A Conceptual Design Tool for RBCC Engine Performance Analysis

Abstract

Recently, a number of vehicle systems utilizing rocket-based combined cycle (RBCC) propulsion have been proposed as possible low-cost space launch solutions. A spreadsheet-based tool has been developed that uses quasi-1D flow analysis with component efficiencies to parametrically model RBCC engine performance in ejector, fan-ramjet, ramjet and pure rocket modes. For a given sea-level static thrust requirement, the current tool generates engine weight and size data, as well as Isp and thrust data vs. altitude and Mach number. The latter is output in tabular form for use in a trajectory optimization program. This paper reviews the current state of the RBCC analysis tool and the effort to upgrade it from a Microsoft Excel spreadsheet to a design-oriented UNIX program in C suitable for integration into a multidisciplinary design optimization framework.