Helical insert for shell and tube heat exchanger

Abstract

A heat transfer tube includes a tube having an internal tube wall, and a tube element extending along a tube length and radially inwardly from the internal tube wall. The tube element has a radial element height less than a hydraulic radius of the tube, and the radial element height is greater than a base element width at the internal tube wall. A tube and shell heat exchanger includes a heat exchanger tube extending through a housing and having a heat transfer medium flowing therethrough. The heat exchanger tube includes a tube having an internal tube wall and tube element extending along a tube length and radially inwardly from the internal tube wall. The tube element has a radial element height less than a hydraulic radius of the tube, and the radial element height is greater than a base element width at the internal tube wall.

What is claimed is: 
     
         1 . A heat transfer tube comprising:
 a tube having an internal tube wall; and   a tube element extending along a tube length and radially inwardly from the internal tube wall, the tube element having a radial element height less than a hydraulic radius of the tube, and the radial element height is greater than a base element width at the internal tube wall.   
     
     
         2 . The heat transfer tube of  claim 1 , wherein the tube element extends helically along the tube length. 
     
     
         3 . The heat transfer tube of  claim 2 , wherein the tube element has a ratio of pitch to hydraulic diameter in the range of 1 to 20. 
     
     
         4 . The heat transfer tube of  claim 1 , wherein the tube element extends intermittently along the tube length. 
     
     
         5 . The heat transfer tube of  claim 4 , wherein the tube element includes a first element portion and a second element portion separate from the first element portion, the first element portion and second element portion overlapping along a lengthwise direction of the tube. 
     
     
         6 . The heat transfer tube of  claim 1 , wherein the tube element is configured to extend through a thermal boundary layer of a heat transfer medium flowing therethrough. 
     
     
         7 . The heat transfer tube of  claim 1 , wherein the tube element is a helical feature formed integral to the tube. 
     
     
         8 . The heat transfer tube of  claim 1 , further comprising a single, unitary tube element extending radially inwardly from the internal tube wall at a cross-section perpendicular to the tube length. 
     
     
         9 . The heat transfer tube of  claim 1 , wherein the tube is formed from a first material, and the tube element is formed from a second material different from the first material. 
     
     
         10 . The heat transfer tube of  claim 1 , further comprising one or more surface enhancements including one or more of axial, helical or crosshatched microfins or reentrant cavities. 
     
     
         11 . A tube and shell heat exchanger, comprising:
 a housing:   a heat exchanger tube extending through the housing and having a heat transfer medium flowing therethrough, the heat exchanger tube including:   a tube having an internal tube wall; and   tube element extending along a tube length and radially inwardly from the internal tube wall, the tube element having a radial element height less than a hydraulic radius of the tube, and the radial element height is greater than a base element width at the internal tube wall; and   a refrigerant inlet to flow a refrigerant over the heat exchanger tube, for thermal energy exchange between the refrigerant and the heat transfer medium.   
     
     
         12 . The tube and shell heat exchanger of  claim 11 , wherein the tube element extends helically along the tube length. 
     
     
         13 . The tube and shell heat exchanger of  claim 12 , wherein the tube element has a ratio of pitch to hydraulic diameter in the range of 1 to 20. 
     
     
         14 . The tube and shell heat exchanger of  claim 11 , wherein the tube element extends intermittently along the tube length. 
     
     
         15 . The tube and shell heat exchanger of  claim 14 , wherein the tube element includes a first element portion and a second element portion separate from the first element portion, the first element portion and second element portion overlapping along a lengthwise direction of the tube. 
     
     
         16 . The tube and shell heat exchanger of  claim 11 , wherein the tube element is configured to extend through a thermal boundary layer of a heat transfer medium flowing therethrough. 
     
     
         17 . The tube and shell heat exchanger of  claim 11 , wherein the tube element is a helical feature formed integral to the tube. 
     
     
         18 . The tube and shell heat exchanger of  claim 11 , further comprising a single, unitary tube element extending radially inwardly from the internal tube wall at a cross-section perpendicular to the tube length. 
     
     
         19 . The tube and shell heat exchanger of  claim 11 , wherein the tube is formed from a first material, and the tube element is formed from a second material different from the first material. 
     
     
         20 . The tube and shell heat exchanger of  claim 11 , further comprising one or more surface enhancements including one or more of axial, helical or crosshatched microfins or reentrant cavities.