Preliminary Design of a Hot Hydrogen Test Loop for Nuclear Thermal Propulsion applications
Open Access
- Author:
- Searight, Will
- Graduate Program:
- Nuclear Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- July 07, 2020
- Committee Members:
- Leigh Winfrey, Thesis Advisor/Co-Advisor
Jean Paul Allain, Program Head/Chair
Elia Merzari, Committee Member
Jean Paul Allain, Committee Member - Keywords:
- Nuclear Thermal Propulsion
Thermal Analysis
Plasma Material Interaction
Space Propulsion
Hydrogen
Composites
Ceramics
High Temperature Materials - Abstract:
- Nuclear Thermal Rockets (NTRs) are one of the leading propulsion system candidates in deep space exploration due to their high thrust to weight ratio and specific impulse, reducing both the cost of deep space missions and the exposure of payloads to space radiation. To aid in NTR system design being done by Ultra Safe Nuclear Corporation, this work presents a preliminary design of a hot hydrogen test loop facility that can subject NTR tie tubes to NTR hydrogen flow conditions. Tie tubes are channel elements through which hot hydrogen coolant/propellant flows in the reactor core; these hydrogen facing components will be subject to plasma embrittlement as hydrogen gas begins exhibiting bulk plasma behavior. It is critical to characterize these effects for NTR longevity in deep space missions, and this test loop design will provide initial data at 1200 °C, moving to 2700 °C in a later design. Preliminary design work was conducted using ANSYS 2020 R1 Student Edition, using both Steady-State Thermal and Fluent models to obtain temperature and velocity distributions in the loop pipes, hydrogen, and tie tubes. The Fluent model was simplified to a linear pipe flow design to improve test section flow results. The heating section was assumed to have a heat load evenly distributed over the pipe surface. In practice, heating will need to provide an equivalent power over the smaller contact area. The selection of a FeCrAl alloy as the test loop pipe material was validated for loop operating conditions, and the loop provided sufficient heating to the hydrogen and tie tube for a variety of pipe cross-sectional areas and thicknesses. The flow was found to be largely laminar for the operating mass flow rate and pressure. The loop produced suitable operating temperatures even under high vacuum conditions, although further study of the cooling system is needed to verify forced convection can be obtained.