Thermal Nonequilibrium Effects on Turbine Cascade Aerodynamics
AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOOL OF ENGINEERING
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The AFIT Total Variation Diminishing Euler Code ATEC was modified to include a thermal nonequilibrium model to investigate high temperature effects associated with vibrational relaxation in a transonic turbine cascade. Incorporation of this model into ATEC and creating ANTEC AFIT Nonequilibrium TVD Euler Code was accomplished in three steps. Steady-state solutions obtained with ANTEC were compared with those obtained with ATEC for various inlet and exit conditions. The Courant-Friedrichs-Levy criterion was held constant to ATEC however, it required variation for ANTEC. Blade temperature profiles, temperature difference contours in the vicinity of the trailing edge and the value of the ratio of specific heats gamma along the blade were analyzed. Even when corrected for high temperatures, the assumptions of a calorically perfect gas and thus a constant value of gamma are inaccurate due to the temperature dependent nature of specific heats at constant pressure and at constant value. Maximum temperature differences of -741 deg K and 539 deg K were found near the trailing edge for the highest temperature case, with differences being most noticeable through the expansion at the trailing edge on the pressure surface and across the shocks from both surfaces. The vibrational relaxation model showed limitations at low temperatures.
- Fluid Mechanics
- Jet and Gas Turbine Engines