Image Processing for Spray Applications - A Comparative Study of Two Different Techniques

Rakesh Prabhakaran, B. Raghunandan, Hrishikesh Ganu
2009 45th AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit   unpublished
The motivation for the present work came from a study on spray characteristics of cryogenic injectors where the spray did not lend itself to probing by conventional diagnostic tools. The work was later extended to gas-liquid type of impinging jet as a possible replacement to shear coaxial atomizers currently employed in cryogenic rocket engines with the attendant drawback of design and manufacturing complexity. In addition to simplicity of design and manufacture, the impinging configuration
more » ... g configuration offers the flexibility in spray shaping and drop sizes variation. Experiments have been conducted with doublet configuration using water and air as the simulants. It has been found that the spray is non uniform with wide variation in the SMD across the spray study of which was not possible with conventional tools like Malvern MasterSizer. In this context an image processing technique called Granulometry was first implemented to study these sprays. This granulometric technique has the drawback that the SMD obtained is sensitive to the threshold parameter chosen for generating the required binary image. Moreover it treats overlapping droplets as a single entity. To overcome these drawbacks another algorithm called Hough Transform is implemented and a comparative study is made in this paper. The SMD values obtained with Granulometry was found to be less than that obtained using Hough Transform.
doi:10.2514/6.2009-5392 fatcat:wwb2dgictnfcdgueydhbwwfe24