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Application of stereology for assessment of two-phase flow structures

Masiukiewicz M., Ulbrich R., Zając D.

Transactions of the Institute of Fluid-Flow Machinery

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2013

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nr 125

39--54

EN

This paper describes a method for two-phase flow structures evaluation of gas-liquid mixture based on theoretical assumptions for the stereology in materials science. This assessment is based on the analysis of digital images, obtained with a high-speed camera. The bright field technique was used for process visualization. The images obtained during the visualisation were, in fact, projections of the structures. For the given recording conditions, the stereological analysis applied was based on the linear method and on the method of random and directed secants. The new methods of determining important parameters of two-phase flow were proposed on the basis of collected data. The parameters are as follows: the volume fraction, the interfacial area, the number of objects in one of the phases of the mixture and two other structural parameters of the selected two-phase fluid obtained from the analysis of the two-dimensional image (average length of chords for projected objects, average free distance for convex shapes from the projection).

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Wybrane parametry stereologiczne w identyfikacji struktur przepływu mieszaniny dwufazowej gaz-ciecz

Masiukiewicz M., Ulbrich R.

Inżynieria i Aparatura Chemiczna

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2013

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Nr 5

445--446

PL

Ukazano zastosowanie metody identyfikacji struktury mieszaniny wielofazowej opartej na analizie obrazu metodami stereologicznymi. Badania realizowano w kanale prostokątnym szczelinowym i czterech minikanałach dla pionowego współprądowego przepływu mieszaniny powietrzno-wodnej. Obliczono pięć parametrów stereologicznych, na podstawie których dokonano ilościowej i jakościowej oceny struktury. Informacje te umożliwiają sprawowanie kontroli nad urządzeniem, w którym taki przepływ zachodzi.

EN

The paper illustrates the method of multi-phase mixture structure identification based on image analysis with stereological methods. The study was conducted in a rectangular slot channel and in minichannels for vertical co- current flow of air - water mixture. The quantitative and qualitative assessment of flow structure was calculated on basis of five specific stereological parameters. These information enable the control of device in which the flow occurs.

3

Measurements of two-phase flow patterns and local void fraction in vertical rectangular minichannel

Kaniowski R., Poniewski M.

Archives of Thermodynamics

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2013

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Vol. 34, no. 2

3--21

EN

Technology advancements entail a necessity to remove huge amounts of heat produced by today’s electronic devices based on highly integrated circuits, major generators of heat. Heat transfer to boiling liquid flowing through narrow minichannels is a modern solution to the problem of heat transfer enhancement. The study was conducted for FC-72 boiling in a rectangular, vertical and asymmetrically heated minichannel that had depths of 0.5–1.5 mm, a width of 20 mm and a length of 360 mm. The heat flux increased and decreased within the range of 58.3–132.0 kWm-2, the absolute pressure ranged from 0.116 to 0.184 MPa and the mass flux was 185–1139.2 kgm-2s-1. The boiling process took place on a flat vertical heating surface made of Haynes-230 0.1 mm thick acid-proof rolled plate with the surface roughness of 121 μm.