White Papers
Collaborative Propulsion System Analysis Tool for Pumpfed Liquid Rocket Engines
Frank Sciorelli, Matt Jones, and Scott Forde
June 30, 2005
Abstract
Aerojet is developing a new tool for the evaluation of prospective liquid rocket engine designs for future government and commercial space launch vehicles. The objective of this effort is to produce a tool that enables the users to develop higher fidelity and more robust conceptual and preliminary engine system design solutions earlier in the design maturation process than previously possible. An enabling core feature of this tool is the ability to rapidly produce closed solutions for engine power balance, specific impulse, and engine mass for given engine parameters (propellant mixture thrust, chamber pressure, nozzle area ratio, etc.). The level of fidelity is roughly equivalent to that normally produced in the preliminary design/analysis phase of a program, but also allows further increases in fidelity in the near future. These automated analyses can be performed in 1 to 2 orders of magnitude less time than previously possible, allowing more designs to be evaluated in the same time than before, leading to a more complete understanding of the impact of design parameters on engine functional attributes. Review of the integrated system solutions in the proposal, conceptual, and preliminary phases will enable better understanding of the complex system interactions that may have previously been overlooked. A proof-of-concept propulsion system tool was successfully developed, leading to a vision and roadmap for a Fully Integrated Rocket Engine Simulation (FIRES) tool that forms the backbone of new programs.
Introduction
Aerojet is motivated to improve on the current modeling and simulation tool suite to automate the evaluation of new liquid rocket engine system concepts that meet the Air Force, DoD, NASA and commercial aerospace customers’ requirements. These requirements include: cost, reliability, safety, and performance while meeting customer imposed constraints such as size, weight and physical interfaces. This improved simulation tool suite needs to quantitatively evaluate a large potential design trade space to allow for multiple variables to be evaluated quickly to understand the system requirements drivers and find the most robust design solution that meets all the customer requirements. A pump-fed engine system can have more than fifty (50) independent design variables that need to be evaluated simultaneously. Just a few of the variables to be considered are: engine cycle concepts; turbopump component layouts; pressure design points for chamber pressure, valve pressure drops, oxygen and fuel discharge pressures; technology levels for bearing systems, inducer design, impeller design, and boost pump impacts to the engine system.
A significant benefit to the customer of this new tool suite will be more thorough requirements analysis. This tool will allow Aerojet to better understand how the system requirements are driving the design and identify quickly the most significant engine system sensitivities to the requirements. Potential changes to the requirements can be evaluated to achieve a better propulsion system choice objectively and quantitatively. This automated tool will also reduce development time by eliminating “blind-alley” design concepts in the trade study phase. Many doors to possible design options are closed when a concept is selected, and in the typical design process system interactions are not evaluated until the preliminary or detail design phases of the program. These interactions often require iterations on the design when it is discovered that requirements and the initial concept design are not compatible. The typical approach is not automated and thereby only a subset of the design space can be evaluated in the conceptual phase. This new tool allows for one to two orders of magnitude improvement in the number of design concepts that can be evaluated. This will allow for more thorough trade studies to be performed, resulting in a more robust design to be selected. Also a more detailed analysis using more complex codes and geometries can be American Institute of Aeronautics and Astronautics
Download The Complete Paper
(A one-time registration will be requested)
