Abstract: A method for inerting a protected space. Process water is delivered to an anode of an electrochemical cell where a portion of the process water is electrolyzed to form protons and oxygen. The protons are transferred across the separator to the cathode, and process water is directed through a process water fluid flow path including a first side of a membrane. Gas is transferred to a second side of the membrane to form a de-gassed process water on the first side of the membrane, and the de-gassed process water is recycled to the anode. Air is delivered to the cathode and oxygen is reduced at the cathode to generate oxygen-depleted air. The oxygen-depleted air is directed from the cathode of the electrochemical cell along an inerting gas flow path to the protected space.

Abstract: A method for operating a rotating detonation engine, having a radially outer wall extending along an axis; a radially inner wall extending along the axis, wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet and an outlet, wherein the method includes flowing liquid phase fuel along at least one wall of the radially inner wall and the radially outer wall in a direction from the outlet toward the inlet to cool the at least one wall and heat the liquid fuel to provide a heated liquid fuel; flowing the heated liquid fuel to a mixer at the inlet to reduce pressure of the heated liquid fuel, flash vaporize the heated liquid fuel and mix flash vaporized fuel with oxidant to produce a vaporized fuel-oxidant mixture; and detonating the mixture in the annular detonation chamber.

Abstract: A combustor for a rotating detonation engine includes a radially outer wall extending along an axis (A); a radially inner wall extending along the axis (A), wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet for fuel and oxidant and an outlet; a first passage for feeding at least one of the fuel and the oxidant along a first passage axis (a1) to the inlet; a second passage for feeding at least one of the fuel and the oxidant along a second passage axis (a2) to the inlet, wherein the second passage axis is arranged at an angle (a) relative to the first passage axis whereby mixing of flow from the first passage and the second passage is induced.

Abstract: A method for operating a rotating detonation engine, having a radially outer wall extending along an axis; a radially inner wall extending along the axis, wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet and an outlet, wherein the method includes flowing liquid phase fuel along at least one wall of the radially inner wall and the radially outer wall in a direction from the outlet toward the inlet to cool the at least one wall and heat the liquid fuel to provide a heated liquid fuel; flowing the heated liquid fuel to a mixer at the inlet to reduce pressure of the heated liquid fuel, flash vaporize the heated liquid fuel and mix flash vaporized fuel with oxidant to produce a vaporized fuel-oxidant mixture; and detonating the mixture in the annular detonation chamber.

Abstract: A combustor for a detonation engine includes a radially outer wall extending along an axis; a radially inner wall extending along the axis, wherein the radially inner wall is positioned at least partially within the radially outer wall to define an annular detonation chamber having an inlet for fuel and oxidant and an outlet; a cooling flow passage defined along at least one of the radially outer wall and the radially inner wall and comprising at least two axially spaced cooling flow passage sections, whereby a different cooling rate can be implemented in the at least two axially spaced cooling flow passage sections.

Abstract: Redundant electrochemical systems and methods for vehicles are described. The systems include a first electrochemical device located at a first position on the vehicle wherein the first electrochemical device is configured to generate at least one of inert gas, oxygen, and electrical power and a second electrochemical device located at a second position on the vehicle wherein the second electrochemical device is configured to generate at least one of inert gas, oxygen, and electrical power. The first electrochemical device is configured to operate in a first mode during normal operation of the vehicle and a second mode when the second electrochemical device fails, wherein in the second mode, the first electrochemical device provides the at least one of inert gas, oxygen, and electrical power for at least one vehicle critical system of the vehicle.

Abstract: A method for operating a rotating detonation engine, having a radially outer wall extending along an axis; a radially inner wall extending along the axis, wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet and an outlet, wherein the method includes flowing liquid phase fuel along at least one wall of the radially inner wall and the radially outer wall in a direction from the outlet toward the inlet to cool the at least one wall and heat the liquid fuel to provide a heated liquid fuel; flowing the heated liquid fuel to a mixer at the inlet to reduce pressure of the heated liquid fuel, flash vaporize the heated liquid fuel and mix flash vaporized fuel with oxidant to produce a vaporized fuel-oxidant mixture; and detonating the mixture in the annular detonation chamber.

Abstract: A combustor for a rotating detonation engine includes a radially outer wall extending along an axis (A); a radially inner wall extending along the axis (A), wherein the radially inner wall is positioned within the radially outer wall to define an annular detonation chamber having an inlet for fuel and oxidant and an outlet; a first passage for feeding at least one of the fuel and the oxidant along a first passage axis (a1) to the inlet; a second passage for feeding at least one of the fuel and the oxidant along a second passage axis (a2) to the inlet, wherein the second passage axis is arranged at an angle (?) relative to the first passage axis whereby mixing of flow from the first passage and the second passage is induced.

Abstract: A combustor for a rotating detonation engine includes an outer tapered wall extending along an axis; an inner tapered wall extending along the axis, wherein the inner tapered wall is positioned within the outer tapered wall to define an annular combustion chamber having an annular gap between the outer tapered wall and the inner tapered wall, wherein the outer tapered wall is moveable relative to the inner tapered wall along the axis, and wherein movement of the outer tapered wall relative to the inner tapered wall changes the annular gap of the annular combustion chamber. Obstacles can be positioned on either or both of inner and outer wall to enhance turbulence within the combustion chamber.

Abstract: Fuel tank inerting systems for aircraft are provided. The systems include a fuel tank, a catalytic reactor arranged to receive a first reactant from a first reactant source and a second reactant from a second reactant source to generate an inert gas that is supplied to the fuel tank to fill an ullage space of the fuel tank, a heat exchanger arranged between the catalytic reactor and the fuel tank and configured to at least one of cool and condense an output from the catalytic reactor to separate out the inert gas, and a controller configured to perform a light-off operation of the catalytic reactor by controlling at least one light-off parameter and, after light-off occurs, adjusting the at least one light-off parameter to an operating level, wherein the at least one light-off parameter comprises a temperature of the catalytic reactor.

Abstract: A fuel system for an engine can include a fuel circuit and a primary fuel pump in fluid communication with the fuel circuit and configured to pump fuel to the engine as a function of engine speed. The primary fuel pump is configured to pump insufficient fuel flow to the engine during at least one engine speed or speed range. The system also includes a supplemental fuel pump in fluid communication with the fuel circuit configured to selectively pump fuel to the engine at least during the at least one engine speed or speed range to supplement fuel flow from the primary fuel pump to provide sufficient total fuel flow to the engine during all engine speeds.

Abstract: A system and method fare disclosed for inerting a protected space. Process water is delivered to an anode of an electrochemical cell where a portion of the process water is electrolyzed to form protons and oxygen. The protons are transferred across the separator to the cathode, and process water is directed through a process water fluid flow path including a first side of a membrane. Gas is transferred to a second side of the membrane to form a de-gassed process water on the first side of the membrane, and the de-gassed process water is recycled to the anode. Air is delivered to the cathode and oxygen is reduced at the cathode to generate oxygen-depleted air. The oxygen-depleted air is directed from the cathode of the electrochemical cell along an inerting gas flow path to the protected space.

Abstract: A system and method for inerting a protected space is disclosed. According to the method, process water is delivered to an anode of an electrochemical cell comprising the anode and a cathode separated by a separator comprising a proton transfer medium. A portion the process water is electrolyzed at the anode to form protons and oxygen, and the protons are transferred across the separator to the cathode. Process water is directed through a process water fluid flow path including a gas outlet, and a pressure differential is applied between the process water fluid flow path and a discharge side of the gas outlet to remove gas from the process water. Air is delivered to the cathode and oxygen is reduced at the cathode to generate oxygen-depleted air, which is directed from the cathode along an inerting gas flow path to the protected space.

Abstract: Fuel tank inerting systems for aircraft are provided. The systems include a fuel tank, a catalytic reactor arranged to receive a first reactant from a first reactant source and a second reactant from a second reactant source to generate an inert gas that is supplied to the fuel tank to fill an ullage space of the fuel tank, a heat exchanger arranged between the catalytic reactor and the fuel tank and configured to at least one of cool and condense an output from the catalytic reactor to separate out the inert gas, and a controller configured to perform a light-off operation of the catalytic reactor by controlling at least one light-off parameter and, after light-off occurs, adjusting the at least one light-off parameter to an operating level, wherein the at least one light-off parameter comprises a space velocity through the catalytic reactor.

Abstract: Redundant electrochemical systems and methods for vehicles are described. The systems include a first electrochemical device located at a first position on the vehicle wherein the first electrochemical device is configured to generate at least one of inert gas, oxygen, and electrical power and a second electrochemical device located at a second position on the vehicle wherein the second electrochemical device is configured to generate at least one of inert gas, oxygen, and electrical power. The first electrochemical device is configured to operate in a first mode during normal operation of the vehicle and a second mode when the second electrochemical device fails, wherein in the second mode, the first electrochemical device provides the at least one of inert gas, oxygen, and electrical power for at least one vehicle critical system of the vehicle.

Abstract: Systems and methods for generating inerting gas on vehicles are described. The systems include a proton exchange membrane (PEM) inerting system, a pure water replenishment system configured to provide pure water to the PEM inerting system, wherein the pure water replenishment system is in fluid communication with the PEM inerting system to replenish water lost during operation of the PEM inerting system, and a control system configured to control operation of the pure water replenishment system to automatically replenish pure water to the PEM inerting system.

Abstract: Systems and methods for generating inerting gas on vehicles are described. The systems include a proton exchange membrane (PEM) inerting system, a pure water supply system configured to provide pure water to the PEM inerting system, wherein the pure water supply system is in fluid communication with the PEM inerting system to replenish water lost during operation of the PEM inerting system, and a recapture loop configured to direct at least one of moisture and water from an output of the PEM inerting system back into the PEM inerting system, wherein the recapture loop includes a water treatment system.

Abstract: A system is disclosed for aircraft life support and generating inert gas. The system includes an electrochemical cell with a cathode and an anode separated by a proton transfer medium. A cathode supply fluid flow path is between an air source and a cathode fluid flow path inlet, and an inerting gas flow path is in operative fluid communication with a cathode fluid flow path outlet and a protected space. An anode supply fluid flow path is between a water source and an anode fluid flow path inlet, and an oxygen gas flow path is in operative fluid communication with an anode fluid flow path outlet and an aircraft occupant breathing device. An electrical connection is between a power source and the electrochemical cell.

Abstract: A fuel system for an engine can include a fuel circuit and a primary fuel pump in fluid communication with the fuel circuit and configured to pump fuel to the engine as a function of engine speed. The primary fuel pump is configured to pump insufficient fuel flow to the engine during at least one engine speed or speed range. The system also includes a supplemental fuel pump in fluid communication with the fuel circuit configured to selectively pump fuel to the engine at least during the at least one engine speed or speed range to supplement fuel flow from the primary fuel pump to provide sufficient total fuel flow to the engine during all engine speeds.

Abstract: A fuel tank inerting system including: a catalytic reactor comprising an inlet, an outlet, a reactive flow path between the inlet and the outlet, a catalyst on the reactive flow path, and a temperature sensor located between the inlet and outlet, wherein the catalytic reactor is arranged to receive fuel from a fuel source and air from an air source that are mixed to form a combined flow, and to react the combined flow along the reactive flow path to generate an inert gas.