Search for: All records

An experimental study was conducted to compare various strategies for UAV propeller icing mitigation. With a propeller model with an untreated hydrophilic blade as the comparison baseline, three icing protection systems (IPSs) were evaluated systematically: 1) a passive method with the propeller blade coated with a super-hydrophobic surface (SHS) coating; 2) an active IPS design to forcefully heat the entire blade surface; and 3) a hybrid IPS design with only limited surface heating along the blade leading edge and the SHS-coated blade. While the passive method with the SHS-coated blade was found to be only marginally effective under the glaze icing condition, it became ineffective or even further deteriorated the propeller performance under the mixed and rime icing conditions. While the active IPS design to forcefully heat the entire blade surface was found to be able to prevent ice accretion on most of the blade surface, some minor “ice crowns” were still observed to accrete near the blade tip. The hybrid IPS design was demonstrated to keep the entire blade surface ice-free under all the icing conditions with substantially less power consumption (i.e., [Formula: see text] power saving), rendering it a compelling UAV propeller icing mitigation strategy. 

We report a comparative study to evaluate the effects of surface coatings with different hydrophobicities and icephobicities on the performance of a hybrid anti-/de-icing system that integrates surface heating with hydro-/ice-phobic coating for aircraft icing mitigation. While a flexible electric film heater wrapped around the leading edge of an airfoil/wing model was used to heat the airfoil frontal surface to prevent ice accretion near the airfoil leading edge, three different kinds of coatings were applied to coat the airfoil model at three distinct spanwise locations, which included an icephobic coating with an outstanding icephobicity but a weak hydrophobicity; a superhydrophobic surface (SHS) coating with outstanding water repellency but a moderate icephobicity; and a commonly used hydrophilic coating with poor hydrophobicity and poor icephobicity. Surface wettability was found to play a more important role than icephobicity in affecting the performance of the hybrid anti-/de-icing systems. In comparison to the approach of forceful heating the hydrophilic airfoil surface, the hybrid approach with the SHS coating was found to be able to achieve about 90% energy savings in keeping the entire airfoil surface ice-free; the corresponding energy savings for the hybrid system with the icephobic coating was only about 10%.