Passenger cabin air distribution system and method of using

Abstract

A passenger cabin air distribution system includes a ventilation system and an ejector-diffuser. The ventilation system is operable to provide a conditioned air. The ejector-diffuser is positioned to receive a flow of the conditioned air from the ventilation system. The ejector-diffuser includes an induction unit and a diffuser section. The induction unit includes a secondary inlet in communication with a cabin air from a passenger cabin and is configured to mix the flow of the conditioned air with an induced flow of the cabin air into a mixed air. The diffuser section includes a discharge to eject the mixed air to the passenger cabin. The diffuser section is shaped to provide for efficient mixing with low backpressure in order to maintain the low motive pressure in the nozzle.

What is claimed is: 
     
         1 . A passenger cabin air distribution system comprising:
 an ejector-diffuser having
 a first end; 
 a second end opposite the first end; 
 a primary inlet positioned at the first end; 
 a nozzle positioned between the first end and the second end, the nozzle including an elongated slot-shaped opening having a first width, the elongated slot-shaped opening in communication with the primary inlet, the nozzle forming an initial chamber adjacent to the first end and a mixing chamber having a second width, the mixing chamber being adjacent to the second end, wherein the first width is substantially equal to the second width; 
 an induction unit including a secondary inlet, the secondary inlet in communication with the mixing chamber; and 
 a diffuser section including a discharge, the diffuse section being positioned at the second end, the discharge in communication with the mixing chamber. 
   
     
     
         2 . The passenger cabin air distribution system of  claim 1 , wherein the mixing chamber includes a rectangular cross-section extending from the elongated slot-shaped opening to the diffuser section. 
     
     
         3 . The passenger cabin air distribution system of  claim 1 , wherein the mixing chamber includes a uniform cross-section extending from the elongated slot-shaped opening to the diffuser section. 
     
     
         4 . The passenger cabin air distribution system of  claim 3 , wherein the uniform cross-section is a rectangular cross-section. 
     
     
         5 . The passenger cabin air distribution system of  claim 3 , wherein the mixing chamber does not include a plurality of vanes. 
     
     
         6 . The passenger cabin air distribution system of  claim 1 , wherein the mixing chamber does not include a plurality of vanes. 
     
     
         7 . The passenger cabin air distribution system of  claim 6 , wherein the discharge includes a plurality of slots. 
     
     
         8 . The passenger cabin air distribution system of  claim 7 , wherein the plurality of slots further comprise a plurality of arcuate slots. 
     
     
         9 . The passenger cabin air distribution system of  claim 1 , wherein the elongated slot-shaped opening includes a first height, the first width of the elongated slot-shaped opening is greater than the first height. 
     
     
         10 . The passenger cabin air distribution system of  claim 9 , wherein the mixing chamber includes a second height, the first height of the elongated slot-shaped opening is less than the second height. 
     
     
         11 . A passenger cabin air distribution system comprising:
 an ejector-diffuser having a discharge;   a ventilation system operable to provide a conditioned air to the ejector-diffuser;   an induction unit comprising a secondary inlet and a nozzle with an elongated slot-shaped opening, the elongated slot-shaped opening causes a local reduction in static pressure of a flow of the conditioned air from the ventilation system flowing through the elongated slot-shaped opening, an induced flow of a cabin air flowing through the secondary inlet due the local reduction in static pressure, the elongated slot-shaped opening having a first width and a first height, the first width is greater than the first height; and   a mixing chamber having a second width and a second height, the first width of the elongated slot-shaped opening is substantially equal to the second width of the mixing chamber, wherein the mixing chamber is positioned to mix conditioned air flowing though the elongated slot-shaped opening with the induced flow before being ejected from the discharge into a passenger cabin.   
     
     
         12 . The passenger cabin air distribution system of  claim 11 , further comprising a sensor positioned within a flow path of the induced flow of the cabin air. 
     
     
         13 . The passenger cabin air distribution system of  claim 12 , wherein the sensor is a smoke detector. 
     
     
         14 . The passenger cabin air distribution system of  claim 11 , wherein the mixing chamber includes a uniform cross-section and does not include a plurality of vanes. 
     
     
         15 . The passenger cabin air distribution system of  claim 11 , further comprising:
 an airflow outlet operable to receive a second flow of the conditioned air from the ventilation system and direct the conditioned air to an electronics system for cooling; and   wherein the passenger cabin is within a spacecraft and the electronics system is an avionics system.   
     
     
         16 . A method of distributing air in a passenger cabin, the method comprising:
 providing a conditioned air from a ventilation system, a flow of the conditioned air is provided to an ejector-diffuser, the ejector-diffuser having a nozzle with an opening;   locally reducing a static pressure within a high-velocity region of the ejector-diffuser by directing the flow of the conditioned air through the opening, wherein locally reducing the static pressure induces a flow of a cabin air from a passenger cabin through a secondary inlet in the ejector-diffuser;   mixing the flow of the conditioned air and the flow of the cabin air into a mixed air; and   ejecting the mixed air into the passenger cabin,   wherein an absolute pressure ratio of the conditioned air in the nozzle to the cabin air in the passenger cabin is less than 3:1.   
     
     
         17 . The method of  claim 16 , wherein the absolute pressure ratio of the conditioned air in the nozzle to the cabin air in the passenger cabin is less than 1.5:1. 
     
     
         18 . The method of  claim 17 , wherein the conditioned air within the nozzle has a motive pressure of between 1.001 atmospheric pressure (atm) to 1.070 atm. 
     
     
         19 . The method of  claim 16 , wherein the opening is an elongated slot-shaped opening and mixing the flow of the conditioned air and the flow of the cabin air into the mixed air comprises mixing the flow of the conditioned air and the flow of the cabin air into the mixed air in a mixing chamber that does not include a plurality of vanes. 
     
     
         20 . The method of  claim 16 , wherein the passenger cabin is in a spacecraft, and further comprising providing a second flow of the conditioned air from the ventilation system to an airflow outlet, the airflow outlet directing the conditioned air to an avionics system of the spacecraft for cooling.