Two-phase flow phenomena assessment in minichannels for compact heat exchangers using image analysis methods

Masiukiewicz, Maciej; Anweiler, Stanisław

doi:10.1016/j.enconman.2015.03.055

Cited by 32 publications

(12 citation statements)

References 30 publications

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“…Three-phase flow is discussed, among others in [8,9]. The classification of flow regimes of airlift pumps is similar to the classifications for gas-liquid flow in vertical channels [10]. There are solutions for pumps with an inclined riser for which the classification is the same as in work [11].…”

Section: Of 19mentioning

confidence: 93%

A New Method of Selecting the Airlift Pump Optimum Efficiency at Low Submergence Ratios with the Use of Image Analysis

Ligus

Zając²,

Masiukiewicz

et al. 2019

Energies

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This paper presents experimental studies on the optimization of two-phase fluid flow in an airlift pump. Airlift pumps, also known as mammoth pumps, are devices applied for vertical transport of liquids with the use of gas. Their operating principle involves the existence of a density gradient. This paper reports the results of experimental studies into the hydrodynamic effects of the airlift pump. The studies involved optical imaging of two-phase gas-liquid flow in a riser pipe. The visualization was performed with high-speed visualization techniques. The studies used a transparent model of airlift pump with a rectangular cross-section of the riser. The assessment of the airlift pump operation is based on the image grey-level analysis to provide the identification of two-phase flow regimes. The scope of the study also involved the determination of void fraction and pressure drops. The tests were carried out in a channel with dimensions 35 × 20 × 2045 mm with the gas flux range 0.2–15.0 m3/h. For the assessment of the two-phase flow pattern Probability Density Function (PDF) was applied. On the basis of the obtained results, a new method for selecting the optimum operating regime of airlift pump was derived. This method provides the finding of stability and efficiency of liquid transport. It can also be applied to determine the correlation between the total lifting efficiency and the required gas flux for proper operation of the airlift pump.

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Section: Of 19mentioning

confidence: 93%

A New Method of Selecting the Airlift Pump Optimum Efficiency at Low Submergence Ratios with the Use of Image Analysis

Ligus

Zając²,

Masiukiewicz

et al. 2019

Energies

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“…More detailed description of applied methods and additional explanation of stereological parameters have been presented in earlier works [20]. These parameters allow quantitative and qualitative assessment of the two-phase gas-solid particles flow structure.…”

Section: Measurement Set-up and Methodsmentioning

confidence: 99%

Application of stereology for two-phase flow structure validation in fluidized bed reactors

Anweiler

Masiukiewicz

2016

THERM SCI

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Paper describes a novel method for two-phase gas-solid flow structure validation in fluidized bed reactors. Investigation is based on application of stereology techniques. This is an innovative approach in the field of fluidization phenomena research. Study is focused on the analysis of flow structure images, obtained with high-speed visualization of the fluidization process. Fluidization is conducted in transparent narrow channel, where plastic balls are fluidized by air. Applied stereological analysis is grounded on the linear method and on the method of random and directed secants. This enables 2-dimensional image measurement and 3-dimensional stereological extrapolation. The major result is that for each twophase gas-solid flow structure a set of stereological parameters exists. This enables quantification of the process. It has been found that the observation of interrelation of all stereological parameters, during the changing of the flow structure, can be used for system control. The basic conclusion is that knowledge about the character of the changes may be used for constant process adjustment for various two phase systems such as gas-solid or gas-liquid.

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“…It has been found that the combination of stereological parameters can be used to monitor operating conditions during changes in flow structure. Therefore, knowledge of the character of changes occurring in inflow structures may be used for constant process adjustments for various two-gas or gas-solid gas-liquid systems [19]. Experimental data were collected and analyzed for the void fraction and the reduction of the two-phase friction pressure from multiple sources.…”

Section: The Void Fraction Of the Churn Flow Patternmentioning

confidence: 99%

Void Fraction Features Using Image Processing on a Clear Capillary Pipe with a 45° Slope to The Horizontal Line of Two-Phase Air-Liquid Flow with High Viscosity

Sukamta

Noviyanto

Sudarja

et al. 2021

ARFMTS

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In supercomputer equipment, X-rays, satellite cryogenic cooling systems, and others, the two-phase flow phenomenon in mini channels are also used. A significant issue for them is the void fraction function induced by superficial velocity, fluid viscosity, and slope. This analysis's objective was to determine the characteristics of void fraction values on the bubble, plug, slug-annular, annular, churn in horizontal capillary pipes. The research was carried out on a mini-pipe with a diameter of 1.6 mm and a length of 130 mm, mounted at a horizontal angle of 45 degrees. A mixture of 40, 50, 60, and 70 percent air-pure water and glycerin concentrations is the fluid used. The flow pattern video was shot using a Nikon J4 camera with a speed of 1200 fps, gas speed (JG) at 2.5x10-2-66.3 m/s intervals, and fluid velocity (JL) at 3.3x10-2 - 4.935 m/s intervals. A digital image processing technique is used to calculate the value of a void fraction with the MATLAB R2014a and Microsoft Excel application software. This paper's new finding is that the value of the void fraction for bubbly flow indicates conditions that are not so stable and have a low value. The void fraction for plug flow tends to be close to 1 over a certain period; this is induced by the air cavity that almost fills the vessel, as shown by the effects of the image processing and the graphs the time series of voids. The void fraction has a value that fluctuates to a moderate value in the churn flow pattern.

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Two-phase flow phenomena assessment in minichannels for compact heat exchangers using image analysis methods

Cited by 32 publications

References 30 publications

A New Method of Selecting the Airlift Pump Optimum Efficiency at Low Submergence Ratios with the Use of Image Analysis

A New Method of Selecting the Airlift Pump Optimum Efficiency at Low Submergence Ratios with the Use of Image Analysis

Application of stereology for two-phase flow structure validation in fluidized bed reactors

Void Fraction Features Using Image Processing on a Clear Capillary Pipe with a 45° Slope to The Horizontal Line of Two-Phase Air-Liquid Flow with High Viscosity

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