scholarly journals Mathematical simulation of forest fire front influence on wood-based building using one-dimensional model of heat transfer

2020 ◽  
Vol 200 ◽  
pp. 03007
Author(s):  
Nikolay V Baranovskiy ◽  
Aleksey Malinin
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Heat Conduction ◽  
Mathematical Simulation ◽  
Forest Fire ◽  
Dimensional Model ◽  
One Dimensional ◽  
Building Enclosures ◽  
Fire Front ◽  
Fire Impact

The purpose of the present paper is to mathematical simulation of heat transfer in enclosures of wood-based building when exposed to thermal radiation from forest fire front. One-dimensional mathematical model is used. Mathematically, heat transfer in building enclosures is described by system of non-stationary equations of heat conduction with corresponding initial and boundary conditions. It is suggested to use several scenarios of forest fire impact. Temperature distribution on wall depth is obtained for different scenarios of forest fire impact on building enclosures.

Thermoelectric Viscoelastic Fluid with Fractional Integral and Derivative Heat Transfer

2015 ◽  
Vol 7 (4) ◽  
pp. 528-548 ◽  
Author(s):  
Magdy A. Ezzat ◽  
A. S. Sabbah ◽  
A. A. El-Bary ◽  
S. M. Ezzat
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Fluid Flow ◽  
Heat Conduction ◽  
General Solution ◽  
Viscoelastic Fluid ◽  
Fractional Integral ◽  
Heat Sources ◽  
One Dimensional ◽  
Time Fractional Derivative

AbstractA new mathematical model of magnetohydrodynamic (MHD) theory has been constructed in the context of a new consideration of heat conduction with a time-fractional derivative of order 0 < α ≤ 1 and a time-fractional integral of order 0 < γ ≤ 2. This model is applied to one-dimensional problems for a thermoelectric viscoelastic fluid flow in the absence or presence of heat sources. Laplace transforms and state-space techniques will be used to obtain the general solution for any set of boundary conditions. According to the numerical results and its graphs, conclusion about the new theory has been constructed. Some comparisons have been shown in figures to estimate the effects of the fractional order parameters on all the studied fields.

Numerical Analysis of Heat Exchangers Used in a Liquid Piston Compressor Using a One-Dimensional Model With an Embedded Two-Dimensional Submodel

2014 ◽  
Author(s):  
Chao Zhang ◽  
Jacob Wieberdink ◽  
Terrence W. Simon ◽  
Perry Y. Li ◽  
James Van de Ven ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Porous Media ◽  
Heat Conduction ◽  
Heat Exchangers ◽  
Piston Compressor ◽  
Two Dimensional ◽  
Dimensional Model ◽  
One Dimensional ◽  
Temperature Distributions ◽  
Liquid Piston

The present study presents a one-dimensional liquid-piston compressor model with an embedded two-dimensional submodel. The submodel is for calculating heat conduction across a representative internal plate of a porous heat exchanger matrix within the compression space. The liquid-piston compressor is used for Compressed Air Energy Storage (CAES). Porous-media-type heat exchangers are inserted in the compressor to absorb heat from air as it is compressed. Compression without heat transfer typically results in a temperature rise of a gas and a drop in efficiency, for the elevated temperature leads to wasted thermal energy, due to cooling during subsequent cooling back to ambient temperature. The use of heat exchangers can reduce the air temperature rise during the compression period. A typical numerical model of a heat exchanger is a one-dimensional simplification of the two-energy-equation porous media model. The present authors proposed a one-dimensional model that incorporates the Volume of Fluid (VOF) method for application to the two-phase flow, liquid piston compressor with exchanger inserts. Important to calculating temperature distributions in both the solid and fluid components of the mixture is heat transfer between the two, which depends on the local temperature values, geometry, and the velocity of fluid through the matrix. In the one-dimensional model, although the axial temperatures vary, the solid is treated as having a uniform temperature distribution across the plate at any axial location. This may be in line with the physics of flow in most heat exchangers, especially when the exchangers are made of metal with high thermal conductivity. However, it must be noted that for application to CAES, the gas temperature in the compression chamber rises rapidly during compression and the core of the solid wall may heat up to a different temperature than that of the surface, depending on the geometry, solid material of the exchanger and fluid flow situation. Therefore, a new, one-dimensional model with embedded two-dimensional submodel is developed to consider two-dimensional heat conduction in a representative solid plate. The VOF concept is used in the model to handle the moving liquid-gas interface (liquid piston). The model gives accurate solutions of temperature distributions in the liquid piston compression chamber. Six different heat exchangers with different length scales and different materials are simulated and compared.

Microprocessor Silicon Die Temperature Prediction by Simplified Boundary Conditions

2015 ◽  
Author(s):  
Koji Nishi ◽  
Tomoyuki Hatakeyama ◽  
Shinji Nakagawa ◽  
Masaru Ishizuka
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Boundary Conditions ◽  
Thermal Resistance ◽  
Hot Spot ◽  
Three Dimensional ◽  
Thermal Design ◽  
Target Temperature ◽  
One Dimensional ◽  
Thermal Network

The thermal network method has a long history with thermal design of electronic equipment. In particular, a one-dimensional thermal network is useful to know the temperature and heat transfer rate along each heat transfer path. It also saves computation time and/or computation resources to obtain target temperature. However, unlike three-dimensional thermal simulation with fine pitch grids and a three-dimensional thermal network with sufficient numbers of nodes, a traditional one-dimensional thermal network cannot predict the temperature of a microprocessor silicon die hot spot with sufficient accuracy in a three-dimensional domain analysis. Therefore, this paper introduces a one-dimensional thermal network with average temperature nodes. Thermal resistance values need to be obtained to calculate target temperature in a thermal network. For this purpose, thermal resistance calculation methodology with simplified boundary conditions, which calculates thermal resistance values from an analytical solution, is also introduced in this paper. The effectiveness of the methodology is explored with a simple model of the microprocessor system. The calculated result by the methodology is compared to a three-dimensional heat conduction simulation result. It is found that the introduced technique matches the three-dimensional heat conduction simulation result well.

One-dimensional model for the Rijke tube

1989 ◽  
Vol 202 ◽  
pp. 83-96 ◽  
Author(s):  
C. Nicoli ◽  
P. Pelcé
Keyword(s):  
Heat Transfer ◽  
Transfer Function ◽  
Dimensional Model ◽  
Unsteady Heat Transfer ◽  
Order Unity ◽  
Rijke Tube ◽  
Thermoacoustic Instability ◽  
One Dimensional ◽  
The Stability ◽  
Stability Limits

We develop a simple model in which longitudinal, compressible, unsteady heat transfer between heater and gas is computed in the small-Mach-number limit. This calculation is used to determine the transfer function of the heater, which plays an important role in the stability limits of the thermoacoustic instability of the Rijke tube. The transfer function is determined analytically in the limit of small expansion parameter γ, and numerically for γ of order unity. In the case ρμ/cp = constant, an analytical solution can be found.

scholarly journals A Useful Equation for Gas Turbine Design

2018 ◽  
Vol 140 (03) ◽  
pp. S52-S53
Author(s):  
Lee S. Langston
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Gas Turbine ◽  
Rankine Cycle ◽  
Combined Cycle ◽  
Brayton Cycle ◽  
Nonlinear Superposition ◽  
Transient Conditions ◽  
One Dimensional ◽  
Turbine Design

This article presents three different gas turbine phenomena and design cases. The sketch in the article shows a schematic of a combined cycle powerplant consisting of a Brayton cycle (gas turbine) whose exhaust provides energy to a Rankine cycle (steam turbine). Frequently, one can use simple but exact one-dimensional (1D) heat conduction solutions to estimate the heat loss or gain of gas turbine components under transient conditions. These easy-to-use solutions are found in most undergraduate heat transfer texts. The article suggests that those three widely different gas turbine phenomena and design cases all have the simple, nonlinear superposition form.

Nonlinear Inverse Heat Conduction With a Moving Boundary: Heat Flux and Surface Recession Estimation

1999 ◽  
Vol 121 (3) ◽  
pp. 708-711 ◽  
Author(s):  
V. Petrushevsky ◽  
S. Cohen
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Fourier Series ◽  
Heat Conduction ◽  
Moving Boundary ◽  
Heat Conduction Problem ◽  
Inverse Heat Conduction Problem ◽  
Variable Order ◽  
Inverse Heat Conduction ◽  
One Dimensional

A one-dimensional, nonlinear inverse heat conduction problem with surface ablation is considered. In-depth temperature measurements are used to restore the heat flux and the surface recession history. The presented method elaborates a whole domain, parameter estimation approach with the heat flux approximated by Fourier series. Two versions of the method are proposed: with a constant order and with a variable order of the Fourier series. The surface recession is found by a direct heat transfer solution under the estimated heat flux.

Numerical Investigation of Heat Transfer Characteristics of Debris Bed After Severe Accident of SFR Based on 1-D Heat Conduction Model

2018 ◽  
Author(s):  
Mengwei Zhang ◽  
Bin Zhang ◽  
Jianqiang Shan
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Transfer Process ◽  
Severe Accident ◽  
Heat Transfer Characteristics ◽  
Conduction Model ◽  
One Dimensional ◽  
The Core ◽  
Transfer Characteristics ◽  
Core Catcher

Nuclear reactor severe accidents can lead to the release of a large amount of radioactive material and cause immense disaster to the environment. Since the Fukushima nuclear accident in Japan, the severe accident research has drawn worldwide attention. Based on the one-dimensional heat conduction model, a DEBRIS-HT program for analyzing the heat transfer characteristics of a debris bed after a severe accident of a sodium-cooled fast reactor was developed. The basic idea of the DEBRIS-HT program is to simplify the complex energy transfer process in the debris bed to a simple one-dimensional heat transfer problem by solving the equivalent thermal conductivity in different situations. In this paper, the DEBRIS-HT program code is prepared by using the existing model and compared with the experimental results. The results show that the DEBRIS-HT program can correctly predict the heat transfer process in the fragment bed. In addition, the heat transfer characteristics analysis program is also used to model the core catcher of the China fast reactor. Firstly, the dryout heat flux when all of molten core dropped on the core catcher was calculated, which was compared with the result of Lipinski’s zero dimensional model, and the error between two values is only 11.2%. Then, the temperature distribution was calculated with the heat power of 15MW.

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