Influence of the Hub Endwall Cavity Flow on the Time-Averaged and Time-Resolved Aero-Thermodynamics of an Axial HP Turbine Stage

Abstract

This experimental research investigates the influence of the hub endwall cavity flow on the aerodynamics and heat transfer of a high-pressure transonic turbine stage tested under engine representative conditions. The measurements include the hub and tip endwall static pressure downstream of the vane, the static pressure and heat transfer on the rotor blade at 15% span and on the hub platform as well as the stage downstream total pressure and temperature. Both steady and unsteady aspects are addressed. The hub endwall cavity flow has a significant influence on both the time-averaged and time-resolved components of the measured quantities. The effects are shown to be mainly due to an increase of the pitchwise averaged static pressure at hub downstream of the vane when cavity flow ejection is activated.

Improving Purge Air Cooling Effectiveness by Engineered End-Wall Surface Structures—Part I: Duct Flow

“…Similar results were also observed by Burd et al [10] and Oke et al [11]. Dénos and Paniagua [12] studied the purge air effect in a high-pressure transonic turbine stage. They found the purge air effectively reduces the heat flux around the rotor leading edge.…”

Experimental Investigation of Disc Cavity Leakage Flow and Hub Endwall Contouring in a Linear Rotor Cascade

“…The cavity must be designed to protect from hot gas ingression. Current designs meter flow bled from the high pressure compressor into the cavity using labyrinth seals, as shown in Figure 1 (Taken from Dénos et al [10]). This flow, used to prevent ingression of hot gas from the passage, offers cooling potential.…”

“…Dénos et al [10], Paniagua et al [17], and Pau et al [18]) focused on the effects of leakage flow on the mainstream flow. Their geometry essentially matches the case previously discussed of a radial outflow disc cavity with no step between the stator rim and the rotor hub; however, it included also the effects of blading, temperature ratio, Figure 6.…”

Effects of Stator/Rotor Leakage Flow and Axisymmetric Contouring on Endwall Adiabatic Effectiveness and Aerodynamic Loss

“…Its interaction with the hot gas path flow as it exits the disc cavity, is the topic of this study. Taken from Dénos et al [2002].…”

“…Several recent numerical/experimental studies from the von Karman Institute [e.g. Dénos et al 2002, Paniagua et al 2004, and Pau et al 2008 have focused on the effects of leakage flow on the mainstream. Their geometry essentially matches the case previously discussed of a radial outflow disc cavity with no step between the stator rim and the rotor hub; however, it includes also the effects of blading, temperature ratio, Mach number, and operating Reynolds number.…”