Flow boiling heat transfer coefficient of DI water and nanofluids inside microscale channels under conditions near the critical heat flux (CHF)

Author(s)

Moreira, Tiago Augusto ; Duarte, Juliana Pacheco ; do Nascimento, Francisco Julio ; Ribatski, Gherhardt

• Document type: Journal article
• Source: Journal of the Brazilian Society of Mechanical Sciences and Engineering; v. 43, n. 6, p. 16-pg., 2021-06-01.

Abstract

This study concerns an experimental evaluation of the heat transfer coefficient for saturated flow boiling of DI water and nanofluids under conditions close to the critical heat flux. Experimental data were gathered for DI-water-based nanofluids (composed of Al2O3 40-80 nm, Al2O3 10 nm, and SiO2 80 nm in volumetric concentrations up to 0.1%) and pure DI water in microscale channels (1.1 mm internal diameter) as received from the manufacturer and with the surface covered with a nanoporous layer resulting from the boiling process. Results were obtained for a saturation temperature of approximately 130 degrees C, mass velocities ranging from 133 to 494 kg/m(2)s, vapor qualities up to 0.9, and heat fluxes up to 2.5 MW/m(2). The DI-water experimental data on the bare surface were compared to prediction methods available in the literature. In general, the nanoporous layer characteristics play a major role in the effects of nanoparticles on the heat transfer coefficient. (AU)

• FAPESP's process: 16/09509-1 - Phase change heat transfer processes of high performance applied to solar energy recovery
• Grantee: Gherhardt Ribatski
• Support Opportunities: Research Projects - Thematic Grants
• FAPESP's process: 11/13119-0 - Investigation of the effects of adding nanoparticle to a fluid on the mechanims of critical heat flux during convectve boiling and surface reweting under film boiling conditions
• Grantee: Francisco Júlio do Nascimento
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 16/16849-3 - THEORETICAL AND EXPERIMENTAL ANALYSIS OF HEAT TRANSFER COEFFICIENT, PRESSURE DROP AND FLOW PATTERNS DURING CONDENSATION OF HYDROCARBONS ZEOTROPIC MIXTURES INSIDE TUBES
• Grantee: Tiago Augusto Moreira
• Support Opportunities: Scholarships in Brazil - Doctorate