Volume 6, Issue 5 (May 2009)
Generalized Equation for Cooling Time Evaluation and Its Verification by CFD Analysis
In this paper, a generalized analytical equation for cooling time evaluation is analyzed and compared with existing exact solutions and verified by computation fluid dynamics (CFD) simulation. The process of quenching of semiaxles and cylindrical forgings in water flow is also considered. Two approaches are analyzed. The traditional approach focuses on quenching, which is based on Newton’s boundary condition between the solid surface and fluid. The second approach solves a conjugate heat transfer problem based on a full set of Navier–Stokes equations. CFD technology does not require knowledge of the heat transfer coefficients at the surface of steel parts. Both approaches and results of calculations were compared and the results showed that a generalized correlation can be used for cooling time calculation both for simple and complicated configurations. Calculation results coincide with each other, which indicates that the generalized equation is a suitable method for calculations and development of intensive quenching technologies. As an example, the processes for quenching semiaxle and cylindrical forgings are considered. CFD analysis successfully detected small stagnant zones at the surface of the steel. Such zones could be related to quench crack formation. These results can be used for designing and development of intensive quenching processes.