More than 10 years ago, when Siemens Energy pioneered the use of additive manufacturing (AM) (also known as 3D printing) in making critical turbine parts, skeptics across the turbomachinery industry doubted our vision. After all, these components—especially combustion parts and stator vanes—are subject to extreme forces and temperatures, yet they must provide reliable service for decades.
Even now, with our AM parts in gas turbines having accumulated more than 1.5 million operating hours of successful operation—more than any other turbine manufacturer in the world—some people in industries using turbomachinery still call AM a “myth” or an “emerging technology.” But in our experience and, most importantly, in our customers’ experience, both observations are simply untrue. Our customers are proving AM’s value every day by incorporating AM-made parts in their production turbines.
AM accelerates the world’s progress toward a decarbonized future
What’s more, with the global imperative to decarbonize power generation, AM is currently enabling us to design, engineer, and manufacture fuel combustion systems capable of burning mixtures with up to 75% hydrogen. This puts us well on our way to our goal of having Siemens Energy turbines capable of burning 100% hydrogen by 2030.
Consider the case of Germany’s Dresdner Stadtwerke (DREWAG) municipal utility, now part of SachsenEnergie AG, the largest power provider in Eastern Germany. It sought to modernize a 25-year-old, combined heat and power plant in Dresden powered by three Siemens Energy 60MW V64.3 gas turbines. As is our practice with all our turbine customers, DREWAG and Siemens Energy engineering teams closely cooperated in this project. We used 3D digital modeling complemented with AM to modernize the plant’s gas turbines. Then we validated their upgrades with 33,000 equivalent operating hours of testing.
DREWAG replaced the first-stage vanes in its turbines with redesigned ones that reduce hotspot temperatures by 50–100° C, lowering cooling air consumption by 25%. In addition, the utility will be able to increase turbine power output and efficiency by operating at higher inlet temperatures. To top off those gains, the turbines now emit less nitrogen oxide, improving air quality and regulatory compliance. AM also simplified manufacturing, cutting lead times from several months to just a few weeks.
How it works: Selective laser melting deposits metal layers 20-μm thick
At Siemens Energy, we use AM technology with selective laser melting (SLM) to produce critical parts, for our industrial, aeroderivative and heavy frame gas turbines. SLM employs a laser with a high-power density to melt and fuse metallic powders together, in layers that are typically just 20-μm thick.
Given this layering process, our engineers can introduce different design features that are simply not possible with other manufacturing processes, whether vacuum investment casting or machining a solid piece of metal. In combustion parts, for example, complex geometries can be produced that improve the mixing of fuel and air, thereby reducing emissions. And damping system components can be optimized to improve combustion acoustics. By avoiding the use of machining parts, we also eliminate the waste of expensive metal alloys.
In addition, the highly efficient cooling structures to reduce cooling air consumption for both combustion and turbine components are also possible through AM processes. This enables higher temperatures to be achieved and service life cycles extended.
The future starts today
As was the case at DREWAG, AM can reduce manufacturing lead time by up to 60% or more, virtually eliminate time and cost of capital equipment acquisition. Spare parts inventories can be reduced, along with the capital tied up in them, if not eliminated altogether. That’s because AM can produce parts on demand. What’s more, after their service life ends, these parts can be recycled into their constituent metal powders for re-use in making new parts.
AM has opened tremendous possibilities for the precise yet flexible design, engineering, and manufacturing of critical parts for gas turbines. Given our long experience with operating with AM-made parts in our installed base of turbines worldwide, we are happy to share our knowledge with you and your engineering teams. We have other customer AM success stories you may be interested in learning more about, too. For more information, including additional articles, white papers, and case studies, visit our Siemens Energy AM website: www.siemens-energy.com/am