Modeling of undercooling effects during the directional solidification of turbine blades
A. Ludwig, I. Steinbach, N. Hofmann, M. Balliel, M. van Voerkom, P. R. Sahm.T. S. Piwonka, V. Voller, L. Katgerman,
Modeling of Casting, Welding and Advanced Solidification Processes, TMS, Warrendale, VI, 87-94, (1993)
Undercooling in the “extremites” of turbine blade shrouds during directional and single crystal solidification leads to deteriorated properties. Thus it is desirable to reduce such effects by an appropriate process control. Based on the LKT-theory for dendritic growth into an undercooled melt and a simplified front tracking method a new numerical model is proposed which takes the undercooling ahead of the solidification front into account. The new algorithm is implemented into a finite element solver for modeling the single crystal directional solidification in Bridgman casting processes. The calculated temperature distribution within a turbine blade shroud is compared with the results of former equilibrum calculations.