Hanwha Power Systems, a global energy equipment company based in South Korea, enlisted the help of 3D printing service provider Stratasys Direct Manufacturing to assist in the development of a 3D printed shrouded turbine wheel for a solar power project. The part has since been successfully prototyped by the partners using VELO3D’s support-free Sapphire metal 3D printing system.
Power generation systems are incredibly complex and are made up of hundreds of critical components. In recent years, additive manufacturing has presented itself as a potentially game-changing technology for power generation application because of its ability to produce geometrically complex parts and consolidate assemblies. In this specific case, these benefits were reinforced by AM’s capacity to rapidly produce prototypes to speed up part development cycles.
A team at Hanwha Power Systems led by senior engineer Chad Robertson has been developing turbomachinery for a high-efficiency power-generation system using Supercritical CO2 (S-CO2) fluid in a recompression Brayton cycle (RCBC). The system being developed transfers heat from a solar array into the S-CO2 liquid, which is channeled through a series of radial expanders to generate power. This approach creates high temperatures and pressures which turbomachinery components must be able to withstand, while also functioning efficiently.
To achieve optimal efficiency, Robertson and his team designed a shrouded turbine wheel for the system with a covered flow path. This complex geometry, however, brought about challenges at the prototyping stage. To address them, Hanwha Power Systems reached out to Stratasys Direct Manufacturing, the manufacturing service arm of 3D printing giant Stratasys.
Initially, the partners explored the potential of using DMLS, though this proved difficult because of the height of the impeller and the many internal supports required. Eventually, they produced the prototype using VELO3D’s Sapphire metal AM system, capable of support-free structures. The part, printed from Nickel Alloy 718, then underwent heat treatments, CNC machining and other post-processing steps to prepare it for functional testing.
In the end (and as can be seen in the following infographic), Stratasys Direct Manufacturing delivered a high quality prototype of the shrouded impeller with significant time and cost savings compared to other metal additive manufacturing technologies. “The success of the centrifugal impeller wheel prototypes Stratasys Direct made for us with the Sapphire machine from VELO3D has definitely increased our interest in additive manufacturing,” said Robertson. “It has opened up design freedoms for our team, and sparked a renewed effort to better quantify the material properties and capabilities of additively manufacturing parts.”