Mathematical Model for Heat Transfer Simulation of Rotary Alumina Kiln

2013 ◽  
Vol 423-426 ◽  
pp. 881-884
Author(s):  
Xiao Yan Yang ◽  
You Gang Xiao ◽  
Xian Ming Lei
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Temperature Distribution ◽  
Phase Change ◽  
Heat Loss ◽  
Chemical Reactions ◽  
Outer Shell ◽  
Test Results ◽  
Distribution Rule ◽  
Heat Transfer Simulation

According to kiln structure and material movement features, considering convective, radioactivity, conductivity and various phase change and chemical reactions, a series of comprehensive models are built for quantifying the thermal fluxes from the gas to the material bed and the heat loss from outer shell to the atmosphere in the rotary alumina kiln. The results show that the temperatures of outer shell accord with test results; the temperature distribution rule of gas is the same with that of materials, but the gas temperatures are higher; it is feasible to use the model to improve alumina kiln performance.

Numerical Simulation of Mark Formation/Erasure in Phase Change Recording

2005 ◽  
Author(s):  
Evan Small ◽  
John Reifenberg ◽  
Yizhang Yang ◽  
Sadegh M. Sadeghipour ◽  
Mehdi Asheghi
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Temperature Distribution ◽  
Finite Elements ◽  
Phase Change ◽  
Finite Elements Method ◽  
Heat Diffusion ◽  
Recording Media ◽  
Heat Diffusion Equation ◽  
Heat Transfer Simulation

Design/optimization of the phase change recording media to create proper marks, in size, shape, and quality, needs a robust modeling tool to predict temperature distribution in the constituting layers and model the phase formation during writing/erasure of the information bits. This requires a modeling of the heat transfer (thermal performance) and the crystallization processes. The thermal modeling, which is based on the solution of the heat diffusion equation for finding temperature distribution in the multilayer media, has been done before, using the finite difference techniques. These techniques have limited potentials for modeling real phase change recording media that have a rather more complex geometry. The finite elements method has, on the other hand, the required flexibility for such applications. In this work, we are reporting on development of a numerical simulation tool that uses the finite elements method for heat transfer simulation. ANSYS is used as the source code for the heat transfer simulation, in this application, with the crystallization model then being built into this media. This code has been used to simulate mark formation during writing on grooved plain and planer patterned media. Patterning the phase change material layer looks very promising in controlling the mark size and the mark edge irregularity which lead to timing jitter.

Study on a New Mathematical Model for Aggregate Air Cooling or Heating

2011 ◽  
Vol 374-377 ◽  
pp. 1882-1886
Author(s):  
Li Juan Wang ◽  
Yan Feng Liu ◽  
Jia Ping Liu ◽  
Fei Lu
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Transfer Coefficient ◽  
Temperature Distribution ◽  
Hydraulic Structure ◽  
Surface Heat ◽  
Air Cooling ◽  
Foundation Engineering ◽  
Heating Capacity ◽  
Surface Heat Transfer Coefficient

Before the construction of hydraulic structure, aggregate must be cooled or heated by air (we call it aggregate air cooling or heating in this paper) or other technologies to the required temperature. Previous model of aggregate air cooling or heating cannot provide the center temperature of each aggregate. So a more accurate mathematical model is developed to determine the thermal performance of aggregate, and the surface heat transfer coefficient of wet aggregate is revised. This model can predict the center temperature of an aggregate and can accurately calculate the cold down time or temperature distribution of aggregate, so that the refrigeration or heating capacity can be reasonably supplied. It’s significant for foundation engineering of hydraulic structure.

scholarly journals Mathematical model of heat transfer in roll caliber

2019 ◽  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Boundary Value Problem ◽  
Boundary Conditions ◽  
Heat Equation ◽  
Rolling Mill ◽  
Thermal Process ◽  
Stationary Heat

A physical model of the thermal process in the roll caliber during the rolling of the tape on a two-roll rolling mill was constructed. A mathematical model of the temperature field of a rolling hollow roll of a rolling state of a cylindrical shape rotating about its axis with constant angular velocity is proposed. The mathematical model takes into account different conditions of heat exchange of the inner and outer surfaces of the roll with the belt and its surrounding environment. The temperature field of a hollow roll of a rolling mill is considered as an initial boundary-value problem for a homogeneous non-stationary heat equation with inhomogeneous, nonlinear boundary conditions, which also depend on the angle of rotation of the roll around its axis. The equation describes the temperature field of the rolls during uncontrolled heat transfer during rolling. It significantly depends on the time and number of revolutions around its axis. With a large number of revolutions of the roll around its axis, a quasi-stationary temperature distribution occurs. Therefore, the simplified problem of determining a quasistationary temperature field, which is associated with a thermal process that is time-independent, is considered further in the work. In this case, the temperature field is described using the boundary value problem in a ring for a homogeneous stationary heat equation with inhomogeneous boundary conditions and heat transfer conditions outside the ring, which lie from the angular coordinate. After the averaging operation, the solution of this problem is reduced to solving the equivalent integral equation of Hammerstein type with a kernel in the form of the Green's function. The Mathcad computer mathematical system builds the temperature distribution of the roll surface. An algorithm for solving a inhomogeneous problem was developed and the temperature distribution of the roll was constructed.

scholarly journals Progress in understanding the four dominant intra-particle phenomena of lignocellulose pyrolysis: chemical reactions, heat transfer, mass transfer, and phase change

2019 ◽  
Vol 21 (11) ◽  
pp. 2868-2898 ◽  
Author(s):  
M. Brennan Pecha ◽  
Jorge Ivan Montoya Arbelaez ◽  
Manuel Garcia-Perez ◽  
Farid Chejne ◽  
Peter N. Ciesielski
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Phase Change ◽  
Chemical Reactions ◽  
Phase Changes ◽  
Lignocellulosic Materials

Four principal intra-particle phenomena occur in a highly concerted manner during the pyrolysis of lignocellulosic materials: heat transfer, mass transfer, chemical reactions, and phase changes.

Heat Transfer under a Flow of the Highly Viscous Crude Oil in a Buried Oil Pipeline

2021 ◽  
Vol 107 ◽  
pp. 122-128
Author(s):  
Aidar Kadyirov ◽  
Julia Karaeva ◽  
Ekaterina Vachagina
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Temperature Distribution ◽  
Crude Oil ◽  
Air Temperature ◽  
High Viscosity ◽  
Numerical Calculations ◽  
Oil Pipeline ◽  
Transfer Processes ◽  
The Republic

The paper presents a mathematical model and the results of numerical calculations of heat transfer processes during the flow of highly viscous crude oil in an oil pipeline. Comparison with literature data is performed. The samples of oil from the field of the Republic of Tatarstan (Russia) that are characterized by high viscosity were considered as crude oil. The influence of air temperature on the temperature distribution in the soil was investigated. The analysis of the distribution of crude oil temperature along the length of the pipeline was carried out.

The Research on the Heat Transfer Process of Low Temperature Hot Water Radiant Heating Phase Change Wallboard

2013 ◽  
Vol 800 ◽  
pp. 18-21
Author(s):  
Quan Ying Yan ◽  
Li Hang Yue ◽  
Ran Huo
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Low Temperature ◽  
Phase Change ◽  
Physical Model ◽  
Transfer Process ◽  
Heat Transfer Process ◽  
Hot Water ◽  
Radiant Heating ◽  
Heating Phase

In this paper, physical model and mathematical model of the hot water radiant heating phase change wallboard were built. The heat transfer process of wallboard was simulated to analyze different influencing factors and optimize the design of the hot water heating phase change wallboard. The research results can provide reference and basis to the optimization of low temperature hot water radiant heating phase change wallboard.

Design of Phase Change Material Based Domestic Solar Cooking System for Both Indoor and Outdoor Cooking Applications

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
S. M. Santhi Rekha ◽  
Sukruedee Sukchai
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Heat Loss ◽  
Phase Change Material ◽  
Storage System ◽  
Efficiency Factor ◽  
Concentric Cylinder ◽  
Optical Efficiency ◽  
Change Material ◽  
Indoor And Outdoor

This paper mainly focuses on the design of solar concentric parabolic cooker with proper arrangement of phase change material (PCM) heat storage system. The receiver is a hollow concentric cylinder with inner and outer radii being 0.09 m and 0.1 m, respectively. The thickness or the gap between the two layers of the receiver is 0.01 m and is filled with heat transfer oil. The outer layer of the receiver is surrounded by the vertical cylindrical PCM tubes of diameter 0.025 m. The three modes of heat transfer, radiation, convection, and conduction, are explained and analyzed by heat transfer network. The schematic view of the receiver is shown with the help of sketchup software. The performance parameters, heat loss factor, optical efficiency factor, cooking power of the solar cooker, were calculated with and without PCM in the receiver. 7.74 W m−2 and 2.46 W m−2 are the heat loss factors, and 0.098 and 0.22 are the optical efficiency factors of the solar cooker without and with PCM presented in the receiver. The optical efficiency factor of the solar cooker with PCM receiver is two times more than that receiver without PCM. The cooking power of the solar cooker with PCM receiver is 125.3 W which is 65.6 W more than that of the cooking power without PCM receiver. From these results, it can be concluded that the design of PCM solar cooking system can expand the applicability of solar cookers as a compatible cooking solution for cooking applications instead of using fossil fuel based cooking systems.

scholarly journals Heat Transfer Enhancement in Microchannel Flow: Presence of Microparticles in a Fluid

2010 ◽  
Author(s):  
Awad B. S. Alquaity ◽  
Salem A. Al-Dini ◽  
Evelyn N. Wang ◽  
Shahzada Z. Shuja ◽  
Bekir S. Yilbas ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Pressure Drop ◽  
Phase Change ◽  
Constant Heat Flux ◽  
Working Fluid ◽  
Microchannel Flow ◽  
Carrier Fluid ◽  
Volume Fractions ◽  
Energy Equations

In the present study, a numerical model was developed for laminar flow in a microchannel with a suspension of microsized phase change material (PCM) particles. In the model, the carrier fluid and the particles are simultaneously present, and the mass, momentum, and energy equations are solved for both the fluid and particles. The particles are injected into the fluid at the inlet at a temperature equal to the temperature of the carrier fluid. A constant heat flux is applied at the bottom wall. The temperature distribution and pressure drop in the microchannel flow were predicted for lauric acid microparticles in water with volume fractions ranging from 0 to 8%. The particles show heat transfer enhancements by decreasing the temperature distribution in the working fluid by 39% in a 1 mm long channel. Meanwhile, particle blockage in the flow passage was found to have a negligible effect on pressure drop in the range of volume fractions studied. This work is a first step towards providing insight into increasing heat transfer rates with phase change-based microparticles for applications in microchannel cooling and solar thermal systems.

Heat Transfer Simulation in the Mold With Generalized Curvilinear Formulation

2005 ◽  
Vol 128 (3) ◽  
pp. 462-466 ◽  
Author(s):  
Eliseu L. M. Monteiro ◽  
Abel I. Rouboa ◽  
António A. C. Monteiro
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Finite Volume ◽  
Change Process ◽  
Complex Geometry ◽  
Mold Design ◽  
Complex Shapes ◽  
Geometry Configuration ◽  
Heat Transfer Simulation ◽  
Volume Method

The production of a part by foundry techniques is influenced by its complex geometry configuration, which affects the solidification conditions and subsequent cooling. For example certain pipes, some vessels and most valves are produced by casting. To model the solidification of the complex shapes such as valves is difficult if Cartesian coordinates are used. Even simpler parts like pipes may become difficult to model because they usually are not orthogonally ruled shapes. The main objective of this paper is to describe the development of a finite volume method intended to simulate the heat transfer phenomena during the phase change process. Because of the mold design complexity, the finite volume is described using the generalized curvilinear formulation.

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