• Title/Summary/Keyword: Staggered Tube Bank

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Numerical Analysis of Turbulent Flow and Heat Transfer Normal to a Staggered Tube Bank (교차된 관군에 수직한 난류유동 및 난류열전달의 수치해석)

  • 이건휘;이병곤;최영돈
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.1
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    • pp.218-228
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    • 1991
  • Since heat exchangers are composed of bank of tubes, the knowledge on the flow and heat transfer characteristics of the tube bank are required for the optimum design and selection of heat exchangers. In this paper, the turbulent flow fields and heat transfers normal to a staggered tube bank are solved numerically employing K-.epsilon. 2 equation turbulence model and non-orthogonal coordinate transformation for the treatment of curved surface of tubes. Predicted mean Nusselt numbers of tube bank agree reasonably well with Grimision's correlation

An Experimental Study on Heat Storage and Heat Recovery Characteristics of a Latent Heat Storage Tank with Horizontal Shell and Tube Type (수평식 셸-튜브형 잠열축열조의 축열 및 방열특성에 관한 실험적 연구)

  • Kwon, Young-Man;Seo, Hye-Sung;Moh, Jung-Ha
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.1
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    • pp.50-59
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    • 2000
  • An experimental study has been carried out in order to investigate the heat storage characteristics for a latent heat storage tank with horizontal shell and tube type. The heat exchanger consisted of horizontal cylindrical capsules with a staggered tube bank layout. Based on the obtained data, the effects of flow rate and inlet fluid temperature on the melting time and heat storage rates were examined. It is found that the melting time decreased with increase of the flow rate and the inlet temperature. Results also show that at the initial stage of heat transfer the heat storage rate represents the maximum value and rapidly decreases.

A Study on the Heat Storage Characteristics of a Latent Heat Storage Tank with Shell and Tube Type (셀-튜브형 잠열축열조의 축열특성에 관한 연구)

  • 권영만;김경우;모정하
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.12 no.8
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    • pp.745-754
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    • 2000
  • An experimental study has been carried out in order to investigate the heat storage characteristics for a latent heat storage tank with horizontal shell and tube type. The heat storage tank consists of cylindrical capsules with a staggered tube bank. The effects of flow rates and initial temperature differences on the melting time and heat storage rates are examined. It is found that the melting time decreases with increase of the flow rates and initial temperature differences. Results also show that the time-averaged overall heat transfer coefficients increase in proportion to the increase of flow rates and initial temperature differences.

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Heat Transfer Enhancement in Cross-flow Heat Exchanger Using Vortex Generator (와류발생기를 사용한 직교류 열교환기의 열전달 촉진)

  • Yoo, Seong-Yeon;Kwon, Hwa-Kil;Lee, Sang-Sub;Kim, Byeong-Chae;Park, Dong-Seong
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.61-66
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    • 2003
  • Fouling is very serious problem in heat exchanger because it rapidly deteriorates the performance of heat exchanger. Cross-flow heat exchanger with vortex generators is developed, which enhance heat transfer and reduce fouling. In the present heat exchanger, shell and baffle are removed from the conventional shell-and-tube heat exchanger. The naphthalene sublimation technique is employed to measure the local heat transfer coefficients. The experiments are performed for single circular tube, staggered array tube bank and in-line array tube bank with and without vortex generators. Local and average Nusselt numbers of single tube and tube bank with vortex generator are investigated and compared to those of without vortex generator.

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An Experimental Study of Fouling Effect on the Heat Transfer Around a Tube in Staggered Tube Banks (엇갈림 관군에서 원관 주위의 열전달에 미치는 파울링 영향에 관한 실험적 연구)

  • Kim, Min-Su;Baek, Byeong-Jun;Park, Bok-Chun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.11
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    • pp.1478-1485
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    • 2000
  • An experimental study has been performed to investigated the forced convection heat transfer characteristics of 6 circular cylinders in staggered arrangement in a cross flow of air. The water scale deposited on condenser wall of power plant was used to investigate the effect of roughness of scaled surfaces. The relative roughness*average diameter of scale/cylinder diameter) was in a range of k/d=0.0066, 0.0111, 0.0167, 0.0222 and 0.0278. The cylinder spacings(L/d) varies from 1.5 to 4.0 where L denote the cylinder spacings along and normal to the upstream uniform flow direction. The Reynolds number was varied in a range of 10, 000$\leq$ Re $\leq$ 50,000. The local and mean Nusselt numbers were investigated as a function of scale roughness, the cylinder spacing and Reynolds number. The results are compared with those of clean cylinder and inline tube bank, subsequently the mean fouling resistance over the entire circumference was estimated from those results as a function of scale roughness, the cylinder spacing and Reynolds number.

The Numerical Simulation of Flow Field and Heat Transfer around 3-D Tube Banks (3차원 튜브 뱅크 주위의 난류 유동장 및 열전달에 대한 수치 해석적 연구)

  • Park, S.K.;Kim, K.W.;Ryou, H.S.;Choi, Y.K.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.8 no.3
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    • pp.375-385
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    • 1996
  • Turbulent flow and heat transfer characteristics around staggered tube banks were studied using the 3-D Navier-Stokes equations and energy equation governing a steady incompressible flow, which were reformulated in a non-orthogonal coordinate system with cartesian velocity components and discretized by the finite volume method with a non-staggered variable arrangement. The predicted turbulent kinetic energy using RNG $k-{\varepsilon}$ model was lower than that of standard $k-{\varepsilon}$ model but showed same result for mean flow field quantities. The prediction of the skin friction coefficient using RNG $k-{\varepsilon}$ model showed better trend with experimental data than standard $k-{\varepsilon}$ model result. The inclined flow showed higher velocity and skin friction coefficient than transverse flow because of extra strain rate ($\frac{{\partial}w}{{\partial}y}$). Also, this was why the inclined flow showed higher local heat transfer coefficient than the transverse flow.

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A Study on Heat Transfer and Pressure Drop Characteristics of Staggered Tube Banks using CFD Analysis (CFD해석을 통한 엇갈린형 관군의 열전달 및 압력강하 특성에 관한 연구)

  • Zhao, Liu;Yoon, Jun-Kyu
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.16 no.5
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    • pp.2985-2992
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    • 2015
  • In this study, the characteristics of heat transfer and pressure drop was theoretically analyzed by changing longitudinal pitch, bump phase, location of vortex generator about the staggered tube banks by applying SST (Shear Stress Transport) turbulence model of ANSYS FLUENT v.14. Before carrying out CFD (Computational Fluid Dynamics) analysis, It is presumed that the boundary condition is the tube surface temperature of 363 K, the inlet air temperature of 313 K and the inlet air velocity of 5-10 m/s. The results indicated that the heat transfer coefficient is not affected by the longitudinal pitch and the bump phase of circle type was more appropriate than serrated type in the characteristics of heat transfer and pressure drop. Additionally, in case of vortex generator location, the heat transfer characteristics showed that forward location of tube was more favorable 4.6% than backward location.

A Numerical Study on Performance Characteristics of a Closed Circuit Cooling Tower with Multi Paths (멀티패스 밀폐식 냉각탑의 성능특성에 대한 수치적 연구)

  • Kim, Eun-Pil
    • Journal of Advanced Marine Engineering and Technology
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    • v.32 no.4
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    • pp.528-533
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    • 2008
  • A closed circuit cooling tower having high temperature of cooling water and small water flow rate is investigated. To study the characteristics of the heat transfer of heat exchanges in a cooling tower with multi paths a numerical method is used. The results show that the staggered tube arrangements in a bank show better performance than aligned ones for temperature variation with various outer diameters of tube bundles. In case of one pass, the 15.88 mm tube case shows about 9% better performance than the 25.4 mm tube case. In two paths, the tube outside diameter of 15.88 mm show about 14.4% better results than the 25.4 mm diameter case.

Numerical Simulation of Heat Transfer Characteristics of Tube Banks with Non-conventional Arrangement (튜브뱅크 배열특성에 따른 전열특성변화 수치모사)

  • Jun, Yong-Du;Nam, Myong-Hwan;Koo, Byeong-Soo;Lee, Kum-Bae
    • Proceedings of the SAREK Conference
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    • 2009.06a
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    • pp.1129-1134
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    • 2009
  • A numerical study has been conducted to investigate the effect of tube arrangement on the heat transfer and the pressure loss for cross flow heat exchangers. By defining a transverse deviation factor, ${\varepsilon}_t=l_T/S_T$, the flow pattern and the heat transfer characteristics are compared for selected ${\varepsilon}_t$ values of 0.0(in-lined), 0.1, 0.2, 0.3, 0.4, 0.5(staggered) by using a commercial software. Computational domain includes 1 pitch in the transverse direction and 5 pitches in the flow direction with due periodic boundary conditions.

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Numerical Study of Thermo-Fluid Features of Electrically Conducting Fluids in Tube Bank Heat Exchangers Exposed to Uniform Magnetic Fields (관군 열교환기에서 균일 자기장에 의한 전기 전도성 유체의 열유동 특성에 관한 수치해석 연구)

  • Oh, Jin Ho;Kang, Namcheol;Park, Il Seouk
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.41 no.10
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    • pp.659-665
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    • 2017
  • When an electrically conducting fluid flows through a staggered tube bank, the heat transfer and fluid flow features are changed by the externally introduced magnetic field. This study provides a numerical investigation of this phenomenon. Heat and fluid flows are investigated for unsteady laminar flows at Reynolds numbers of 50 and 100 with the Hartmann number gradually increasing from zero to 100. As the Hartmann number increases, and owing to the effects of the introduced magnetic field, the velocity boundary layer near the tube wall is thinned, the flow separation is delayed downstream, and the shrinkage of a recirculation zone formed near the rear side is observed. Based on these thermo-fluid deformations, the resulting changes in the local and average Nusselt number are investigated.