Three-dimensional conjugate heat transfer in partitioned enclosures: Determination of geometrical and thermal properties by an inverse method

A high-pressure vane equipped with a realistic film-cooling configuration has been studied. The vane is characterized by the presence of multiple rows of fan-shaped holes along pressure and suction side while the leading edge is protected by a showerhead system of cylindrical holes. Steady three-dimensional Reynolds-Averaged Navier-Stokes (RANS) simulations have been performed. A preliminary grid sensitivity analysis with uniform inlet flow has been used to quantify the effect of spatial discretization. Turbulence model has been assessed in comparison with available experimental data. The effects of the relative alignment between combustion chamber and high-pressure vanes are then investigated considering realistic inflow conditions in terms of hot spot and swirl. The inlet profiles used are derived from the EU-funded project TATEF2. Two different clocking positions are considered: the first one where hot spot and swirl core are aligned with passage and the second one where they are aligned with the leading edge. Comparisons between metal temperature distributions obtained from conjugate heat transfer simulations are performed evidencing the role of swirl in determining both the hot streak trajectory within the passage and the coolant redistribution. The leading edge aligned configuration is resulted to be the most problematic in terms of thermal load, leading to increased average and local vane temperature peaks on both suction side and pressure side with respect to the passage aligned case. A strong sensitivity of both injected coolant mass flow and heat removed by heat sink effect has also been highlighted for the showerhead cooling system.

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A Numerical Thermal Analysis of the Heating Process of Large Size Forged Ingots

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.2278 ◽

2018 ◽

Vol 941 ◽

pp. 2278-2283

Author(s):

Nima Bohlooli Arkhazloo ◽

Farzad Bazdidi-Tehrani ◽

Morin Jean-Benoit ◽

Mohammad Jahazi

Keyword(s):

Heat Transfer ◽

Heat Treatment ◽

Conjugate Heat Transfer ◽

Computational Cost ◽

Three Dimensional ◽

Temperature Evolution ◽

Heating Process ◽

Computational Domain ◽

Cfd Model ◽

Large Size

Simulation and analysis of thermal interactions during heat treatment is of great importance for accurate prediction of temperature evolution of work pieces and consequently controlling the final microstructure and mechanical properties of products. In the present study, a three-dimensional CFD model was employed to predict the heating process of large size forged ingots inside an industrial gas-fired heat treatment furnace. One-ninth section of a loaded furnace, including details such as fixing bars and high-momentum cup burners, was employed as the computational domain. The simulations were conducted using the ANSYS-FLUENT commercial CFD package. The k-ε, P-1 and Probability Density Function (PDF) in the non-premix combustion, as low computational cost numerical approaches were employed to simulate the turbulent fluid flow, thermal radiation, combustion and conjugate heat transfer inside the furnace. Temperature measurement at different locations of the forged ingot surfaces were used to validate the transient numerical simulations. Good agreement was obtained between the predictions of the CFD model and the experimental measurements, demonstrating the reliability of the proposed approach and application of the model for process optimization purposes. Detailed analysis of conjugate heat transfer together with the turbulent combustion showed that the temperature evolution of the product was significantly dependant on the furnace geometry and the severity of turbulent flow structures in the furnace.

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Conjugate Flow and Heat Transfer Investigation of a Turbo Charger: Part I — Numerical Results

Volume 3: Turbo Expo 2003 ◽

10.1115/gt2003-38445 ◽

2003 ◽

Cited By ~ 18

Author(s):

Dieter Bohn ◽

Tom Heuer ◽

Karsten Kusterer

Keyword(s):

Heat Transfer ◽

Three Dimensional ◽

Heat Fluxes ◽

Inlet Temperature ◽

Three Dimensional Model ◽

Flow And Heat Transfer ◽

Turbine Inlet ◽

Turbo Charger ◽

Conjugate Calculation

In this paper a three-dimensional conjugate calculation has been performed for a passenger car turbo charger. The scope of this work is to investigate the heat fluxes in the radial compressor which can be strongly influenced by the hot turbine. As a result of this, the compressor efficiency may deteriorate. Consequently, the heat fluxes have to be taken into account for the determination of the efficiency. To overcome this problem a complex three-dimensional model has been developed. It contains the compressor, the oil cooled center housing, and the turbine. 12 operating points have been numerically simulated composed of three different turbine inlet temperatures and four different mass flows. The boundary conditions for the flow and for the outer casing were derived from experimental test data (part II of the paper). Resulting from these conjugate calculations various one-dimensional calculation specifications have been developed. They describe the heat transfer phenomena inside the compressor with the help of a Nusselt number which is a function of an artificial Reynolds number and the turbine inlet temperature.

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Parametric Study of Vortex Generator Effects in an Additive Manufactured Minichannel Heat Exchanger

ASME 2019 17th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2019-4236 ◽

2019 ◽

Author(s):

Hamidreza Rastan ◽

Tim Ameel ◽

Björn Palm

Keyword(s):

Heat Transfer ◽

Thermal Properties ◽

Additive Manufacturing ◽

Heat Exchanger ◽

Angle Of Attack ◽

Three Dimensional ◽

High Energy ◽

Vortex Generators ◽

Design Parameters ◽

Minichannel Heat Exchanger

Abstract Heat exchangers with mini- and micro-channel components are capable of high energy exchange due to their incumbent large surface area to volume ratio. Concurrently, recent advances in additive manufacturing simplify the creation of metallic minichannels that incorporate turbulators for heat transfer enhancement. As part of the development of a minichannel heat exchanger with turbulators, this study analyzes the three-dimensional conjugate heat transfer and laminar flow in a minichannel heat exchanger equipped with rectangular winglet vortex generators (VGs) through numerical simulation. The minichannels have a hydraulic diameter of 2.86 mm and are assumed to be made from aluminum alloy AlSi10Mg. This material is one of the popular alloys in the additive manufacturing industry (three-dimensional (3D) printing) because of its light weight and beneficial mechanical and thermal properties. The working fluid is distilled water with temperature-dependent thermal properties. The minichannel is heated by a constant heat flux of 5 W cm−2 and the Reynolds number is varied from 230 to 950. The simulations are performed using the COMSOL® platform, which solves the governing mass, momentum, and energy equations based on the finite element method. The effect of the VG design parameters, which include VG angle of attack, height, length, thickness, longitudinal pitch, and distance from the sidewalls, is investigated. It is found that the generation of three-dimensional vortices caused by the presence of the vortex generators can notably boost the convective heat transfer, at the cost of increased pressure drop, potentially reducing the heat exchanger size for a given heat duty. A sensitivity analysis indicates that the angle of attack, VG height, VG length, and longitudinal pitch have the most significant effects on the heat transfer and flow friction characteristics. In contrast, the VG thickness and distance from the sidewalls only had minor influences on the heat exchanger performance over the studied range of design parameters.

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Systematic Investigation on Conjugate Heat Transfer Rates of Film Cooling Configurations

International Journal of Rotating Machinery ◽

10.1155/ijrm.2005.211 ◽

2005 ◽

Vol 2005 (3) ◽

pp. 211-220 ◽

Cited By ~ 7

Author(s):

Dieter Bohn ◽

Jing Ren ◽

Karsten Kusterer

Keyword(s):

Heat Transfer ◽

Film Cooling ◽

Conjugate Heat Transfer ◽

Local Heat Transfer ◽

Local Heat ◽

Systematic Investigation ◽

Transfer Condition ◽

Film Cooling Effectiveness ◽

Conjugate Calculation

For the determination of the film-cooling heat transfer, the design of a turbine blade relies on the conventional determination of the adiabatic film-cooling effectiveness and heat transfer conditions for test configurations. Thus, additional influences by the interaction of fluid flow and heat transfer and influences by additional convective heat transfer cannot be taken into account with sufficient accuracy. Within this paper, calculations of a film-cooled duct wall and a film-cooled real blade with application of the adiabatic and a conjugate heat transfer condition have been performed for different configurations. It can be shown that the application of the conjugate calculation method comprises the influence of heat transfer within the cooling film. The local heat transfer rate varies significantly depending on the local position.

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Influence Of Relative Size Of The U-Shaped Silicon Rod On Conjugate Heat Transfer In The Regime Of Gas Buayancy Induced Convection

Siberian Journal of Physics ◽

10.54362/1818-7919-2015-10-3-76-88 ◽

2015 ◽

Vol 10 (3) ◽

pp. 76-88

Author(s):

Vladimir Berdnikov ◽

Konstantin Mitin ◽

Alina Mitina

Keyword(s):

Heat Transfer ◽

Cross Section ◽

Solid Body ◽

Conjugate Heat Transfer ◽

Relative Size ◽

Three Dimensional ◽

Boussinesq Approximation ◽

Temperature Fields ◽

Spatial Form ◽

Section Size

The influence of relative cross-section size of an electrically heated U-shaped silicon rod which is placed in a gas-filled rectangle container with isothermal cold walls on conjugate heat transfer in the regime of buoyancy induced convection was numerically studied in three-dimensional formulation. The natural convection equations in the Boussinesq approximation in term temperature, velocity vortex and velocity vector potential were solved by the finite element method. The spatial form of convective flow and temperature fields in liquid and solid body were studied. It was show that spatial form and intensity of convective flows is significantly depends on the cross-section size of U-shaped silicon rod. This is has strong influence on the temperature field in a solid body.

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