scholarly journals Modeling of the Two-Dimensional Thawing of Logs in an Air Environment

Author(s):  
Nencho Deliiski ◽  
Ladislav Dzurenda ◽  
Natalia Tumbarkova

A two-dimensional mathematical model has been created, solved, and verified for the transient nonlinear heat conduction in logs during their thawing in an air environment. For the numerical solution of the model, an explicit form of the finite-difference method in the computing medium of Visual FORTRAN Professional has been used. The chapter presents solutions of the model and its validation towards own experimental studies. During the validation of the model, the inverse task of the heat transfer has been solved for the determination of the logs’ heat transfer coefficients in radial and longitudinal directions. This task has been solved also in regard to the logs’ surface temperature, which depends on the mentioned coefficients. The results from the experimental and simulative investigation of 2D nonstationary temperature distribution in the longitudinal section of poplar logs with a diameter of 0.24 m, length of 0.48 m, and an initial temperature of approximately –30°C during their many hours thawing in an air environment at room temperature are presented, visualized, and analyzed.

Author(s):  
Aleksandr S. MYAKOCHIN ◽  
Petr V. NIKITIN ◽  
Sergey Yu. POBEREZHSKIY ◽  
Anna A. SHKURATENKO

The paper presents a method, tools and a newly developed algorithm for experimentally determining heat transfer coefficients in organic liquids and solutions. This work is made relevant by the problem of development of a new generation of aerospace technology. In this connection, improvements have been made to the pulse method of determining heat transfer coefficients that is based on the use of a micron-thick film sensor. The measurement setup was modified. A math model was constructed for the measuring sensor. Algorithms were developed for conducting the experiment and processing measurement results to determine heat transfer coefficients. Experimental uncertainties were analyzed. The paper provides results of experimental studies on certain organic liquids. The authors believe that the material presented in the paper will find application in research conducted at research institutions, engineering offices and universities, among researches, postgraduates and students. Key words: thermal and physical characteristics, organic liquids and their solutions, film-type electrical resistor, thin-film temperature sensor, voltage pulse, resistance thermometer, irregular heat transfer regime.


1985 ◽  
Vol 56 (5) ◽  
pp. 239-246 ◽  
Author(s):  
Ulrich Reiners ◽  
Rudolf Jeschar ◽  
Reinhard Scholz ◽  
Dietmar Zebrowski ◽  
Wolfgang Reichelt

Author(s):  
Sebastian Herbst ◽  
Kim Florian Steinke ◽  
Hans Jürgen Maier ◽  
Andrzej Milenin ◽  
Florian Nürnberger

2011 ◽  
Vol 130 (1-2) ◽  
pp. 179-185 ◽  
Author(s):  
José N. Silva ◽  
Daniel J. Moutinho ◽  
Antonio L. Moreira ◽  
Ivaldo L. Ferreira ◽  
Otávio L. Rocha

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