Convective and Film Cooled Nozzle Extension for a High Pressure Rocket Subscale Combustion Chamber

Experimental investigations have been carried out to study heat transfer, flow separation, and side loads in a subscale nozzle extension. A Vulcain 2-like nozzle geometry has been tested with combustion chamber pressures up to 13 MPa. A new manufacturing technology has been demonstrated with minimized contour deformation during fabrication. Gaseous hydrogen was used to cool the upper part of the nozzle while flowing through helical, rectangular cooling channels. At a nozzle area expansion ratio of approx. 32 the hydrogen has been injected with supersonic velocity as a film to protect the lower part of the nozzle from the influences of the hot gas. Investigations with varying coolant mass flow rates have shown a stable and safe nozzle operation at real rocket engine-like conditions

Determination of Linear and Nonlinear Parameters of Combustion Chamber Wall Materials

A study for the determination of elastic elastoplastic parameters of a typical combustion chamber material (Cu alloy) with different test sample geometries is presented. Based on the experimental results of elastic and elasto-plastic tests of thre sample geometries the appropriate elasto-plastic parameters such as yield stress and hardening parameters are determined. Furthermore, details about the loading during the tests, the advantages and disadvantages of each of the sample geometries and of the appropriate range of testing are pointed out

Thermomechanical Analysis and Optimization of Cryogenic Liquid Rocket Engines

A coupled finite element fluid-structure interaction analysis of regeneratively cooled rocket combustion chambers, which allows the computation of the coolant flow and the heat conduction between the coolant and the combustion chamber structure, is presented. Furthermore, the resulting elasto-plastic deformation of the combustion chamber under cyclic thermal and mechanical loading is analyzed. The developed solution strategy is applied to the prediction of the heat transfer and thermomechanical load-induced deformation process of the European rocket engine Vulcain. Based on the results, the failure mechanism of the combustion chamber and its governing parameters are identified. It is demonstrated that this mechanism significantly reduces the lifetime of the rocket engine. Besides the conceptual design by the engineer, a mathematical optimization procedure based on the finite element model of the combustion chamber is investigated. This optimization method allows the improvement of an initial design with respect to a finite number of design variables such that the stress, plastic strain, or temperature levels are decreased, and accordingly. the lifetime will be increased