An application of the non-continuous Trefftz method to the determination of heat transfer coefficient for flow boiling in a minichannel

Maciejewska, Beata; Piasecka, Magdalena

doi:10.1007/s00231-016-1895-1

Cited by 43 publications

(36 citation statements)

References 23 publications

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“…In this paper, the Trefftz method [5] was used to solve direct problems by approximating the unknown solution to a differential equation with a linear combination of functions strictly satisfying the governing differential equation. The Trefftz method was explored in more detail in [6][7][8][9][10][11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

The heat transfer coefficient determination with the use of the Beck-Trefftz method in flow boiling in a minichannel

Strąk¹,

Maciejewska

Piasecka³

2018

EPJ Web Conf.

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Abstract. In this paper, the solution of the two-dimensional inverse heat transfer problem with the use of the Beck method coupled with the Trefftz method is proposed. This method was applied for solving an inverse heat conduction problem. The aim of the calculation was to determine the boiling heat transfer coefficient on the basis of temperature measurements taken by infrared thermography. The experimental data of flow boiling heat transfer in a single vertical minichannel of 1.7 mm depth, heated asymmetrically, were used in calculations. The heating element for two refrigerants (FC-72 and HFE-7100, 3M) flowing in the minichannel was the plate enhanced on the side contacting with the fluid. The analysis of the results was performed on the basis of experimental series obtained for the same heat flux and two different mass flow velocities. The results were presented as infrared thermographs, heated wall temperature and heat transfer coefficient as a function of the distance from the minichannel inlet. The results was discussed for the subcooled and saturated boiling regions separately.

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Section: Introductionmentioning

confidence: 99%

The heat transfer coefficient determination with the use of the Beck-Trefftz method in flow boiling in a minichannel

Strąk¹,

Maciejewska

Piasecka³

2018

EPJ Web Conf.

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“…The plate temperature in each of subdomains The coefficients ij a minimize the functional which expresses the mean square error of the approximate solution on the boundary and on the common edges of the neighbouring subdomains [35]. The heat flux from Eq.…”

Section: The Non-continuous Trefftz Methodsmentioning

confidence: 99%

Comparison of the 1D and 2D calculation models used for determination of the heat transfer coefficient during flow boiling heat transfer in a minichannel

2019

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The paper discusses the results of the flow boiling heat transfer in a vertical minichannel with rectangular cross-section. The heating element for FC-72 flowing in the minichannel is a thin plate. Infrared thermography is used to determine changes in the temperature on its outer side. The aim of the calculation is to determine the heat transfer coefficient using 1D and 2D calculation models. Local values of heat transfer coefficient on the surface between the heated plate and boiling fluid are calculated from the Newton`s and Fourier`s laws. In 2D model the plate temperature distribution is obtained by solving the inverse heat conduction problem. The governing equation is solved by means of two methods: the non-continuous Trefftz method and the Beck method. The results are presented as plate temperature and heat transfer coefficient calculated using 1D and 2D models as a function of the distance from the minichannel inlet. The analysis of the results revealed that the values and distributions of the heat transfer coefficient calculated by means of both models were similar. This suggests that all mentioned methods are interchangeable.

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“…The boundary conditions in the form of temperature distributions on the outer sides of the minichannel walls were determined from the experimental measurement data The problem was analysed numerically using either the ANSYS CFX program or special calculation procedures based on the finite element method and Trefftz functions [5][6][7][8][9][10][11][12][13][14][15][16] in the thermal boundary layer.…”

Section: Main Aimmentioning

confidence: 99%

Determination of the temperature distribution in a minichannel using ANSYS CFX and a procedure based on the Trefftz functions

Maciejewska¹,

Błasiak

Piasecka

2017

EPJ Web Conf.

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Abstract. This work discusses the mathematical model for laminar-flow heat transfer in a minichannel. The boundary conditions in the form of temperature distributions on the outer sides of the channel walls were determined from experimental data. The data were collected from the experimental stand the essential part of which is a vertical minichannel 1.7 mm deep, 16 mm wide and 180 mm long, asymmetrically heated by a Haynes-230 alloy plate. Infrared thermography allowed determining temperature changes on the outer side of the minichannel walls. The problem was analysed numerically through either ANSYS CFX software or special calculation procedures based on the Finite Element Method and Trefftz functions in the thermal boundary layer. The Trefftz functions were used to construct the basis functions. Solutions to the governing differential equations were approximated with a linear combination of Trefftz-type basis functions. Unknown coefficients of the linear combination were calculated by minimising the functional. The results of the comparative analysis were represented in a graphical form and discussed.

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An application of the non-continuous Trefftz method to the determination of heat transfer coefficient for flow boiling in a minichannel

Cited by 43 publications

References 23 publications

The heat transfer coefficient determination with the use of the Beck-Trefftz method in flow boiling in a minichannel

The heat transfer coefficient determination with the use of the Beck-Trefftz method in flow boiling in a minichannel

Comparison of the 1D and 2D calculation models used for determination of the heat transfer coefficient during flow boiling heat transfer in a minichannel

Determination of the temperature distribution in a minichannel using ANSYS CFX and a procedure based on the Trefftz functions

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