• Title/Summary/Keyword: Single-Phase Heat Transfer

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Experimental Study on Heat Transfer and Pressure Drop Characteristics for Single-Phase Flow in Plate and Shell Heat Exchangers. (Plate and Shell 열교환기의 단상유동 열전달 및 압력강하 특성에 관한 실험적 연구)

  • 서무교;김영수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.4
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    • pp.422-429
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    • 2000
  • Plate and shell heat exchanger(P&SHE) is widely applied as evaporators or condensers in the refrigeration and air conditioning systems for their high efficiency and compactness. In order to set up the database for the design of the P&SHE, heat transfer and pressure drop characteristics for single phase flow of water in a plate & shell heat exchanger are experimentally investigated in this study. Single phase heat transfer coefficients were measured for turbulent water flow in a plate and shell heat exchangers by Wilson plot method. The shell side heat transfer resistance was varied and the overall heat transfer coefficients were measured. The single-phase heat transfer coefficients in a plate side were obtained by Wilson plot method. Single-phase heat transfer correlations based on projected heat transfer area and friction factor correlations have been proposed for single phase flow in a plate and shell heat exchanger.

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Experimental Study on Heat Transfer Characteristics for Single-phase Flow in Plate & Shell Heat Exchangers by Using Wilson Plot Method (Wilson plot법을 이용한 Plate & Shell 열교환기의 단상유동 열전달 특성에 관한 실험적 연구)

  • Seo, M.K.;Kim, Y.S.;Lee, S.K.
    • Journal of Power System Engineering
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    • v.3 no.4
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    • pp.22-27
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    • 1999
  • Single phase heat transfer coefficients were measured for turbulent water flow in a plate & shell heat exchangers by using Wilson plot method. An experiment for counterflow heat exchange between the plate and shell was performed. The shell side heat transfer resistance was varied and the overall heat transfer coefficients were measured. The single-phase heat transfer coefficients in a plate side were obtained by Wilson plot method. Single-phase heat transfer correlations based on projected heat transfer area have been proposed for a plate & shell heat exchanger.

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Heat transfer coefficients for single-Phase flow in a micro-fin tube (마이크로휜 관내의 단상유동 열전달계수)

  • 권정태;김무환
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.10 no.4
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    • pp.423-430
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    • 1998
  • Single phase heat transfer coefficients were measured for turbulent water flow in a micro-fin tube by using Wilson plot technique. An experiment for counterflow heat exchange between the micro-fin tube and its outer annulus passage was performed. The annulus side heat transfer resistance was varied and the overall heat transfer coefficients were measured. The single-phase heat transfer coefficients in a micro-fin tube were obtained by Wilson plot technique. Nusselt numbers based on the real heat transfer area and the nominal area were about 35% and 50% larger than those for smooth tube respectively Also, single-phase heat transfer correlations based on real heat transfer area and nominal area have been proposed for a micro-fin tube.

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Study on the Single-Phase Heat Transfer and Pressure Drop Characteristics of R-718 in Small Diameter Tubes (세관 내 R-718의 단상 열전달 및 압력강하 특성에 관한 연구)

  • 박기원;권옥배;홍진우;손창효;오후규
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.3
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    • pp.522-530
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    • 2004
  • Single-phase heat transfer coefficients and pressure drops of R-718 were measured in smooth, horizontal copper tubes with inner diameters of 3.36 ㎜, 5.35 ㎜. 6.54 ㎜ and 8.12 ㎜, respectively. The experiments were conducted in the closed loop, which was driven by a magnetic gear pump. Data are presented for the following range of variables : Reynolds from 1000 to 20000. Single-phase heat transfer coefficients increased by 10∼30 % as the inner diameter of tube was reduced and it was found that a well-known previous correlation, Gnielinski's correlation was not suitable for the small diameter tubes. But the pressure drop in the small diameter tubes have been shown slightly deviations with Blauius' correlation. Based on an analogy between heat and mass transfer. the new heat transfer correlation is proposed to predict the experimental data successfully.

Experiments on Single Phase Cooling Heat Transfer and Pressure Drop Characteristics in Microfin Tubes (마이크로휜관 내 단상 냉각 유동 열전달 및 압력 강하 특성에 관한 실험적 연구)

  • 이규정;한동혁
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.14 no.3
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    • pp.231-239
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    • 2002
  • Experiments on the single phase cooling heat transfer and pressure drop with microfin tubes were performed using water as a test fluid. Experimental data were obtained in the range of Reynolds number 3000 ~40000 and Prandtl number 4-6. The data of microfin tubes presented the characteristics of rough surface tube in pressure drop and heat transfer Experimental data were compared with the heat transfer and friction factor correlations of smooth tubes. Heat transfer enhancements of microfin tubes were lower than pressure drop penalty factors. The helix angle is more significant parameter in both of the pressure drop and heat transfer than the relative roughness. The correlations of Nusselt number and friction factor were suggested for the tested microfin tubes. Maximum deviations between correlations and experimental data were within $\pm15$% for Nusselt number and $\pm10$% for friction factor.

Experimental measurements of R-22 two-phase friction factor in plate heat exchangers (판형열교환기에서 R-22 냉매의 이상 압력 손실계수 평가)

  • Yoo, Sang-Roon;Jeong, Ji-Rwan
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2273-2278
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    • 2007
  • Brazed Plate Heat Exchanger (BPHE) is a type of compact plate heat exchanger with parallel corrugated plates which are brazed together in series. Each plate hascorrugation called herringbone pattern. Inside a BPHE, hot fluid and cold fluid alternate its flow direction to establish counter current flow configuration. Two-phase flow heat transfer and pressure drop of R-22 in BPHE were experimentally measured in this study. In the present experiments, single-phase region and two-phase region coexist in a BPHE. Therefore, the inside of a BPHE have to be divided into single phase region and two phase region and analyzed accordingly. The results from the single phase flow analysis are then extended to the two phase flow analysis to correlate the condensation and evaporation heat transfer and pressure drop for the refrigerant R-22 in the BPHEs. Previous models for two- phase friction factor have been compared with the present experimental results.

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Study on the Single-Phase Heat Transfer and Pressure Drop Characteristics of R-718 in Small Diameter Tubes (세관 내 액단상 열전달 및 압력강하 특성에 관한 연구)

  • Hong, Jin-Woo;Jeong, Jae-Cheon;Kim, Jong-Ryeol;Roh, Geon-Sang;Ku, Hag-Geun;Oh, Hoo-Kyu
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.425-432
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    • 2001
  • Single-phase heat transfer coefficients and pressure drops of R-22 were measured in smooth, horizontal copper tubes with inner diameters of 3.36 mm, 5.35 mm, 6.54 mm and 8.12 mm, respectively. The experiments were conducted in the closed loop, which was driven by a magnetic gear pump. Data are presented for the following range of variables: Reynolds from 1000 to 20000. Single-phase heat transfer coefficients increased by $10{\sim}30%$ as the inner diameter of tube was reduced and it was found that a well-known previous correlation, Gnielinski's correlation, was not suitable for the small diameter tubes. But the pressure drop in the small diameter tubes have been shown slightly deviations with Blauius' correlation. Based on an analogy between heat and mass transfer, the new heat transfer correlation is proposed to predict the experimental data successfully.

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Study on Single-Phase Heat Transfer, Pressure Drop Characteristics and Performance Prediction Program in the Oblong Shell and Plate Heat Exchanger (Oblong 셀 앤 플레이트 열교환기에서의 단상 열전달, 압력강하 특성 및 성능예측 프로그램 개발에 관한 연구)

  • 권용하;김영수;박재홍
    • Journal of Advanced Marine Engineering and Technology
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    • v.28 no.6
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    • pp.1026-1036
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    • 2004
  • In this study, single-phase heat transfer experiments were conducted with Oblong Shell and Plate heat exchanger using water. An experimental water loop has been developed to measure the single-phase heat transfer coefficient and pressure drop in a vertical Oblong Shell and Plate heat exchanger. Downflow of hot water in one channel receives heat from the cold water upflow of water in the other channel. Similar to the case of a plate heat exchanger, even at a very low Reynolds number, the flow in the Oblong Shell and Plate heat exchanger remains turbulent. The present data show that the heat transfer coefficient and pressure drop increase with the Reynolds number. Based on the present data, empirical correlations of the heat transfer coefficient and pressure drop in terms of Nusselt number and friction factor were proposed. Also, performance prediction analyses for Oblong Shell and Plate heat exchanger were executed and compared with experiments. $\varepsilon$-NTU method was used in this prediction program. Independent variables are flow rates and inlet temperatures. Compared with experimental data, the accuracy of the program is within the error bounds of $\pm$5% in the heat transfer rate.

Heat Transfer and Pressure Drop Characteristics of Secondary Refrigerants Applying to Indirect Refrigeration System (간접 냉동 시스템용 2차 냉매의 열전달과 압력강하 특성)

  • Oh, Hoo-Kyu;Son, Chang-Hyo;Jo, Hwan;Yi, Wen-Bin;Jeon, Min-Ju
    • Journal of Power System Engineering
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    • v.17 no.4
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    • pp.45-50
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    • 2013
  • This paper presents the comparison of heat transfer and pressure drop of various secondary refrigerants (single-phase and two-phase) in the indirect refrigeration system. The main results were summarized as follows: In case of heat transfer, it is useful to use secondary refrigerants in low evaporating temperature region and the heat transfer coefficient of single-phase is larger than two-phase secondary refrigerants. In case of pressure drop, it is useful to use secondary refrigerants in high evaporating temperature region and the pressure drop of two-phase is smaller than single-phase secondary refrigerant. Also, $CO_2$ is the best useful because pressure drop of $CO_2$ among the secondary refrigerants is the smallest.

Measurement of Single Phase and Condensation Heat Transfer Coefficients of Ammonia in a Horizontal Tube (암모니아의 수평관내 단상 및 응축 열전달계수의 측정)

  • 백영진;장영수;김영일
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.6
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    • pp.561-569
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    • 2000
  • Single phase and condensation heat transfer characteristics of ammonia in a horizontal tube have been investigated experimentally The horizontal test section is composed of smooth SUS316 tube for refrigerant flow, surrounding annulus for water flow, and temperature and Pressure measuring sensors. For single phase test, subcooled ammonia mass flux was varied from 320 to 501 kg/mrs and temperature was varied from 18 to $47^{\circ}C$. For condensation test, mass flux and saturation temperature were varied from 86 to 128 kg/$m^2$s and 34 to $47^{\circ}C$, respectively. The equations of Gnielinski Soliman et al., Traviss et at., Cavallini and Zecchin, Shah, Chen et al., Tandon et al., and Chilli and Anand were compared with the experimental data. New correlations are proposed based on the experimental results and the absolute mean deviation of the experimental data becomes 1.0% for single phase test and 4.9% for condensation test.

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