FLOW CONTROL CHANNEL INSTRUMENTATION DESIGN AND MODELING

Abstract

Primary causes of compressor stalls in gas turbines are tip leakage, casing corner leakage, and boundary layer separation flow over the rotor blades. With the fluctuation of static pressure, a self-recirculating flow channel can help increase the stall margin while still maintaining efficiency. To better visualize air flow in the recirculation passage, instrumentation will be added to the transonic compressor at Naval Postgraduate School. One aim of this study was to redesign the main structural casing that encompasses the casing insert with the flow channel to accommodate enhanced instrumentation. Another aim of this study is to create a new method that automates the development of the flow channel. Previous works have manually designed recirculating flow channels within a solid model that have proved to improve the stall margin of the transonic compressor. Using code, the flow channel was able to be changed according to the user's needs. The automated code developed allowed for multiple recirculation passages to be developed within the course of this study. Finally, the last aim of the study was to additively manufacture the two casing inserts with different flow channels. Both were tested in the transonic compressor. These were able to improve the stall margin while maintaining and improving the efficiency.Distribution Statement A. Approved for public release: Distribution is unlimited.Ensign, United States NavyONR 35, Arlington V