Patent Description:
Ice protection systems used in typical subsonic aircraft fall primarily into one of five categories. The first category includes systems that use hot bleed air from the engine compressor section and blow it against the region that needs to be protected against ice accretion. The second category includes systems that use electrical heating mats to protect critical areas against ice accretion. The third category includes inflatable rubber "boots" mounted on the outside of the area of the aircraft to be protected such that when the boot is inflated, the ice is cracked off. The fourth category includes electro-mechanical systems that shock the surface of interest to "knock" the ice off. All of these types of systems need power from the aircraft engines in order to perform their function. The fifth category includes freezing point depression systems that apply a chemical/fluid to the leading edge to decrease the freezing point of water.

Such conventional methods and systems have generally been considered satisfactory for their intended purpose. However, there is a need in the art for improved deicing systems, e.g., that can reduce weight and/or power draw for use with high-speed vehicles. The present disclosure provides a solution for this need. <CIT> describes an apparatus for removing heat. <CIT> describes a device for detecting critical states of a surface. <CIT> describes methods and compositions for inhibiting surface icing. <CIT> describes a rotary wing aircraft propulsion system with electric power generation. <CIT> describes a combined hybrid thermionic and thermoelectric generator. A1 <CIT> describes a hypersonic aircraft and thermal protection structure and coolant circulating system. <CIT> describes a water cooling system for an aeroplane.

According to a first aspect, an aerodynamic friction energy deicing system is provided according to claim <NUM>. The aircraft structure can include, for example, at least one of a leading edge of a wing, a leading edge of a tail, a fuselage, a control surface, an instrument probe, or a windscreen.

In accordance with at least one aspect of this disclosure, the system can be an aerodynamic friction energy generation system for providing electrical energy to an aircraft wherein the heat energy device can be configured to be operatively connected to an aircraft structure and to convert heat energy due to aerodynamic friction on the aircraft structure into electrical energy for use by an aircraft system. The aerodynamic friction energy generation system can include an electrical storage device operatively connected to the heat energy device to receive electrical energy therefrom.

According to a second aspect, a method is provided according to claim <NUM>.

Storing the heat energy as heat can include storing the heat energy in an aircraft fluid. The aircraft fluid can include at least one of aircraft fuel, aircraft hydraulic fluid, aircraft coolant, aircraft refrigerant, or aircraft oil, or a dedicated energy storage fluid. The method can include using the stored heat or heat energy for preventing ice formation or deicing the aircraft structure.

In certain embodiments, storing the heat energy can include converting the heat energy into electrical energy and storing the electrical energy in an electrical storage device. The method can include using the stored electrical energy to power an aircraft system (e.g., avionics, pumps, etc.).

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, an illustrative view of an embodiment of a system in accordance with the disclosure is shown in <FIG> and is designated generally by reference character <NUM>. Other embodiments and/or aspects of this disclosure are shown in <FIG> and <FIG>. Certain embodiments described herein can be used for, e.g., deicing and/or for energy production for any other use.

Referring to <FIG>, an aerodynamic friction energy system <NUM> includes a heat energy device <NUM> configured to be operatively connected to an aircraft structure <NUM> and to convert heat energy due to friction on the aircraft structure <NUM> into another form (e.g., electrical energy) or to store heat energy (e.g., as heat or chemical energy) due to friction on the aircraft structure <NUM>. The converted and/or stored energy can be used for any suitable purpose, e.g., for use in ice prevention and/or deicing and/or powering one or more aircraft systems. The system <NUM> includes the aircraft structure <NUM>, for example.

The aircraft structure <NUM> can include at least one of a leading edge of a wing, a leading edge of a tail, a fuselage, a control surface, an instrument probe, or a windscreen. Any other suitable aircraft structure is contemplated herein.

As shown in <FIG>, the heat energy device <NUM> includes a heat energy storage medium <NUM> configured to store the heat energy as heat for later use. The heat energy storage medium <NUM> includes a phase change material configured to receive heat due to friction and to change phase from a solid to a liquid as a result to store heat for later use, e.g., for ice prevention and/or deicing. As shown in <FIG>, the heat energy storage medium <NUM> includes at least one fluid <NUM> circulating through the heat energy device <NUM> including at least one of aircraft fuel, aircraft hydraulic fluid, aircraft coolant, aircraft refrigerant, or aircraft oil, or a dedicated energy storage fluid (e.g., a fluid solely used for the heat energy device <NUM>). The at least one fluid <NUM> can include a plurality of fluids in a fluidly separate circuit through the heat energy device <NUM>, for example. The at least one fluid <NUM> can be from any suitable source, e.g., from a tank <NUM> circulated by pump <NUM>, for example.

Referring to <FIG>, the heat energy device <NUM> includes a thermoelectric generator <NUM> configured to convert heat due to friction into electrical energy. An electrical storage device <NUM> (e.g., a battery, a capacitor, etc.) is operatively connected to the thermoelectric generator <NUM> to receive electrical energy therefrom. The system <NUM> includes an electrical deicing system <NUM> attached to a structure <NUM> of an aircraft for receiving energy from the electrical storage device <NUM>, e.g., to provide deicing heat to the aircraft structure.

The system <NUM> can be an aerodynamic friction energy generation system for providing electrical energy to an aircraft. The heat energy device <NUM> is configured to be operatively connected to an aircraft structure <NUM> and to convert heat energy due to aerodynamic friction on the aircraft structure <NUM> into electrical energy for use by an aircraft system, e.g., electrical deicing system <NUM> and avionics <NUM>. The aerodynamic friction energy generation system <NUM> includes an electrical storage device <NUM> operatively connected to the heat energy device <NUM> to receive electrical energy therefrom.

In certain embodiments, the aircraft system can be an electrical deicing system <NUM>. Any other suitable systems (e.g., aircraft avionics <NUM>) are contemplated herein.

In accordance with at least one aspect of this disclosure, a method includes receiving heat energy caused by aerodynamic friction on an aircraft structure, and storing the heat energy for later use. Storing the heat energy includes storing the heat energy as heat. Storing the heat energy as heat includes storing the heat energy in a phase change material.

Storing the heat energy as heat can include storing the heat energy in an aircraft fluid or a fluid dedicated to this purpose. The aircraft fluid can include at least one of aircraft fuel, aircraft hydraulic fluid, aircraft coolant, aircraft refrigerant, or aircraft oil, or a dedicated energy storage fluid. The method includes using the stored heat or heat energy for preventing ice formation or deicing the aircraft structure.

In certain embodiments, storing the heat energy can include converting the heat energy into electrical energy and storing the electrical energy in an electrical storage device. The method can include using the stored electrical energy for preventing ice formation or deicing the aircraft structure. The method can include using the stored electrical energy to power an aircraft system (e.g., one or more of avionics, pumps, etc.). Embodiments include using the heat generated by skin friction of a high speed aircraft (e.g., supersonic or hypersonic aircraft) to perform ice protection. Instead of actively powering an ice protection system, embodiments can store the heat generated by the kinetic energy of the speed of flight through the atmosphere to be used later in the flight when at lower speeds and lower altitudes in icing conditions, for example. Depending on the time spent in icing and the severity of the icing conditions, certain embodiments could either be the sole means of ice protection or can act as partial or supplemental ice protection to reduce the burden on an active system or power requirements on an engine, for example. Embodiments can include a variety of methods to store the heat for use later, including using phase-change materials (e.g., a solid that turns into liquid when heated, then resists freezing to provide deicing), storing in an existing fluid used on the aircraft for other purposes (e.g., hydraulic, fuel, or water), or conversion of heat energy to other forms, e.g., electrical. While energy can be stored for later use, certain embodiments can be used to actively power electronics or other aircraft systems in high speed flight, e.g., in a primary electrical generator failure. Embodiments can reduce the overall size and/or weight of deicing systems, for example.

Embodiments can leverage the unique aspects of high speed vehicles (e.g., supersonic or hypersonic) to provide ice protection more efficiently than aircraft that fly at lower speeds. High-speed aircraft can accelerate and climb so quickly on takeoff that exposure to icing conditions may be limited enough to enable a passive means of dealing with any ice accretion (such as a wing design robust to such minimal accretion) during that flight phase. However, it is more likely that these vehicles will spend a significant amount of time in icing conditions during descent, approach, and landing. These phases of flight are often most critical for icing because the engines are at low power and it can be difficult to generate enough ice protection energy without increasing thrust to unacceptable levels, for example.

Using the heat energy that is unavoidably created by flying at high speeds as a source for ice protection either eliminates or reduces the need to burden the engines with creating that power for ice protection. In addition, depending on the implementation of the energy storage system it is possible to eliminate bleed air lines or electrical power distribution for an ice protection system.

Any suitable combination(s) of any disclosed embodiments and/or any suitable portion(s) thereof are contemplated herein as appreciated by those having ordinary skill in the art.

Claim 1:
An aerodynamic friction energy system (<NUM>), comprising:
a heat energy device (<NUM>) configured to be operatively connected to an aircraft structure (<NUM>) and to convert heat energy due to aerodynamic friction on the aircraft structure into another form or to store heat energy due to friction on the aircraft structure, wherein the system (<NUM>) is configured for use in ice prevention and/or deicing;
characterised in that:
the heat energy device (<NUM>) includes a heat energy storage medium (<NUM>) configured to store the heat energy as heat for later use;
the heat energy storage medium (<NUM>) includes a phase change material configured to receive heat due to friction and to change phase from a solid to a liquid as a result to store heat for later use in ice prevention and/or deicing;
the heat energy storage medium (<NUM>) includes at least one fluid (<NUM>) circulating through the heat energy device (<NUM>) including at least one of aircraft fuel, aircraft hydraulic fluid, aircraft coolant, aircraft refrigerant, aircraft oil, or a dedicated energy storage fluid;
and in that the heat energy device (<NUM>) includes a thermoelectric generator (<NUM>) configured to convert heat due to friction into electrical energy, further comprising an electrical storage device (<NUM>) operatively connected to the thermoelectric generator to receive electrical energy therefrom, further comprising an electrical deicing system (<NUM>) attached to a structure (<NUM>) of an aircraft for receiving energy from the electrical storage device.