The Effect of Heat Transfer on Coal Devolatilization

1990 ◽  
Vol 112 (1) ◽  
pp. 192-200 ◽  
Author(s):  
J.-T. Yang ◽  
G.-G. Wang
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Coal Particle ◽  
Transient Behavior ◽  
Transfer Effect ◽  
Radiation Diffusion ◽  
Modified Model ◽  
Temperature Distributions ◽  
Reactive Gases ◽  
Ignition And Combustion

This study investigates the heat transfer effect on the transient behavior of preheating, ignition, and combustion of a single coal particle pyrolyzed in a hot convective environment. The theoretical model covers two aspects: (1) heat and mass transfer and pyrolysis within the particle, (2) thermal radiation, diffusion, and combustion of the reactive gases and air outside of the particle. Semenov’s criteria are adopted to define ignition and a modified model derived from droplet combustion is used to estimate the flame radius and temperature. Distributions of temperature, species concentrations, and combustion rate are solved simultaneously. The prediction is verified by a set of experimental data.

Drying of Industrial Hollow Ceramic Brick: A Numerical Analysis Using CFD

2019 ◽  
Vol 391 ◽  
pp. 48-53 ◽  
Author(s):  
Morgana Vasconcellos Araújo ◽  
R.S. Santos ◽  
R. Moura da Silva ◽  
J.B. Silva do Nascimento ◽  
W.R. Gomes dos Santos ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Moisture Content ◽  
Dynamics Analysis ◽  
Unit Operation ◽  
Drying Process ◽  
Ceramic Brick ◽  
Temperature Distributions ◽  
Computational Fluid Dynamics Analysis ◽  
Good Agreement

The drying process can be defined how unit operation for removing water of one moist solid to an unsaturated gaseous phase due to heat transfer. Numerical simulation emerges like a tool that allows the reproduction of drying experiments using computers and suitable softwares. In this sense, this works aims to predict drying process of an industrial hollow ceramic brick inside the kiln using computational fluid dynamics analysis. For one drying temperature of 60°C, results of the drying and heating kinetics, and moisture content, velocity and temperature distributions are shown and analyzed. A comparison between predicted and experimental data of the moisture content and temperature of the brick along the process was done and a good agreement was obtained.

A Heat Transfer and Solidification Model of Continuous Cast

2010 ◽  
Vol 154-155 ◽  
pp. 1431-1434
Author(s):  
Qi Zhang ◽  
La Dao Yang
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Material Properties ◽  
Shell Thickness ◽  
Phase Changes ◽  
Continuous Cast ◽  
Solidification Model ◽  
Temperature Distributions ◽  
Linear Material ◽  
Heat Transfer And Solidification

A model of heat transfer and solidification of continuous cast has been established, including boundary conditions in the mold and spray zones. A finite difference method was used for the numerical simulation. The model calculates the shell thickness and temperature distributions of the slab real time. The importance effect of non-linear material properties of specific heat and thermal conductivity as well as phase changes during solidification is treated. The adequacy of model has been proved by industrial and experimental data. The model can be applied to solve some practical problems in continuous cast.

scholarly journals Experimental analysis and ANN prediction on performances of finned oval-tube heat exchanger under different air inlet angles with limited experimental data

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 968-980
Author(s):  
Xueping Du ◽  
Zhijie Chen ◽  
Qi Meng ◽  
Yang Song
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Exchanger ◽  
Correlation Equation ◽  
Tube Heat Exchanger ◽  
Flow Friction ◽  
Air Inlet ◽  
Comparison Results ◽  
Wide Range ◽  
Oval Tube

Abstract A high accuracy of experimental correlations on the heat transfer and flow friction is always expected to calculate the unknown cases according to the limited experimental data from a heat exchanger experiment. However, certain errors will occur during the data processing by the traditional methods to obtain the experimental correlations for the heat transfer and friction. A dimensionless experimental correlation equation including angles is proposed to make the correlation have a wide range of applicability. Then, the artificial neural networks (ANNs) are used to predict the heat transfer and flow friction performances of a finned oval-tube heat exchanger under four different air inlet angles with limited experimental data. The comparison results of ANN prediction with experimental correlations show that the errors from the ANN prediction are smaller than those from the classical correlations. The data of the four air inlet angles fitted separately have higher precisions than those fitted together. It is demonstrated that the ANN approach is more useful than experimental correlations to predict the heat transfer and flow resistance characteristics for unknown cases of heat exchangers. The results can provide theoretical support for the application of the ANN used in the finned oval-tube heat exchanger performance prediction.

scholarly journals Predicting unsteady heat transfer effect of vehicle thermal management system using steady velocity equivalent method

2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110259
Author(s):  
Xiao Guoquan ◽  
Wang Huaming ◽  
Chen Lin ◽  
Hong Xiaobin
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Management System ◽  
Exhaust System ◽  
Transfer Effect ◽  
Unsteady Heat Transfer ◽  
Thermal Management System ◽  
Comparison Results ◽  
Equivalent Method ◽  
Steady Velocity

In the process of vehicle development, the unsteady simulation of thermal management system is very important. A 3D-CFD calculation model of vehicle thermal management is established, and simulations were undertaken for uphill with full loads operations condition. The steady results show that the surface heat transfer coefficient increases to the quadratic parabolic relationship. The unsteady results show that the pulsating temperatures of exhaust and external airflow are higher than about 50°C and lower than 10°C, respectively, and the heat dissipating capacities are higher than about 11%. Accordingly, the conversion equivalent exhaust velocity increased by 1.67%, and the temperature distribution trend is basically the same as unsteady results. The comparison results show that the difference in the under-hood should be not noted, and that the predicted exhaust system surface temperatures using steady velocity equivalent method are low less 10°C than the unsteady results. These results show the steady velocity equivalent method can be used to predict the unsteady heat transfer effect of vehicle thermal management system, and the results obtained by this method are basically consistent with the unsteady results. It will greatly save computing resources and shorten the cycle in the early development of the vehicle thermal management system.

scholarly journals The Single-Blow Problem Including the Effects of Longitudinal Conduction

1964 ◽  
Author(s):  
C. P. Howard
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Heat Conduction ◽  
Transient Behavior ◽  
Step Change ◽  
Graphical Form ◽  
Compact Heat Exchanger ◽  
Fluid Temperature ◽  
Transfer Data ◽  
Method Of Calculation

The results are presented from a numerical finite-difference method of calculation for the transient behavior of porous media when subjected to a step change in fluid temperature considering the case where the longitudinal thermal heat conduction cannot be neglected. These results, given in tabular and graphical form, provide a useful means for evaluating the heat-transfer data obtained from the transient testing of compact heat-exchanger surfaces.

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