Characterization of the Interaction of Gas Free Jets under Static Conditions

Abstract: In the present thesis, the interaction of methane jets emerged from various multi-hole injectors is studied. A constant volume chamber and two optical measurement techniques are employed for the investigation. Schlieren photography is used to visualize gas injections, which are recorded by means of a high-speed camera. Images are processed in order to calculate penetration depth and cone angle. Besides, particle image velocimetry is applied for the measurement of velocity fields. The entrainment rate if the surrounding medium is evaluated for selected nozzle designs. Entrainment rate, penetration depth and cone angle are important parameters which jointly contribute to the characterization of jet interaction. A significant discovery is made while observing injections at high fuel and low chamber pressures. As a result of rapid entrainment, jets issued by some symmetrical six-hole injectors strongly attracted each other and merged. It is revealed that the interjection velocity decreases during the merging process and increases when a single jet is formed.