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

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Principal Investigators
Klaus Brun
Robert J. McKee

Inclusive Dates:  07/01/03 - 09/01/04

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 will consist 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; no internal bearings or gears required; no lube oil cooling or buffer gas requirements; high tolerance to injection of particulate matter; simple construction; and low manufacturing costs.

Approach - The project includes the conceptual design, structural and aerodynamic analysis, performance prediction modeling, detailed design, prototype fabrication, test rig instrumentation, and full speed/full load testing of the proposed centrifugal gas turbine. During year one (Phase I), the performance of the compressor and turbine elements will be individually mapped to allow for the development of accurate centrifugal gas turbine performance prediction tools. Year two (Phase II) will consist primarily of combustor development, combustor testing, and full gas turbine performance validation.

Accomplishments - Using the gas turbine and compressor design codes written for this project, the centrifugal gas turbine geometry was designed, optimized, and fabricated from Inconel 718 superalloy and stainless steel. Figure 1 shows the optimized gas turbine rotor and stator, and the as-built rotor is shown in Figure 2. A gas turbine test rig was built using a 200-horsepower electric motor, a high-speed gearbox, and 200-kilowatt load cells. The skid has been tested up to 25,000 revolutions per minute output shaft speed. Figure 3 shows the skid design, and Figure 4 is a photograph of the skid as built. Data acquisition hardware was acquired, and basic data acquisition software for the first phase of this project (compressor and turbine performance testing) was written and functionally verified. During the anticipated Phase II of this project, the gas turbine combustor will be designed, and the gas turbine will be load tested.

Figure 1.  Final Rotor and Stator Design

Figure 2.  Gas Turbine Rotor

Figure 3.  Gas Turbine Test Skid Design

Figure 4.  Gas Turbine Test Skid

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