The results of the simulation of the heat insulation properties of wood polymer-sand composite

2016 ◽  
Vol 6 (1) ◽  
pp. 140-146
Author(s):  
Аскомитный ◽  
Aleksey Askomitnyy
Keyword(s):  
Mathematical Model ◽  
Thermal Diffusivity ◽  
Heat Insulation ◽  
Wood Chips ◽  
Wood Polymer ◽  
Frag Ments

For the study and prediction of insulation properties of wood polymer-sand composite (WPSC) developed a mathematical model. It is established that the thermal diffusivity of the wood with a protective resin-sand coating, were comparable to the diffusivity of pure wood (ef-fective diffusivity 15-25 % higher). If the filler used is fragmented wood (chips, large frag-ments), the thermal diffusivity of the sample was significant, since heat is mainly distributed on the polymer-sandy channels between the pieces of wood.

Features of mathematical modeling of wood-polymer composite sandy

10.12737/8462 ◽  
2015 ◽  
Vol 4 (4) ◽  
pp. 130-139
Author(s):  
Стародубцева ◽  
Tamara Starodubtseva ◽  
Аскомитный ◽  
Aleksey Askomitnyy
Keyword(s):  
Mathematical Modeling ◽  
Mechanical Properties ◽  
Mathematical Model ◽  
Initial Data ◽  
Algebraic Equations ◽  
Wood Polymer ◽  
Composite Interface ◽  
Input Form ◽  
The Mathematical Model ◽  
Wood Polymer Composite

This article describes a technique for modeling of wood polymer-sandy composite. Interface input form of initial data for modeling; differential equations underlying the mathematical model are presented. To solve the system of differential and algebraic equations computer program "Program to simulate the struc-ture and mechanical properties of wood polymer-sandy composite" is developed. The program, developed in the environment of Borland Delphi 7.0, programming language Object Pascal, is intended for modeling the mechanical behavior of wood polymer-sandy composite of given composition.

Accounting for Finite Flash Duration in Diffusivity Experiments

2009 ◽  
Author(s):  
Robert L. McMasters ◽  
Ralph B. Dinwiddie
Keyword(s):  
Mathematical Model ◽  
Thermal Diffusivity ◽  
Nonlinear Regression ◽  
Laser Flash ◽  
Measured Data ◽  
Flash Method ◽  
Flash Intensity ◽  
Flash Duration ◽  
Three Samples ◽  
The Mathematical Model

The laser flash method, as a means of measuring thermal diffusivity, is well established, and several manufacturers produce equipment for performing these types of experiments. Most analysis methods used for interpreting the data from these experiments assume one-dimensional transient conduction, with insulated surfaces during the time subsequent to the flash. More recently, models of greater sophistication employing nonlinear regression have been applied to flash diffusivity experiments. These models assume an instantaneous flash and are highly accurate for most samples of moderate diffusivity and sample thickness. As samples become thinner and more highly conductive, the duration of the experiments becomes very short. Since the duration of the flash is typically on the order of several milliseconds, the assumption that this period of time is instantaneous becomes less valid for very short experiments. A model accounting for the duration of the flash is applied to three samples of stainless steel of varying thicknesses and analyzed with two different mathematical models. One model accounts for the finite duration of the flash and the other does not. The model accounting for the flash duration generates results that are much more consistent between samples than the model assuming an instantaneous flash. Moreover, the conformance of the mathematical model accounting for flash duration is much closer to the measured data than the model which assumes an instantaneous flash. As part of the finite flash duration model, the length of the flash is estimated by nonlinear regression, optimizing the conformance of the model to the measured data. Additionally, the starting time of the flash is treated as a parameter and is determined simultaneously with flash duration, thermal diffusivity and flash intensity. Statistical methods are also used for showing the validity of the added level of sophistication of the more advanced mathematical model.

Mathematical model of steam drying of wood chips and other hygroscopic porous media

AIChE Journal ◽  
1996 ◽  
Vol 42 (9) ◽  
pp. 2491-2502 ◽  
Author(s):  
Christian Fyhr ◽  
Anders Rasmuson
Keyword(s):  
Mathematical Model ◽  
Porous Media ◽  
Wood Chips ◽  
Steam Drying

scholarly journals Defining the Mathematical Dependencies of NOx and CO Emission Generation after Biomass Combustion in Low-Power Boiler

2019 ◽  
Vol 29 (3) ◽  
pp. 153-163 ◽  
Author(s):  
Ladislav Lukáč ◽  
Ján Kizek ◽  
Gustáv Jablonský ◽  
Yevgeniy Karakash
Keyword(s):  
Mathematical Model ◽  
Regression Analysis ◽  
Low Power ◽  
Measured Data ◽  
Wood Chips ◽  
Biomass Combustion ◽  
Regression Equations ◽  
The Mathematical Model ◽  
Power Boiler ◽  
Co Emission

Abstract The paper deals with the study of the influence of various factors, which have an impact on emissions such as NOx, CO, which have been verified by measurements. Biomass in the form of wood chips as fuel of different moisture content from 9% to 25% has been tested at various boiler outputs. The presented work also defines the mathematical dependencies of NOx and CO emission generation by using regression analysis from measured data after biomass combustion in low-power boilers. The paper also describes a mathematical model of biomass combustion. The mathematical model was created to verify the measured data and prediction of emission generation in the process of biomass combustion. This model consists of combustion of stoichiometry, calculation of combustion temperatures, obtained regression equations of NOx and CO. At the end of this paper, the obtained results are compared with the calculated models as well as the results of the defined dependencies from the regression analysis.

scholarly journals Improvement of the photoacoustic response in thermal diffusivity measurements

2020 ◽  
Vol 3 (4) ◽  
pp. 196-205
Author(s):  
David Gasca-Figueroa ◽  
Micael Gerardo Bravo-Sánchez ◽  
Adriana Guzmán-López ◽  
José Guadalupe Zavala-Villalpando ◽  
Francisco Javier García-Rodríguez
Keyword(s):  
Mathematical Model ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Room Temperature ◽  
Heat Energy ◽  
Photoacoustic Cell ◽  
Solid Materials ◽  
Diffusivity Measurements ◽  
Materials Used

An alternative photoacoustic cell configuration for the determination of the thermal diffusivity (α), at room temperature, for solid materials is presented. The method is based on the use of two identical photoacoustic chambers, inside both of them, a metallic foil thermally thin is used to transform the light energy to heat energy.  A Reference material placed parallel to a study material allows to relate the thermal properties of the materials used as support in the photoacoustic chambers of the experimental arrangement presented here. The ratio between experimental and theoretical photoacoustic amplitudes is realized to validate a proposed mathematical model.

Research of Vacuum Degree Influence on Performance of Vacuum Heat Insulation Oil Pipe

2013 ◽  
Vol 732-733 ◽  
pp. 172-175
Author(s):  
Zhong Hua Wang ◽  
Hai Qian Zhao
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Internal Pressure ◽  
Heat Conductivity ◽  
Heat Insulation ◽  
Thermal Barrier ◽  
Vacuum Degree ◽  
Insulation Oil

In this paper, mathematical model for heat transfer in thermal barrier is established based on the experiment which tested apparent heat conductivity of heat insulation oil pipes. Vacuum degree influence on performance of vacuum heat insulation oil pipe is analyzed by contrasting heat insulation oil pipes in different grades. The main conclusions are as follow. When internal pressure in the thermal barrier is between 0~20Pa or greater than 40Pa, the apparent heat conductivity increases with the pressure. And when internal pressure in the thermal barrier is between 20~40Pa, the apparent heat conductivity decreases with the pressure in volatility. When internal pressure in the thermal barrier is between 30~40Pa, the apparent heat conductivity of heat insulation oil pipe is lesser.

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