Boiling Synchronization in Two Parallel Minichannels—Image Analysis

Rafałko, Gabriela; Zaborowska, Iwona; Grzybowski, Hubert; Mosdorf, Romuald

doi:10.3390/en13061409

Cited by 6 publications

(3 citation statements)

References 17 publications

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“…This mechanism was observed in a heat exchanger with an extended geometry which included 51 parallel minichannels. In the systems with parallel minichannels, dynamic instabilities are accompanied by synchronization of processes in neighboring minichannels including heating sur-face temperature fluctuations [14], pressure drop fluctuations [15], and changes of the presence of two-phase flow patterns [16].…”

Section: Introductionmentioning

confidence: 99%

Image Analysis of Flow Maldistribution during Boiling in Parallel Minichannels

et al. 2021

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The boiling flow of distilled water with reverse flow in three parallel, rectangular, horizontal minichannels was investigated. The analyzed data was in the form of a set of video frames. An image analysis and statistical analysis of changes of pixel brightness in minichannels was conducted. A self-organizing process was identified for short slug flow in neighboring minichannels. The identified synchronization process was accompanied by the increase in standard deviation of pixel brightness changes. The process of synchronization was observed for short slugs, but not for long slugs. It can be concluded that the synchronization of heat and mass transfer in minichannels can be achieved when the character of two-phase flow patterns in each channel is not fully blocking the flow.

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Section: Introductionmentioning

confidence: 99%

Image Analysis of Flow Maldistribution during Boiling in Parallel Minichannels

et al. 2021

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“…The boiling behavior and flow patterns have attracted considerable attention from many researches. They mainly focuses on flow patterns classification [13][14][15], bubble formation [16] and mass transfer in flow boiling [17]. Many works report that different types of instabilities are superimposed on each other [18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Application of RQA and SOM for identification of two-phase flow patterns during boiling in horizontal minichannel

2021

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In the paper, numerical methods of data analysis recurrence quantification analysis (RQA) and self-organizing map (SOM) have been used to analyse pressure drop oscillations during the flow boiling in minichannel. The performed analysis allows us to identify flow patterns based on the character of the pressure drop oscillations. The following two-phase flow patterns have been identified: liquid flow, liquid flow with small vapour bubble, slug flow, long slug flow and confined bubble flow. In the experiment, the open-loop boiling system in a circular horizontal minichannel with an inner diameter of 1 mm was investigated. The two-phase flow patterns at the outlet of the heated section were observed through the glass tube (with an inner diameter of 1 mm) and recorded by a high-speed camera Phantom v1610.

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“…Another interesting topic is image analysis during multiphase flow in minichannels. Such analysis, including the boiling synchronization of two-phase flow structure in two parallel minichannels, each of 1 mm diameter, was discussed in [33]. In Ref.…”

Section: Introductionmentioning

confidence: 99%

Heat Transfer Coefficient Determination during FC-72 Flow in a Minichannel Heat Sink Using the Trefftz Functions and ADINA Software

2020

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This work focuses on subcooled boiling heat transfer during flow in a minichannel heat sink with three or five minichannels of 1 mm depth. The heated element for FC-72 flowing along the minichannels was a thin foil of which temperature on the outer surface was measured due to the infrared thermography. The test section was oriented vertically or horizontally. A steady state heat transfer process and a laminar, incompressible flow of the fluid in a central minichannel were assumed. The heat transfer problem was described by the energy equations with an appropriate system of boundary conditions. Several mathematical methods were applied to solve the heat transfer problem with the Robin condition to determine the local heat transfer coefficients at the fluid/heated foil interface. Besides the 1D approach as a simple analytical method, a more sophisticated 2D approach was proposed with solutions by the Trefftz functions and ADINA software. Finite element method (FEM) calculations were conducted to find the temperature field in the flowing fluid and in the heated wall. The results were illustrated by graphs of local heated foil temperature and transfer coefficients as a function of the distance from the minichannel inlet. Temperature distributions in the heater and the fluid obtained from the FEM computations carried out by ADINA software were also shown. Similar values of the heat transfer coefficient were obtained in both the FEM calculations and the 1D approach. Example boiling curves indicating nucleation hysteresis are shown and discussed.

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Boiling Synchronization in Two Parallel Minichannels—Image Analysis

Cited by 6 publications

References 17 publications

Image Analysis of Flow Maldistribution during Boiling in Parallel Minichannels

Image Analysis of Flow Maldistribution during Boiling in Parallel Minichannels

Application of RQA and SOM for identification of two-phase flow patterns during boiling in horizontal minichannel

Heat Transfer Coefficient Determination during FC-72 Flow in a Minichannel Heat Sink Using the Trefftz Functions and ADINA Software

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