Faculty Publications
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Publications by NITK Faculty
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Item Effect of thermal conductivity and viscosity on cooling performance of liquid quench media(Maney Publishing Suite 1C, Joseph's Well, Hanover Walk Leeds LS3 1AB, 2014) Ramesh, G.; Prabhu, K.In this present work, the effect of the thermophysical properties of quenchants on its cooling performance was investigated. Water, brine solutions, polymer solutions and mineral oils were chosen to have quench media with varying thermophysical properties. Cooling curve analyses were carried out by using standard ISO/DIS 9950 quench probe. Grossmann H quench severity of the quench media was determined from the relation of H and cooling rate. Cooling curve analysis results showed that the change in thermophysical properties of the quench media had significant effect on the cooling history of the quench probe. The viscosity of the quenchant used for immersion quenching is the most important factor that controls the cooling performance of the quenchant compared to thermal conductivity of the quench medium. © 2014 IHTSE Partnership.Item A dimensional parameter for prediction of cooling performance of quenchants(ASTM International, 2014) Prabhu, K.; Ramesh, G.Computer aided cooling curve analysis was carried out during immersion quenching of ISO/DIS 9950 quench probe. Water, brine solutions, polymer solutions, mineral oils, and vegetable oils were used as quench media. The results showed that the quench medium used had a significant effect on the quench probe cooling curve parameters. An empirical correlation was proposed to predict the average cooling rate from surface tension, wetting angle, thermal conductivity, and kinematic viscosity of the quench medium. © 2014 by ASTM International.Item Comparative study of wetting and cooling performance of polymer-salt hybrid quench medium with conventional quench media(Taylor and Francis Ltd., 2015) Ramesh, G.; Prabhu, K.Wetting kinetics, kinematics, and cooling performance of a polymer-salt hybrid quenchant were investigated. The rewetting phenomenon for brine, water, polymer, and polymer-salt hybrid solutions was characterized as rapid uniform, fast non-uniform, slow uniform, and fast uniform processes, respectively. A dimensionless rewetting time was proposed to assess the nature of the wetting front. The hybrid quenchant showed higher heat transfer during vapor and transition boiling and lower heat transfer during nucleate boiling and convective cooling. The presence of salt in the hybrid solution resulted in early destabilization of the vapor film and an increase in wetting front velocity and rewetting temperature. The polymer constituent delayed the rewetting phenomenon. © 2015 Taylor & Francis Group, LLC.