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.

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.

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.

How Turbulence Models Perform in Simulating Pipeflow Response to Targeted Wall-Shapes?

2021 ◽  
Author(s):  
Mehran Masoumifar ◽  
Suyash Verma ◽  
Arman Hemmati
Keyword(s):  
Three Dimensional ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Navier Stokes ◽  
Flow Response ◽  
High Reynolds Numbers ◽  
Flow Features ◽  
Rans Models ◽  
Response And Recovery ◽  
High Reynolds

Abstract This study evaluates how Reynolds-Averaged-Navier-Stokes (RANS) models perform in simulating the characteristics of mean three-dimensional perturbed flows in pipes with targeted wall-shapes. Capturing such flow features using turbulence models is still challenging at high Reynolds numbers. The principal objective of this investigation is to evaluate which of the well-established RANS models can best predict the flow response and recovery characteristics in perturbed pipes at moderate and high Reynolds numbers (10000-158000). First, the flow profiles at various axial locations are compared between simulations and experiments. This is followed by assessing the well-known mean pipeflow scaling relations. The good agreement between our computationally predicted data using Standard k-epsilon model and those of experiments indicated that this model can accurately capture the pipeflow characteristics in response to introduced perturbation with smooth sinusoidal axial variations.

scholarly journals Two-Equation Turbulence Models for Prediction of Heat Transfer on a Transonic Turbine Blade

2001 ◽  
Author(s):  
Vijay K. Garg ◽  
Ali A. Ameri
Keyword(s):  
Heat Transfer ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Suction Side ◽  
Navier Stokes ◽  
Production Term ◽  
Passage Vortex ◽  
Sst Model ◽  
Transonic Turbine

Two versions of the two-equation k-ω model and a shear stress transport (SST) model are used in a three-dimensional, multi-block, Navier-Stokes code to compare the detailed heat transfer measurements on a transonic turbine blade. It is found that the SST model resolves the passage vortex better on the suction side of the blade, thus yielding a better comparison with the experimental data than either of the k-ω models. However, the comparison is still deficient on the suction side of the blade. Use of the SST model does require the computation of distance from a wall, which for a multi-block grid, such as in the present case, can be complicated. However, a relatively easy fix for this problem was devised. Also addressed are issues such as (1) computation of the production term in the turbulence equations for aerodynamic applications, and (2) the relation between the computational and experimental values for the turbulence length scale, and its influence on the passage vortex on the suction side of the turbine blade.

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.

Thermal Mixing Length Determination by RANS Models in T-Junction

2010 ◽  
Author(s):  
M. Aounallah ◽  
M. Belkadi ◽  
L. Adjlout ◽  
O. Imine
Keyword(s):  
Turbulent Mixing ◽  
Thermal Field ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Numerical Results ◽  
Test Case ◽  
Thermal Mixing ◽  
Rans Turbulence Models ◽  
Rans Models ◽  
Length Determination

In the present study, a numerical simulation is carried out in order to optimize the length of the mixing part of a T-junction to obtain a homogenous temperature distribution at the outlet. Different RANS turbulence models are tested: the Realizable k-ε the k-ω standard and the k-ω SST. The behavior of turbulent mixing flow in the mixing part of the pipe has helped in understanding the causes of discrepancy between the models used. The test case analysed in this paper is an unsteady state three-dimensional turbulent flow. The numerical results obtained show that there is a difference in the prediction of the thermal field when different models are used. The results obtained for both k-ω standard and SST models are closer compared with those given by the Realizable k-ε model. The numerical results show that a distance of x/L = 0.625 from the branch is enough to supply devices with a constant temperature.

scholarly journals Heat transfer intensification by jet impingement – numerical analysis using RANS approach

2019 ◽  
Vol 108 ◽  
pp. 01025
Author(s):  
Tomasz Kura ◽  
Elżbieta Fornalik-Wajs ◽  
Jan Wajs ◽  
Sasa Kenjeres
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Jet Impingement ◽  
Accurate Method ◽  
Navier Stokes ◽  
Engineering Systems ◽  
Rans Models ◽  
Complex Boundary ◽  
Surface Jet ◽  
Fast Flow

Jet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically complex. Therefore the numerical analysis is necessary to understand the phenomena, especially in the range of turbulent flow. The well-known and accurate method is Reynolds Averaged Navier-Stokes (RANS) approach. However, depending on the applied turbulence model, various results can be obtained. The reason is that the jet impingement strongly depends on the complex boundary layer effects and their resolving is still challenging for RANS models and until now it is their weakest point. In the paper, the hydrodynamic and thermal, numerical results of jet impingement are presented, depending on selected RANS based models. The aim was to indicate their ability to anticipate the turbulence parameters.

Numerical Simulation of Piston Cooling With Oil Jet Impingement

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
G. Nasif ◽  
R. M. Barron ◽  
R. Balachandar
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Three Dimensional ◽  
Jet Impingement ◽  
Engine Oil ◽  
Navier Stokes ◽  
Maximum Heat ◽  
Maximum Heat Transfer ◽  
Piston Cooling

Convective heat transfer of an impinging jet is numerically evaluated for piston cooling process. A circular jet of subcooled engine oil that impinges normally onto the inner surface of the piston for an engine operating at normal condition is considered in the study. The k−ω  shear stress transport (SST) based on transient three-dimensional governing Navier–Stokes (Reynolds-averaged Navier–Stokes (RANS)) equations are computationally solved using a finite-volume technique. The conjugate heat transfer method is used to obtain a coupled heat transfer solution between the solid and fluid regions, to predict the heat transfer coefficient at the piston walls and then the temperature distribution in the piston. It is shown that the cooling jet can significantly decrease the piston temperature. The location of the incidence of maximum heat transfer coefficient is moved away from the impingement point as the nozzle size increases.

Effects of stator splitter blades on aerodynamic performance of a single-stage transonic axial compressor

2020 ◽  
Vol 14 (4) ◽  
pp. 7369-7378
Author(s):  
Ky-Quang Pham ◽  
Xuan-Truong Le ◽  
Cong-Truong Dinh
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Aerodynamic Performance ◽  
Numerical Results ◽  
Single Stage ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Operating Stability ◽  
Length Coverage

Splitter blades located between stator blades in a single-stage axial compressor were proposed and investigated in this work to find their effects on aerodynamic performance and operating stability. Aerodynamic performance of the compressor was evaluated using three-dimensional Reynolds-averaged Navier-Stokes equations using the k-e turbulence model with a scalable wall function. The numerical results for the typical performance parameters without stator splitter blades were validated in comparison with experimental data. The numerical results of a parametric study using four geometric parameters (chord length, coverage angle, height and position) of the stator splitter blades showed that the operational stability of the single-stage axial compressor enhances remarkably using the stator splitter blades. The splitters were effective in suppressing flow separation in the stator domain of the compressor at near-stall condition which affects considerably the aerodynamic performance of the compressor.

scholarly journals A Code for Simulating Heat Transfer in Turbulent Channel Flow

Mathematics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 756
Author(s):  
Federico Lluesma-Rodríguez ◽  
Francisco Álcantara-Ávila ◽  
María Jezabel Pérez-Quiles ◽  
Sergio Hoyas
Keyword(s):  
Heat Transfer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Turbulent Channel Flow ◽  
Passive Scalar ◽  
Direct Numerical Simulations ◽  
Time Dependent ◽  
Navier Stokes ◽  
Thermal Flow ◽  
Navier Stokes Equations

One numerical method was designed to solve the time-dependent, three-dimensional, incompressible Navier–Stokes equations in turbulent thermal channel flows. Its originality lies in the use of several well-known methods to discretize the problem and its parallel nature. Vorticy-Laplacian of velocity formulation has been used, so pressure has been removed from the system. Heat is modeled as a passive scalar. Any other quantity modeled as passive scalar can be very easily studied, including several of them at the same time. These methods have been successfully used for extensive direct numerical simulations of passive thermal flow for several boundary conditions.

Sign in / Sign up

Export Citation Format

Share Document