Experimental investigation of the atomization characteristics of pre-filming atomizer with low-temperature fuel

Pre-filming atomizers are used in low pollution center staged combustion chambers, which face high-altitude and low-temperature ignition problems during the operation of aircraft engines. By using a pre-filming atomizer, a thin liquid sheet is formed on the plate and encounters a high-velocity swirling airstream which lead to the atomization of the fuel. In this study, an experimental investigation was conducted to explore the flow characteristics and atomization characteristics of a pre-filming atomizer with low-temperature fuel. The dynamic process of the fuel atomization in the pre-filming atomizer was measured, and the fluctuation frequency, breakup length of the liquid film surface, and the spray particle size in the secondary atomization area were obtained. The results demonstrate that the atomizer flow number increases with a reduction in fuel temperature, attributed to the increased fuel density and mitigated cavitation effects. Concurrently, as the fuel temperature decreases, the surface fluctuation frequency of liquid film diminishes due to the heightened surface tension and internal viscosity of the fuel. The aerodynamic shear force reduces as the relative velocity between the fuel and air flow decreases, leading to an extended average liquid film breakup length. And the spray particle size generated in the secondary atomization area increases slightly due to the relatively minor impact of fuel temperature on atomization characteristics compared to the dominant role of aerodynamic forces. Finally, the fuel temperature mainly affects the atomization characteristics of the pre-filming atomizer by the physical properties and fuel flow rate, which is primarily represented under small air flow conditions.