Aerodynamic and Heat-Flux Measurements With Predictions on a Modern One and 1/2 Stage High Pressure Transonic Turbine

Abstract

Aerodynamic and heat-transfer measurements were acquired using a modern stage and 1/2 high-pressure turbine operating at design corrected conditions and pressure ratio. These measurements were performed using the Ohio State University Gas Turbine Laboratory Turbine Test Facility (TTF). The research program utilized an uncooled turbine stage for which all three airfoils are heavily instrumented at multiple spans to develop a full database at different Reynolds numbers for code validation and flow-physics modeling. The pressure data, once normalized by the inlet conditions, was insensitive to the Reynolds number. The heat-flux data for the high-pressure stage suggests turbulent flow over most of the operating conditions and is Reynolds number sensitive. However, the heat-flux data does not scale according to flat plat theory for most of the airfoil surfaces. Several different predictions have been done using a variety of design and research codes. In this work, comparisons are made between industrial codes and an older code called UNSFLO-2D initially published in the late 1980’s. The comparisons show that the UNSFLO-2D results at midspan are comparable to the modern codes for the time-resolved and time-averaged pressure data, which is remarkable given the vast differences in the processing required. UNSFLO-2D models the entropy generated around the airfoil surfaces using the full Navier-Stokes equations, but propagates the entropy invisicidly downstream to the next blade row, dramatically reducing the computational power required. The accuracy of UNSFLO-2D suggests that this type of approach may be far more useful in creating time-accurate design tools, than trying to utilize full time-accurate Navier-stokes codes which are often currently used as research codes in the engine community, but have yet to be fully integrated into the design system due to their complexity and significant processor requirements.

Turbine Aero-Heat Transfer Studies in Rotating Research Facilities

“…The value of T 0 can be set at almost any desired value in the range of 800 o R (171 o C) to 3500 o R (1671 o C). The pressure ratio across the turbine is established by altering the throat diameter of a flow control nozzle located near the exit end of the device housing the turbine [26]. The thin-film heat flux gauges were made of (~100 A° thick) platinum and were hand painted on an insulating Pyrex 7740 substrate.…”

“…The response time of these thin films is in the order of 5 × 10 -8 s. The turbine stage shown in Fig. 17 is a 1.5 stage (High-Pressure Turbine Vane-HPTV, High-Pressure Turbine Blade-HPTB, and Low-Pressure Turbine Vane-LPTV) turbine, configured in a manner that is representative of the highly 3D airfoil rows in a modern engine [26]. Fig.…”

“…By controlling the pressure ratio across the stage, the inlet pressure, the corrected speed, and a wide variety of engine operating conditions can be replicated. The overall research effort performed in this rig was comprised of the aerodynamics of the turbine stage and unsteady heat transfer measurements performed around the rotor, rotor shroud and vane [26]. Molter et al [27] recently presented heat-flux measurements and predictions from the blade tip region of this HP turbine.…”

Experimental Turbine Aero-Heat Transfer Studies in Rotating Research Facilities

“…The response time of these thin films is in the order of 5 × 10 -8 s. The turbine stage shown in Fig. 17 is a 1.5 stage (High-Pressure Turbine Vane-HPTV, High-Pressure Turbine Blade-HPTB, and Low-Pressure Turbine Vane-LPTV) turbine, configured in a manner that is representative of the highly 3D airfoil rows in a modern engine [26]. [26] and Nusselt number distribution [25].…”