Due to the great importance of disk skimmers in fighting oil spills, an integrated and comprehensive research program has been devoted intending towards understanding the hydrodynamic behavior, the physics standing behind, and the main features of disk skimmers during the process of oil recovery from water.
In order to achieve the task, extensive parametric experimental investigation has been carried out on disk skimmers rotating in a vertical plane to the oil-water surface. It has been accomplished for a wide range of disk design and operating parameters such as disk diameter, disk thickness, disk rotational speed, disk center height above oil-water interface, spilled oil film thickness, and oil type to study their influence on the oil recovery rate (ORR) and the oil recovery efficiency (ORE). Here, both are entirely expressed as a function of the disk rotational speed and appropriately used as an indicating measure of the performance. In fact, the present work is focused on evaluating ORE, as well as ORR which is the almost only performance parameter reported by other investigators, as an important parameter in defining the quality of the recovered oil which plays a significant role in deciding the nature of the handling processes next to the skimming process. In addition, an optical observation study has been performed to help in the interpretation and illustration of the various behaviors and trends appeared on the results figures encountered in the parametric study, wherever a considerable amount of consistency and matching between the two are recognized. Generally, the results revealed reliable good agreement with that obtained previously by other investigators. An optimum disk rotational speed value, which almost depends on the spilled oil film thickness, was noticed where ORR reaches its maximum at an appropriate value of ORE. Any further increase of speed results in a reduction in both. In addition, the results clearly experienced that while an increase in the disk diameter improves ORR, and decreases ORE. However, the inverse was shown for increasing the disk center height above the oil-water interface or the disk thickness. Finally, the increases in either the spilled oil viscosity or the spilled oil film thickness enhance both ORR and ORE.