CFD Quenching Simulation using Experimentally Determined Flow Boiling Database

Heat treating, including a liquid or gas quenching step, is an integral component of the production of most metal components. The rapid cooling that occurs during quenching largely defines the phase distribution, microstructure, residual stress, and distortion in the as-quenched part. While the application of numerical analysis tools to heat treating operations provides a method for developing process improvements, the prediction of surface heat flux rates during liquid quenching has continued to be a challenge. Instrumented tests can provide that data, but are time-consuming, expensive, and have limited applicability. Highly detailed CFD-based boiling models are inappropriate for the simulation of industrial quenching operations, while physics-based boiling models may depend, in part, on tunable parameters.

Extensive flow boiling heat flux data has been collected for Houghton 3420 quench oil using an experimental test rig specifically developed for this purpose. In an earlier publication, it was shown that direct application of those heat flux data to a cylindrical part shape provided cooldown predictions that closely matched actual experimental data. In the present paper, the same quench modeling approach is applied to a representative turbine disk forging quenched in Houghton 3420 and also in Houghton's Hanoline quench oil. For the latter oil, the boiling heat flux curves were approximated based on a limited set of property and quenching data, rather than being fully characterized in the same way as the 3420 oil. Comparisons between simulated and predicted cooling curves for both cases are presented.