Design Concepts for Low Aspect Ratio High Pressure Turbines for High Bypass Ratio Turbofans

N&R Engineering worked with NASA Glenn Research Center on a SBIR Phase I project titled: “Design Concepts for Low Aspect Ratio High Pressure Turbines for High Bypass Ratio Turbofans.”

The objectives of this project were:

1) Quantify the benefit of reduced fuel burn from shrouding a Ceramic Matrix Composite (CMC) High Pressure Turbine (HPT) rotor blade.

2) Determine the increase in component stresses due to shrouding the CMC blade. Shrouding HPT rotor blades becomes feasible when metallic blades are replaced with CMC blades because of the lower density of CMC materials.

The following tasks will accomplish these objectives:

  • Define reference vane, rotor blade, and flow path geometries and flow conditions.
  • A simplified 3D N-S CFD analysis will be used to determine pressure and thermal loads for structural analysis.
  • Determine aerodynamic efficiency for unshrouded and shrouded rotor blades. Emphasis will be placed on accurate efficiency calculation.
  • Collaborate with The Ohio State University Engineering department to produce the best results.
  • A detailed 3D Navier-Stokes rotor blade analysis will be done using STAR-CCM+.
  • Perform stress analysis for unshrouded and shrouded rotor blades using metal and CMC material properties.
  • Perform creep analysis for the shrouded CMC turbine.
  • Accurate determination of creep effects is needed due to tight shroud-to-casing clearances.
  • Determine mission fuel burn reduction due to shrouded HPT rotor blades.

For more in-depth detail, please reference the following figure below.


This project is expected to continue through the remainder of 2016. If you have questions regarding this project or our capabilities, please contact us.