Combustion Characteristics in an Ultra-Compact Trapped Vortex Combustor with Liquid Fuel Sprays

In the design of small-scale power generation systems using a combustor, achievement of high-efficiency, stable operation, and size reduction are critical challenges. To address these issues, studies on the concept and design of small-size combustors and their combustion characteristics are highly desirable. In this study, a small-scale trapped vortex combustor with fuel atomizing sprays is designed and combustion characteristics is experimentally studied. Visible and OH* chemiluminescence imaging are performed to visually inspect the flame and observe the spatial distribution of the primary chemical reaction region. Because the atomization and vaporization of the liquid fuel are critical to the combustion performance, qualitative and quantitative investigation of fuel sprays are conducted using X-ray phase contrast imaging. Combustion efficiency measurement is performed to examine the combustion performance. Combustion characteristics in the combustor are discussed with obtained spray information, heat release zone images, and combustion efficiencies. Using the designed combustor, stable combustion and good combustion efficiency are achieved, but relatively low performance is observed at atmospheric combustor pressure.