TP-B4: Experimentelle Untersuchung von transienten Einspritzphänomenen in Raketenbrennkammern unter Vakuumbedingungen mit Flashverdampfung

Kurzfassung

TP-B4 focuses on the experimental investigation of superheated liquid nitrogen (LN2) injected into a near vacuum atmosphere, which causes the so-called flash evaporation. Hence, the new test bench M3.3 with a specific cryogenic injection system was developed for a systematical and detailed characterisation of cryogenic flash evaporation as a function of the injection conditions and geometries. After first run-in tests to validate the test bench performance and its data acquisition system three test campaigns with LN2 were performed: campaign #1 with high-speed shadowgraphy to visualize the resulting LN2 sprays and their spray patterns, campaign #2 with a Phase Doppler Anemometry (PDA) system in the Dual-Mode configuration to determine droplet size and velocity distributions in fully flashing LN2 sprays and campaign #3 with the PDA system in an optimized 2D-Fiber configuration with modified optical accesses to the vacuum chamber. The generated experimental data of flash boiling LN2 provide a comprehensive data base for the validation of numerical models and further numerical investigations and are used within TP-B5 for model validation.