Applied sciences

Archives of Thermodynamics

Content

Archives of Thermodynamics | 2011 | No 1 April |

Abstract

In the paper the paths of bubbles emitted from the brass nozzle with inner diameter equal to 1.6 mm have been analyzed. The mean frequency of bubble departure was in the range from 2 to 65.1 Hz. Bubble paths have been recorded using a high speed camera. The image analysis technique has been used to obtain the bubble paths for different mean frequencies of bubble departures. The multifractal analysis (WTMM - wavelet transform modulus maxima methodology) has been used to investigate the properties of bubble paths. It has been shown that bubble paths are the multifractals and the influence of previously departing bubbles on bubble trajectory is significant for bubble departure frequency fb > 30 Hz.

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Abstract

In the paper, the Reynolds transport theorem (RTT) for three phase systems is developed, in terms associated with a moving control volume. The basic tools applied to the derivation are the generalized transport theorem by Truesdell and Toupin, and generalized surface transport theorem by Aris as well as Slattery. The final results referenced to a generic extensive quantity demonstrate the theorem in the integral instantaneous form. As a further illustration of applicability of the theorem relation developed some specific forms are deduced from such as for multiphase systems in terms of fixed control volume, surface systems and homogeneous spatial systems.

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Abstract

Combustion technology of the coal-water suspension creates a number of new possibilities to organize the combustion process fulfilling contemporary requirements, e.g. in the environment protection. Therefore the in-depth analysis is necessary to examine the technical application of coal as a fuel in the form of suspension. The research undertakes the complex investigations of the continuous coal-water suspension as well as cyclic combustion. The cyclic nature of fuel combustion results from the movement of the loose material in the flow contour of the circulating fluidized bed (CFB): combustion chamber, cyclone and downcomer. The experimental results proved that the cyclic change of oxygen concentration around fuel, led to the vital change of both combustion mechanisms and combustion kinetics. The mathematical model of the process of fuel combustion has been presented. Its original concept is based on the allowance for cyclic changes of concentrations of oxygen around the fuel. It enables the prognosis for change of the surface and the centre temperatures as well as mass loss of the fuel during combustion in air, in the fluidized bed and during the cyclic combustion.

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Abstract

The tubular type instrument (flux tube) was developed to identify boundary conditions in water wall tubes of steam boilers. The meter is constructed from a short length of eccentric tube containing four thermocouples on the fire side below the inner and outer surfaces of the tube. The fifth thermocouple is located at the rear of the tube on the casing side of the water-wall tube. The boundary conditions on the outer and inner surfaces of the water flux-tube are determined based on temperature measurements at the interior locations. Four K-type sheathed thermocouples of 1 mm in diameter, are inserted into holes, which are parallel to the tube axis. The non-linear least squares problem is solved numerically using the Levenberg-Marquardt method. The heat transfer conditions in adjacent boiler tubes have no impact on the temperature distribution in the flux tubes.

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Abstract

In the paper the experimental analysis of dryout in small diameter channels is presented. The investigations were carried out in vertical pipes of internal diameter equal to 1.15 mm and 2.3 mm. Low-boiling point fluids such as SES36 and R123 were examined. The modern experimental techniques were applied to record liquid film dryout on the wall, among the others the infrared camera. On the basis of experimental data an empirical correlation for predictions of critical heat flux was proposed. It shows a good agreement with experimental data within the error band of 30%. Additionally, a unique approach to liquid film dryout modeling in annular flow was presented. It led to the development of the three-equation model based on consideration of liquid mass balance in the film, a two-phase mixture in the core and gas. The results of experimental validation of the model exhibit improvement in comparison to other models from literature.

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Editorial office

Honorary Editor
Wiesław Gogół, Warsaw University of Technology, Poland

Editor-in-Chief
Jarosław Mikielewicz, The Szewalski Institute of Fluid-Flow Machinery PAS, Poland

Deputy
Marian Trela, The Szewalski Institute of Fluid-Flow Machinery PAS, Poland

Members of Editorial Commitee
Roman Domanski, Warsaw University of Technology, Poland
Andrzej Ziębik, Technical University of Silesia, Poland

Managing Editor
Jarosław Frączak, The Szewalski Institute of Fluid-Flow Machinery PAS, Poland

International Advisory Board
J. Bataille, Ecole Central de Lyon, Ecully, France
A. Bejan, Duke University,  Durham, USA
W. Blasiak, Royal Institute of Technology,  Stockholm, Sweden
G. P. Celata, ENEA,  Rome, Italy
M. W. Collins, South Bank University,  London, UK
J. M. Delhaye, CEA, Grenoble, France
M. Giot, Université Catholique de Louvain, Belgium
D. Jackson, University of Manchester, UK
S. Michaelides, University of North Texas, Denton, USA
M. Moran, Ohio State University,  Columbus, USA
W. Muschik, Technische Universität, Berlin, Germany
I. Müller, Technische Universität, Berlin, Germany
V. E. Nakoryakov, Institute of Thermophysics, Novosibirsk, Russia
M. Podowski, Rensselaer Polytechnic Institute, Troy, USA
M.R. von Spakovsky, Virginia Polytechnic Institute and State University, Blacksburg, USA

Contact

IFFM Publishers (Wydawnictwo IMP),

The Szewalski Institute of Fluid-Flow Machinery,
Fiszera 14, 80-952 Gdańsk, Poland,
telephone: +48 58 6995141, fax: +48 58 3416144,
e-mail: jfrk@imp.gda.pl; now@imp.gda.pl

 

 

Instructions for authors

Archives of Thermodynamics publishes original papers which have not previously appeared in other journals. The language of the papers is English. No paper should exceed the length of 25 pages. All pages should be numbered. The plan and form of the papers should be as follows:
 

1. The heading should specify the title (as short as possible), author, his/her complete affiliation, town, zip code, country and e-mail. Please show the corresponding author. The heading should be followed by Abstract of maximum 15 typewritten lines.

2. More important symbols used in the paper can be listed in Nomenclature, placed below Summary and arranged in a column, e.g.:
u – velocity, m/s
v – specific volume, m/kg
etc.
The list should begin with Latin symbols in alphabetical order followed by Greek symbols also in alphabetical order and with a separate heading. Subscripts and superscripts should follow Greek symbols and should be identified with separate headings. Physical quantities should expressed in SI units.

3. The equations should be each in a separate line. The numbers of the equations should run on, irrespective of the division of the paper into sections. The numbers should be given in round brackets on the right-hand side of the page.
 
4. Particular attention should be paid to the differentiation between capital and small letters. If there is a risk of confusion, the symbols should be explained (for example small c) in the margins. Indices of more than one level (such as Bfa ) should be avoided wherever possible.

5. Computer-generated figures should be produced using pretty bold lines and characters. No remarks should be written directly on the figures, except numerals or letter symbols only, the relevant explanations given below in the caption.
 
6. The figures, including photographs, diagrams etc., should be numbered with Arabic numerals in the same order in which they appear in the text.

7. Computer files on an enclosed disc or sent by e-mail to the Editorial Office are welcome. The manuscript should be written as a Word file – ¤:doc or LATEX file –¤:tex.
 
8. The references for the paper should be numbered in the order in which they are called in the text. Calling the references is by giving the appropriate numbers in square brackets. The references should be listed with the following information provided: the author’s surname and the initials of his/her names, the complete title of the work (in English translation) and, in addition:
 
(a) for books: the publishing house and the place and year of publication, for example:
`1` Holman J.P.: Heat Transfer. McGraw-Hill, New York 1968.
 
(b) for journals: the name of the journal, volume (Arabic numerals in bold), year of publication (in round brackets), number and, if appropriate, numbers of relevant pages, for example: 
`2` Rizzo F.I., Shippy D.I.: A method of solution for certain problems of transient heat conduction.
AIAA Journal 8(1970), No. 11, 2004–2009.
 
9. As the papers are published in English, the authors who are not native speakers of English are obliged to have the paper thoroughly reviewed language-wise before submitting for publication.

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