Investigation of the cooling process with nanofluids according to ISO 9950 and ASTM D 6482 standards
Preiskava postopka ohlajanja v nanotekočini po standarih ISO 9950 in ASTM 6482

english

2013

volume 47, issue 1

quenching    nanofluids    agitation    nanoparticles 

Inštitut za kovinske materiale in tehnologije
(Obvezni izvod spletne publikacije)

Introducing nanofluids as liquid quenchants in order to improve the heat-transfer characteristics is a novel approach in heat treatment. These new liquid quenchants are called nanoquenchants and are colloid suspensions of nanoparticles in the base fluid (BF). For the purpose of this research standard liquid quenchants, such as water and polymer solution, were used as base fluids. Nanoparticles were added to the base fluid in order to increase its thermal properties without a significant effect on the viscosity of the fluid. The added nanoparticles cause an enhancement of the heat-transfer characteristics of the liquid quenchants. In this research TiOsub2 nanoparticles, with the average size of 50 nm, were added to the base fluid. The cooling curves for every tested quenchant were recorded using the IVF SmartQuench system and the quenching process parameters were determined and compared. The tested quenchants were deionised water and polyalkylene-glycol (PAG) water solutions of (5, 10 and 20) % in volume fractions of polymer concentrations. Quenching experiments were first conducted in pure BFs without the addition of nanoparticles and without agitation according to the ISO 9950 standard. The experiments were then repeated with an addition of 0.2 g/l TiOsub2 nanoparticles. The second series of experiments was conducted in a quenching bath with agitation according to the ASTM D 6482 standard. All of the recorded cooling curves were compared and the effects of the nanoparticle addition and agitation were investigated. The addition of the nanoparticles and quenching with agitation caused an increase in the maximum cooling rate and a shorter full-film stage.

09.05.2014