Date of Award

5-4-2026

Degree Type

Capstone Project

First Advisor

Professor Bahram Nassersharif

Abstract

This project focused on the design, analysis, and optimization of a gas turbine intended to drive the Centrifugal Fuel Element (CFE) in a Centrifugal Nuclear Thermal Rocket (CNTR) system. The primary objective was to develop a turbine capable of achieving rotational speeds approaching 10,000 RPM while operating within the geometric and experimental constraints of a laboratory-scale model. Achieving this rotational speed is critical to maintaining proper containment of liquid nuclear fuel and enabling efficient propulsion performance.

The design process began with the evaluation of two initial turbine concepts: the Coriolis turbine and the J-blade turbine. Each design utilized a different mechanism for generating torque from airflow. The Coriolis turbine relied on offset internal passages to produce tangential velocity, while the J-blade turbine used momentum change from redirected airflow to generate rotational motion. Both designs were analyzed using computational fluid dynamics (CFD) and tested experimentally. Although each configuration successfully produced rotation, both were limited by flow inefficiencies and restricted mass flow, preventing them from achieving high rotational speeds.

Based on these findings, a redesigned turbine utilizing a C-shaped airfoil geometry was developed. This design focused on improving flow continuity and reducing turbulence by allowing the airflow to follow a smoother path along the blade surfaces. CFD analysis and experimental testing confirmed that the airfoil design provided improved aerodynamic performance and more efficient energy transfer. The final turbine achieved a maximum rotational speed of approximately 2800 RPM, exceeding both initial designs and the previous year’s benchmark.

A key outcome of this project was the identification of system-level flow path design as a critical factor influencing turbine performance. In order to better represent the actual CNTR configuration, an internal tube used in prior designs was removed. While this improved the physical accuracy of the model, it introduced an air gap that resulted in a loss of pressure before the airflow reached the turbine. This pressure loss significantly limited the available energy for rotation and contributed to the lower-than-target rotational speeds observed during testing.

Despite not achieving the 10,000 RPM target, the project successfully met its objectives by improving turbine performance, validating design improvements through simulation and testing, and identifying the primary limitation within the system. The results demonstrate that the turbine design is capable of higher performance under improved conditions. Future work focused on minimizing pressure losses within the flow path and increasing the available airflow pressure is expected to enable the system to achieve the desired rotational speed.

Comments

Team Name: Team 9H

Sponsor: Professor Bahram Nassersharif

Document Reference: URI-MCE-2026-FDR-009H

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