Development of a Computational Model of a High Temperature Lithium-Carbon Dioxide Reactor for Space Power Generation
Open Access
- Author:
- Moser, Eric
- Graduate Program:
- Mechanical Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- June 14, 2022
- Committee Members:
- Alexander S Rattner, Thesis Advisor/Co-Advisor
Joseph John Cor, Thesis Advisor/Co-Advisor
Daniel J. Leonard, Committee Member
Daniel Connell Haworth, Program Head/Chair
Michael Manahan, Committee Member - Keywords:
- CFD Modeling
Lithium-CO2 Combustion
Power Generation
Multiphase Flow - Abstract:
- There are significant challenges in powering a planetary lander mission to Venus due to its extreme temperatures. A planetary lander will require a refrigeration system to keep cool which requires a power system that can generate enough power for this purpose. A reaction that uses lithium metal and the in-situ carbon dioxide from the Venus atmosphere offers a promising solution to this power requirement. Previously, experimental tests have been conducted at various lithium bath temperatures, mass flow rates, and reactor geometries, to determine the thermal energy output of this reaction. The overall energy output is unknown because the specific energy produced from this reaction will be lower than theory due to issues such as crusting which could prematurely end the reaction. The purpose of this thesis is to create a computational fluid dynamics (CFD) model of previously-completed experimental tests that includes the reaction between lithium and carbon dioxide. This CFD model is being developed as part of the development process of a tool for analyzing the performance of a stored chemical energy propulsion system (SCEPS) combustor. The goal of this experimentally-developed model is to help guide SCEPS designs and gain insight into the operation of SCEPS combustors. It is currently unknown why some experimental reactors experienced crusting that prematurely ended the combustion inside the reactor and why some reactors did not. Accordingly, the CFD model developed here has been exercised in a simplified configuration to explore this crusting phenomenon in greater detail. The CFD model is compared against experimental results for product yield, mass flow rate, and overall degree of completion of the reaction. The product yield of the simulated reaction is similar to experimental results. Likewise, the degree of completion correlates well to the experimental results and to theory. A similar utilization rate of lithium was achieved in the baseline model upon comparison to the experimental results. Additionally, simulations exploring crust formation may point to ways to study this phenomenon computationally. Further research should be conducted into the model that experienced crust formation to better understand the mechanisms that caused the crust formation to occur. This crust formation is important to understand so that future reactors can be operated in such a way that all the energy available in this reaction can be accessed without being limited by a crust of products prematurely ending the reaction. These additions to the model could contribute to making it a tool for reactor design.