Stratified and Buoyancy-Induced Flow in Closed Compressor Rotors

Abstract The radial growth of compressor discs is strongly influenced by conjugate heat transfer between conduction in the co-rotating and buoyancy-driven convection rotating fluid core discs. An accurate prediction metal temperatures these an important issue thermo-mechanical design, where blade-tip clearances must be controlled carefully to ensure safety efficiency under all operating conditions. This paper presents experimental study dynamics a closed cavity, comparing results with theoretical models introducing new compressibility parameter χ. At large values χ, effects are significant, air temperature approaches that shroud; such conditions suppress buoyancy flow cavity becomes stratified, replaced inside core. There practical consequences stratification significant differences distributions stresses influence χ also shown on for shroud correlations, which compared qualitatively previously published data collected relatively small. experiments reveal there critical value convective flux zero. distribution disc was expected from pure cylinder. A correlation based measured presented. unsteady characteristics were investigated, identifying coherent structures across range These cyclonic/anti-cyclonic vortex pairs generate nondimensional circumferential pressure difference necessary outflow (of cold fluid) inflow hot through show magnitude variations can correlated against Grashof number at high do not exist. combined will interest engine designers validation computational models.