Anti-icing performance using the surface dielectric barrier discharge plasma actuator is studied using detailed visualization and surface thermal measurements. To reveal the physical mechanism of coupled aerodynamic and thermal effects on anti-icing, three types of actuators are designed and mounted on a NACA 0012 airfoil. The coupled aerodynamic and thermal effects are confirmed in still air. The results show that the plasma actuation is effective for in-flight anti-icing, and the anti-icing performance is directly related to the design of the plasma actuators based on the coupled aerodynamic and thermal effects. When the direction of plasma induced flow is consistent with the incoming flow, the heat generated by plasma discharge is concentrated in the region of the actuator and the ability of the actuator for heat transfer downstream is relatively weak during the anti-icing. When the induced flow is opposite to the incoming flow, there is less heat accumulation in the actuator region, while the ability of heat transfer downstream becomes stronger. With the consistent and opposite direction of induced flow, the plasma actuation can ensure that 57% and 81% chord of the lower surface of the airfoil are free of the ice accumulation, respectively. Another actuator is designed to induce the air jets approximately perpendicular to the airfoil surface. This exhibits both a stronger ability of heat accumulation locally and heat transfer downstream and hence ensures that there is no ice on the entire lower surface of the airfoil.

Up to 78.6% of levoglucosan was obtainable from cellulose by combining non-thermal plasma pretreatment at room temperature and subsequent pyrolysis at 350–450 °C. The yield already reached 77.6% when the pretreated cellulose was pyrolyzed at 375 °C.

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%.

An experimental campaign was conducted to study dynamic ice accretion on rotating aeroengine fan blades and evaluate the icing-induced performance degradation to the fan rotor. The experiments were performed in an icing research tunnel with a scaled spinner-fan model exposed to typical dry rime and wet glaze icing conditions. Although the accreted ice layers were found to conform well with the shapes of the fan blades under the rime icing condition, the performance of the fan rotor was found to degrade substantially due to the much rougher blade surfaces, causing up to 60% reduction in the pressure increment after 360 s of the rime icing experiment. More complicated, needlelike icicles were found to grow rapidly over the rotating spinner and fan blades under the glaze icing condition due to the combined effects of the aerodynamic forces and the centrifugal forces associated with the rotation motion. The irregular-shaped glaze ice structures were found to induce tremendous detrimental effects on the fan rotor, making the airflow depressurized, instead of pressurized, after passing the iced fan rotor. The iced spinner-fan model was always found to consume more power, regardless of rime or glaze ice structures accreted on the fan blades.