Comparison of Various RANS Models for Impinging Round Jet Cooling From a Cylinder

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Ketan Atulkumar Ganatra ◽  
Dushyant Singh
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Turbulence Model ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Jet Impingement ◽  
Target Surface ◽  
Point Of View ◽  
Nozzle Diameter ◽  
Round Jet

The numerical analysis for the round jet impingement over a circular cylinder has been carried out. The v2f turbulence model is used for the numerical analysis and compared with the two equation turbulence models from the fluid flow and the heat transfer point of view. Further, the numerical results for the heat transfer with original and modified v2f turbulence model are compared with the experimental results. The nozzle is placed orthogonally to the target surface (heated cylindrical surface). The flow is assumed as the steady, incompressible, three-dimensional and turbulent. The spacing between the nozzle exit and the target surface ranges from 4 to 15 times the nozzle diameter. The Reynolds number based on the nozzle diameter ranges from 23,000 to 38,800. From the heat transfer results, the modified v2f turbulence model is better as compared to the other turbulence models. The modified v2f turbulence model has the least error for the numerical Nusselt number at the stagnation point and wall jet region.

scholarly journals A Combined Experimental and Numerical Investigation of the Flow and Heat Transfer Inside a Turbine Vane Cooled by Jet Impingement

2017 ◽  
Vol 140 (3) ◽  
Author(s):  
Emmanuel Laroche ◽  
Matthieu Fenot ◽  
Eva Dorignac ◽  
Jean-Jacques Vuillerme ◽  
Laurent Emmanuel Brizzi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Jet Impingement ◽  
Numerical Results ◽  
Point Of View ◽  
Navier Stokes ◽  
Recirculation Flow ◽  
Rans Models ◽  
Unsteady Effects

The present study aims at characterizing the flow field and heat transfer for a schematic but realistic vane cooling scheme. Experimentally, both velocity and heat transfer measurements are conducted to provide a detailed database of the investigated configuration. From a numerical point of view, the configuration is investigated using isotropic and anisotropic Reynolds-averaged Navier–Stokes (RANS) turbulence models. A hybrid RANS/large eddy simulation (LES) technique is also considered to evaluate potential unsteady effects. Both experimental and numerical results show a very complex three-dimensional (3D) flow. Air is not evenly distributed between different injections, mainly because of a large recirculation flow. Due to the strong flow deviation at the hole inlet, the velocity distribution and the turbulence characteristics at the hole exit are far from fully developed profiles. The comparison between particle image velocimetry (PIV) measurements and numerical results shows a reasonable agreement. However, coming to heat transfer, all RANS models exhibit a major overestimation compared to IR thermography measurements. The Billard–Laurence model does not bring any improvement compared to a classical k–ω shear stress transport (SST) model. The hybrid RANS/LES simulation provides the best heat transfer estimation, exhibiting potential unsteady effects ignored by RANS models. Those conclusions are different from the ones usually obtained for a single fully developed impinging jet.

Numerical Study of Flow and Heat Transfer of Impingement Cooling on Model of Turbine Blade Leading Edge

2010 ◽  
Author(s):  
Zhao Liu ◽  
Zhenping Feng ◽  
Liming Song
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Numerical Study ◽  
Leading Edge ◽  
Jet Impingement ◽  
Target Surface ◽  
Nozzle Diameter ◽  
Impingement Cooling ◽  
Jet Nozzle ◽  
Blade Leading Edge

In this paper a numerical simulation is performed to simulate the impingement cooling on internal leading edge region, which is stretched by the middle cross section of the first stage rotor blade of GE-E3 engine high pressure turbine, and in the condition that jets flow is ejected from a row of four different diameter circular nozzles. The relative performances of three versions of turbulence models including the RNG κ-ε model, the standard κ-ω model and the SST κ-ω model in the simulation of a row of circle jet impingement heat transfer are compared with available experimental data. The results show that SST κ-ω model is the best one based on simulation accuracy. Then the SST κ-ω model is adopted for the simulation. The grid independence study is also carried out by using the Richardson extrapolation method. A single array of circle jets is arranged to investigate the impingement cooling and its effectiveness. Four different jet nozzle diameters are studied and seven different inlet flow Mach numbers of each jet nozzle diameter are calculated. The influence of the ratio of the spacing of jet nozzle from the target surface to the jet nozzle diameter on impingement cooling is also studied, in case of a constant ratio of jet spacing to jet nozzle diameter in different jet nozzle diameters. The results indicate that the heat transfer coefficient on the turbine blade leading edge increases with the increase of jet Mach number and jet nozzle diameter, the spanwise area weight average Nusselt number decreases with the increase of the ratio of the spacing of jet nozzle from the target surface to jet nozzle diameter, and a lower ratio of spacing of jet nozzle from the target surface to the jet nozzle diameter is desirable to improve the performance of impingement cooling on turbine leading edge.

Numerical Analysis of Local Heat Transfer From a Flat Plate to a Pair of Circular Air Impingining Jets

2004 ◽  
Author(s):  
X. Terry Yan ◽  
Yavaraj Saravanan
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Flat Plate ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Impinging Jets ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients

Local heat transfer from a flat plate to a pair of circular air impinging jets is investigated numerically. A pair of impinging jets from fully-developed pipe flows are used for the numerical simulations. The Reynolds Averaged Navier-Stokes equations(RANS) and energy equation are solved for the three dimensional flow. Eddy-viscocity based turbulence models, RNG k-epsilon and V2F models, are used. Hybrid meshes are used for the three dimensional flows and mesh independent solutions are obtained. The flow Reynolds number, which is based on the jet diameter, is kept at 23,000. In the analysis, local heat transfer coefficients are obtained for the jet-to-plate distance, L/D, ranging from 2 to 10 and the jet-to-jet spacing, S/D, in the range of 1.75 to 7.0. Both local and average heat transfer coefficients are evaluated and compared with available experimental data under same flow conditions. The effect of using different turbulence models in the numerical analysis is evaluated and the selection of proper turbulence models under such a flow condition is suggested.

Experimental Investigation of Leading Edge Impingement Under High Rotation Numbers With Racetrack Shaped Jets

2014 ◽  
Author(s):  
Weston V. Harmon ◽  
Cassius A. Elston ◽  
Lesley M. Wright
Keyword(s):  
Heat Transfer ◽  
Rotation Number ◽  
Cross Flow ◽  
Leading Edge ◽  
Jet Impingement ◽  
Target Surface ◽  
Transfer Coefficients ◽  
Round Jet ◽  
Rotation Numbers ◽  
Circular Target

The effect of rotation on leading edge jet impingement is experimentally investigated in this study. Cooling air travels radially outward through a square supply channel, turns 90° into a cross-over hole, and impinges on a semi-circular surface. To eliminate the effect of jet cross-flow, regionally averaged heat transfer coefficients are measured on the surface surrounding a single jet. The heat transfer performance of a round jet is compared to that afforded by a 2:1 racetrack shaped jet. Two jet Reynolds numbers were investigated, Rejet = 15,000 and Rejet = 25,000. This, in addition to a varying rotational speed, allows for the consideration of rotation numbers varying from 0.0–0.076 (based on the jet velocity and jet hydraulic diameter). The results obtained are benchmarked against stationary results to highlight enhancement due to rotation. It is shown that as the rotation number increases, the heat transfer is enhanced on all regions of the semi-circular target surface. For rotation numbers of less than 0.030, enhancement due to rotation is marginal. Once rotation numbers breach this value, heat transfer begins to increase significantly on all surfaces. Additionally, it was shown that a racetrack shaped jet consistently out performs a round jet at an equivalent rotation number. The racetrack jet offers better and more consistent coverage of the leading edge surface, yielding higher average heat transfer enhancement.

Reynolds Averaged and Large Eddy Computations of Flow and Heat Transfer Under Round Jet Impingement

2014 ◽  
Author(s):  
Thangam Natarajan ◽  
James Jewkes ◽  
Ramesh Narayanaswamy ◽  
Yongmann M. Chung ◽  
Anthony D. Lucey
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Turbulence Models ◽  
Jet Impingement ◽  
Navier Stokes ◽  
Round Jet ◽  
Eddy Simulation ◽  
Impingement Heat Transfer ◽  
Turbulent Statistics ◽  
Large Eddy

The fluid dynamics and heat transfer characteristics of a turbulent round jet are modelled numerically using Reynolds-Averaged Navier-Stokes (RANS) and Large Eddy Simulation (LES). Meshes with varying degrees of coarseness, with both radial and axial refinements are investigated. Discretization is carried out using the finite volume method. The jet configurations are chosen to enable validation against well-established experimental jet-impingement heat-transfer studies, particularly that of Cooper et al. [1]. The Reynolds number studied is 23000. The height of discharge from the impingement wall is fixed at twice the jet diameter. The work critically examines the effect of Reynolds number, standoff distance and helps to ascertain the relative merits of various turbulence models, by comparing turbulent statistics and the Nusselt number distributions. The present work is carried out as a preliminary validation, in a wider study intended to determine the thermofluidic behaviour of jets impinging upon an oscillating surface.

scholarly journals A Combined Experimental and Numerical Investigation of the Flow and Heat Transfer Inside a Turbine Vane Cooled by Jet Impingement

2017 ◽  
Author(s):  
Emmanuel Laroche ◽  
Matthieu Fenot ◽  
Eva Dorignac ◽  
Jean-Jacques Vuillerme ◽  
Laurent Emmanuel Brizzi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Turbulence Models ◽  
Jet Impingement ◽  
Numerical Results ◽  
Point Of View ◽  
Navier Stokes ◽  
Recirculation Flow ◽  
Flow Deviation ◽  
Rans Models ◽  
Unsteady Effects

The present study aims at characterizing the flow field and heat transfer for a schematic but realistic vane cooling scheme. Experimentally, both velocity and heat transfer measurements are conducted to provide a detailed database of the investigated configuration. From a numerical point of view, the configuration is investigated using isotropic as well as anisotropic Reynolds-Averaged Navier-Stokes (RANS) turbulence models. An hybrid RANS/LES technique is also considered to evaluate potential unsteady effects. Both experimental and numerical results show a very complex 3D flow. Air is not evenly distributed between the different injections, mainly because of a large recirculation flow. Due to the strong flow deviation at the hole inlet, the velocity distribution and the turbulence characteristics at the hole exit are far from fully developed profiles. The comparison between PIV measurements and numerical results shows a reasonable agreement. However, coming to heat transfer, all RANS models exhibit a major overestimation compared to IR thermography measurements. The Billard-Laurence model does not bring any improvement compared to a classical k-ω SST model. The hybrid RANS/LES simulation provides the best heat transfer estimation, exhibiting potential unsteady effects ignored by RANS models. Those conclusions are different from the ones usually obtained for a single fully developed impinging jet.

Computations of Flow Field and Heat Transfer in a Stator Vane Passage Using the v2¯−f Turbulence Model

2005 ◽  
Vol 127 (3) ◽  
pp. 627-634 ◽  
Author(s):  
A. Sveningsson ◽  
L. Davidson
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Turbulence Model ◽  
Eddy Viscosity ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Mean Flow ◽  
Stator Vane ◽  
Good Agreement

In this study three-dimensional simulations of a stator vane passage flow have been performed using the v2¯−f turbulence model. Both an in-house code (CALC-BFC) and the commercial software FLUENT are used. The main objective is to investigate the v2¯−f model’s ability to predict the secondary fluid motion in the passage and its influence on the heat transfer to the end walls between two stator vanes. Results of two versions of the v2¯−f model are presented and compared to detailed mean flow field, turbulence, and heat transfer measurements. The performance of the v2¯−f model is also compared with other eddy-viscosity-based turbulence models, including a version of the v2¯−f model, available in FLUENT. The importance of preventing unphysical growth of turbulence kinetic energy in stator vane flows, here by use of the realizability constraint, is illustrated. It is also shown that the v2¯−f model predictions of the vane passage flow agree well with experiments and that, among the eddy-viscosity closures investigated, the v2¯−f model, in general, performs the best. Good agreement between the two different implementations of the v2¯−f model (CALC-BFC and FLUENT) was obtained.

Turbulence Model Dependencies on Conjugate Simulation of Flow and Heat Conduction

2007 ◽  
Author(s):  
Takahiro Bamba ◽  
Takashi Yamane ◽  
Yoshitaka Fukuyama
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Turbulence Model ◽  
Flow Simulation ◽  
Turbulence Models ◽  
Jet Impingement ◽  
Turbine Cascade ◽  
Turbulent Transition ◽  
Simulation Based ◽  
The Common

This paper discusses the influences of the turbulence model selection on the heat transfer prediction in the conjugate simulation of flow and heat conduction. It is known that the heat transfer prediction by the flow simulation based on RANS is dependent upon the turbulence model. Common difficulties are the anomalous production of turbulent kinetic energy in a flow with large rates of strain and the laminar-turbulent transition, both of which are persistent aspects in typical turbine cascade flow. Similar and possibly greater impact is expected when these turbulence models are applied to the conjugate simulation of flow and heat conduction. An anomaly treatment called a time-scale bound is applied to the low Reynolds number k-ω and the SST turbulence models installed in the common CFD platform UPACS. The turbulence model dependencies on the conjugate simulation of flow and heat conduction are investigated in an axisymmetric turbulent jet impingement and the 2D turbine cascade vanes.

Computations of Flow Field and Heat Transfer in a Stator Vane Passage Using the v2–f Turbulence Model

2004 ◽  
Author(s):  
Andreas Sveningsson ◽  
Lars Davidson
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Turbulence Model ◽  
Eddy Viscosity ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Mean Flow ◽  
Stator Vane ◽  
Good Agreement

In this study three-dimensional simulations of a stator vane passage flow have been performed using the v2–f turbulence model. Both an in-house code (CALC-BFC) and the commercial software Fluent are used. The main objective is to investigate the v2–f model’s ability to predict the secondary fluid motion in the passage and its influence on the heat transfer to the endwalls between two stator vanes. Results of two versions of the v2–f model are presented and compared with detailed mean flow field, turbulence and heat transfer measurements. The performance of the v2–f model is also compared with other eddy-viscosity based turbulence models, including a version of the v2–f model, available in Fluent. The importance of preventing unphysical growth of turbulence kinetic energy in stator vane flows, here by use of the realizability constraint, is illustrated. It is also shown that the v2–f model predictions of the vane passage flow agree well with experiments and that, amongst the eddy-viscosity closures investigated, the v2–f model in general performs the best. Good agreement between the two different implementations of the v2–f model (CALC-BFC and Fluent) was obtained.

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