Abstract
(English)
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The ACP2000 is an extensive project to test and monitor Alstom Power's GT26 gas turbine and it's upgrade potentials at Alstom's gas turbine test centre in Birr, Switzerland. Fuel flexibility will also be demonstrated using gasified coal fuel at a burner test centre in Cologne Germany.
The BBW contribution is planned to support our efforts specifically in the measuring and understanding of the GT26's rotor concept where the potential for better distribution of cooling air would lead to higher efficient gas turbine. The development of a flame sensing project in order to better understand temperature distributions within the machine.
The rotor measurement and analysis efforts included a test rig (1/5 scale) and full scale testing order to confirm/update design assumptions as well as full scale testing. The contribution of BBW supported approximately one third of the scaled and full size testing. Included here are manufacturing and building of the test rig, design, manufacture and installation of telemetric measuring system on the full scale test rotor as well as testing and evaluation of the full scale rotor.
In the scale rig, rotating system air pressure and temperatures were measured. Both 1 dimensional and 3 dimensional modelling were done to predict the behaviour. Evaluation of the data showed that some tuning of both models were needed to match test data. This tuning has allowed Alstom Power to determine more precise calculations methods for such systems.
Telemetric measurements in the full size gas turbine allow measurements under full operating conditions, where as normally, these measurements are done on the rotor alone in a rotor test bed under atmospheric conditions. Measurements were done in the hot gas path for turbine blade frequencies and both air and metal temperatures. Although fewer measurements were made in the full scale test than in the 1/5th scale rotor test rig, the modelling of the air flow based on the small scale rotor test rig could be confirmed by measurements in the full scale engine. We were also able to confirm the blade frequency calculations done during design and thereby confirm that the effects of engine conditions were properly modelled. Specifically, we were able to determine the effects that the blade coatings have on frequencies and to determine the speed at which the rear stage shrouds interlock under full load conditions. Unfortunately, the strain gauges applied to the rotor disk did not survive long enough to measure under full load conditions, but the expectations at the measured part load points were confirmed here as well.
The blade temperature measurements were not quite as successful as several of the thermocouple signals were disturbed after only a few test runs. Analysis of the situation after an engine opening showed that there are some critical locations in the wiring that need to be considered during the next installation. Unfortunately, the test conditions run while the signals were still operating were not at design conditions, so only partial evaluation was possible. What we have noted is that trends and reactions to part load conditions are as predicted.
The flame sensing measurement technique allows understanding and manipulation of the temperature distribution over the circumference at the turbine inlet. With the ability to keep this distribution as even as possible, turbine designers can more effectively design the cooling of their blades and vanes. More efficient cooling can be directly seen in power plant performance increase. The first phase of system testing was completed where 3 sensors were tested. All three worked well, providing signal intensities as expected. However, due to a shift in engine testing priorities and delay in engine testing, final testing of filtered and processed signals could not be conducted. The system has proven to be able to survive the gas turbine conditions, further testing of the system is being considered.
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