ID 141

Quantitative Analysis of an Airblast Atomizer in the Near-field Region Using Broadband and Narrowband X-ray Measurements

 

Abstract:

Airblast atomizers are widely used in many industries including fuel combustion, atomization drying, and spray painting. The quality of the spray, however, has a large impact on the efficiency and effectiveness of the spray process. Understanding the primary breakup mechanism(s) in the near-field region of the spray is critical if one wants to control it to provide better spray characteristics. Traditional optical imaging methods in this region are extremely challenging because the near-field region is generally optically dense. In contrast, X-ray imaging can penetrate the near-field region and provide quantitative measurements to enhance our knowledge of this spray region. In this study, a broadband and narrowband X-ray source were used in the near-field region of a canonical coaxial airblast atomizer. To enhance imaging contrast with the broadband source, 20% potassium iodide was added to the liquid phase. The narrowband X-ray source was used to determine the equivalent mean path length because the X-ray absorption coefficient is known exactly for the given monochromatic X-ray beam. These measurements were compared to a calibrated broadband source where a penumbra and beam hardening correction were needed to provide accurate results.