Alumina nanofluids to quenching applications

• Grant number: 12/03305-4
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Effective date (Start): April 01, 2012
• Effective date (End): September 30, 2013
• Field of knowledge: Engineering - Materials and Metallurgical Engineering - Transformation Metallurgy
• Principal Investigator: Lauralice de Campos Franceschini Canale
• Grantee: Bruno Adarme de Castro
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Quenching is a heat process that is highly used in the industry to achieve good properties of hardness and mechanical strength. In the numerous quenchants used in this process, their physical properties are very different from each other. The performance of these fluids is dependent on the bath temperature, agitation, and, concentration of the solute. This research project consists in studying the effects of nanofluids applied in the quenching process. Nanofluids are particle suspensions varying from sizes of 1-100 nm in heat transfer fluids. Recent studies in nanofluids indicate a significant rise in thermal conductivity and in the critical heat flux with a concentration of the nanoparticles smaller than 0.1% in volume. This occurs, among other reasons, mainly due to the higher thermal conductivity of the solids in suspension. In this research, even though the existence of many types of nanofluids, the nanofluids studied will be the alumina nanofluid, water, and soya oil-based, in the concentrations of 0.01%, 0.05%, and 0.1% in volume and average particle size varying from 40 to 60 nm, as a quenching fluid. The nanofluids will be prepared via milling and then mixed in the base fluids with the specified concentrations. The cooling behavior will be analyzed with an Inconel probe with a type K thermocouple in its geometrical center, that will capture the variation of temperature through an acquisition data system (cooling curves). Heat transfer rates and the heat transfer coefficients will also be calculated. The results will be compared and analyzed.(AU)