Variable geometry heat exchanger

Abstract

A heat exchanger includes a core having a nonrectangular cross-sectional area, a plurality of cold flow layers centered about a centerline with each of the plurality of cold flow layers separated by corresponding walls. The heat exchanger also includes a plurality of hot flow tubes corresponding to each of the plurality of cold flow layers.

1 . A heat exchanger comprising:
 a core having a nonrectangular cross-sectional area;   a plurality of cold flow layers centered about a centerline, each of the plurality of cold flow layers separated by corresponding walls; and   a plurality of hot flow tubes corresponding to each of the plurality of cold flow layers.   
     
     
         2 . The heat exchanger of  claim 1 , wherein the core has a circular cross-sectional area and the plurality of cold flow layers are annular in shape, coaxial about the centerline, and are separated by corresponding annular walls. 
     
     
         3 . The heat exchanger of  claim 2 , wherein the plurality of cold flow layers comprises:
 a first cold flow layer having a first annular wall on a radially inner boundary;   a second cold flow layer radially outward from the first cold flow layer and having a second annular wall between the first cold flow layer and the second cold flow layer; and   a third cold flow layer radially outward from the second cold flow layer and having a third annular wall between the second cold flow layer and the third cold flow layer and a fourth annular wall radially outward from the third cold flow layer.   
     
     
         4 . The heat exchanger of  claim 3 , wherein the plurality of hot flow tubes comprises:
 a first set of hot flow tubes radially inward from the first cold flow layer with each hot flow tube being incorporated into the first annular wall;   a second set of hot flow tubes radially between the first cold flow layer and the second cold flow layer with each hot flow tube being incorporated into the second annular wall;   a third set of hot flow tubes radially between the second cold flow layer and the third cold flow layer with each hot flow tube being incorporated into the third annular wall; and   a fourth set of hot flow tubes radially outward from the third cold flow layer with each hot flow tube being incorporated into the fourth annular wall.   
     
     
         5 . The heat exchanger of  claim 4 , wherein the first set of hot flow tubes has an equal number of hot flow tubes as the second set of hot flow tubes, the third set of hot flow tubes has a greater number of hot flow tubes than the number of hot flow tubes of the second set of hot flow tubes, and the fourth set of hot flow tubes has an equal number of hot flow tubes as the number of hot flow tubes of the third set of hot flow tubes. 
     
     
         6 . The heat exchanger of  claim 4 , further comprising:
 a first plurality of radial walls extending between radially adjacent hot flow tubes of the first set of hot flow tubes and the second set of hot flow tubes;   a second plurality of radial walls extending between radially adjacent hot flow tubes of the second set of hot flow tubes and the third set of hot flow tubes; and   a third plurality of radial walls extending between radially adjacent hot flow tubes of the third set of hot flow tubes and the fourth set of hot flow tubes.   
     
     
         7 . The heat exchanger of  claim 6 , wherein a circumferential distance between adjacent radial walls of the first plurality of radial walls is less than a circumferential distance between adjacent radial walls of the second plurality of radial walls, and the circumferential distance between adjacent radial walls of the second plurality of radial walls is less than a circumferential distance between adjacent radial walls of the third plurality of radial walls. 
     
     
         8 . The heat exchanger of  claim 4 , wherein each hot flow tube of the second set of hot flow tubes has a greater cross-sectional area than each hot flow tube of the first set of hot flow tubes, and wherein each hot flow tube of the third set of hot flow tubes has a greater cross-sectional area than each hot flow tube of the second set of hot flow tubes. 
     
     
         9 . The heat exchanger of  claim 4 , further comprising:
 a first set of hot flow tubes extending through the first cold flow layer;   a second set of hot flow tubes extending through the second cold flow layer; and   a third set of hot flow tubes extending through the third cold flow layer.   
     
     
         10 . The heat exchanger of  claim 3 , wherein a radial height of the first cold flow layer, the second cold flow layer, and the third cold flow layer are equal to one another. 
     
     
         11 . The heat exchanger of  claim 3 , wherein a radial height of the first cold flow layer is greater than a radial height of the second cold flow layer and the radial height of the second cold flow layer is greater than a radial height of the third cold flow layer. 
     
     
         12 . The heat exchanger of  claim 1 , wherein each hot flow tube of the plurality of hot flow tubes has a circular cross-sectional shape. 
     
     
         13 . The heat exchanger of  claim 1 , wherein each hot flow tube of the plurality of hot flow tubes has an elliptical cross-sectional shape. 
     
     
         14 . The heat exchanger of  claim 1 , wherein each hot flow tube of the plurality of hot flow tubes has a polygonal cross-sectional shape. 
     
     
         15 . The heat exchanger of clam  1 , wherein each hot flow tube of the plurality of hot flow tubes has a tear-drop cross-sectional shape. 
     
     
         16 . The heat exchanger of  claim 1 , further comprising:
 a first fluid configured to flow through the plurality of hot flow tubes; and   a second fluid configured to flow through the plurality of annular cold flow layers in an opposite direction from a flow of the first fluid.   
     
     
         17 . The heat exchanger of  claim 16 , further comprising:
 a first header having a first hot flow route connected to a first end of the plurality of hot flow tubes, the first hot flow route configured to transition the flow of the first fluid from a first duct into the plurality of hot flow tubes; and   a second header having a second hot flow route connected to a second end of the plurality of hot flow tubes, the second hot flow route configured to transition the flow of the first fluid from the plurality of hot flow tubes into a second duct.   
     
     
         18 . The heat exchanger of  claim 17 , wherein the first header includes a first outer shell configured to contain the second fluid exiting the plurality of cold flow layers and the second header includes a second outer shell configured to guide the second fluid into the plurality of cold flow layers. 
     
     
         19 . The heat exchanger of  claim 1 , wherein the core has an oval cross-sectional shape and the plurality of cold flow layers are oval in shape and are separated by corresponding oval-shaped walls. 
     
     
         20 . A method comprising:
 constructing the heat exchanger of  claim 1  utilizing an additive manufacturing process.