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

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.

Conjugate Heat Transfer U-Shaped Silicon Rod with the Environment with Gas Thermogravitational Convection

2014 ◽  
Vol 9 (3) ◽  
pp. 63-74
Author(s):  
Vladimir Berdnikov ◽  
Konstantin Mitin ◽  
Alina Mitina
Keyword(s):  
Heat Transfer ◽  
Control Point ◽  
Three Dimensional ◽  
Boussinesq Approximation ◽  
Temperature Fields ◽  
Spatial Form ◽  
Convective Flows ◽  
Rectangular Container ◽  
Cold Walls ◽  
Selection Of

The conjugated natural convective heat transfer of electrically heated U-shaped silicon rod which placed in a rectangular container filled with gas with isothermal cold walls was numerically studied in a three-dimensional formulation of the problem. The temperature was maintained constant at the control point which placed on a surface of the U-shaped rod by selection of voltage. Temperature difference between the control point and the cold walls is 70 K. The equations of natural convections in Cartesian coordinates with Boussinesq approximation in terms of temperature, vortex and vector potential of velocity field were solver by FEM. Convective flows spatial form and temperature fields inside gas and the solid were investigated

scholarly journals Experimental Study and Conjugate Heat Transfer Simulation of Turbulent Flow in a 90° Curved Square Pipe

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 94
Author(s):  
Guanming Guo ◽  
Masaya Kamigaki ◽  
Qiwei Zhang ◽  
Yuuya Inoue ◽  
Keiya Nishida ◽  
...  
Keyword(s):  
Heat Transfer ◽  
High Temperature ◽  
Turbulent Flow ◽  
Cross Section ◽  
Conjugate Heat Transfer ◽  
Air Flow ◽  
Temperature Fields ◽  
Spatial Average ◽  
Flow And Heat Transfer ◽  
Curved Pipes

This paper discusses the turbulent flow and heat transfer from a uniform air flow with high temperature to the outside through a 90° curved square pipe. Both conjugate heat transfer (CHT) simulation and experiments of temperature field measurements at cross sections of the pipe are performed. A straight pipe is investigated and compared with the 90° curved pipe. The temperature of the air flow at the inlet of the pipe is set at 402 K, and the corresponding Reynolds number is approximately 6 × 104. To obtain the spatial average temperature at each cross section, the temperature fields are measured along the streamwise of the pipes and in the circumferential direction using thermocouples at each cross section from the inlet to the outlet of both the straight and curved pipes. Furthermore, the simulation is performed for turbulent flow and heat transfer inside the pipe wall using the Re-normalization group (RNG) k-ε turbulence model and CHT method. Both the experimental and numerical results show that the curvature of the pipe result in a deviation and impingement in the high-temperature core and a separation between the wall and air, resulting in a secondary flow pattern of the temperature distribution.

scholarly journals Numerical Simulation of Secondary Flow in Gas Turbine Disc Cavities, Including Conjugate Heat Transfer

1996 ◽  
Author(s):  
Y.-H. Ho ◽  
M. M. Athavale ◽  
J. M. Forry ◽  
R. C. Hendricks ◽  
B. M. Steinetz
Keyword(s):  
Heat Transfer ◽  
Secondary Flow ◽  
Conjugate Heat Transfer ◽  
Gas Flow ◽  
Numerical Study ◽  
Labyrinth Seal ◽  
Temperature Fields ◽  
Heat Transfer Analysis ◽  
Flow Rates ◽  
Turbine Disc

A numerical study of the flow and heat transfer in secondary flow elements of the entire inner portion of the turbine section of the Allison T-56/501D engine is presented. The flow simulation included the interstage cavities, rim seals and associated main path flows, while the energy equation also included the solid parts of the turbine disc, rotor supports, and stator supports. Solutions of the energy equations in these problems usually face the difficulty in specifications of wall thermal boundary conditions. By solving the entire turbine section this difficulty is thus removed, and realistic thermal conditions are realized on all internal walls. The simulation was performed using SCISEAL, an advanced 2D/3D CFD code for predictions of fluid flows and forces in turbomachinery seals and secondary flow elements. The mass flow rates and gas temperatures at various seal locations were compared with the design data from Allison. Computed gas flow rates and temperatures in the rim and labyrinth seal show a fair 10 good comparison with the design calculations. The conjugate heat transfer analysis indicates temperature gradients in the stationary intercavity walls, as well as the rotating turbine discs. The thermal strains in the stationary wall may lead to altered interstage labyrinth seal clearances and affect the disc cavity flows. The temperature, fields in the turbine discs also may lead to distortions that can alter the rim seal clearances. Such details of the flow and temperature fields are important in designs of the turbine sections to account for possible thermal distortions and their effects on the performance. The simulation shows that the present day CFD codes can provide the means to understand the complex flow field and thereby aid the design process.

Clocking Effects of Inlet Non-Uniformities in a Fully Cooled High-Pressure Vane: A Conjugate Heat Transfer Analysis

2015 ◽  
Author(s):  
Duccio Griffini ◽  
Massimiliano Insinna ◽  
Simone Salvadori ◽  
Francesco Martelli
Keyword(s):  
Heat Transfer ◽  
High Pressure ◽  
Film Cooling ◽  
Conjugate Heat Transfer ◽  
Cooling System ◽  
Hot Spot ◽  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Heat Transfer Analysis

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.

Heat Transfer for Laminar Flow in Spiral Ducts of Rectangular Cross Section

2005 ◽  
Vol 127 (3) ◽  
pp. 352-356 ◽  
Author(s):  
Michael W. Egner ◽  
Louis C. Burmeister
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Laminar Flow ◽  
Cross Section ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Radius Of Curvature ◽  
Dean Number ◽  
Aspect Ratios ◽  
Small Pitch

Laminar flow and heat transfer in three-dimensional spiral ducts of rectangular cross section with aspect ratios of 1, 4, and 8 were determined by making use of the FLUENT computational fluid dynamics program. The peripherally averaged Nusselt number is presented as a function of distance from the inlet and of the Dean number. Fully developed values of the Nusselt number for a constant-radius-of-curvature duct, either toroidal or helical with small pitch, can be used to predict those quantities for the spiral duct in postentry regions. These results are applicable to spiral-plate heat exchangers.

A Comparison Between 2-D and 3-D Conduction Shape Factors

2003 ◽  
Author(s):  
Devashish Shrivastava ◽  
Robert Roemer
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Cross Section ◽  
Three Dimensional ◽  
Cylindrical Vessel ◽  
Shape Factors ◽  
Axial Conduction ◽  
Power Deposition ◽  
Tissue Matrix

Conduction shape factors are frequently used in a variety of heat transfer applications to evaluate heat transfer from one three-dimensional body to another three-dimensional body. Previous investigators have used conduction shape factors derived using the 2-D cross-section of the 3-D geometries for non-heating conditions as approximations to 3-D conduction shape factors with heating and no-heating present. This paper investigates the suitability of neglecting the axial conduction and power deposition in deriving expressions for conduction shape factors for the case of a single, cylindrical vessel imbedded concentrically in a cylindrical, uniformly heated tissue matrix. It is shown that 1) conduction shape factors are functions of the deposited power and the temperature distribution and 2) the magnitudes of conduction shape factors are affected significantly by axial conduction.

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

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.

scholarly journals Optimizing air velocity for the underfloor forced ventilation to protect a refrigerated warehouse from frost heaving

2018 ◽  
Vol 38 (3) ◽  
pp. 321-327
Author(s):  
Jingfu Jia ◽  
Manjin Hao ◽  
Jianhua Zhao
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Natural Ventilation ◽  
Ventilation System ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Frost Heave ◽  
Forced Ventilation ◽  
Air Velocity ◽  
Set Up

Forced or natural ventilation is the most common measure of frost heave protection for refrigerated warehouse floor. To optimize air velocity for the underfloor forced ventilation system of refrigerated warehouse, a steady state three-dimensional mathematical model of heat transfer is set up in this paper. The temperature fields of this system are simulated and calculated by CFD software PHOENICS under different air velocity, 1.5m/s, 2.5m/s or 3.5m/s. The results show that the optimized air velocity is 1.5m/s when the tube spacing is 1.5m.

scholarly journals Large Eddy Simulations with Conjugate Heat Transfer (CHT) modeling of Internal Combustion Engines (ICEs)

2019 ◽  
Vol 74 ◽  
pp. 51 ◽  
Author(s):  
Angela Wu ◽  
Seunghwan Keum ◽  
Volker Sick
Keyword(s):  
Heat Transfer ◽  
Surface Temperature ◽  
Wall Temperature ◽  
Conjugate Heat Transfer ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Large Eddy Simulations ◽  
Temperature Fields ◽  
Large Eddy ◽  
The Impact

In this study, the effects of the thermal boundary conditions at the engine walls on the predictions of Large-Eddy Simulations (LES) of a motored Internal Combustion Engine (ICE) were examined. Two thermal boundary condition cases were simulated. One case used a fixed, uniform wall temperature, which is typically used in conventional LES modeling of ICEs. The second case utilized a Conjugate Heat Transfer (CHT) modeling approach to obtain temporally and spatially varying wall temperature. The CHT approach solves the coupled heat transfer problem between fluid and solid domains. The CHT case included the solid valves, piston, cylinder head, cylinder liner, valve seats, and spark plug geometries. The simulations were validated with measured bulk flow, near-wall flow, surface temperature, and surface heat flux. The LES quality of both simulations was also discussed. The CHT results show substantial spatial, temporal, and cyclic variability of the wall heat transfer. The surface temperature dynamics obtained from the CHT model compared well with measurements during the compression stroke, but the absolute magnitude was 5 K (or 1.4%) off and the prediction of the drop in temperature after top dead center suffered from temporal resolution limitations. Differences in the predicted flow and temperature fields between the uniform surface temperature and CHT simulations show the impact of the surface temperature on bulk behavior.

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