Combustion apparatus and methods

Abstract

A combustion apparatus is described having a generally elongated combustion container with a longitudinal axis, a proximal end, an exhaust end spaced axially forward from the proximal end, a proximal end wall, an exhaust end wall, and an all-around sidewall extending between the end walls and about the longitudinal axis. The end walls and sidewall substantially define a combustion chamber. The apparatus also includes a combustion chamber exhaust positioned on the exhaust end, a fuel-air delivery system positioned to direct fuel into the combustion chamber, and an air inlet located generally tangentially on the sidewall to direct air flow generally tangentially into the chamber and induce swirl about the longitudinal axis.

What is claimed is: 
     
         1 . A combustion apparatus comprising:
 a generally elongated combustion container having a longitudinal axis, a proximal end, an exhaust end spaced axially forward from the proximal end, proximate end wall, an exhaust end wall, and an all-around sidewall extending between the end walls and about the longitudinal axis, the end walls and sidewall substantially defining a combustion chamber;
 a combustion chamber exhaust positioned on the exhaust end; 
 a delivery system positioned to direct fuel into the combustion chamber for combustion; and 
 an air inlet located generally tangentially on the sidewall to direct air flow generally tangentially into the chamber and induce swirl about the longitudinal axis. 
   
     
     
         2 . The combustion apparatus of  claim 1 , wherein the air inlet is positioned forwardly of a longitudinal axis midpoint of the chamber such that the tangentially directed air flow into the chamber commences a swirl flow axially proximate the exhaust and such that the swirl flow advances axially therefrom toward the proximal end. 
     
     
         3 . The combustion apparatus of  claim 1 , wherein the exhaust includes an exhaust opening located on the exhaust end wall, the air inlet is located on the sidewall axially proximate the exhaust opening, and the delivery system is located on the proximal end wall to initiate combustion in the proximate end of the combustion chamber. 
     
     
         4 . The combustion apparatus of  claim 3 , wherein the combustion container is cylindrical and is configured such that a distance of a clear direct path between the air inlet and the exhaust opening is less than a diameter of the combustion container. 
     
     
         5 . The combustion apparatus of  claim 1 , wherein the air inlet includes a plurality of tangentially directed radial guide vanes arranged circumferentially about the sidewall. 
     
     
         6 . The combustion apparatus of  claim 1 , further comprising an air supply; and
 an outer casing spaced circumferentially outward of and about the combustion container to define an annulus between the combustion container and the outer casing, the outer casing further including an outer air inlet fluidly communicating the air supply with both the annulus and the air inlet of the combustion container.   
     
     
         7 . The combustion apparatus of  claim 1 , wherein the delivery system includes an air swirler positioned to express an annular air swirl into the combustion chamber at the proximate end and includes a radial inlet, a swirl chamber having an outlet with a swirl axis that is substantially parallel or coincident with the longitudinal axis of the combustion chamber, and a swirl nozzle outlet extending axially forward about the swirl axis into the combustion chamber, the swirl nozzle outlet defining a fuel and air delivery zone radially internal thereof. 
     
     
         8 . The combustion apparatus of  claim 7 , wherein the air swirler nozzle includes a base portion including a swirl chamber for receiving air flow and an axially diverging outlet extending forwardly of the base for expressing an annular swirling air outflow. 
     
     
         9 . The combustion apparatus of  claim 7 , wherein the fuel-air delivery system is a fuel-air delivery system that includes a fuel nozzle directed axially into the air nozzle, the fuel nozzle including an outlet tip positioned for directing fuel into a region defined internally by the nozzle outlet. 
     
     
         10 . The combustion apparatus of  claim 9 , wherein the air swirler has a longitudinal swirl axis and an axial opening about the swirl axis, the swirl axis being aligned with an axis of the nozzle outlet, and wherein the fuel nozzle is directed through the axial opening and the radial inlet is configured to deliver a swirling air flow about the swirl axis, and wherein the axial opening defines an annular gap about the fuel nozzle, the air swirler being configured to receive air flow though the annular gap and to a region of the nozzle outlet about the nozzle tip. 
     
     
         11 . The combustion apparatus of  claim 1 , wherein the combustion chamber includes a diaphragm dividing the combustion chamber into a dilution region and a local combustion zone proximate the proximate end wall, the diaphragm including a partial barrier wall extending into the chamber generally transversely to the longitudinal axis. 
     
     
         12 . The combustion apparatus of  claim 1 , wherein the delivery system includes an air swirler and fuel nozzle, the apparatus further comprising a supply air inlet in direct fluid communication with the delivery system, the combustion container being further configured to separate air inlet flow into the combustion chamber from supply air flow to the delivery system. 
     
     
         13 . The combustion apparatus of  claim 12 , further comprising an air chamber adjacent and in fluid communication with the supply air inlet and the fuel-air delivery system, the air chamber being separate from the combustion chamber and the air inlet thereto. 
     
     
         14 . A method of combustion comprising the steps of:
 providing an elongated combustion container having a longitudinal axis, a pair of axially spaced apart end walls generally defining a proximate end and a distal end, a sidewall extending between the end walls, and an exhaust opening in the distal end;   delivering fuel into the chamber at the proximal end;   introducing tangential air flow into the combustion chamber to induce swirl flow about the longitudinal axis, whereby the swirl flow further induces meridional circulation in the combustion chamber;   including circulatory regions and flow through regions exiting the exhaust opening; and   initiating combustion in the combustion chamber including exhausting hot gases through the exhaust opening.   
     
     
         15 . The method of  claim 14 , wherein during the step of introducing tangential air flow, the swirl flow further induces meridional circulation including circulatory regions and flow through regions exiting the exhaust opening. 
     
     
         16 . The combustion method of  claim 14 , further comprising the steps of:
 positioning an air swirler in the proximate end whereby a swirl axis is parallel or   coincidental with the longitudinal axis of the combustion chamber and a swirler outlet includes a sidewall that extends axially forward into the chamber and defines an outlet zone radially internal thereof;   generating a local circulation region in the proximate end, including generating a swirling flow about the swirler axis such that suction is generated at the swirl axis and the swirling air flow is expressed outwardly and annularly along the sidewall and directing fuel spray into the outlet zone, whereby the fuel spray is separate from the annular air swirl and whereby a counterflow of hot gases from the combustion chamber is drawn into the outlet zone by the swirl suction to substantially vaporize fuel therein.   
     
     
         17 . The combustion method of  claim 16 , wherein the step of introducing tangential air flow further induces circulated meridional motion of combustion fluids said method further comprising delivering a liquid fuel spray at the proximate end and an annular swirling air flow about the fuel spray, whereby the swirling flow diverges axially outward away from the fuel spray and a suction is generated to induce a generally axial counterflow radially inward of the annular swirling flow, and whereby the counterflow includes hot gases from the combustion chamber that substantially vaporizes fuel droplets from the liquid fuel spray. 
     
     
         18 . The combustion method of  claim 17 , wherein the annular swirling air flow and the generally axial counterflow generates a local circulation region in the proximate end. 
     
     
         19 . The combustion method of  claim 18 , wherein the meridional circulation includes both global circulation regions and flow through regions in the combustion chamber, wherein the flow through regions are concentrated along the sidewall and about the longitudinal axis to exit through an exhaust opening on the distal end wall and the circulation regions are surrounded by the flow through regions and interact therewith. 
     
     
         20 . The combustion method of  claim 19 , wherein the step of introducing tangential air flow includes introducing the tangential air flow proximate the exhaust opening, whereby swirl flow and flow through regions commence in the distal end. 
     
     
         21 . A fuel and air delivery system comprising:
 a radial air swirler having a swirl chamber positioned about a swirl axis, a radial inlet for introducing rotational air flow into the swirl chamber, and a central opening positioned to receive swirling flow from the chamber; and   a fuel nozzle directed axially through the central opening of the swirler; and   wherein the air swirler further includes a nozzle outlet in fluid communication with the central opening and having an all around forwardly diverging sidewall for directing a diverging annular swirl flow outward.   
     
     
         22 . The system of  claim 21 , wherein the sidewall defines an outlet zone internal thereof, the fuel nozzle being positioned to direct a fuel spray into the outlet zone. 
     
     
         23 . The system of  claim 21 , wherein the fuel nozzle and the sidewall are configured such that the fuel nozzle directs a spray angle relative to the swirl axis that is less than a sidewall angle relative to the swirl axis, such that the fuel spray is spaced inwardly of the annular swirl flow along the sidewall. 
     
     
         24 . The system of  claim 21 , wherein the central opening defines an annular gap between the fuel nozzle and the swirl chamber, the annular gap being configured to pass an axial air flow into the outlet zone, and
 wherein the air swirler includes a throat defined by a reduced diameter area of the sidewall, the air swirler being operable to generate a low pressure area about the throat such that a counterflow is drawn toward the throat.