Accession Number:

ADA626771

Title:

Understanding and Mitigating Vortex-Dominated, Tip-Leakage and End-Wall Losses in a Transonic Splittered Rotor Stage

Descriptive Note:

Final rept.

Corporate Author:

NAVAL POSTGRADUATE SCHOOL MONTEREY CA

Personal Author(s):

Report Date:

2015-04-23

Pagination or Media Count:

49.0

Abstract:

The requirement for higher power-to-weight ratios in modern jet engines leads to a reduced number of stages at increased loading per stage or blade row. Splittered, blade rows enable a large flow deflection and a correspondingly high-pressure rise within a short distance. In the 1970s Wennerstrom and Hearsey 1 undertook the task of designing, building and testing a supersonic axial flow stage with a pressure ratio of 3.0 and an isentropic efficiency of 0.82. Upon testing, the stage fell dramatically short of design. This was blamed largely on poor flow control within the rotor passage. Recognizing the splitters had long been used to improve performance of centrifugal compressors, the decision was made to use a splitter, in the hopes that better flow control could be achieved without incurring additional losses 2. Due to time constraints, many decisions regarding the splitter were based upon engineering judgment with little analysis. The result of adding the splitter was that the rotor performance improved, but the overall stage performance was still short of the goal, as the pressure ratio was 2.76 and the efficiency was only 0.68. However the stage was much less sensitive to incidence variations at off-design conditions, indicating that the splitter did indeed improve the flow control within the rotor 3.

Subject Categories:

  • Fluid Mechanics
  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE