Design and Evaluation of a High Temperature Radial Turbine.

Radial turbines offer greater stage work capacity than axial turbines. If this advantage can be coupled with a capability of accommodating high turbine inlet temperatures, radial turbines will permit appreciable simplification of small gas turbine engines for use in future Army vehicles. A two-phase program is being conducted involving the design and testing of a cooled, single-stage, radial inflow turbine. A bicast rotor with solid blades was spun to failure, which occurred at a speed lower than predicted. Two spindle failures prevented a successful destructive spin-test of the rotor damaged in Turbine Build One. The third and final nozzle section was chosen from the two castings submitted by the casting vendor for evaluation. An integral-cored rotor casting was not acceptable for rig test and is being evaluated for possible use as a spin-test part. Turbine Build One was hot tested for seven hours. Considerable foreign object damage was experienced by the turbine, and performance data is not believed to be representative of the turbine design. A replacement turbine rotor and nozzle were prepared and used in Turbine Build Two. Testing was aborted because of high vibrations caused by a turbine rotor-to-shroud rub during the initial stand checkout. Turbine Build Three is now in progress, using hardware salvaged from Build Two. Author