressure drop, the heat transfer is maximized with a microstructure with maximum specific surface area.

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배기열(排氣熱) 회수용(回收用) 평판(平板) - 휜형(形) 밀집형(密集形) 현열(顯熱) 열교환기(熱交換器)의 최적설계(最適設計)에 관한 연구(硏究) (A Study on the Optimum Design of Plate-Fin Compact Sensible Heat Exchanger for the Heat Recovery of Exhaust Gas)

  • 최영돈;박상동;우정선;태춘섭
    • 설비공학논문집
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    • 제2권2호
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    • pp.85-98
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    • 1990
  • Method of optimum design of a compact sensible plate-fin heat exchanger for the heat recovery of exhaust gas from the air conditioning space was developed in consideration of the econamics of investment cost and profit according to the installation of heat exchanges. In the counterflow heat exchanger, the frontal area was fixed and the length of heat exchanger was optimized in order to maximize the net gain according to the setting of the heat exchanger. In the cross flow heat exchanger, the size of the exchanger was also optimized to maximize the net gain.

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