NUMERICAL STUDY ON FLOW AND HEAT TRANSFER IN A RECTANGULAR CHANNEL WITH 45 DEG RIB TURBULATORS AND BLEED HOLES

2012 ◽  
Vol 19 (5) ◽  
pp. 477-487
Author(s):  
Di Zhang ◽  
Zhong Yang Shen ◽  
Ya Jun Song ◽  
Yong Hui Xie
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Flow And Heat Transfer ◽  
Rib Turbulators

Numerical Study of Flow and Heat Transfer in Rectangular Channel With Periodic Longitudinal Vortex Generators Under Pulsating Flow

2012 ◽  
Author(s):  
Lin Tian ◽  
Wei Bai ◽  
Shanhu Xue ◽  
Zipeng Huang ◽  
Qiuwang Wang
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Factor ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Vortex Generators ◽  
Longitudinal Vortex ◽  
Small Scale ◽  
Inlet Velocity ◽  
Flow And Heat Transfer

The unsteady turbulent flow and heat transfer in rectangular channel with periodic longitudinal vortex generators on up and bottom walls are investigated by standardized k-ε two equation turbulent model combined with standardized wall function which has been validated by steady experimental data. Influence of varying frequency and amplitude of inlet velocity varying by sine function on heat transfer and friction factor are discussed. It is found that parameters such as Tout, Tf, Tw, Nusselt number and the friction factor f vary with time periodically, phase difference occurred compared with inlet velocity. Pulsating frequency has little impact on time averaged Nusselt number. However, when amplitude increases from 0.2us to 0.8us, the heat transfer rate is augmented by about 4%. Furthermore, a critical frequency has been captured when amplitude equals to 0.8us for the channel studied. The current study will deepen understanding of unsteady flow in plate fuel assembly, which can be used in small-scale reactors.

Computation of Flow and Heat Transfer in Two-Pass Rotating Rectangular Channels (AR=1:1, AR=1:2, AR=1:4) With 45-deg. Angled Ribs by Reynolds Stress Turbulence Model

2004 ◽  
Author(s):  
Guoguang Su ◽  
Hamn-Ching Chen ◽  
Je-Chin Han ◽  
James D. Heidmann
Keyword(s):  
Heat Transfer ◽  
Rectangular Channel ◽  
Density Ratio ◽  
Heat Fluxes ◽  
Turbulent Heat ◽  
Mean Velocity ◽  
Flow And Heat Transfer ◽  
Aspect Ratios ◽  
Numerical Predictions ◽  
Rib Turbulators

Numerical predictions of three-dimensional flow and heat transfer are presented for rotating two-pass rectangular channel with 45-deg rib turbulators. Three channels with different aspect ratios (AR=1:1; AR=1:2; AR=1:4) were investigated. Detailed predictions of mean velocity, mean temperature, and Nusselt number for two Reynolds numbers (Re = 10,000 and Re = 100,000) were carried out. The rib height is fixed as constant and the rib-pitch-to-height ratio (P/e) is 10, but the rib height-to-hydraulic diameter ratios (e/Dh) are 0.125, 0.094, and 0.078, for AR=1:1, AR=1:2, and AR=1:4 channel, respectively. The channel orientations are set at 90 deg, corresponding to the cooling passages between mid-portion and the leading edge of a turbine blade. The rotation number varies from 0.0 to 0.28 and the inlet coolant-to-wall density ratio varies from 0.13 to 0.40, respectively. The primary focus of this study is the effect of the channel aspect ratio on the nature of the flow and heat transfer enhancement in a rectangular ribbed channel under rotating conditions. A multi-block Reynolds-averaged Navier-Stokes (RANS) method was employed in conjunction with a near-wall second-moment turbulence closure to provide detailed resolution of the Reynolds stresses and turbulent heat fluxes induced by the rib turbulators under both the stationary and rotating conditions.

Prediction of Flow and Heat Transfer in Rotating Two-Pass Rectangular Channels With 45-deg Rib Turbulators

2002 ◽  
Vol 124 (2) ◽  
pp. 242-250 ◽  
Author(s):  
Mohammad Al-Qahtani ◽  
Yong-Jun Jang ◽  
Hamn-Ching Chen ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Rectangular Channel ◽  
Density Ratio ◽  
Convective Transport ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Rectangular Channels ◽  
Rib Turbulators ◽  
Channel Aspect Ratio

Numerical predictions of three-dimensional flow and heat transfer are presented for a rotating two-pass rectangular channel with 45-deg rib turbulators and channel aspect ratio of 2:1. The rib height-to-hydraulic diameter ratio e/Dh is 0.094 and the rib-pitch-to-height ratio P/e is 10. Two channel orientations are studied: β=90deg and 135 deg, corresponding to the mid-portion and the trailing edge regions of a turbine blade, respectively. The focus of this study is twofold; namely, to investigate the effect of the channel aspect ratio and the channel orientation on the nature of the flow and heat transfer enhancement. A multi-block Reynolds-averaged Navier-Stokes (RANS) method was employed in conjunction with a near-wall second-moment turbulence closure. In the present method, the convective transport equations for momentum, energy, and turbulence quantities are solved in curvilinear, body-fitted coordinates using the finite-analytic method. The numerical results compare reasonably well with experimental data for both stationary and rotating rectangular channels with rib turbulators at Reynolds number (Re) of 10,000, rotation number (Ro) of 0.11 and inlet coolant-to-wall density ratio (Δρ/ρ) of 0.115.

Numerical study of flow and heat transfer in a rectangular channel with pin fin arrays and back ribs

2021 ◽  
Author(s):  
Vladimir Olegovich Kindra ◽  
Andrey Nikolaevich Rogalev ◽  
Sergey Konstantinovich Osipov ◽  
Olga Vladimirovna Zlyvko ◽  
Andrey Nikolaevich Vegera
Keyword(s):  
Heat Transfer ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Pin Fin ◽  
Flow And Heat Transfer ◽  
Pin Fin Arrays

scholarly journals Numerical study of Unsteady Fluid Flow and Heat Transfer Through a Rotating Curved Rectangular Channel

2018 ◽  
Vol 37 ◽  
pp. 73-92 ◽  
Author(s):  
Md Zohurul Islam ◽  
Md Arifuzzaman ◽  
Rabindra Nath Mondal
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Steady State ◽  
Unsteady Flow ◽  
Numerical Study ◽  
Rectangular Channel ◽  
Chaotic Flow ◽  
Flow And Heat Transfer ◽  
Unsteady Fluid Flow ◽  
Unsteady Fluid

Numerical study of unsteady fluid flow and heat transfer through a rotating curved rectangular channel with aspect ratio 2 and curvature ratio 0.05 has been performed by using a spectral-based numerical method, and covering a wide range of the rotational parameter, the Taylor number Ta, for both the positive and negative rotation of the channel. In this paper, unsteady flow characteristics are investigated under combined action of the centrifugal, Coriolis and buoyancy forces for the Dean number De = 1000. For positive rotation, we investigated unsteady solutions for 0 ≤Ta ≤500, and it is found that the chaotic flow turns into steady-state flow through periodic or multi-periodic flows. For negative rotation, on the other hand, unsteady solutions are investigated for –500 ≤Ta≤0, and it is found that the unsteady flow undergoes through various flow instabilities. Typical contours of secondary flow patterns and temperature profiles are obtained at several values of Ta, and it is found that the unsteady flow consists of asymmetric two- to eightvortex solutions. The present study shows that convective heat transfer is significantly enhanced as the secondary flow becomes stronger and the chaotic flow enhances heat transfer more effectively than the steady-state or periodic solutions.GANIT J. Bangladesh Math. Soc.Vol. 37 (2017) 73-92

Prediction of Flow and Heat Transfer in Rotating Two-Pass Rectangular Channels With 45° Rib Turbulators

2001 ◽  
Author(s):  
Mohammad Al-Qahtani ◽  
Yong-Jun Jang ◽  
Hamn-Ching Chen ◽  
Je-Chin Han
Keyword(s):  
Heat Transfer ◽  
Aspect Ratio ◽  
Rectangular Channel ◽  
Density Ratio ◽  
Convective Transport ◽  
Flow And Heat Transfer ◽  
Numerical Predictions ◽  
Rectangular Channels ◽  
Rib Turbulators ◽  
Channel Aspect Ratio

Numerical predictions of three-dimensional flow and heat transfer are presented for a rotating two-pass rectangular channel with 45° rib turbulators and channel aspect ratio of 2:1. The rib height-to-hydraulic diameter ratio (e/Dh) is 0.094 and the rib-pitch-to-height ratio (P/e) is 10. Two channel orientations are studied: β = 90° and β = 135° corresponding to the mid-portion and the trailing edge regions of a turbine blade, respectively. The focus of this study is twofold; namely, to investigate the effect of the channel aspect ratio and the channel orientation on the nature of the flow and heat transfer enhancement. A multi-block Reynolds-Averaged Navier-Stokes (RANS) method was employed in conjunction with a near-wall second-moment turbulence closure. In the present method, the convective transport equations for momentum, energy, and turbulence quantities are solved in curvilinear, body-fitted coordinates using the finite-analytic method. The numerical results compare reasonably well with experimental data for both stationary and rotating rectangular channels with rib turbulators at Reynolds number (Re) of 10,000, rotation number (Ro) of 0.11 and inlet coolant-to-wall density ratio (Δρ/ρ) of 0.115.

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