Degree Name

BS in Mechanical Engineering


Mechanical Engineering Department


Thomas Mackin


Solar Turbines Gas Compressor Engineering Division of San Diego, California called upon the Mechanical Engineering students of California Polytechnic University, San Luis Obispo to provide recommendations for optimization of compressor end cap port design. Various sizes of compressors have end caps with numerous ports that exchange fluids between the inside and outside of the working fluid pressure vessel. Because so many ports must exist on the end caps, unusual flow paths are created to supply the appropriate location within the compressor. These flow paths commonly consist of a drilled inlet hole which intersects with a sudden expansion. The sudden expansion is deemed the “fly cut” because of its semicircular shape.

Sudden expansions in general cause very high energy losses in fluid flow. This is one of the primary concerns when designing the compressor end cap port layout. Due to the unusual nature of the fly cuts found in Solar Turbines’ end caps, published information on the pressure losses for this particular flow path do not exist. For this reason, Solar Turbines were required to base their port design on the best information available, including: historical compressor design methods, conservative design analysis estimates, and computational fluid mechanics software. Of these options, the computational method could provide the best estimate but only if validated experimentally. In response to this problem, PreFlow Systems was formed and investigated the solution of designing, building, and testing a scaled experimental test apparatus.

This report outlines the details involved in every aspect of the project, including: technical specifications and objectives, design conceptualization, engineering analysis, manufacturing, testing, and results. Each of these phases was crucial in creating the final flow test apparatus which simulated the gas port flow of Solar Turbines’ compressor end caps. This apparatus ultimately provided an experimental basis for concluding that computation fluid mechanics software is a reasonable aide in end cap port design.