Polyhedral array heat transfer tube

Abstract

A heat exchanger tube that comprises a tubular member having a longitudinal axis and having an inner surface that is divided into at least two regions along the circumferential direction. A first plurality of polyhedrons are formed on the inner surface along at least one polyhedral axis. Each of the polyhedrons have four opposite sides. The polyhedrons have first and second faces that are disposed parallel to the polyhedral axis and have third and fourth faces disposed oblique to the polyhedral axis. The polyhedral axis is disposed at a first helical angle with respect to the longitudinal axis of the tube. A second plurality of polyhedrons is formed on the inner surface adjacent to the first plurality of polyhedrons. The second plurality of polyhedrons is disposed along at least one polyhedral axis. Each of the polyhedrons has four opposite sides. The polyhedrons have first and second faces disposed parallel to the polyhedral axis and have third and fourth faces disposed oblique to the polyhedral axis. The polyhedral axis is disposed at a second helical angle with respect to the longitudinal axis of the tube. The orientation of the second helical angle is opposite to the orientation of the first helical angle.

1 . A heat exchanger tube, comprising: 
 a tubular member having a longitudinal axis and having an inner surface that is divided into at least two regions along the circumferential direction;    a first plurality of polyhedrons formed on the inner surface along at least one polyhedral axis, each of the polyhedrons having four opposite sides, the polyhedrons having first and second faces disposed parallel to the polyhedral axis and having third and fourth faces disposed oblique to the polyhedral axis, the polyhedral axis disposed at a first helical angle with respect to the longitudinal axis of the tube; and,    a second plurality of polyhedrons formed on the inner surface adjacent the first plurality of polyhedrons and along at least one polyhedral axis, each of the polyhedrons having four opposite sides, the polyhedrons having first and second faces disposed parallel to the polyhedral axis and having third and fourth faces disposed along an axis oblique to the polyhedral axis, the polyhedral axis disposed at a second helical angle with respect to the longitudinal axis of the tube, the orientation of the second helical angle being opposite to the orientation of the first helical angle.    
   
   
       2 . The heat exchanger tube of  claim 1 , wherein the first helical angle is between 5 and 40 degrees.  
   
   
       3 . The heat exchanger tube of  claim 1 , wherein the first helical angle is approximately 15 degrees.  
   
   
       4 . The heat exchanger tube of  claim 1 , wherein the second helical angle is between 5 and 40 degrees.  
   
   
       5 . The heat exchanger tube of  claim 1 , wherein the second helical angle is approximately 15 degrees.  
   
   
       6 . The heat exchanger tube of  claim 1 , wherein the first and second helical angles are equal and opposite.  
   
   
       7 . The heat exchanger tube of  claim 1 , wherein the first and second helical angles are asymmetrical.  
   
   
       8 . The heat exchanger tube of  claim 1 , wherein the angle between the axis of the third and fourth faces and the longitudinal axis of the tube is less than 10 degrees.  
   
   
       9 . The heat exchanger tube of  claim 1 , wherein the angle between the axis of the third and fourth faces and the longitudinal axis of the tube is approximately 0 degrees.  
   
   
       10 . The heat exchanger tube of  claim 1 , wherein the angle between the axis of the third and fourth faces and the longitudinal axis of the tube is less than 7 degrees.  
   
   
       11 . The heat exchanger tube of  claim 1 , wherein the first plurality of polyhedrons and second plurality of polyhedrons occupy regions having an approximately equal area of the inner surface of the tube.  
   
   
       12 . The heat exchanger tube of  claim 1 , wherein the first plurality of polyhedrons and the second plurality of polyhedrons occupy regions having areas that are not equal.  
   
   
       13 . The heat exchanger tube of  claim 1 , wherein the ratio of polyhedron height to outside diameter is approximately 0.005 to 0.05.  
   
   
       14 . The heat exchanger tube of  claim 1 , wherein the at least two regions comprise four regions.  
   
   
       15 . The heat exchanger tube of  claim 1 , wherein the at least two regions comprise more than four regions.  
   
   
       16 . The heat exchanger tube of  claim 1 , wherein there are approximately 500 to 10,000 polyhedrons per square inch.  
   
   
       17 . A heat exchanger tube, comprising: 
 a tubular member having a longitudinal axis and having an inner surface that is divided into at least two regions along the circumferential direction;    a first plurality of polyhedrons formed on the inner surface along at least one polyhedral axis, each of the polyhedrons having four opposite sides, the polyhedrons having first and second faces disposed parallel to the polyhedral axis and having third and fourth faces disposed oblique to the polyhedral axis, the polyhedral axis disposed at a first helical angle with respect to the longitudinal axis of the tube, the first helical angle being between 5 and 40 degrees, the angle between the axis of the third and fourth faces and the longitudinal axis of the tube is approximately 0 degrees; and,    a second plurality of polyhedrons formed on the inner surface adjacent the first plurality of polyhedrons and along at least one polyhedral axis, each of the polyhedrons having four opposite sides, the polyhedrons having first and second faces disposed parallel to the polyhedral axis and having third and fourth faces disposed along an axis oblique to the polyhedral axis, the polyhedral axis disposed at a second helical angle with respect to the longitudinal axis of the tube, the second helical angle being 5 to 40 degrees with the orientation of the second helical angle being opposite to the orientation of the first helical angle, the angle between the axis of the third and fourth faces and the longitudinal axis of the tube is approximately 0 degrees.    
   
   
       18 . The heat exchanger tube of  claim 17 , wherein the first plurality of polyhedrons and second plurality of polyhedrons occupy regions having an approximately equal area of the inner surface of the tube.  
   
   
       19 . The heat exchanger tube of  claim 17 , wherein the first plurality of polyhedrons and the second plurality of polyhedrons occupy regions having areas that are not equal.  
   
   
       20 . The heat exchanger tube of  claim 17 , wherein the ratio of polyhedron height to outside diameter is approximately 0.005 to 0.05.  
   
   
       21 . The heat exchanger tube of  claim 17 , wherein the at least two regions comprise four regions.  
   
   
       22 . The heat exchanger tube of  claim 17 , wherein the at least two regions comprise more than four regions.  
   
   
       23 . The heat exchanger tube of  claim 17 , wherein there are approximately 500 to 10,000 polyhedrons per square inch.