Gas Generator Side-Flow Balancing in the Frame of Engine Cycle Analysis

Abstract

The paper describes the methodology of DLRs new engine cycle analysis tool. The tool KOBRA, which is currently under development, is built on a heritage of cycle analysis software. Compared with its predecessor (LRP), the aim is to improve the component models, especially for turbomachinery and piping. The calculation of combustion processes and general uid properties shall also be improved, providing the user with more options and a wider selection of propellant combinations. In a text input �le the user de�nes the arrangement of the engine components. Changes in fuid properties are sequentially calculated in order of propellant flow direction. Components are linked by user specified constraints and subjected to automatic component parameter variations in order to obtain solutions for steady state nominal engine operation. The paper brie y presents the tool and the implemented methods. The side-flow, which is the exhaust of the gas generator and drives the turbines, is analyzed in terms of mass ow and required gas generator temperature. Parametric variations of gas generator mixture ratio and main chamber pressure are performed.