Tube heat exchanger with varying diameters

Abstract

A tube bundle heat exchanger includes a flow space for a first heat exchange medium; and a plurality of heat exchange tubes for a second heat exchange medium, wherein the plurality of heat exchange tubes extends at least partially across the flow space, wherein the plurality of heat exchange tubes comprises at least a first plurality of tubes having a first diameter and a second plurality of tubes having a second diameter different from the first diameter.

We claim: 
     
         1 . A tube bundle heat exchanger, comprising:
 a flow space for a first heat exchange medium; and   a plurality of heat exchange tubes for a second heat exchange medium, wherein the plurality of heat exchange tubes extends at least partially across the flow space, wherein the plurality of heat exchange tubes comprises at least a first plurality of tubes having a first diameter and a second plurality of tubes having a second diameter different from the first diameter.   
     
     
         2 . The tube bundle heat exchanger of  claim 1 , wherein the second plurality of tubes are positioned relative to the first plurality of tubes such that, during expected flow conditions through the flow space, wake shedding frequency exhibited by the plurality of heat exchange tubes does not match natural frequency of the plurality of heat exchange tubes. 
     
     
         3 . The tube bundle heat exchanger of  claim 1 , wherein the second diameter is larger than the first diameter. 
     
     
         4 . The tube bundle heat exchanger of  claim 3 , wherein the second plurality of tubes are positioned in alternating rows relative to the first plurality of tubes, the rows extending transverse to flow direction through the flow space. 
     
     
         5 . The tube bundle heat exchanger of  claim 4 , wherein the first set of tubes are not aligned with the second set of tubes in the flow direction. 
     
     
         6 . The tube bundle heat exchanger of  claim 5 , wherein the first set of tubes are arranged across the flow direction of the heat exchanger with gaps defined between each pair of adjacent tubes, and wherein tubes of the second set of tubes are aligned in the flow direction with the gaps in the first set of tubes. 
     
     
         7 . The tube bundle heat exchanger of  claim 4 , wherein the first set of tubes and the second set of tubes are aligned with each other in the flow direction. 
     
     
         8 . The tube bundle heat exchanger of  claim 4 , wherein the first plurality of tubes and the second plurality of tubes are arranged in staggered alternating rows extending in the flow direction. 
     
     
         9 . The tube bundle heat exchanger of  claim 3 , wherein a ratio of second diameter to the first diameter is greater than 1:1 and up to 3:1. 
     
     
         10 . The tube bundle heat exchanger of  claim 3 , wherein the second set of tubes has a diameter that is at least 10% larger than the first set of tubes. 
     
     
         11 . The tube bundle heat exchanger of  claim 3 , wherein the second set of tubes comprises between about 30 and about 70% by number of the plurality of heat exchange tubes. 
     
     
         12 . The tube bundle heat exchanger of  claim 3 , wherein the plurality of heat exchanger tubes are arranged at a transverse spacing (ST) such that a ratio of the transverse spacing to an average diameter (D) of the plurality of tubes (ST/D) is between 1.5 and 2.5. 
     
     
         13 . The tube bundle heat exchanger of  claim 3 , wherein the plurality of heat exchanger tubes are arranged at a longitudinal spacing (SL) such that a ratio of the longitudinal spacing to an average diameter (D) of the plurality of tubes (SL/D) is between 1.0 and 3.0. 
     
     
         14 . The tube bundle heat exchanger of  claim 3 , wherein the second set of tubes comprises a row of the second set of tubes extending across the flow direction to reset any wake shedding flow conditions from upstream of the row. 
     
     
         15 . The tube bundle heat exchanger of  claim 3 , wherein the first set of tubes are arranged in hexagonal patterns around each of the second set of tubes. 
     
     
         16 . A method for operating a tube bundle heat exchanger comprising a flow space for a first heat exchange medium; and a plurality of heat exchange tubes for a second heat exchange medium, wherein the plurality of heat exchange tubes extends at least partially across the flow space, wherein the plurality of heat exchange tubes comprises at least a first plurality of tubes having a first diameter and a second plurality of tubes having a second diameter different from the first diameter, the method comprising:
 flowing the first heat exchange medium through the flow space at flow conditions to generate vortex shedding frequency; and   flowing the second heat exchange medium through the plurality of heat exchange tubes at tube flow conditions to generate natural frequency, wherein the second set of tubes are positioned such that there is no resonance between the vortex shedding frequency and the natural frequency.   
     
     
         17 . The method of  claim 16 , wherein the flowing steps result in heat exchange between the first heat exchange medium and the second heat exchange medium. 
     
     
         18 . The method of  claim 16 , wherein the second diameter is at least 10% greater than the first diameter. 
     
     
         19 . The method of  claim 16 , wherein tubes of the plurality of heat exchanger tubes are arranged at a transverse spacing (ST) such that a ratio of the transverse spacing to an average diameter (D) of the plurality of tubes (ST/D) is between 1.5 and 2.5. 
     
     
         20 . The method of  claim 16 , wherein tubes of the plurality of heat exchanger tubes are arranged at a longitudinal spacing (SL) such that a ratio of the longitudinal spacing to an average diameter (D) of the plurality of tubes (SS/D) is between 1.0 and 3.0.