scholarly journals A two-stage heat transfer model for the peripheral layers of a grain store

2003 ◽  
Vol 7 (3) ◽  
pp. 147-164
Author(s):  
Alexsandar Antic ◽  
James M. Hill
Keyword(s):  
Heat Transfer ◽  
Present Model ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Two Stage ◽  
Peripheral Layer ◽  
Proposed Model ◽  
Grain Bulk ◽  
Insight Into ◽  
Good Agreement

An understanding of the flow of heat in grain store structures, in particular, within the peripheral layer, is important from many industrial perspectives. To analyse the heat transfer within such regions a mathematical model known as the two-stage heat transfer model is proposed. This model makes a distinction between the air and grain within the grain bulk, and thus takes into consideration the fact that the rate of heat transfer through the grain is different to that through the interstitial air surrounding the grain. Such a model lends itself to a solution via Laplace transforms and approximate analytical results are obtained for small and large times. In addition, the Stehfest numerical algorithm is used for the inversions and very good agreement is obtained between the two approaches. The present model is compared to a previously developed double-diffusivity heat transfer model by the authors, and good agreement is obtained. At present, no experimental data is available to validate the model as it is very difficult to measure the air and grain temperatures separately, particularly in the peripheral layer. The proposed model provides insight into the potential difference existing between the air and grain temperatures.

Heat Transfer Model and Analysis of Oil-Immersed Electrical Transformers with Heat Pipe Radiator

2012 ◽  
Vol 516-517 ◽  
pp. 312-315
Author(s):  
Guang Hua Li ◽  
Hong Lei Liu ◽  
De Jian Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Heat Pipe ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Cooling Device ◽  
Transformer Design ◽  
Electrical Transformers ◽  
Good Agreement

This paper has formulated a heat transfer model for analyzing the cooling properties of a heat pipe cooling device of oil-immersed electrical transformer. Based on the model, the oil temperature field of a 30 KVA oil-immersed transformer has been numerical simulated, and experiments also had been conducted. Results showed that the numerical simulation has good agreement with experiment results. Results also showed that heat pipe radiator is feasible for oil-immersed electrical transformer cooling. The model can be used to analyze the oil temperature distribution properties in an oil-immersed electrical transformer with heat pipe cooling device, and provide theoretical guide for transformer design and improvement.

Heat Transfer Modeling of Nanoparticle Packings on a Substrate

2018 ◽  
Author(s):  
Anil Yuksel ◽  
Edward T. Yu ◽  
Michael Cullinan ◽  
Jayathi Murthy
Keyword(s):  
Heat Transfer ◽  
Laser Power ◽  
Thermal Conductance ◽  
Heat Transfer Model ◽  
Experimental Result ◽  
Transfer Model ◽  
Heat Transfer Modeling ◽  
Interfacial Thermal Conductance ◽  
High Laser ◽  
Good Agreement

The temperature evolution of nanoparticle packings on a substrate under high laser power is investigated both experimentally and via numerical simulations. Numerical modeling of temperature distributions in copper nanoparticle packings on a glass substrate is performed and results are compared with experiment under 2.6 kW/cm2 laser power. A coupled electromagnetic-heat transfer model is implemented to understand the nanoparticle temperature distribution. Very good agreement between the coupled electromagnetic-heat transfer model and the experimental results is obtained by matching the interfacial thermal conductance, G, between the nanoparticles using the experimental result in the coupled electromagnetic-heat transfer model.

Analytical Model for Heat Transfer Phenomena in Cup-Cast Method

2006 ◽  
Vol 116-117 ◽  
pp. 569-572
Author(s):  
Farshid Pahlevani ◽  
J. Yaokawa ◽  
M. Itamura ◽  
M. Kikuchi ◽  
O. Nagasawa ◽  
...  
Keyword(s):  
Heat Transfer ◽  
A356 Alloy ◽  
Nucleation And Growth ◽  
Heat Transfer Model ◽  
Solid Particles ◽  
Transfer Model ◽  
Heat Transfer Phenomenon ◽  
Semi Solid ◽  
Slurry Preparation ◽  
Good Agreement

Cup-cast method is a new method deals with semi-solid slurry preparation recently developed by the authors. In this method, suspension of globular solid particles in molten metal is prepared by controlling the nucleation and growth of solid-particles through the simplest and quickest techniques. In this method, heat transfer phenomenon plays an important role in governing the shape, size, and fraction of solid particles. In the current study, a heat transfer model was proposed and applied to Al-A356 alloy semi-solid slurry preparation. The heat transfer model was based on heat balance consideration between cup and slurry and it was in a good agreement with experimental results.

A one dimensional heat transfer model for wolverine (gulo-gulo) hair

2018 ◽  
Vol 30 (4) ◽  
pp. 548-558
Author(s):  
HongYan Liu ◽  
Addie Bahi ◽  
Frank K. Ko
Keyword(s):  
Heat Transfer ◽  
Cold Weather ◽  
Transfer Model ◽  
Counting Method ◽  
Content Type ◽  
Box Counting ◽  
Proposed Model ◽  
Extreme Cold ◽  
Box Counting Method ◽  
Good Agreement

Purpose Wolverine hairs with superior heat transfer properties have been used as fur ruffs for extreme cold-weather clothing. In order to understand the exclusive mechanism of wolverine surviving in the cold areas of circumpolar, the purpose of this paper is to establish a one-dimensional fractional heat transfer equation to reveal the hidden mechanism for the hairs, and also calculate the fractal dimension of the wolverine hair using the box counting method to verify the proposed theory. The observed results (from the proposed model) found to be in good agreement with the box counting method. This model can explain the phenomenon which offers the theoretical foundation for the design of extreme cold weather clothing. Design/methodology/approach The authors calculated the fractal dimension of the wolverine hair using the box counting method to verify the proposed theory. The observed results (from the proposed model) found to be in good agreement with the box counting method. Findings The box counting method proves that the theoretical model is applicable. Originality/value The authors propose the first heat transfer model for the wolverine hair.

Numerical Simulation of Hot Rolled Coil Temperature Field in Hot Coil Box

2011 ◽  
Vol 338 ◽  
pp. 572-575
Author(s):  
Gui Jie Zhang ◽  
Kang Li ◽  
Ying Zi Wang
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Coil Temperature ◽  
Hot Rolled ◽  
Strip Coil ◽  
Good Agreement

The heat transfer model was developed and the heat transfer of the strip coil stay in the hot coil box was analyzed. The temperature distribution of the strip coil was investigated use the model. The measured results are in good agreement with the calculated ones, has a guiding significance to further improve the technology.

scholarly journals Investigation of Heat Diffusion at Nanoscale Based on Thermal Analysis of Real Test Structure

Energies ◽  
2020 ◽  
Vol 13 (9) ◽  
pp. 2379 ◽  
Author(s):  
Tomasz Raszkowski ◽  
Mariusz Zubert
Keyword(s):  
Heat Transfer ◽  
Numerical Algorithms ◽  
Silicon Layer ◽  
Heat Transfer Model ◽  
Test Structure ◽  
Heat Diffusion ◽  
Transfer Model ◽  
Phase Lag ◽  
Bottom Part ◽  
Proposed Model

This paper presents an analysis related to thermal simulation of the test structure dedicated to heat-diffusion investigation at the nanoscale. The test structure consists of thin platinum resistors mounted on wafer made of silicon dioxide. A bottom part of the structure contains the silicon layer. Simulations were carried out based on the thermal simulator prepared by the authors. Simulation results were compared with real measurement outputs yielded for the mentioned test structure. The authors also propose the Grünwald–Letnikov fractional space-derivative Dual-Phase-Lag heat transfer model as a more accurate model than the classical Fourier–Kirchhoff (F–K) heat transfer model. The approximation schema of proposed model is also proposed. The accuracy and computational properties of both numerical algorithms are presented in detail.

scholarly journals Numerical study of mixing and heat transfer of SRF particles in a bubbling fluidized bed

2019 ◽  
Vol 142 (2) ◽  
pp. 1087-1096
Author(s):  
Mohamed Sobhi Alagha ◽  
Botond Szucs ◽  
Pal Szentannai
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Fluidized Bed ◽  
Present Model ◽  
Numerical Study ◽  
Sand Particle ◽  
Particle Sizes ◽  
Proposed Model ◽  
Bubbling Fluidized Bed ◽  
Good Agreement

AbstractIn this article, numerical investigations on mixing and heat transfer of solid refused fuel (SRF) particles in a bubbling fluidized bed are carried out. The numerical model is based on the Eulerian–Eulerian approach with empirical submodels representing gas–solid and solid–solid interactions. The model is verified by experimental data from the literature. The experimental data include SRF vertical distribution in SRF–sand mixtures of different sand particle sizes ($$d_{\mathrm{pm}} = 654,810$$ d pm = 654 , 810 and 1110 $$\upmu$$ μ m) at different fluidization velocities ($$u/u_{\mathrm{mf}} = 1.2$$ u / u mf = 1.2 –2.0). We proposed magnification of drag force exerted by the gas on SRF particles based on Haider and Levenspiel (Powder Technol 58(1):63–70, 1989) drag coefficient. The proposed model shows good agreement with the experimental data at high fluidization velocities ( $$u/u_{\mathrm{mf}} = 1.5$$ u / u mf = 1.5 –2.0) and poor predictions at low fluidization velocities ($$u/u_{\mathrm{mf}} = 1.2$$ u / u mf = 1.2 –1.5). Heat transfer results showed that the present model is valid and gives good agreement with the experimental data of wall–bed heat transfer coefficient.

Prediction of Heat Leakage Through Fish Hold Wall Sections

1989 ◽  
Vol 33 (03) ◽  
pp. 229-235
Author(s):  
De-qian Wang ◽  
Edward Kolbe
Keyword(s):  
Heat Transfer ◽  
Finite Difference ◽  
West Coast ◽  
Heat Transfer Model ◽  
Transfer Model ◽  
Model Design ◽  
Fishing Vessels ◽  
Heat Leakage ◽  
Good Agreement

Heat transfer through hold wall sections was investigated to improve prediction of heat leakage through fish hold boundaries of steel fishing vessels in the range of 14 to 32 m (45 to 105 ft). A finite-difference heat-transfer model was developed and eight fish hold wall sections representative of a 14 m (45 ft) boat were tested using the "guarded hot box" technique (ASTM C 236-80). Good agreement was obtained between the predicted and tested results. By applying the model, design curves of wall sections representative of typical West Coast steel vessels are presented.

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