Dimensionless analysis of flow and heat transfer characteristics in a high-speed rotor-stator disk cavity based on similarity criteria

Turbine disk cavity system is of great importance for improving the rotating turbine blades cooling efficiency and preventing gas invasion. This study focuses on turbine disk cavity characteristics at high-speed rotational conditions due to complicated flow and heat transfer mechanisms. Then, a novelty method is proposed to reveal multiple similarity criterion numbers of rotor-stator disk cavity between actual engine and experimental case conditions, based on the dimensionless analysis. Especially, a new evaluation standard including the dimensionless adiabatic wall temperature and dimensionless heat flux is put forward and proved to be equally important with the Nusselt number. Results show that the dimensionless heat flux in the turbine disk cavity mainly depends on Reynolds number and Mach number, while the dimensionless adiabatic wall temperature is dominated only by the same Mach number. When only Reynolds numbers or Mach numbers are considered, the relative error can reach 14.5% on the similarity of dimensionless heat flux. Noteworthily, the effect of thermal boundary of turbine disk cavity should not be ignored in the rotor-stator disk cavity, which will bring 28.8% deviation to the similarity of the Nusselt number. Therefore, this study can provide a theoretical method and engineering application to obtain flow and heat transfer characteristics of actual engine turbine disk cavity under experiment case with normal temperature conditions.