An experimental investigation of the liquid jet breakup characteristics in a vaporizer under equivalent operating conditions of a microturbine combustion chamber.

This study experimentally investigates the liquid jet breakup process in a vaporizer of a microturbine combustion chamber under equivalent operating conditions, including temperature and air mass flow rate. A high-speed camera experimental system, coupled with an image processing code, was developed to analyze the jet breakup length. The fuel jet is centrally positioned in a vaporizer with an inner diameter of 8mm. Airflow enters the vaporizer at controlled pressures, while thermal conditions are maintained between 298 K and 373 K using a PID-controlled heating system. The liquid is supplied through a jet with a 0.4 mm inner diameter, with a range of Reynolds numbers (Reliq=2300-3400), and aerodynamic Weber numbers (Weg=4-10), corresponding to the membrane and/or fiber breakup modes of the liquid jet. Based on the results of jet breakup length, a new model has been developed to complement flow regimes by low Weber and Reynolds numbers. The analysis of droplet size distribution indicates that it follows a normal distribution pattern, with the majority of droplet sizes ranging from 150 to 250 m. These results are crucial for improving the air-fuel mixing process inside the vaporizer before it enters the primary combustion zone.