Heat transfer mechanism, pressure drop and flow patterns during FC-72 flow boiling in horizontal and vertical minichannels with enhanced walls

Piasecka, Magdalena

doi:10.1016/j.ijheatmasstransfer.2013.07.046

Cited by 39 publications

(56 citation statements)

References 17 publications

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“…The supply and control system contained: an inverter welder, a shunt, an ammeter and a voltmeter. The experimental stand is discussed in detail in [11][12][13].…”

Section: Experimental Issuesmentioning

confidence: 99%

“…The results correspond to steady-state regimes. Details of the mathematical model are presented in [11,13]. The local values of the heat transfer coefficient α(y) in the area between the fluid and the heated surface of the minichannel were determined using the Robin boundary condition (third-kind boundary condition) on the basis of the known local fluid temperature and the distribution of temperature on the heated plate measured by means of infrared thermography, according to the following equation [13]: …”

Section: Experimental Issuesmentioning

confidence: 99%

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Numerical calculations of the thermal deformations of the rectangular minichannel walls

Piasecka

Błasiak

Musiał

2016

EPJ Web of Conferences

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Abstract. This paper analyzes the thermal deformations of the walls of a rectangular minichannel. The distribution of temperature on the walls and the local coefficients of heat transfer between the heated wall and the boiling fluid were determined on the basis of the experimental data. The thermal deformations were examined for two vertical walls: a heated Hastelloy X plate and an unheated stainless steel plate. The heat conduction and displacement equations were solved numerically using Ansys Workbench software. The distributions of temperature and the thermal deformations of the walls were obtained by appropriately combining the software modules with the mathematical description of the physical phenomena occurring in the minichannel and introducing the boundary conditions and the experimental data. It was found that, for the predetermined thermal conditions and the assumed thicknesses of the minichannel walls, thermal deformations can be omitted from further analysis. However, it is important to note that, if the geometrical dimensions of the minichannel had been different, the difference in the temperature along the minichannel length would have resulted in changes in the minichannel shape, i.e. its local narrowing, a reduction in the heat transfer efficiency, and, finally, a local change in the fluid flow rate.

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“…The supply and control system contained: an inverter welder, a shunt, an ammeter and a voltmeter. The experimental stand is discussed in detail in [11][12][13].…”

Section: Experimental Issuesmentioning

confidence: 99%

Section: Experimental Issuesmentioning

confidence: 99%

Numerical calculations of the thermal deformations of the rectangular minichannel walls

Piasecka

Błasiak

Musiał

2016

EPJ Web of Conferences

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“…Review of relevant literature and the selected publications covering flow boiling heat transfer in minichannels is presented in [1][2][3], and in addition, having enhanced surfaces -in [4,5].…”

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confidence: 99%

“…In order to collect experimental data for further calculations, current supplied the heating foil, voltage drop, volumetric flow rate and pressure in the inlet and outlet to the minichannel were measured. The complete experimental stand was presented in detail in [3][4][5][6][7]. The data and the image acquisition system consist of digital cameras (figure 1a, #8, #9), the data acquisition station, a computer with special software and lighting systems.…”

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Numerical modelling of temperature fields in the flow boiling liquid through a vertical minichannel with an enhanced heating surface

Hożejowska

Piasecka

2014

EPJ Web of Conferences

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Equalizing calculus in Trefftz method for solving two-dimensional temperature field of FC-72 flowing along the minichannel

Hożejowska

Piasecka

2014

Heat Mass Transfer

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The paper focuses on the numerical solution to two-dimensional temperature field of boiling liquid flowing along a vertical, asymmetrically heated minichannel with a rectangular cross-section. One of the walls of a minichannel is DC supplied single-sided enhanced foil with mini-recesses distributed unevenly in the selected area. The parallel walls are made of glass panes for thermal insulation and they are intended for observation of the two-phase flow and the void fraction. The thin layer of thermosensitive liquid crystal paint on the outer side of the foil enabled to record two-dimensional temperature distribution of outer foil surface. The paper described computations based on Trefftz method for finding two-dimensional temperature field of boiling liquid flowing along the minichannel. The presented research is limited only to the liquid phase of the two-phase mixture observed in the minichannel. The velocity of liquid flowing through the minichannel is represented by a piecewise linear approximating function. To solve energy equation for liquid phase, Trefftz functions specially generated for this purpose were employed. Temperature field in the fluid was approximated by a linear combination of Trefftz functions. Equalizing calculus was applied to the Trefftz method to smooth temperature measurements and reduce measurement errors.Temperature at the interface between working fluid and foil amounts to the saturation temperature. Temperature distribution in the foil and the glass pane was also computed using proper Trefftz functions. List of symbols

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Heat transfer mechanism, pressure drop and flow patterns during FC-72 flow boiling in horizontal and vertical minichannels with enhanced walls

Cited by 39 publications

References 17 publications

Numerical calculations of the thermal deformations of the rectangular minichannel walls

Numerical calculations of the thermal deformations of the rectangular minichannel walls

Numerical modelling of temperature fields in the flow boiling liquid through a vertical minichannel with an enhanced heating surface

Equalizing calculus in Trefftz method for solving two-dimensional temperature field of FC-72 flowing along the minichannel

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