Session: 02-01 Mechanical Behavior of Ceramics & Composites

Paper Number: 82669

82669 - Reducing Fuel Burn Using SiC/SiC CMC HPT Vanes and Rotor Blades 

This paper explores issues with using SiC/SiC CMC vanes and rotor blades in the High Pressure Turbine of future commercial aircraft engines to reduce fuel burn, and consequent CO2 emissions.The higher temperature capability of SiC/SiC CMCs relative to Superalloys allows for less vane and especially rotor blade cooling, which leads to reduced cruise SFC. The paper shows that using current vane and rotor cooling fractions allows takeoff T40 to increase. Increasing takeoff T40 decreases the size and weight of core components. The decrease in engine weight, especially for long range flights, can be as significant as decreasing cruise SFC in terms of reduced fuel burn. Specific work increases as T40 increases. This decreases engine core weight. SiC/SiC CMCs allow a substantial increase in T40, when cooling air fractions are maintained at current values. The work focuses on the first stage vane, and shows that film cooled SiC/SiC vanes are highly desirable, since otherwise excessive thermal stresses are likely to develop in the SiC/SiC vanes. Historically, increases in T40 accompany increases in engine OPRs. This combination leads to small spans in the high pressure components. The effect of decreased spans on high pressure blade row efficiency is examined. Cycle analyses are presented which show the effects of changes in blade row efficiency on SFC and specific work.

Presenting Author: Robert Boyle N&R Engineering

Presenting Author Biography: Has worked in the area of gas turbine heat transfer and aerodynamics since 1980

Authors:

Robert Boyle N&R Engineering