Combined cabin air and heat exchanger RAM air inlets for aircraft environmental control systems, and associated methods of use

An environmental control system (ECS) for use with an aircraft, the ECS comprising:

• a ram air inlet, wherein the ram air inlet includes:
• an inlet lip portion;
• and
• an inlet door movably positioned at least approximately adjacent to the inlet lip portion to form a variable inlet opening therebetween, the inlet door including:
• a first surface portion movably positioned upstream of the inlet lip portion, wherein the first surface portion includes a forward edge region spaced apart from the inlet lip portion by a first distance;
• and
• a second surface portion fixed at an angle relative to the first surface portion and movably positioned downstream of the inlet lip portion, wherein the second surface portion includes an aft edge region spaced apart from the forward edge region by a second distance that is greater than the first distance, and wherein movement of the inlet door in a first direction reduces the inlet opening to decrease a flow of ram air through the inlet opening, and wherein movement of the inlet door in a second direction enlarges the inlet opening to increase the flow of ram air through the inlet opening;
• an air conditioning pack that receives a first portion of air from the ram air inlet;
• and
• a heat exchanger that receives a second portion of air from the ram air inlet, wherein the first portion of air from the ram air inlet flows from the air conditioning pack and through the heat exchanger before flowing into a cabin of the aircraft, and wherein the second portion of air from the ram air inlet cools the first portion of air in the heat exchanger.

An aircraft comprising:

• a cabin;
• and
• an environmental control system (ECS) that provides air to the cabin, the ECS comprising:
• a ram air inlet having a variable inlet opening in flow communication with an inlet duct;
• a ram air outlet having a variable outlet opening in flow communication with an exhaust duct;
• an air conditioning pack that receives a first portion of air from the inlet duct, the air conditioning pack including at least one of an air cycle machine and a vapor cycle machine;
• a heat exchanger that receives a second portion of air from the inlet duct, wherein the first portion of air flows from the air conditioning pack and through the heat exchanger before flowing into the cabin, and wherein the second portion of air flows through the heat exchanger to cool the first portion of air before flowing out the ram air outlet via the exhaust duct;
• and
• means for automatically selecting positions of the variable inlet opening and the variable outlet opening during operation of the aircraft based on a ram air inlet mass flow requirement and based on data indicating desired positions of the variable inlet opening and the variable outlet opening to increase air pressure recovery in the inlet duct and reduce aerodynamic drag caused by the ECS.

A system for providing outside air to a cabin of an aircraft, the system comprising:

• means for receiving a flow of outside air while the aircraft is in flight, wherein the means for receiving a flow of outside air include a variable inlet opening;
• means for dividing the flow of outside air into a first air flow portion and a second air flow portion;
• means for cooling the first air flow portion with the second air portion before providing the first air flow portion to a cabin of the aircraft;
• means for exhausting the second air flow portion away from the aircraft after the second air flow portion has cooled the first air portion, wherein the means for exhausting the second air flow portion away from the aircraft include a variable outlet opening;
• and
• means for automatically modulating at least one of the variable inlet opening and the variable outlet opening while the aircraft is in flight to reduce loss of air pressure downstream from the variable inlet opening while simultaneously reducing aerodynamic drag, wherein the means for automatically modulating include:
• means for automatically selecting a position of the variable inlet opening based on a ram air inlet mass flow requirement;
• and
• means for automatically selecting a position of the variable outlet opening based on the selected position of the variable inlet opening.

A method for providing air to an aircraft cabin during flight, the method comprising:

• receiving a flow of outside air via an air inlet;
• separating the flow of outside air into a first air flow portion and a second air flow portion;
• compressing the first air flow portion;
• after compressing the first air flow portion, cooling the first air flow portion with the second air flow portion;
• after cooling the first air flow portion with the second air flow portion, directing the first air flow portion into the aircraft cabin and exhausting the second air flow portion via an air outlet;
• and
• automatically modulating the air inlet and the air outlet during flight of the aircraft to achieve a desired temperature of the first air flow portion flowing into the aircraft cabin while optimizing pressure recovery and reducing aerodynamic drag,
• wherein automatically modulating the air inlet and the air outlet during flight comprises selecting a ram air inlet mass flow requirement based on the desired temperature of the first air flow portion flowing into the aircraft cabin;
• selecting a position of the air inlet based on the selected ram air inlet mass flow requirement;
• and selecting a position of the air outlet based on the selected position of the air inlet.