Liquid Rocket Engine Thermal Analysis
Faculty Mentor Name
Andy Gerrick
Format Preference
Poster
Abstract
Heat sink engines serve as a starting point for engine and injector development. They work by absorbing and dissipating heat into the chamber. While not utilized for flight, the design process for heat sinks is far simpler than that for ablative or regeneratively cooled engines. Test fires of Heat sink engines will provide the necessary data to validate injector design and chamber geometry. The most important detail of a test is how safe it is. The engine design plays a key role in this, but so does the test duration. Heat sinks are limited in how long they can fire based on the property of the material it is made of. Maximizing test duration while maintaining safety is crucial for teams wanting to test their engine and collect the most data from it. However, no software is available for teams to run thermal analysis to determine their test duration. The software developed in this project aims to fill that gap. A critical component of the thermal analysis is a stop condition. At first glance, one might think that the stop condition is when the material melts but due to a non uniform temperature gradient in the chamber thermal stresses will become very large and upon cool down will not go away entirely causing the engine to crack, if this happens and a team does not know they could attempt to fire their engine again and the crack could cause the chamber to blow up. Transient thermal analysis is run using a numeric solution in MATLAB's partial differential equation toolbox. The analysis is run for a small time step, then reads the temperature of the nodes to determine if it has reached a critical temperature; if so, the solver will stop and report back the time at which the chamber reaches critical temperature, if it has not reached critical temperature then another time step is solved and the process repeats. The software allows users to input their own engine geometry and thermal data from Rocket Propulsion Analysis, a commonly used program to determine chamber geometry and propellant flow rate requirements. This software will be experimentally validated through the test firing of a 3001bf Lox/Ethanol heat sink engine. The engine will use an additively manufactured impinging doublet injector for simplicity and will have radial and axial thermal couples to validate the heat transfer model and stop conditions. Once validated, the software will be available to any team wishing to run a thermal analysis on their engine to allow for the safest test which yields the most amount of data.
Liquid Rocket Engine Thermal Analysis
Heat sink engines serve as a starting point for engine and injector development. They work by absorbing and dissipating heat into the chamber. While not utilized for flight, the design process for heat sinks is far simpler than that for ablative or regeneratively cooled engines. Test fires of Heat sink engines will provide the necessary data to validate injector design and chamber geometry. The most important detail of a test is how safe it is. The engine design plays a key role in this, but so does the test duration. Heat sinks are limited in how long they can fire based on the property of the material it is made of. Maximizing test duration while maintaining safety is crucial for teams wanting to test their engine and collect the most data from it. However, no software is available for teams to run thermal analysis to determine their test duration. The software developed in this project aims to fill that gap. A critical component of the thermal analysis is a stop condition. At first glance, one might think that the stop condition is when the material melts but due to a non uniform temperature gradient in the chamber thermal stresses will become very large and upon cool down will not go away entirely causing the engine to crack, if this happens and a team does not know they could attempt to fire their engine again and the crack could cause the chamber to blow up. Transient thermal analysis is run using a numeric solution in MATLAB's partial differential equation toolbox. The analysis is run for a small time step, then reads the temperature of the nodes to determine if it has reached a critical temperature; if so, the solver will stop and report back the time at which the chamber reaches critical temperature, if it has not reached critical temperature then another time step is solved and the process repeats. The software allows users to input their own engine geometry and thermal data from Rocket Propulsion Analysis, a commonly used program to determine chamber geometry and propellant flow rate requirements. This software will be experimentally validated through the test firing of a 3001bf Lox/Ethanol heat sink engine. The engine will use an additively manufactured impinging doublet injector for simplicity and will have radial and axial thermal couples to validate the heat transfer model and stop conditions. Once validated, the software will be available to any team wishing to run a thermal analysis on their engine to allow for the safest test which yields the most amount of data.