Eventos Anais de eventos
ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
EXPERIMENTAL EVALUATION OF THE FLOW BOILING HEAT TRANSFER COEFFICIENT OF R600A AND R134A INSIDE A 9.43 MM INNER DIAMETER TUBE.
Submission Author:
Guilherme Henrique de Sena e Oliveira , SP
Co-Authors:
Guilherme Henrique de Sena e Oliveira, Tiago Augusto Moreira, Gherhardt Ribatski
Presenter: Guilherme Henrique de Sena e Oliveira
doi://10.26678/ABCM.ENCIT2020.CIT20-0358
Abstract
This paper details an experimental investigation on the heat transfer coefficient during flow boiling of R134a and R600a in horizontal smooth circular tube with an inner diameter of 9.4 mm, using water flowing in counter-current as the heating source. Experiments were performed for mass velocities from 50 to 400 kg/m2s, heat fluxes of 10 and 30 kW/m2, vapor qualities up to 1, and saturation temperature of 5oC. Generally, an increase in the heat transfer coefficient was observed with increasing the heat flux and mass velocity. The heat transfer coefficient increases with increasing vapor quality until dryout conditions are reached. Additional vapor quality increments beyond dryout causes a decrease in the heat transfer coefficient. The comparison reveals that, in general, R600a provides a heat transfer coefficient higher than R134a under similar experimental conditions. The experimental results were compared with predictive methods from literature, and satisfactory predictions were observed only for R134a.
Keywords
Flow boiling, Heat transfer coefficient, Two-phase Flow, R134a, R600a
DOWNLOAD PDF VIEW PRESENTATION
