• Title/Summary/Keyword: Fin-and-Tube Heat Exchanger

Search Result 264, Processing Time 0.024 seconds

Heat Transfer and Combustion Characteristics and Performance of U type Radiation Tube Burner with fin (핀 부착 U형 복사튜브 버너의 열전달 및 연소성능 실험)

  • Lee, Hyun-Chan;You, Hyun-Seok;Lee, Joong-Seong
    • Proceedings of the KSME Conference
    • /
    • 2001.06d
    • /
    • pp.516-521
    • /
    • 2001
  • Present study deals with combustion characteristics and performance of U type radiation tube burner with fin which combustion capacity is 30,000kcal/hr and the maximum capacity of supply fuel is $30Nm^{3}/hr$. Temperature difference of radiation tube is about $173^{\circ}C$ at 25% capacity and this show relatively small temperature difference for convenient type. Thermal efficiency is satisfactory as $72{\sim}81%$. Also, radiative efficiency of radiation tube is $52{\sim}73%$. The efficiency of heat exchanger is $27{\sim}37%$. Therefore, radiative efficiency is improved to $1{\sim}10%$ after installing fin.

  • PDF

The Study of Performance Evaluation Coefficient of Fin-and-Tube Heat Exchangers with Frosting (착상을 수반한 핀-관 열교환기의 성능평가계수에 관한 연구)

  • 최봉준;황준현;신종민
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.15 no.2
    • /
    • pp.132-136
    • /
    • 2003
  • For the study of performance evaluation on different shape heat exchangers that have the same energy consumption in a refrigerator, we make performance evaluation coefficient (PEC) which can distinguish performance of different shape heat exchangers. The results were reported in order to compare with for the dry frosting and wet frosting test as various definition of PECs. Results showed that PEC of dry frosting test is higher than that of wet frosting test because attached water droplet increases pressure drop of air-side then this decreases performance of heat exchanger.

Performance Test of Low Temperature Waste Heat Recovery Heat Exchanger Using Self-excited Oscillating Heat Pipe (자려 진동형 히트 파이프를 이용한 저온 폐열 회수 열교환기의 성능 실험)

  • 이욱현;이종현;김종수
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.12 no.9
    • /
    • pp.853-859
    • /
    • 2000
  • In this study, low temperature waste heat recovery heat exchanger was developed using a principle of self-excited oscillating heat pipe. The heat exchanger of serpentine type was composed of extruded flat aluminum tube with 6 channels (3 nm$\times$ 2.75nm) and louvered fin. The heat transfer area density of heat exchanger was $331.9 m^2/m^3$. Working fluid is R141b and charge ratio was 40% by volume. Heat transfer rate and the effectiveness of heat exchanger was primary concern of this study. As a result, the effectiveness of heat exchanger was about 0.4-0.67, and recovered waste heat rate was about 4.5 kW per one unit of heat exchanger.

  • PDF

Heat Transfer and Pressure Drop Characteristics of Plain Finned Heat Exchangers Having 5.0 mm Tubes

  • Kim, Nae-Hyun;Cho, Jin-Pyo;Oh, Wang-Ku;Choi, Yong-Hwa;Gaku, Hayase
    • International Journal of Air-Conditioning and Refrigeration
    • /
    • v.16 no.1
    • /
    • pp.9-14
    • /
    • 2008
  • In this study, pressure drop and heat transfer characteristics of plain finned heat exchangers having 5.0 mm diameter (fin collar 5.3 mm) tubes were investigated. Six samples having different fin pitches (1.1 to 1.3 mm) and tube rows (1 and 2 row) were tested. The fin pitch had a negligible effect on j and f factors. Both j and f factors decreased as the number of tube row increased, although the difference was not significant for the f factor. When compared with the j and f factors of the samples having 7.3 mm diameter tubes, the present j and f factors yielded lower values. However, the j/f ratio was larger at low Reynolds numbers. Possible reasoning is provided from the flow pattern consideration. Comparison with existing correlations were made.

Performance Characteristic of Large Diameter Oval Finned-Tube Heat Exchanger for Dryer (건조기용 타원관 대구경 핀-관 열교환기의 성능특성)

  • Bae, Kyung-Jin;Cha, Dong-An;Kwon, Oh-Kyung
    • Journal of Power System Engineering
    • /
    • v.18 no.5
    • /
    • pp.22-27
    • /
    • 2014
  • The objectives of this paper are to obtain an empirical equations regarding the correlations between heat transfer and pressure drop of oval fin-tube heat exchanger having large diameter using wilson plot method. It was difficult to find any recommendable heat transfer and friction factor correlation available for our large diameter experimental cases. Overall heat transfer coefficients are composed of the heat transfer coefficients both inside and outside tubes. The resulting empirical correlations for the Nui and f-factor are given as $Nu_i=0.0146Re^{0.809}Pr^{0.3}$ and $f=4.366Re^{-0.64}$, respectively. The empirical correlations of the Nui and f-factors were developed for the large diameter oval finned-tube heat exchanger as a function of the Reynolds number. As the EG(Ethylene glycol) and air flow rate increases, the heat transfer rate and pressure drop is increased largely.

Analysis of a Cryogenic Nitrogen-Ambient Air Heat Exchanger Including Frost Formation (착상을 고려한 극저온 질소-대기 열교환기의 해석)

  • 최권일;장호명
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
    • /
    • v.12 no.9
    • /
    • pp.825-834
    • /
    • 2000
  • A heat exchanger analysis is performed to investigate the heating characteristics of cryogenic nitrogen by ambient air for the purpose of cryogenic automotive propulsion. The heat exchanger is a concentric triple-passage for supercritical nitrogen, and the radial fins are attached on the outermost tube for the crossflow of ambient air. The temperature distribution is calculated for the nitrogen along the passage, including the real gas properties of nitrogen, the fluid convections and the conductions through the tube walls and the fins. Since the wall temperature of the outer (ambient side) tube is very low in most cases, a heavy frost can be formed on the surface, affecting the heat exchange performance. By the method of the similarity between the heat and the mass transfer of moist air, the frost growth and the time-dependent effectiveness of the heat exchanger are calculated for various operating conditions. It is concluded that the frost formation can augment the heating of nitrogen during the initial period because of the latent heat, then gradually degrades the heat exchange because of the increased thermal resistance. Practical design issues are discussed for the flow rate of nitrogen, the velocity and humidity of ambient air, and the sizes of the fin.

  • PDF

Experimental Study of Heat Transfer Performance of Louver-Fin Heat Exchanger (Louver-Fin 열교환기의 열전달 특성 실험 연구)

  • Chang, K.S.;Kweon, Y.C.;Hong, S.R.;Kim, J.D.;Lee, H.S.;Park, B.K.
    • Proceedings of the SAREK Conference
    • /
    • 2007.11a
    • /
    • pp.209-215
    • /
    • 2007
  • This study presents the air side heat transfer and friction characteristics of fin-tube heat exchangers. Variations of heat transfer performance in each row are investigated in the present work. Experiments were performed for the Louver fin-tube heat exchangers using air-enthalpy type calorimeter, which is based on air-enthalpy method described in ASHRAE standards. The air velocity was varied from 0.7 to 2.5 m/s with 0.3 m/s interval. The results are plotted in terms of Colburn j-factor and friction factor of with respect to Reynolds number in the range of 200 to 1100.

  • PDF

Flow/Heat Transfer Analysis and Shape Optimization of a Heat Exchanger with Internally Finned Tube (내부휜이 부착된 원형관 열교환기의 열/유동 해석 및 최적설계)

  • Lee Juhee;Lee Sanghwan;Lim Hyo-Jae;Park Kyoungwoo
    • Transactions of the Korean Society of Mechanical Engineers B
    • /
    • v.29 no.4 s.235
    • /
    • pp.460-468
    • /
    • 2005
  • Analyses of flow and heat transfer characteristics and shape optimization of internally finned circular tubes have been performed for three-dimensional periodically fully developed turbulent flow and heat transfer. CFD and mathematical optimization are coupled in order to optimize the shape of heat exchanger. The design variables such as fin widths $(d_{1},\;d_{2})$ and fin height (h) are numerically optimized by minimizing the pressure loss and maximizing the heat transfer rate for limiting conditions of $d_{1}=0.2\~1.5\;mm,\;d_{2}=0.2\~1.5\;mm,$ and $h=0.2\~1.5mm$. Due to the periodic boundary conditions along main flow direction, the three layers of meshes are considered. The flow and thermal fields are predicted using the finite volume method and the optimization is carried out by means of the sequential quadratic programming (SQP) method which is widely used in the constrained nonlinear optimization problem.

Comparisons of Performance with Heat Exchanger Constitution in the Fin-tube Gascooler (핀-관 가스쿨러에서 열교환기 구성에 따른 성능 비교)

  • Bae, Kyung-Jin;Shin, Eun-Sung;Hong, Myung-Suk;Cho, Hong-Hyun
    • Proceedings of the SAREK Conference
    • /
    • 2009.06a
    • /
    • pp.1294-1299
    • /
    • 2009
  • Since the operating pressure of $CO_2$ gascooler is so high compared with that of previous subcritical condenser, the optimization of gascooler is needed for improve heat exchanger performance. In this study, the performance characteristics of five kinds of heat exchangers were analyzed and compared with operating conditions. As a result, the 4-20 HX-tube shows the maximum gascooler capacity because the heat transfer is effective and pressure drop is small. Beside, the high performance of 4-20 HX-tube could be keep for wide operating condition.

  • PDF

Design of an Indoor Heat Exchanger that Apply Refrigerant R410A (냉매 R410A를 적용한 실내 열교환기 설계)

  • Kim, Beom-Chan;Park, Chang-Sug;Cha, Woo-Ho;Kim, Sung-Soo;Kang, Yong-Tae
    • Proceedings of the SAREK Conference
    • /
    • 2008.06a
    • /
    • pp.317-322
    • /
    • 2008
  • The objectives of this paper are to study the effects of thermal and geometric conditions on the performance of indoor heat exchanger with R410A for Gas Engine Driven Heat Pump (GHP) application and to find optimum design conditions of indoor heat exchanger by parametric analysis for the key parameters. In the air side, moisture out of the humid air condenses on the fin surface while the refrigerant (R410A) boils inside the smooth tube. Therefore this study uses Log Mean Enthalpy Difference (LMHD) method to analyze the heat transfer from the humid air to the refrigerant of R410A. The results show that fin pitch and longitudinal pitch have significant effect on the heat exchanger preformance. This study will provide the guideline for optimum design of indoor heat exchanger with R410A for GHP application.

  • PDF