System for protecting an outer surface of an aircraft comprising at least two fuel cells (112, 212) from icing, characterized in that it comprises a first and a third liquid circuit (114, 214) each causing a cooling liquid of the fuel cells (112, 212) to flow, a second and a fourth liquid circuit (118a, 118b) each causing an icing protection liquid to flow, at least two icing protection heat exchangers (120a-d, 220a-d) arranged on the outer surface of the aircraft and having each icing protection liquid pass through them when it flows in the second or fourth liquid circuit (118a, 118b), and two liquid-liquid heat exchangers (116, 216) in which the cooling liquids form a hot pass and the icing protection liquids form a cold pass to reheat the icing protection liquid by the heat from the cooling liquids.

System for protecting an outer surface of an aircraft comprising at least two fuel cells (112, 212) from icing, characterized in that it comprises a first and a third liquid circuit (114, 214) each causing a cooling liquid of the fuel cells (112, 212) to flow, a second and a fourth liquid circuit (118a, 118b) each causing an icing protection liquid to flow, at least two icing protection heat exchangers (120a-d, 220a-d) arranged on the outer surface of the aircraft and having each icing protection liquid pass through them when it flows in the second or fourth liquid circuit (118a, 118b), and two liquid-liquid heat exchangers (116, 216) in which the cooling liquids form a hot pass and the icing protection liquids form a cold pass to reheat the icing protection liquid by the heat from the cooling liquids.

According to one implementation, a propulsion system includes a rotor, a motor and an anti-icing mechanism. The rotor has blades. The motor rotates the rotor. The anti-icing mechanism deices the blades using heat generated by driving of the motor. Further, according to one implementation, an aircraft includes the above-mentioned propulsion system. Further, according to one implementation, an anti-icing method of a rotor having blades includes deicing the blades using heat generated by driving of a motor for rotating the rotor.

According to one implementation, a propulsion system includes a rotor, a motor and an anti-icing mechanism. The rotor has blades. The motor rotates the rotor. The anti-icing mechanism deices the blades using heat generated by driving of the motor. Further, according to one implementation, an aircraft includes the above-mentioned propulsion system. Further, according to one implementation, an anti-icing method of a rotor having blades includes deicing the blades using heat generated by driving of a motor for rotating the rotor.

In certain embodiments, the invention is directed to apparatus comprising a liquid-impregnated surface, said surface comprising an impregnating liquid and a matrix of solid features spaced sufficiently close to stably contain the impregnating liquid therebetween or therewithin, and methods thereof. In some embodiments, one or both of the following holds: (i) 0<ϕ≤0.25, where ϕ is a representative fraction of the projected surface area of the liquid-impregnated surface corresponding to non-submerged solid at equilibrium; and (ii) S.sub.ow(a)<0, where S.sub.ow(a) is spreading coefficient, defined as γ.sub.wa−γ.sub.wo−γ.sub.oa, where γ is the interfacial tension between the two phases designated by subscripts w, a, and o, where w is water, a is air, and o is the impregnating liquid.

In certain embodiments, the invention is directed to apparatus comprising a liquid-impregnated surface, said surface comprising an impregnating liquid and a matrix of solid features spaced sufficiently close to stably contain the impregnating liquid therebetween or therewithin, and methods thereof. In some embodiments, one or both of the following holds: (i) 0<ϕ≤0.25, where ϕ is a representative fraction of the projected surface area of the liquid-impregnated surface corresponding to non-submerged solid at equilibrium; and (ii) S.sub.ow(a)<0, where S.sub.ow(a) is spreading coefficient, defined as γ.sub.wa−γ.sub.wo−γ.sub.oa, where γ is the interfacial tension between the two phases designated by subscripts w, a, and o, where w is water, a is air, and o is the impregnating liquid.

A method for precise control of movement of a motive phase on a lubricant-impregnated surface includes providing a lubricant-impregnated surface, introducing the motive phase onto the lubricant-impregnated surface, and exposing the droplets to an electric and/or magnetic field to induce controlled movement of the droplets on the surface. The lubricant-impregnated surface includes a matrix of solid features spaced sufficiently close to stably contain the impregnating lubricant therebetween or therewithin. The motive phase is immiscible or scarcely miscible with the impregnating lubricant.

A method for precise control of movement of a motive phase on a lubricant-impregnated surface includes providing a lubricant-impregnated surface, introducing the motive phase onto the lubricant-impregnated surface, and exposing the droplets to an electric and/or magnetic field to induce controlled movement of the droplets on the surface. The lubricant-impregnated surface includes a matrix of solid features spaced sufficiently close to stably contain the impregnating lubricant therebetween or therewithin. The motive phase is immiscible or scarcely miscible with the impregnating lubricant.

In certain embodiments, the invention is directed to apparatus comprising a liquid-impregnated surface, said surface comprising an impregnating liquid and a matrix of solid features spaced sufficiently close to stably contain the impregnating liquid therebetween or therewithin, and methods thereof. In some embodiments, one or both of the following holds: (i) 0<0.25, where is a representative fraction of the projected surface area of the liquid-impregnated surface corresponding to non-submerged solid at equilibrium; and (ii) S.sub.ow(a)<0, where S.sub.ow(a) is spreading coefficient, defined as .sub.wa.sub.wo.sub.oa, where is the interfacial tension between the two phases designated by subscripts w, a, and o, where w is water, a is air, and o is the impregnating liquid.

In certain embodiments, the invention is directed to apparatus comprising a liquid-impregnated surface, said surface comprising an impregnating liquid and a matrix of solid features spaced sufficiently close to stably contain the impregnating liquid therebetween or therewithin, and methods thereof. In some embodiments, one or both of the following holds: (i) 0<0.25, where is a representative fraction of the projected surface area of the liquid-impregnated surface corresponding to non-submerged solid at equilibrium; and (ii) S.sub.ow(a)<0, where S.sub.ow(a) is spreading coefficient, defined as .sub.wa.sub.wo.sub.oa, where is the interfacial tension between the two phases designated by subscripts w, a, and o, where w is water, a is air, and o is the impregnating liquid.