• 대한기계학회논문집
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• 제19권1호
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• pp.212-218
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• 1995

Turbulent flow and heat transfer characteristics around staggered tube bundles were studied using a non-orthogonal boundary fitted coordinate system and the low Reynolds .kappa. - .epsilon. turbulence model suggested by Lam and Bremhorst. The predicted flow characteristics for two tube pitches and tube arrangement showed good agreement with the experimental data except the strongly curved region. The predicted Nusselt number was compared with measurements obtained in the staggered rough bundles and it revealed the similar trend to measurements, but the location of the maximum and minimum heat transfer differed somewhat from the measurements.

• 설비공학논문집
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• 제13권7호
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• pp.595-601
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• 2001

We applied PIV method to obtain instantaneous and ensemble averaged velocity fields from the first row to the fifth row of a staggered tube bundle. The Reynolds number based on the tube diameter and the maximum velocity was set to be 4,000. Remarkably different natures are observed in the developing bundle flow. Such differences are depicted in the mean recirculating bubble length and the vorticity distributions. The jet-like flow seems to be a dominant feature after the second row and usually skew. However, the ensemble averaged fields show symmetric profiles and the flow characteristics between the third and fourth measuring planes are not so different. comparison between the PIV data and the RANS simulation yields severe disagreement in spite of the same Reynolds number. It can be explained that the distinct jet-like unsteady motions are not to be accounted in th steady numerical analysis.

• 한국산학기술학회논문지
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• 제16권5호
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• pp.2985-2992
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• 2015

본 연구에서는 엇갈린형 관군에 대해 ANSYS FLUENT v.14의 SST 난류모델을 적용하여 가로피치, 튜브표면, 와류발생기위치 등의 변화에 따른 열전달 및 압력강하 특성을 이론적으로 해석하였다. CFD 해석시 튜브표면의 온도는 363 K, 입구측 공기온도는 313 K이고 입구측 속도는 5 m/s에서 10 m/s까지 가정하였다. 그 해석결과로서 열전달계수는 가로피치에 대한 영향은 큰 차이가 없었고, 튜브표면의 돌기형상은 열전달 및 압력강하 특성에서 원형이 톱니형보다 적절하게 나타내었으며, 와류발생기의 설치 경우에는 열전달특성이 튜브의 전방부 위치가 후방부 위치보다 약 4.6% 정도로 우수함을 보였다.

• 대한기계학회논문집B
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• 제24권1호
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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.

• 설비공학논문집
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• 제12권8호
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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.

• 설비공학논문집
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• 제8권3호
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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.