Combustion performance of a novel injector using flow-blurring for efficient fuel atomization

摘要

A recent paper by Ganan-Calvo [1] describes a simple nozzle geometry that atomizes a liquid jet by creating a backflow of gas into the nozzle supplying the liquid. In this design, the gas is forced through a small gap between the exit of nozzle with inside diameter 'd' and a coaxial orifice in a perpendicular plate located about 0.25d downstream of the nozzle. The backflow causes a vigorous combination of turbulent mixing and effervescing, or the so-called "flow-blurring", which results in a spray with very fine droplets. The author claims that atomization achieved in this manner is far more efficient than other existing methods. In the current paper, we apply the flow-blurring concept in a swirl-stabilized combustor and compare its combustion performance with a commercially available air-assist atomizer. Experiments are performed at atmospheric pressure using diesel and kerosene fuels burning with air. Detailed emissions measurements are taken for fixed fuel and total air flow rates, while the airflow split through the injector and the co-flow swirler is varied. Results show that for a given fuel and atomizing air flow rate, the emissions of nitric oxides (NO_x) and carbon monoxide (CO) are lower for the flow-blurring atomizer compared to those for the commercial air-assist atomizer.