Investigation of the API-Injection Concept in a LOX/LH2 Combustion Chamber at GG/PB Operation Conditions

Kurzfassung

A proper design of an injection system for liquid propellant rocket engines (LPRE) has to ensure a homogenous mixture of the injected propellants, which should result in a stable and highly efficient combustion process. In addition to combustion stability and efficiency it determines the propellant pressure losses upstream of the combustion chamber as well as the combustion chamber size required for a complete reaction of the injected propellants. This publication deals with the application of a new injection concept to operating conditions typically found in fuel rich LOX/H2 gas-generator (GG) or preburner (PB) combustion chambers. This injection concept was developed at the German Aerospace Center’s Institute of Space Propulsion and was named “Advanced Porous Injector” (API). Its feasibility has been demonstrated for operating conditions typical for main combustion chamber (MCC) applications during various test campaigns. The injection conditions typical for GG or PB applications impose new challenges on the injection system. The test campaign reported here was performed using the propellant combination LOX/H2 with a hydrogen injection temperature of 50 K and an oxidizer to fuel ratios ranging from 1 to 0.6. The successful operation of an 80 mm diameter combustion chamber equipped with a porous injector head has been demonstrated for chamber pressures up to 330 bar.