Flow structure and surface heat transfer from numerical predictions for a double wall effusion plate with impingement jet array cooling

An experimental investigation has been conducted into the use of a combined impingement-pedestal cooling geometry to improve uniformity of surface heat transfer coefficient over traditional combustor liner impingement arrays. Various pedestal arrangements have been investigated by altering the height-to-diameter (H/D) and pitch-to-diameter (P/D) ratios and measurements have been made over a range of impingement jet Reynolds numbers between ∼20 and 40×103. The surface heat transfer coefficient has been determined using a transient liquid crystal thermography measurement technique and the data presented in terms of Nusselt number. A ‘shielded impingement’ concept has also been defined featuring full-height pedestals positioned upstream of each impingement jet and arranged to shield the impingement jets from the developing cross-flow. Aerodynamic measurements have also been made to evaluate the influence of changes to the pedestal geometry on the pressure drop incurred across the different cooling patterns. The analysis indicates superior heat transfer performance can be achieved for the shielded impingement arrangements, with the greatest improvement over equivalent geometries displayed towards the rear of the cooling channel.

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SIMILARITY AND DISSIMILARITY BETWEEN THE SURFACE HEAT TRANSFER AND THE FLOW STRUCTURE IN TURBULENT FLOWS OVER SURFACE-MOUNTED CUBES

Proceeding of International Heat Transfer Conference 11 ◽

10.1615/ihtc11.2410 ◽

1998 ◽

Cited By ~ 2

Author(s):

E.R. Meinders ◽

Kemal Hanjalic ◽

Theodorus H. Van der Meer

Keyword(s):

Heat Transfer ◽

Turbulent Flows ◽

Flow Structure ◽

Surface Heat ◽

Surface Heat Transfer

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A numerical investigation of dimple effects on internal heat transfer enhancement of a double wall cooling structure with jet impingement

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-02-2015-0081 ◽

2016 ◽

Vol 26 (7) ◽

pp. 2175-2197 ◽

Cited By ~ 13

Author(s):

Lei Luo ◽

Chenglong Wang ◽

Lei Wang ◽

Bengt Ake Sunden ◽

Sangtao Wang

Keyword(s):

Heat Transfer ◽

Heat Transfer Enhancement ◽

Friction Factor ◽

Flow Behavior ◽

Target Surface ◽

Surface Heat ◽

Transfer Enhancement ◽

Content Type ◽

Surface Heat Transfer ◽

Double Wall

Purpose The dimple is adopted into a double wall cooling structure which is widely used in hot gas components to increase the heat transfer effects with relatively low pressure drop penalty. The purpose of this paper is to study the effect of dimple depth and dimple diameter on the target surface heat transfer and the inlet to outlet friction factor. Design/methodology/approach The study is carried out by using the numerical simulations. The impingement flow is directly impinging on the dimple and released from the film holes after passing the double wall chamber. The ratio between dimple depth and dimple diameter is varied from 0 to 0.4 and the ratio between dimple diameter and impingement hole diameter is ranging from 0.5 to 3. The Reynolds number is between 10,000 and 70,000. Results of the target surface Nusselt number, friction factor and flow structures are included. For convenience of comparison, the double wall cooling structure without the dimple is considered as the baseline. Findings It is found that the dimple can effectively enhance the target surface heat transfer due to thinning of the flow boundary layer and flow reattachment as well as flow recirculation outside the dimple near the dimple rim especially for the large Re number condition. However, the stagnation point heat transfer is reduced. It is also found that for a large dimple depth or large dimple diameter, a salient heat transfer reduction occurs for the toroidal vortex. The thermal performance indicates that the intensity of the heat transfer enhancement depends upon the dimple depth and dimple diameter Originality/value This is the first time to adopt a dimple into a double wall cooling structure. It suggests that the target surface heat transfer in a double wall cooling structure can be increased by the use of the dimple. However, the heat transfer characteristic is sensitive for the different dimple diameter and dimple depth which may result in a different flow behavior

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Computation of Flow and Heat Transfer in Turbine Blade Cooling Passages by Reynolds Stress Turbulence Model (Keynote Paper)

Volume 2: Symposia and General Papers, Parts A and B ◽

10.1115/fedsm2002-31194 ◽

2002 ◽

Cited By ~ 1

Author(s):

Hamn-Ching Chen ◽

Je-Chin Han

Keyword(s):

Heat Transfer ◽

Turbine Blade ◽

Surface Heat ◽

Heat Fluxes ◽

Surface Heat Transfer ◽

Second Moment ◽

Turbine Blade Cooling ◽

Blade Cooling ◽

Flow And Heat Transfer ◽

Numerical Predictions

Numerical predictions of three-dimensional flow and heat transfer are presented for non-rotating and rotating turbine blade cooling passages with or without the rib turbulators. A multi-block Reynolds-averaged Navier-Stokes method was employed in conjunction with a near-wall second-moment closure to provide detailed velocity, pressure, and temperature distributions as well as Reynolds stresses and turbulent heat fluxes in various cooling channel configurations. These numerical results were systematically evaluated to determine the effect of blade rotation, coolant-to-wall density ratio, rib shape, channel aspect ratio and channel orientation on the generation of flow turbulence and the enhancement of surface heat transfer in turbine blade cooling passages. The second-moment solutions show that the secondary flow induced by the angled ribs, centrifugal buoyancy, and Coriolis forces produced strong nonisotropic turbulent stresses and heat fluxes that significantly affected flow field and surface heat transfer coefficients.

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Surface heat transfer study of ultra heavy plate during quenching process of jet array impingement

Applied Thermal Engineering ◽

10.1016/j.applthermaleng.2016.12.012 ◽

2017 ◽

Vol 117 ◽

pp. 522-533 ◽

Cited By ~ 4

Author(s):

Tian-liang Fu ◽

Zhao-dong Wang ◽

Xiang-tao Deng ◽

Jun Han ◽

Guo-dong Wang

Keyword(s):

Heat Transfer ◽

Surface Heat ◽

Surface Heat Transfer ◽

Heavy Plate ◽

Quenching Process ◽

Transfer Study ◽

Jet Array

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Transonic Turbine Blade Tip Aero-Thermal Performance With Different Tip Gaps: Part I—Tip Heat Transfer

Volume 4: Heat Transfer, Parts A and B ◽

10.1115/gt2010-22779 ◽

2010 ◽

Cited By ~ 2

Author(s):

Q. Zhang ◽

D. O. O’Dowd ◽

L. He ◽

M. L. G. Oldfield ◽

P. M. Ligrani

Keyword(s):

Heat Transfer ◽

Thermal Performance ◽

High Speed ◽

Hot Spot ◽

Structural Characteristics ◽

Surface Heat ◽

Tip Leakage Flow ◽

Surface Heat Transfer ◽

Numerical Predictions ◽

Blade Tip

A closely combined experimental and CFD study on a transonic blade tip aero-thermal performance at engine representative Mach and Reynolds numbers (Mexit = 1, Reexit = 1.27×106) is presented in this and its companion paper (Part II). The present paper considers surface heat transfer distributions on tip surfaces, and on suction and pressure side surfaces (near-tip region). Spatially-resolved surface heat transfer data are measured using infrared thermography and transient techniques within the Oxford University High Speed Linear Cascade research facility. The Rolls-Royce PLC HYDRA suite is employed for numerical predictions for the same tip configuration and flow conditions. The CFD results are generally in good agreement with experimental data, and show that the flow over a large portion of the blade tip is supersonic for all three tip gaps investigated. Mach numbers within the tip gap become lower as the tip gap decreases. For the flow regions near the leading edge of the tip gap, surface Nusselt numbers decrease as the tip gap decreases. Opposite trends are observed for the trailing edge region. Several ‘hot spot’ features on blade tip surfaces are attributed to enhanced turbulence thermal diffusion in local regions. Other surface heat transfer variations are attributed to flow variations induced by shock waves. Flow structure and surface heat transfer variations are also investigated numerically when a moving casing is present. The inclusion of moving casing leads to notable changes to flow structural characteristics and associated surface heat transfer variations. However, significant portions of the tip leakage flow remain transonic with clearly identifiable shock wave structures.

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Transonic Turbine Blade Tip Aerothermal Performance With Different Tip Gaps—Part I: Tip Heat Transfer

Journal of Turbomachinery ◽

10.1115/1.4003063 ◽

2011 ◽

Vol 133 (4) ◽

Cited By ~ 47

Author(s):

Q. Zhang ◽

D. O. O’Dowd ◽

L. He ◽

M. L. G. Oldfield ◽

P. M. Ligrani

Keyword(s):

Heat Transfer ◽

High Speed ◽

Hot Spot ◽

Structural Characteristics ◽

Leading Edge ◽

Surface Heat ◽

Tip Leakage Flow ◽

Surface Heat Transfer ◽

Numerical Predictions ◽

Blade Tip

A closely combined experimental and computational fluid dynamics (CFD) study on a transonic blade tip aerothermal performance at engine representative Mach and Reynolds numbers (Mexit=1,Reexit=1.27×106) is presented here and its companion paper (Part II). The present paper considers surface heat-transfer distributions on tip surfaces and on suction and pressure-side surfaces (near-tip region). Spatially resolved surface heat-transfer data are measured using infrared thermography and transient techniques within the Oxford University high speed linear cascade research facility. The Rolls-Royce PLC HYDRA suite is employed for numerical predictions for the same tip configuration and flow conditions. The CFD results are generally in good agreement with experimental data and show that the flow over a large portion of the blade tip is supersonic for all three tip gaps investigated. Mach numbers within the tip gap become lower as the tip gap decreases. For the flow regions near the leading edge of the tip gap, surface Nusselt numbers decrease as the tip gap decreases. Opposite trends are observed for the trailing edge region. Several “hot spot” features on blade tip surfaces are attributed to enhanced turbulence thermal diffusion in local regions. Other surface heat-transfer variations are attributed to flow variations induced by shock waves. Flow structure and surface heat-transfer variations are also investigated numerically when a moving casing is present. The inclusion of moving casing leads to notable changes to flow structural characteristics and associated surface heat-transfer variations. However, significant portions of the tip leakage flow remain transonic with clearly identifiable shock wave structures.

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