A comprehensive two-dimensional numerical study on unsteady conjugate heat transfer in magnetic refrigerator with Gd plates

2017 ◽  
Vol 79 ◽  
pp. 217-225 ◽  
Author(s):  
Yonghua You ◽  
Zhongda Wu ◽  
Shuifang Xiao ◽  
Hao Li ◽  
Xuecheng Xu
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Numerical Study ◽  
Two Dimensional ◽  
Magnetic Refrigerator

Conjugate Heat Transfer Simulation of the Intercooled Compressor Vanes Based on Discontinuous Galerkin Method

2016 ◽  
Author(s):  
Long-gang Liu ◽  
Chun-wei Gu ◽  
Xiao-dong Ren
Keyword(s):  
Heat Transfer ◽  
Discontinuous Galerkin ◽  
Gas Turbines ◽  
Conjugate Heat Transfer ◽  
Main Stream ◽  
Two Dimensional ◽  
Convective Cooling ◽  
Cooling Channels ◽  
Transfer Method ◽  
Aero Engines

Convective cooling channels are applied in a two-dimensional compressor vane to use the intercooling method to improve the efficiency of Brayton cycle and reduce the temperature of the vane. In this paper, we analyze the effect of coolant to the aerodynamic performance and heat transfer performance of the main stream and the vane. For the case of a two-dimensional compressor vane NACA65-(12A2I8b)10, the vane which has five convective cooling channels has been numerically simulated in different test conditions by discontinuous Galerkin (DG) method. The coolant is supercritical carbon dioxide whose pressure is 10MPa. Conjugate heat transfer method has been used in this paper. The numerical simulation result is similar to the experiment data and has been compared with the result of the vane without cooling channels to prove the effect of cooling channels. Cooling channels have large effect on the distribution of temperature and heat transfer coefficient. In addition, the relationship between Nu and Re on the fluid-solid interface has been analyzed and a suitable empirical equation has been obtained. This work analyzes the effect of intercooling system in the compressor and give several advice on future engineering applications in aero engines and gas turbines.

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.

A Two-Dimensional Conjugate Heat Transfer Model for Forced Air Cooling of an Electronic Device

1989 ◽  
Vol 111 (1) ◽  
pp. 41-45 ◽  
Author(s):  
A. Zebib ◽  
Y. K. Wo
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Electronic Device ◽  
Transfer Problem ◽  
Maximum Temperature ◽  
Transfer Model ◽  
Air Cooling ◽  
Two Dimensional ◽  
Component Design ◽  
Forced Air

Thermal analysis of forced air cooling of an electronic component is modeled as a two-dimensional conjugate heat transfer problem. The velocity field in a constricted channel is first computed. Then, for a typical electronic module, the energy equation is solved with allowance for discontinuities in the thermal conductivity. Variation of the maximum temperature with the average air velocity is presented. The importance of our approach in evaluating possible benefits due to changes in component design and the limitations of the two-dimensional model are discussed.

Numerical Study on Heat Transfer Characteristics From Parallel Plates With Cavities Swept by a Visco-Elastic Fluid

2010 ◽  
Author(s):  
Hiroshi Suzuki ◽  
Shinpei Maeda ◽  
Yoshiyuki Komoda
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Thermal Field ◽  
Numerical Study ◽  
Geometric Parameters ◽  
Two Dimensional ◽  
Parallel Plates ◽  
Heat Transfer Characteristics ◽  
Elastic Fluid ◽  
Heat Transfer Augmentation

Two-dimensional numerical computations have been performed in order to investigate the development characteristics of flow and thermal field in a flow between parallel plates swept by a visco-elastic fluid. In the present study, the effect of the cavity number in the domain and of Reynolds number was focused on when the geometric parameters were set constant. From the results, it is found that the flow penetration into the cavities effectively causes the heat transfer augmentation in the cavities in any cavity region compared with that of water case. It is also found that the development of thermal field in cases of the present visco-elastic fluid is quicker compared with that of water cases. The present heat transfer augmentation technique using Barus effect of a visco-elastic fluid is effective in the range of low Reynolds number.

Integrated Fluxes in Magneto-Hydrodynamic Mixed Convection in a Cavity Sustained by Conjugate Heat Transfer

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Orkodip Mookherjee ◽  
Shantanu Pramanik
Keyword(s):  
Magnetic Field ◽  
Heat Transfer ◽  
Heat Flux ◽  
Kinetic Energy ◽  
Mixed Convection ◽  
Conjugate Heat Transfer ◽  
Numerical Study ◽  
Horizontal Magnetic Field ◽  
Flow And Heat Transfer ◽  
Stationary Interface

Abstract A numerical study of magneto-hydrodynamic mixed convection in a cavity has been conducted to investigate the influence of magnetic field on integrated flux of thermal energy, linear momentum, and kinetic energy. Shear force through lid motion establishes the forced convection effect and buoyancy force due to differential heating of the moving lid and the stationary interface ensures the natural convection phenomenon. Additionally, conduction through the solid slab with prescribed temperature at the outer surface attached to the cavity induces conjugate heat transfer. Further, the top and bottom walls throughout the domain are kept insulated and a uniform horizontal magnetic field is applied on the interface toward left. Fluid flow and heat transfer characteristics are examined for a range of Hartmann number (Ha): 0, 10, 50, and 120 at fixed values of Reynolds number, Grashof number, and Prandtl number of 300, 9 × 104 and 0.71, respectively. The result shows that the transport of heat in the near wall regions of the fluid domain is primarily governed by diffusion, whereas advection appears stronger in the central region of the cavity. Increase in magnetic field strength from Ha = 0 to 120 gradually suppresses the recirculating structure of the flow signifying a reduction in advective strength as depicted by the decrease in the value of total integrated heat flux from 25.15×10-3 to 6.0×10-3. The reduction in heat flux, momentum fluxes, and kinetic energy fluxes with increase in magnetic field has been well correlated in the range of 0≤Ha≤120.

Experimental and numerical study of conjugate heat transfer in an open square-cavity solar receiver

2020 ◽  
Vol 156 ◽  
pp. 106458 ◽  
Author(s):  
R. Alvarado-Juárez ◽  
M. Montiel-González ◽  
H.I. Villafán-Vidales ◽  
C.A. Estrada ◽  
J. Flores-Navarrete
Keyword(s):  
Heat Transfer ◽  
Conjugate Heat Transfer ◽  
Numerical Study ◽  
Square Cavity ◽  
Solar Receiver

scholarly journals Numerical study on the thermohydraulic performance of a reciprocating room temperature active magnetic regenerator

2019 ◽  
Vol 128 ◽  
pp. 07001
Author(s):  
Georges El Achkar ◽  
Bin Liu ◽  
Rachid Bennacer
Keyword(s):  
Heat Transfer ◽  
Room Temperature ◽  
Transient Flow ◽  
Numerical Study ◽  
Working Fluid ◽  
Comsol Multiphysics ◽  
Transfer Model ◽  
Two Dimensional ◽  
Active Magnetic Regenerator ◽  
Magnetic Regenerator

In this paper, the thermohydraulic performance of a reciprocating room temperature active magnetic regenerator (AMR), with gadolinium (Gd) particles used as a magnetocaloric material (MCM) and water used as a working fluid, was numerically investigated. A two-dimensional transient flow model was developed using COMSOL Multiphysics, in order to determine the water flow distribution in two AMRs of cross and parallel Gd particles distributions for different water inlet velocities of 0.06 m.s-1, 0.08 m.s-1 , 0.1 m.s-1 and 0.12 m.s-1. The Gd particles have a radius of 1.5 mm and a distance from one another of 0.9 mm. Based on the simulations results of the first model, a two-dimensional transient coupled flow and heat transfer model was then developed using COMSOL Multiphysics, in order to characterise the convective heat transfer in the AMR of cross Gd particles distribution for the same water inlet velocities.

Heat Transfer From an Isothermal Vertical Surface With Adjacent Heated Horizontal Louvers: Validation

2002 ◽  
Vol 124 (6) ◽  
pp. 1078-1087 ◽  
Author(s):  
M. Collins ◽  
S. J. Harrison ◽  
D. Naylor ◽  
P. H. Oosthuizen
Keyword(s):  
Heat Transfer ◽  
Transfer Rate ◽  
Numerical Study ◽  
Surface Flux ◽  
Element Model ◽  
Vertical Surface ◽  
Two Dimensional ◽  
Local Surface ◽  
Conjugate Conduction ◽  
Steady Laminar

The present study examines the influence of heated, horizontal, and rotateable louvers on the convective heat transfer from a heated or cooled vertical isothermal surface. The system represents an irradiated Venetian blind adjacent to the indoor surface of a window. Detailed temperature field and local surface flux data were obtained using a Mach-Zehnder Interferometer for two window temperatures (warm and cool compared to ambient) and irradiation levels, two louver to plate spacings, and three louver angles. The results have been compared to a steady, laminar, two-dimensional, conjugate conduction/convection/radiation finite element model of this problem. The effect of the heated louvers on the heat transfer rate from the plate surface has been demonstrated and the results of the numerical study have been validated.

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