Development of clay based nanofluids for quenching

In the present work the effect of addition of nanoclay particles having concentrations varying from 0.001-0.5vol% on cooling performance of water during immersion quenching was investigated. Cooling curve analyses were carried out by using standard ISO/DIS 9950 quench probe. An inverse heat conduction model is employed to estimate the metal/nanoquenchant interfacial heat flux transients from the measured temperature field and thermo-physical properties of the quench probe material. The addition of nanoclay particles had a significant effect on the cooling performance of the quench media. Quenching in nanofluid shows longer vapour blanket stage as compared to water. Further, all the six cooling curve parameters were found to be altered by the addition of nanoparticles to water. The heat flux curve shows a maximum shortly and then drops rapidly during quenching. The peak cooling rate and heat flux of water increased by the addition of very low volume fraction of nanoparticles. Both parameters decrease with increase in concentration of nanoparticles. Wetting behavior of nanoquenchant was studied using dynamic contact angle analyzer. The spreading behavior of droplets of quench media on INCONEL 600 substrate indicates improved wetting behavior of nanofluids.

Keywords: cooling curve analysis; nanoclay; heat flux transients; contact angle.