Assessment of the Effect of Quench Probe Parameters on Cooling Behavior by Numerical Simulation

Abstract

The cooling severity of liquid quenchants is generally assessed by measuring the cooling rate inside a metallic probe. In the present study, numerical simulation of heat transfer was carried out to assess the effect of quench probe parameters on the cooling behavior. Simulations were carried out for different combinations of size, geometry, material and boundary heat transfer coefficients. Factorial experiments were carried out to assess the significance of probe parameters on mean cooling rate of the probe during quenching. Factorial analysis results showed significant influence of size and material of the probe on the mean cooling rate during quenching. The percentage contribution of the size and material parameters to the overall effect of various parameters on the mean probe cooling rate were about 45 and 16 pct. respectively. Among the interaction effects of various parameters, the interaction among probe material and size was found to be most significant. Factorial experiments showed that the effect of probe geometry on the mean cooling rate was insignificant particularly for probes of higher thermal conductivity. It was found that for a given geometry, the cooling parameter (L2CR/α) increased exponentially with increase in Biot number (Bi). The effect of probe geometry on mean cooling rate was significant when Bi was greater than 0.8.