JOURNAL OF MATERIALS PROCESSING TECHNOLOGY, vol.180, no.1-3, pp.279-290, 2006 (SCI-Expanded)
The purpose of this study is to reduce the thermally induced stress in a solid disk heated by moving ring heat flux (radially periodic expanding and contracting) and cooled by means of coolant following this heat flux (the subsequent cooling process). It was assumed that the ring heat flux per unit area at the each ring surface was uniform. The applied heat transfer rate, Q, regularly increases from 3.14 to 311 W and then decreases to 3.14 W in one period depending on the area of heated ring. The FLUENT 6.1 program was chosen as computer code to calculate these numerical solutions. Furthermore, a computer program, applying the SIMPSON integration method to the obtained temperature distributions from the heat transfer calculations, has been developed to calculate numerically the governing thermal stress distributions. The calculations were performed individually for a wide range of coolant (liquid) heat transfer coefficient, from 1000 to 10,000 W/m(2) K stepped by 1000 W/m(2) K and for the various ring heat flux expansion and contraction speeds, from 0.0005 to 0.001 m/s stepped by 0.0001 m/s, under transient conditions. The thermal stress differences in the axial direction are quite high around the heated ring and the coolant rings with respect to the other rings due to the non-uniform heating at the surface. However, the levels of the thermal stress in the disk are reduced (from 6 to 31% depending on coolant heat transfer coefficient), by means of the subsequent cooling process. (c) 2006 Elsevier B.V. All rights reserved.