Numerical and Experimental Evaluation and Heat Transfer Characteristics of a Soft Magnetic Transformer Built from Laminated Steel Plates

The present work evaluates, both experimentally and numerically, the heat transfer characteristics of a 5 kW three-phase transformer built from laminated steel sheets. The transformer is operated at different powers, and its temperature distribution is monitored using 108 thermocouples. The experimental measurements are used firstly to determine the heat dissipated at the core and the windings of the transformer. This information is used as an input for a finite element numerical model, which evaluates the heat transfer characteristics of the transformer. The model proposed in this work simply solves the diffusion equation inside the transformer, accounting for the anisotropic thermal conductivity of the different components of the transformer, together with well-known correlations at its boundaries. The results reveal that the proposed numerical model can correctly reproduce the maximum temperature, the temperature distribution, and the time-evolution of the temperature at specific points of the transformer measured during the experimental campaign. These results are of great use for the subsequent development of transformers of the same type in lab-scale or industrial-scale size and reveal the applicability of simplified numerical models to accurately predict the heat transfer characteristics of this kind of transformers.

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Temperature distribution and heat transfer characteristics of an inverse diffusion flame with circumferentially arranged fuel ports

International Journal of Heat and Mass Transfer ◽

10.1016/j.ijheatmasstransfer.2004.02.015 ◽

2004 ◽

Vol 47 (14-16) ◽

pp. 3119-3129 ◽

Cited By ~ 32

Author(s):

L.K Sze ◽

C.S Cheung ◽

C.W Leung

Keyword(s):

Heat Transfer ◽

Temperature Distribution ◽

Diffusion Flame ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Inverse Diffusion ◽

Inverse Diffusion Flame

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Fundamental study on the flattening of temperature distribution of a high temperature steel slab. 3rd report Heat transfer characteristics due to a confined turbulent impinging jet flow.

TRANSACTIONS OF THE JAPAN SOCIETY OF MECHANICAL ENGINEERS Series B ◽

10.1299/kikaib.53.511 ◽

1987 ◽

Vol 53 (486) ◽

pp. 511-515 ◽

Cited By ~ 4

Author(s):

Koichi ICHIMIYA ◽

Keiji KOBAYASHI ◽

Ryozo ECHIGO

Keyword(s):

Heat Transfer ◽

High Temperature ◽

Temperature Distribution ◽

Impinging Jet ◽

Jet Flow ◽

Heat Transfer Characteristics ◽

Fundamental Study ◽

Transfer Characteristics ◽

Steel Slab

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Experimental and Numerical Investigation of Heat Transfer Characteristics of Liquid Flow With Micro-Encapsulated Phase Change Material

Heat Transfer: Volume 2 ◽

10.1115/ht2008-56113 ◽

2008 ◽

Cited By ~ 6

Author(s):

Rami Sabbah ◽

Jamal Yagoobi ◽

Said Al Hallaj

Keyword(s):

Heat Transfer ◽

Numerical Model ◽

Pressure Drop ◽

Phase Change ◽

Phase Change Material ◽

Operating Conditions ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Encapsulated Phase Change Material ◽

Change Material

This experimental and numerical study investigates Micro-Encapsulated Phase Change Material (MEPCM) heat transfer characteristics and corresponding pressure drop. To conduct this study, an experimental setup consisting of a steel tube with an inner diameter of 4.3mm, outer diameter of 6.5mm and a length of 1,016mm is selected. A MEPCM mass concentration of 20% slurry with particle diameter ranging between 5–15μm is included in this study. Tube wall temperature profile, fluid inlet, outlet temperatures, the pressure drop across the tube are measured and corresponding Nusselt number are determined for various operating conditions. The experimental results are used to validate the numerical model predictions. The numerical model results show good agreement with the experimental data under various operating conditions. The controlling parameters are identified and their effects on the heat transfer characteristics of micro-channels with MEPCM slurries are evaluated.

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Effect of Upstream Viscous Dissipation on Laminar Heat Transfer in Microtubes

ASME 2008 6th International Conference on Nanochannels, Microchannels, and Minichannels ◽

10.1115/icnmm2008-62376 ◽

2008 ◽

Author(s):

I. Ghai ◽

G. Biswas

Keyword(s):

Heat Transfer ◽

Nusselt Number ◽

Temperature Distribution ◽

Viscous Dissipation ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Number Variation ◽

Uniform Wall ◽

Uniform Wall Heat Flux

The effect of viscous dissipation on heat transfer in microtubes is analyzed. In particular, the effect of upstream viscous dissipation on the entrance temperature distribution and thereby on the downstream temperature field and Nusselt number is analyzed. Heat transfer characteristics of a steady laminar flow of hydrodynamically developed and thermally developing Newtonian fluid are presented. The case of adiabatic upstream preparation of the fluid and uniform wall heat flux condition in the downstream region is considered. The temperature distribution and Nusselt number variation in the thermally developing region of the tube is shown. The heat transfer characteristics are also contrasted with the solution available in literature, which assumes a uniform temperature distribution in the entrance cross section. A case study quantifying the viscous dissipation effect on water flowing through a microtube is presented.

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Numerical study of chemical kinetics and radiation heat transfer characteristics on the temperature distribution in the oxy-fuel combustion

Heat and Mass Transfer ◽

10.1007/s00231-018-2491-3 ◽

2018 ◽

Vol 55 (7) ◽

pp. 2025-2036 ◽

Cited By ~ 3

Author(s):

E. Ebrahimi Fordoei ◽

Kiumars Mazaheri

Keyword(s):

Heat Transfer ◽

Temperature Distribution ◽

Chemical Kinetics ◽

Numerical Study ◽

Radiation Heat Transfer ◽

Fuel Combustion ◽

Heat Transfer Characteristics ◽

Radiation Heat ◽

Transfer Characteristics

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Development and Fundamental Characteristics of a Prototype Magnetocaloric Heat Pump

MRS Proceedings ◽

10.1557/opl.2011.479 ◽

2011 ◽

Vol 1310 ◽

Author(s):

Tsuyoshi Kawanami ◽

Shigeki Hirano

Keyword(s):

Heat Transfer ◽

Fluid Flow ◽

Heat Exchange ◽

Heat Pump ◽

Flow Rate ◽

Rotational Frequency ◽

Heat Transfer Fluid ◽

Maximum Temperature ◽

Heat Transfer Characteristics ◽

Transfer Characteristics

ABSTRACTThe primary objective of this study is to discuss the optimum operating conditions of magnetocaloric heat pumps according to the fundamental heat transfer characteristics of an active magnetic regenerator (AMR) bed. The AMR cycle has four sequential processes: magnetization, heat exchange fluid flow, demagnetization, and heat exchange fluid blow. The fundamental heat transfer characteristics of each process of the AMR cycle is investigated minutely. Moreover, the cooling power and the overall system performance are evaluated when the system is running continuously.In addition to the aforementioned investigation, we have developed a prototype rotational magnetocaloric heat pump having a compact component arrangement and an uncomplicated control system. A performance evaluation has been conducted to obtain the optimum conditions for practical operation. The operation parameters such as the heat transfer fluid flow rate, rotational frequency, and initial temperature of the heat transfer fluid are examined, and the variations of the maximum temperature span between the inlet and outlet for the heat transfer fluid are discussed. As a result, the values of the optimum rotational frequency and flow rate are obtained to obtain the maximum temperature span between the inlet and outlet of the present magnetocaloric heat pump.

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A Study of Heat Transfer Characteristics of LED Heat Sink and Graphite Heat Sink Process Technology Development

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.284-287.819 ◽

2013 ◽

Vol 284-287 ◽

pp. 819-823 ◽

Cited By ~ 3

Author(s):

Shie Chen Yang ◽

Tsuo Fei Mao ◽

Tzer Ming Jeng ◽

Sheng Chung Tzeng ◽

Tzung Ying Shie ◽

...

Keyword(s):

Heat Transfer ◽

Heat Sink ◽

Technology Development ◽

Experimental Results ◽

Maximum Temperature ◽

Pressure Casting ◽

Heat Transfer Characteristics ◽

Process Technology ◽

Transfer Characteristics ◽

Graphite Heat

This study investigated the heat transfer characteristics of LED heat sink and the development process technology of graphite heat sink with micro-sized metal powders. Employing the reverse engineering technology, the three-dimension LED heat sink entity was rebuilt and the heat transfer characteristics of LED heat sink were analyzed by CFD numerical simulation and experimental measurement. The numerical results were validated with experimental results and it showed a good agreement. The experimental and simulation results showed that the heat dissipation of LED device could be removed by natural convection effectively. The difference between the maximum temperature and minimum temperature of cooling efficiency was 10°C. For the process technology development of LED graphite heat sink, the graphite powder, metal powder and resin were mixed in specific ratios. The vacuum casting, vacuum pressure casting and rapid die technology were used to manufacture LED graphite heat sink. The experimental results showed that the LED graphite heat sinks developed in this study have advantages of low cost, light weight and attractive appearance as compared with the heat sink of aluminum alloy, and the overall heat transfer capacity is still within acceptable range.

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Numerical Investigation of the Single Phase Forced Convection Heat Transfer Characteristics of Nanofluid Flowing in Smooth and Micro-Fin Tubes

Volume 7: Fluids and Heat Transfer, Parts A, B, C, and D ◽

10.1115/imece2012-85036 ◽

2012 ◽

Author(s):

Nurullah Kayacı ◽

Mahdi Tabatabaei ◽

Ali Celen ◽

Oğuzhan Yıldız ◽

Ahmet Selim Dalkılıç ◽

...

Keyword(s):

Heat Transfer ◽

Numerical Model ◽

Forced Convection ◽

Single Phase ◽

Smooth Tube ◽

Shear Stresses ◽

Heat Transfer Characteristics ◽

Constant Wall Temperature ◽

Transfer Characteristics ◽

Fin Tubes

Forced convection flows of nanofluids containing of water with TiO2 nanoparticles in smooth and micro-fin tubes with constant wall temperature are studied numerically in this paper. A single-phase numerical model having three-dimensional equations is solved with either constant heat flux or temperature dependent properties to determine the hydrodynamics and thermal behaviors of the nanofluid flow by means of a CFD program for the water flow in a smooth tube and micro-fin tubes having various helix angles (0°, 18°). An intensive literature review on the determination of the physical properties (k, μ, ρ, Cp) of nanofluids is given in the paper. The numerical model is validated by means of a CFD program using the experimental smooth tube data as a case study and it is also solved in the CFD program for several micro-fin tubes as a simulation study. Velocity, temperature and pressure distributions are shown in the paper. Besides this, the values of experimental and numerical are compared with each other in terms of friction factors, shear stresses, convective heat transfer coefficients and pressure drops. Moreover, the effects of the presence of nanofluids and micro-fins in the inner surface of the test tube on the heat transfer characteristics are investigated in detail.

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