In a development that’s been hailed as a major step forward in the use of additive manufacturing to produce critical functional components, engineers at Siemens have completed full load engine tests for additively produced gas turbine blades.
Subjecting the components to 13,000 revolutions per minute and temperatures beyond 1,250°C the company successfully validated multiple AM printed turbine blades with a conventional blade design at full engine conditions, and also tested a new blade design with a completely revised and improved internal cooling geometry.
The tests were carried out at Siemens’ industrial gas turbine factory in Lincoln, and used blades manufactured at its newly acquired company, Worcester based 3D printing specialist Materials Solutions.
The blades, which were installed in a 13MW Siemens SGT-400 industrial gas turbine were made out of a powder of high performing polycrystalline nickel superalloy. This allowed them to endure high pressure, hot temperatures and the rotational forces of the turbine’s high-speed operation.
At full load each of these turbine blades was travelling at over 1,600km/h, carrying 11 tons or equivalent to a fully loaded London bus, surrounded by gas at 1,250 °C and cooled by air at over 400 °C.
“This is a breakthrough success for the use of Additive Manufacturing in the power generation field, which is one of the most challenging applications for this technology,” said Will Meixner, CEO of the Siemens Power and Gas Division.”
Meixner added that the breakthrough will help Siemens accelerate the development of new gas turbine designs. “This new flexibility in manufacturing also allows Siemens to develop closer to the customer’s requirements and also to provide spare parts on demand,” he added.
I don’t suppose Siemens have made public more detailed results? For example, if the new blade design (presumably only possible using AV methods, hence the test?) demonstrated any improvement in performance, such as a lower blade temperature?
What about long term expansion and contraction ability?
Interesting; no mention of what the peak temperature of the blades is; I believe Frank Whittle suffered from this sort of myopia. (If there is sufficient cooling air then that temperature is likely to be 400 degC). With an appropriate hollow structure the main issue would most likely be creep. And yes, as suggested, powder deposition should be able to give thinner walled/lighter blade (than casting) – and possibly a more sophisticated mechanical structure too (with centrifugal loads being carried by cooler material)
Interesting that a major GT manufacturer is getting this involved. Long term properties of the blades will be key: normally they would be optimised for creep (single crystal/directionally solidified) and fatigue (are impurities/defects an issue with the powder feed stock or the spraying process). Some way to go yet before commercialisation, but good stuff none the less.
I hope this was a simulation of application in a real turbine running conditions. Duration of test should have been mentioned. It is a great step. However, the advantages vs shortcomings with existing machining methods would have been more revealing.
Upfront and replacement cost would prove a significant advantage, a longer life is not necessarily the priority. Ill be betting on a composite configuration prior to commercialisation.