Effects of Rib Arrangements on Heat Transfer and Flow Behavior in a Rectangular Rib-Roughened Passage: Application to Cooling of Gas Turbine Blade Trailing Edge

Kiml, Robert; Mochizuki, Sadanari; Murata, Akira

doi:10.1115/1.1378019

Cited by 79 publications

(20 citation statements)

References 19 publications

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“…Han et al (1992) and Kiml et al (2001) reported that attack angle of jags with 60° has the better results than 45°. evaluated the heat transfer and pressure reduction in the completely expanded area in a square canal with discrete transverse jags.…”

Section: Fig1 Important Geometric Parameter Of Jags (Han Et Al 1978)mentioning

confidence: 99%

Empirical assessment of heat transmission and pressure loss in turbojet blades

Raad¹,

Roudbari²

2016

IOSR

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Section: Fig1 Important Geometric Parameter Of Jags (Han Et Al 1978)mentioning

confidence: 99%

Empirical assessment of heat transmission and pressure loss in turbojet blades

Raad¹,

Roudbari²

2016

IOSR

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“…One of such features is a significant amplification of heat transfer [1][2][3][4]. This phenomenon is more and more widely used in engineering, for instance, for effective cooling of turbine blades or for increasing heat output in heat exchangers.…”

mentioning

confidence: 98%

Thermal and dynamic characteristics of the separated flow behind a flat rib with different angles of alignment toward the flow

Терехов

Yarygina

Smulsky

2007

J Appl Mech Tech Phys

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Results of an experimental study of a turbulent flow past a flat rib with different angles of alignment toward the flow and with different rib heights are presented. The angle of rib alignment toward the flow is varied within ϕ = 50-90 • . Vortex formation is visualized, and the coordinates of the reattachment line are determined. It is demonstrated that a decrease in the angle ϕ forms a reattachment region and makes the flow behind the rib more three-dimensional. Pressure coefficients are measured in different longitudinal sections of the channel behind the rib with a varied angle of rib alignment ϕ. Temperature fields on the surface behind the rib are measured by means of an infrared imager and by thermocouples, and the corresponding heat-transfer coefficients are calculated. The effect of the angle of rib alignment toward the flow and the rib height on dynamic and thermal characteristics of the separated flow is analyzed.Introduction. Heat transfer in channels of various devices used in power engineering is often intensified with the help of various obstacles, e.g., flat ribs. In a separated flow, both upstream and downstream of the rib, generation of large-scale vortex structures and interaction of coherent structures with the wall promote intensification of heat transfer on the wall. At the same time, the presence of obstacles leads to an undesirable increase in pressure losses. Thus, the task is to increase heat transfer and simultaneously reduce pressure losses. To solve this problem, one has to study the physical mechanisms of controlling vortex formation in separated flows and carefully measure the dynamic and thermal characteristics in a system of ribs and behind a single obstacle, in particular, behind a single rib.Separated turbulent flow behind a flat obstacle aligned at an angle to the flow has some specific features, as compared to the flow behind an obstacle placed perpendicular to the flow. One of such features is a significant amplification of heat transfer [1][2][3][4]. This phenomenon is more and more widely used in engineering, for instance, for effective cooling of turbine blades or for increasing heat output in heat exchangers. As the obstacle is aligned at an angle to the free stream, the flow is three-dimensional. Numerical calculations of three-dimensional separated turbulent flows require large computational resources and do not ensure a necessary accuracy. In modeling oblique flows, a question arises whether there are regions and directions with invariant values of both dynamic and thermal characteristics, which is particularly important in the case of a single obstacle.There are few papers that describe experimental investigations of the flow structure behind a single obstacle aligned at an angle to the flow, and there are even fewer papers where the thermal characteristics under these conditions are studied. Hancock and McCluskey [5] considered the flow behind a rib aligned at an angle ϕ = 65 • to the flow and compared the results with the data for ϕ = 90 • . The components of the me...

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“…The boundary conditions for the V-shaped ribs combined with dimple ribs are applied as experimental conditions. [7][8][9][10][11][12][13][14][15][16][17][18] Fi g. It is therefore, RNG k-ε model has been employed for the present CFD study. Fig.4 shows the velocity profiles for the V-down shaped ribs combined with dimple ribs with different values of α = 35°-70°, and kept other rib parameters used to roughened an air duct with a fixed value of Re=8000.…”

Section: Governing Equationsmentioning

confidence: 99%

“…[12][13][14][15][16][17][18][19][20][21][22][23] Taslim et al 20) presented the effect of V-shaped rib roughness with variation of relative rib height, relative rib pitch and flow attack angle on heat transfer and friction factor in a flow through SAH duct. They reported that the V-shaped rib showed higher performance compared to the angled rib.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on overall thermal performance in SAH duct with compound roughness of V-shaped ribs and dimples

Kumar¹,

Kim²

2015

Journal of the Korean Solar Energy Society

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: This paper presents the thermal hydraulic performance of a three dimensional rib-roughened solar air heater (SAH) duct with the one principal wall subjected to uniform heat flux. The SAH duct has aspect ratio of 12.0 and the Reynolds number ranges from 2000 to 12000. The roughness has relative rib height of 0.045, ratio of dimple depth to print diameter of 0.5 and rib pitch ratio of 8.0. The flow attack angle is varied from 35°to 70°. Various turbulent flow models are used for the heat transfer and fluid flow analysis and their results are compared with the experimental results for smooth surfaces. The computational fluid dynamics (CFD) results based on the renormalization k-epsilon model are in better outcomes compared with the experimental data. This model is used to calculate heat transfer and fluid flow in SAH duct with the compound roughness of V-shaped ribs and dimples. The overall thermal performance based on equal pumping power is found to be the highest (2.18) for flow attack angle of 55°. The thermo-hydraulic performance for V-pattern shaped ribs combined with dimple ribs is higher than that for dimple rib shape and V-pattern rib shape air duct.

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Effects of Rib Arrangements on Heat Transfer and Flow Behavior in a Rectangular Rib-Roughened Passage: Application to Cooling of Gas Turbine Blade Trailing Edge

Cited by 79 publications

References 19 publications

Empirical assessment of heat transmission and pressure loss in turbojet blades

Empirical assessment of heat transmission and pressure loss in turbojet blades

Thermal and dynamic characteristics of the separated flow behind a flat rib with different angles of alignment toward the flow

Numerical study on overall thermal performance in SAH duct with compound roughness of V-shaped ribs and dimples

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