REDTOP-2: Rocket Engine Design Tool Featuring Engine Performance, Weight, Cost, and Reliability

The Rocket Engine Design Tool for Optimal Performance-2 (REDTOP-2) is a newly created engineering design tool for use in the conceptual and preliminary design of space transportation systems utilizing liquid propulsion rocket engines. REDTOP-2, one of many unique engineering tools commercially available from SpaceWorks Engineering, Inc. (SEI), represents a novel entry into the current suite of propulsion modeling tools. REDTOP-2 is capable of analyzing the flowpath characteristics of numerous engine configurations to perform a power balance of the turbomachinery hardware (pumps and turbines) to achieve a user specified main chamber combustion pressure. The engine performance, in terms of thrust and specific impulse (Isp), is then determined based on the results of this power balance and the flow conditions (pressure, temperature, flowrate, etc.) in the chamber(s) and nozzle(s). Engine weight is assessed at the main component level using a combination of empirical and physics based analysis methods to provide vacuum, ambient, and sea-level thrust-to-weight (T/W) values. A cost model capable of predicting engine development, first unit, and production costs has been incorporated. Additionally, REDTOP-2 features a topdown modeling approach for computing engine safety and reliability metrics. REDTOP-2 is written in the modern, object-oriented C++ programming language and will execute on PC, Mac, and SGI platforms. Execution times are on the order of 30 seconds to 5 minutes, depending on the computing platform, engine configuration and design option selected by the user. User interface options currently include a command-line execution with ASCII file manipulation, filewrappers for use in Phoenix Integration’s ModelCenter© environment, and a PC-based graphical user interface (GUI). This paper will describe the REDTOP-2 tool and its capabilities. Sample results obtained from exercising the tool for a number of different existing engine designs will be presented. Results from a multi-variable sensitivity study on a LOX/LH2 fuel-rich, single preburner staged-combustion engine will be highlighted. Two sample applications involving vehicle designs will be discussed. The first involves probabilistic/uncertainty analysis for an all-rocket vehicle design and the second the rocket main propulsion system analysis of an airbreathing, two-stage RLV concept with first stage tail-rockets and all-rocket second stage propulsion. Finally, future directions in the development of REDTOP-2 will be discussed.