Computation of flow and heat transfer in rotating two-pass rectangular channels (AR=1:1, 1:2, and 1:4) with smooth walls by a Reynolds stress turbulence model

Su, Guoguang; Chen, Hamn‐Ching; Han, Je-Chin; Heidmann, James D.

doi:10.1016/j.ijheatmasstransfer.2004.07.019

Cited by 53 publications

(20 citation statements)

References 24 publications

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“…A remedy would be to use a LES or a DES model of turbulence, which are however very time-consuming and computationally intensive making them impractical for engineering design. Su et al [33] computed flow and heat transfer in a two-pass smooth channel (with rotation as well as non-rotation) with RANS equations in conjunction with a near-wall Reynolds stress turbulence model. The difference between the computed Nusselt numbers and experimental data at the inlet pass for non-rotating channel were found to be as high as 19% while at bend the maximum difference was found to be about 38%.…”

Section: Validationmentioning

confidence: 99%

“…[28], Su et al [33], Okamura et al [34] and Shih et al [35]. Though at the bend it exceeds a little, the fact that the overall performance of the selected turbulence model in the inlet and outlet passes is good, and that it provided fast and robust convergence of the simulations, these advantages overweighed somewhat decreased accuracy in the bend area.…”

Section: Validationmentioning

confidence: 99%

See 1 more Smart Citation

Flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular smooth channels

Siddique

El-Gabry

Shevchuk³

et al. 2011

Heat Mass Transfer

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Two-pass channels are used for internal cooling in a number of engineering systems e.g., gas turbines. Fluid travelling through the curved path, experiences pressure and centrifugal forces, that result in pressure driven secondary motion. This motion helps in moving the cold high momentum fluid from the channel core to the side walls and plays a significant role in the heat transfer in the channel bend and outlet pass. The present study investigates using Computational Fluid Dynamics (CFD), the flow structure, heat transfer enhancement and pressure drop in a smooth channel with varying aspect ratio channel at different divider-to-tip wall distances. Numerical simulations are performed in two-pass smooth channel with aspect ratio W in /H = 1:3 at inlet pass and W out /H = 1:1 at outlet pass for a variety of divider-to-tip wall distances. The results show that with a decrease in aspect ratio of inlet pass of the channel, pressure loss decreases. The divider-totip wall distance (W el ) not only influences the pressure drop, but also the heat transfer enhancement at the bend and outlet pass. With an increase in the divider-to-tip wall distance, the areas of enhanced heat transfer shifts from side walls of outlet pass towards the inlet pass. To compromise between heat transfer and pressure drop in the channel, W el /H = 0.88 is found to be optimum for the channel under study.

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Section: Validationmentioning

confidence: 99%

Section: Validationmentioning

confidence: 99%

Flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular smooth channels

Siddique

El-Gabry

Shevchuk³

et al. 2011

Heat Mass Transfer

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“…Su et al 73,74 also studied the flow and heat transfer in rotating two-pass square (A R = 1:1) and low aspect ratio (A R = 1:2 and 1:4) rectangular channels with smooth walls and 45-deg angled ribs, for the rotating direction perpendicular to the channel axis. A total of 30 test cases were investigated with various combinations of Reynolds numbers (Re = 10 4 and 10 5 ), rotation numbers (0.0, 0.14, and 0.28), and coolant-to-wall density ratios (0.13, 0.20, and 0.40).…”

Section: Computational Heat Transfer In Rotating Coolant Passagesmentioning

confidence: 99%

Turbine Blade Cooling Studies at Texas A&M University: 1980-2004

Han

2006

Journal of Thermophysics and Heat Transfer

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102

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Gas turbines are used extensively for aircraft propulsion, land-based power generation, and industrial applications. Developments in turbine cooling technology play a critical role in increasing the thermal efficiency and power output of advanced high-temperature gas turbine engines. Gas turbine blades are cooled internally by passing the coolant through several rib-enhanced serpentine passages to remove heat conducted from the outside surface. External cooling of turbine blades by film cooling is achieved by injecting relatively cooler air from the internal coolant passages out of the blade surface to form a protective layer between the blade surface and hot gas-path flow. The most important research contributions on turbine blade cooling studies at Texas A&M University's Turbine Heat Transfer Laboratory from 1980 to 2004 are summarized. For turbine blade internal cooling, the focus is on the effect of rotation on rotor blade coolant passage heat transfer with rib turbulators, pin fins, dimples, and impinging jets. For turbine blade external cooling, the focus is on unsteady high freestream turbulence effects on film-cooling performance with a special emphasis on turbine blade edge region heat transfer and cooling problems. Nomenclature A = cooling channel width A R = cooling channel aspect ratio, A:B B = cooling channel height Bo = buoyancy parameter, ( ρ/ρ)Ro 2 (R/D h ) D = cooling channel hydraulic diameter, dimple diameter d = pin-fin diameter e = rib height F c,cor = Coriolis force acting on the coolant flow F cen = centrifugal force F j,cor = Coriolis force acting on the jet flow f = friction factor f 0 = Blasius fully developed friction factor in a nonrotating, smooth tube H = cooling channel height h = heat transfer coefficient L = cooling channel length; cooling channel leading surface M = blowing ratio for film coolant, (ρV ) c /(ρV ) ∞ N u = regionally averaged Nusselt number, h D/k N u r = ribbed-side Nusselt Number N u 0 = Nusselt number for fully-developed, turbulent flow in a non-rotating, smooth tube P = rib pitch R = cooling channel rotating radius Re = Reynolds number, ρV D/μ Ro = rotation number, D/V s = equivalent slot length for film cooling holes T = cooling channel trailing surface= bulk velocity in streamwise direction x = streamwise location within cooling channel z 0 = cooling channel streamwise location β = angle of cooling channel orientation ρ/ρ = coolant-to-wall density ratio δ = dimple depth η = film cooling effectiveness, (T − T

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“…Son et al (2002) carried out particle image velocimetry (PIV) tests to investigate the flow field at high Reynolds numbers in order to detect the physical correlations with the main features of the convective heat transfer coefficient maps. A numerical analysis has been performed by Su et al (2004) to study the effects caused by Re, AR and buoyancy on both the heat transfer and flow field.…”

Section: Introductionmentioning

confidence: 99%

“…The effects of channel rotation (Coriolis and centrifugal forces), turn and channel orientation with respect to axis of rotation on the flow field and convective heat transfer coefficient distributions were investigated by Al-Qahtani et al (2002), while the influence of AR, Re and buoyancy was studied by Su et al (2004). Murata and Mochizuki (2004) studied how the secondary flow field, modified by rotation, influences the convective heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Thermo-fluid-dynamic analysis of the flow in a rotating channel with a sharp “U” turn

2012

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Infrared thermography has been employed to carry out a detailed convective heat transfer measurements at Re = 20,000 in a two-pass square channel both for the static case (absence of channel rotation) and for the rotating case (Ro = 0.3). At the same time, the main and secondary flow fields have been measured by means of particle image velocimetry with the aim to investigate how the flow behavior affects the local distributions of the convective heat transfer coefficient for the two cases. The normal-towall velocity component (w) and the turbulent kinetic energy, both measured close to the heat exchanging wall, have been used to formulate an empirical heat transfer correlation within an attempt to identify the role performed by these two quantities on the convective heat transfer coefficient distributions. The latter ones have been reported in terms of normalized Nusselt number (Nu/Nu*) maps, where Nu* is the Nusselt number evaluated with the classical Dittus-Bölter correlation.

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Computation of flow and heat transfer in rotating two-pass rectangular channels (AR=1:1, 1:2, and 1:4) with smooth walls by a Reynolds stress turbulence model

Cited by 53 publications

References 24 publications

Flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular smooth channels

Flow structure, heat transfer and pressure drop in varying aspect ratio two-pass rectangular smooth channels

Turbine Blade Cooling Studies at Texas A&M University: 1980-2004

Thermo-fluid-dynamic analysis of the flow in a rotating channel with a sharp “U” turn

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