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Experimental analysis of the effect of the microchannel geometry on the two-phase flow pattern, heat transfer coefficient and pressure drop during convective boiling.

Grant number: 10/17605-4
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): May 01, 2011
Effective date (End): April 30, 2015
Field of knowledge:Engineering - Mechanical Engineering - Transport Phenomena
Principal researcher:Gherhardt Ribatski
Grantee:Daniel Felipe Sempértegui Tapia
Home Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil


In general,this doctoral research project deals with the analysis of the effect of the channel geometry on the two-phase flow pattern, heat transfer coefficient and the pressure drop during convective boiling inside channels of an equivalent diameter close to 1 mm. Experiments will be performed for refrigerants R134a and R245fa for triangular and rectangular channels with aspect ratios equal to 4, 2, 1 and ½. Experimental results determined with the implementation of this research proposal will be compared with results for circular cross section obtained by the group during the doctoral thesis of Tibiriça (Grand number 2007/53950-5 from FAPESP). Experimental techniques and data analysis procedures already developed by the group will be used in order to investigate the effect of the channel cross section geometry on the two-phase flow pattern, heat transfer coefficient and pressure drop. An extensive database will be obtained in an experimental setup in the Department of Mechanical Engineering, EESC-USP, which is available and operational. The objective method for identifying two-phase flow patterns developed during the dissertation of the applicant (Grand number 2008/56930-8 from FAPESP) and described in Sempértegui Ribatski (2010) will be used. This will allows the development of pressure losses and heat transfer coefficient models which include the predominant physical mechanisms of each flow regime. Aspects related to the effects of aspect ratio of rectangular channels, effects of the edges of the rectangular channels and triangular channels, will be studied through a careful visual analysis of images obtained by a high speed camera (8000 frames/s).

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Scientific publications (4)
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
SEMPERTEGUI-TAPIA, DANIEL FELIPE; RIBATSKI, GHERHARDT. The effect of the cross-sectional geometry on saturated flow boiling heat transfer in horizontal micro-scale channels. EXPERIMENTAL THERMAL AND FLUID SCIENCE, v. 89, p. 98-109, DEC 2017. Web of Science Citations: 4.
SEMPERTEGUI-TAPIA, DANIEL FELIPE; RIBATSLZI, GHERHARDT. Two-phase frictional pressure drop in horizontal micro-scale channels: Experimental data analysis and prediction method development. INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID, v. 79, p. 143-163, JUL 2017. Web of Science Citations: 16.
SEMPERTEGUI-TAPIA, DANIEL FELIPE; RIBATSKI, GHERHARDT. Flow boiling heat transfer of R134a and low GWP refrigerants in a horizontal micro-scale channel. INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, v. 108, n. B, p. 2417-2432, MAY 2017. Web of Science Citations: 18.
SEMPERTEGUI-TAPIA, DANIEL; ALVES, JESSIKA DE OLIVEIRA; RIBATSKI, GHERHARDT. Two-Phase Flow Characteristics During Convective Boiling of Halocarbon Refrigerants Inside Horizontal Small-Diameter Tubes. HEAT TRANSFER ENGINEERING, v. 34, n. 13, SI, p. 1073-1087, OCT 21 2013. Web of Science Citations: 6.
Academic Publications
(References retrieved automatically from State of São Paulo Research Institutions)
TAPIA, Daniel Felipe Sempértegui. Experimental analysis of the cross-sectional geometry effect and low GWP refrigerants performance during convective boiling inside micro-scale channels. 2016. Doctoral Thesis - Universidade de São Paulo (USP). Escola de Engenharia de São Carlos São Carlos.

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