Development and Testing of a Novel Centrifugal Gas Turbine Design, 18-9408

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Principal Investigator
Klaus Brun

Inclusive Dates:  07/01/03 – 01/01/05

Background - This project aims to develop a novel centrifugal gas turbine design that will give the Institute the proprietary patent for a marketable power generation product. The research effort consists of the design, development, and full prototype testing of a 50-horsepower centrifugal gas turbine. The novelty of the centrifugal gas turbine concept is that it is based on a radial flow gas turbine consisting of a centrifugal compressor and impulse turbine mounted on the same side of a rotating wheel. The radial flow-vaned combustor is mounted on the wheel's stationary shroud; consequently, there is no 180-degree flow turning required as in conventional radial flow gas turbines. This very simple and rugged gas turbine concept has the following major advantages: 

  • Single rotating component; i.e., mechanically simple and compact gas turbine
  • Portability
  • Short axial span
  • High tolerance to injection of particulate matter
  • Simple construction; low manufacturing costs

Approach - This two-phase project includes the conceptual design, structural and aerodynamic analysis, performance prediction modeling, detailed design, prototype fabrication, test rig instrumentation, compressor/turbine characterization, rotordynamic signature, and full speed/full load testing of the proposed centrifugal gas turbine. During year one (Phase I) the following major tasks were completed:

Gas Turbine Design - Based on internally developed and commercially available software, the gas turbine was designed. Analyses that were performed included one-dimensional thermodynamics, FE structural analysis, rotordynamic, two-dimensional blade path optimization, and three-dimensional computational fluid dynamics. Based on results from these analyses, a rotor and stator geometry was optimized and engineering drawings were prepared.

Test Rig and Data Acquisition - A variable speed (200 horsepower, 40,000 revolutions/minute) test rig was designed and built to be able to operate both as the gas turbine driver (for compressor testing) and for startup as well as a load absorber/break for gas turbine operational tests. The instrumentation and data acquisition required for compressor, turbine, and full gas turbine tests were implemented and tested to allow for accurate component/gas turbine performance measurement and operational control.

Gas Turbine Testing - Based on the optimized geometry designed by SwRI, a stainless steel rotor was manufactured using a five-axis milling machine. A polymer stator was manufactured using a rapid prototyping machine. Using this hardware on the high-speed test rig, the dynamic and thermodynamic performance of the gas turbine's compressor and turbine elements was individually assessed, mapped, and employed to verify the code predictions. Results from these tests are critical to be able to properly design the gas turbine nozzles and combustor (proposed as Phase II of this project).

Accomplishments - The above tasks were successfully completed with the relevant details provided in this report. The proposed Phase II of this project will consist primarily of combustor development, combustor testing, and gas turbine performance validation. We have also started the commercialization of this gas turbine by publishing two ASME papers and presenting the concept at GMRC and GTUS conferences. Several gas turbine manufacturers have expressed interest in the product development of the gas turbine after the prototype has been functionally demonstrated. 

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