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Theoretical and experimental analysis of heat transfer coefficient, pressure drop and flow patterns during condensation of hydrocarbons ZEOTROPIC mixtures inside tubes

Grant number: 16/16849-3
Support type:Scholarships in Brazil - Doctorate
Effective date (Start): March 01, 2017
Effective date (End): August 31, 2020
Field of knowledge:Engineering - Mechanical Engineering
Principal Investigator:Gherhardt Ribatski
Grantee:Tiago Augusto Moreira
Home Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil
Associated scholarship(s):18/06057-8 - Extend and assessment of the accuracy of current liquid film thickness measurement technique for flat surfaces to a curved geometry, BE.EP.DR

Abstract

The legislations around world are becoming progressively more restrict to the emission of gases harmful to the environment. In this context, the HVACR sector experiences the gradual replacement of the halocarbon refrigerants by fluids with low impact on the environment. Among these fluids, hydrocarbons mixtures are being speculated as a promising choice. The present proposal of doctoral research concerns the study of in-tube condensation of zeotropic mixtures of hydrocarbons. Experimental results will be obtained for heat transfer coefficient, pressure drop, void fraction and flow pattern for pure R290, R600a and R1270 and the following mixtures of them: R290/R600a (propane/isobutane), molar fraction 30/70%, and R1270/R600a (propylene/isobutane), molar fraction 25/75%. Experiments will be performed for tube diameters of 6 and 9 mm, mass velocities from 50 to 400 kg/m2s, dew point temperatures of 35 and 45°C and vapor quality ranging from 1 to 0. These results will be compared with data obtained in the present study for R134a in order to evaluate the relative performance of the mixtures and a conventional refrigerant, that although presents a null ODP (ozone depletion potential), presents a high GWP (global warming potential). Special attention will be given to the evaluation of the liquid film thickness during annular flow in order to estimate the void fraction. The experimental database will be considered in the development of semi-empirical models to be used as design tools of heat exchangers. The experiments will be performed in an experimental apparatus located in the Department of Mechanical Engineering of EESC-USP. Currently, this apparatus is being modified in order to become capable of performing flow boiling and convective condensation tests for hydrocarbons. The adjustments of the test facility counts with funds from research grants provided by FAPESP (2011/50176-2) and CNPq (476763/2013-4). It is worth to highlight that the Heat Transfer Research Group at EESC-USP has reasonable experience on experimental studies involving heat transfer during phase-change processes. It will also contribute to the success of this proposal, the fact that the candidate is working in the same research group, investigating similar research topic for more than three years. Moreover, the candidate already finished all the graduate courses necessary to receive the Doctoral degree.

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)
DO NASCIMENTO, FRANCISCO JULIO; MOREIRA, TIAGO AUGUSTO; RIBATSKI, GHERHARDT. Flow boiling critical heat flux of DI-water and nanofluids inside smooth and nanoporous round microchannels. INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER, v. 139, p. 240-253, AUG 2019. Web of Science Citations: 0.
MOREIRA, TIAGO AUGUSTO; ALMEIDA COLMANETTI, ALEX ROGER; TIBIRICA, CRISTIANO BIGONHA. Heat transfer coefficient: a review of measurement techniques. Journal of the Brazilian Society of Mechanical Sciences and Engineering, v. 41, n. 6 JUN 2019. Web of Science Citations: 0.
MOREIRA, TIAGO AUGUSTO; MOREIRA, DEBORA CARNEIRO; RIBATSKI, GHERHARDT. Nanofluids for heat transfer applications: a review. Journal of the Brazilian Society of Mechanical Sciences and Engineering, v. 40, n. 6 JUN 2018. Web of Science Citations: 5.
MOREIRA, TIAGO AUGUSTO; DO NASCIMENTO, FRANCISCO JUILO; RIBATSKI, GHERHARDT; GRP, HEAT TRANSFER RES. An investigation of the effect of nanoparticle composition and dimension on the heat transfer coefficient during flow boiling of aqueous nanofluids in small diameter channels (1.1 mm). EXPERIMENTAL THERMAL AND FLUID SCIENCE, v. 89, p. 72-89, DEC 2017. Web of Science Citations: 7.

Please report errors in scientific publications list by writing to: cdi@fapesp.br.