Final Design

Sponsored by Solar Turbines, this project dives into industrial gas turbine technology, specifically focusing on the redesign and additive manufacturing of a pre-swirler component in one of their mid-sized turbines, the Taurus 70. Conventionally used to channel cool air into the rotating disk and blade assemblies, the existing pre-swirler design necessitates improvements in structural durability and manufacturing quality. The project aims to leverage additive manufacturing, particularly 3D metal printing, to overcome limitations associated with the traditional manufacturing processes of machining and brazing, reference Figure 1. A large factor in favoring additive manufacturing stems from the desire to have parts be mass-produced, which can lower cost and time for production.

Figure 1: Solar turbine design, which consists of three key components: the inner ring, outer ring, and 52 vanes. The vanes are strategically positioned between the inner and outer rings and are treated with a braze paste to integrate the entire Pre-Swirler assembly seamlessly. Figure A presents an exploded view of the Solar Turbines design, showcasing all of its components. Meanwhile, Figure B offers a comprehensive view of the complete assembly.

The primary project objective is to design, analyze (temperature and stress), and 3D print a prototype that meets specified mechanical and flow requirements including making sure bulk stress and local stress concentration are below their respected material threshold of yield strength and that the throat area of the new design matches the previous design. The final prototype, printable by Solar Turbines, will be shared with students for dimensional inspections and potential airflow testing.

Figure 2: All nine segments are shown to display the final Pre-Swirler assembly. 

The initial step in the Design for Additive Manufacturing (DfAM) process involved examining segmentation, vane count, and throat area. Finally, each segment of the Pre-Swirler required modification to incorporate printing orientation, crucial for ensuring printing accuracy. These modifications encompassed supporting fillets, addressing elephant's foot, adjusting printing tilt, and refining the shape of the fastener holes. Thus, resulting in a successfully 3D printed metal component showcasing our DfAM approach in action. 

Figure 3: Figure A displays a printed version of the Pre-Swirler showcasing exposed vanes for inspection. Meanwhile, Figure B illustrates the as-printed version used in the Manufacturing process

Figure 6: FEA simulation showcasing a close up of Rev 3 interior vane geometry performance under operating conditions. 

By employing Ansys Simulations (Version 2024), we successfully met the bulk stress requirement. However, we encountered challenges in addressing local stress concentrations due to insufficient meshing capacity inherent in the student license. This limitation was compounded by the complex geometries of the component, ultimately leading to fictitious maximum stress.

This endeavor underscores the transformative potential of additive manufacturing in pushing the boundaries of structural durability and manufacturing quality for industrial gas turbine components. The project not only addresses immediate technical challenges but also reflects a forward-looking approach to advanced manufacturing techniques, positioning additive manufacturing as a key driver of innovation in the field.