NUMERICAL SIMULATIONS OF FLOW FIELDS AND HEAT TRANSFER CHARACTERISTICS IN TENON JOINT GAP BETWEEN TURBINE BLADE AND DISK UNDER ROTATING CONDITIONS

摘要

Turbine blades and the disks are connected by tenons. There is a pair of jagged assembly clearance between each .tenon and corresponding mortise. In practical engineering applications, flow and heat transfer characteristics in assembly clearance used to be simplified. In order to obtain more accurate temperature fields of the turbine blades and disks, detailed study of the flow and heat transfer mechanism in tenon joint gap is necessary. In this paper, two typical assembly clearances under the stationary and rotating conditions were investigated numerically, including double S-shaped and double Crescent-shaped. The inlet Reynolds numbers range from 5,500 to 50,000 and the Rotation numbers range from 0 to 0.005. The results show that the fluids in the two branches of the double S-shaped channel have different flow characteristics under rotating conditions. A vortex is formed at the corner of the left branch and the vortex scale can be influenced by Re and Ro. The large vortex decreases the local heat transfer coefficient. In the right branch, the three-dimensional flow from the flat wall to the concave wall increases the local heat transfer coefficient of different regions. For the double Crescent-shaped channel, the region with higher velocity is offset to the right of the channel which leads to higher local heat transfer coefficient under rotating conditions. The simulation results have great significance to the heat transfer analysis of turbine blades and disks.