Heat exchanger for high prandtl number fluids

Abstract

A fluid heat exchanger including a channel for passing a first fluid therethrough arranged along a primary axis including at least two segments of a first flow pattern, wherein a length of at least one segment being set in relation to a hydraulic diameter and a Prandtl number of the first fluid, and a first pattern flow disruptor interspersed between each of the segments of the first flow pattern configured to reduce a pressure loss of the fluid flow along the channel.

What is claimed is: 
     
         1 . A fluid heat exchanger comprising:
 a channel for passing a first fluid therethrough arranged along a primary axis including at least two segments of a first flow pattern, wherein a length of at least one segment being set in relation to a hydraulic diameter and a Prandtl number of the first fluid; and   a first pattern flow disruptor interspersed between each of the segments of the first flow pattern configured to reduce a pressure loss of the fluid flow along the channel.   
     
     
         2 . The heat exchanger of  claim 1 , wherein at least one segment of the at least two segments defines a length greater than five times a hydraulic diameter of the channel. 
     
     
         3 . The heat exchanger of  claim 1 , wherein a first segment of the at least two segments defines a length different from a length of a second segment of the at least two segments. 
     
     
         4 . The heat exchanger of  claim 3 , wherein the length of the first segment is defined by the equation 5D h <L<4D h Pr wherein L is the length of the first segment, D h  is the hydraulic diameter of the first segment, and Pr is the expected steady state Prandtl number of the first fluid at a location along the first segment. 
     
     
         5 . The heat exchanger of  claim 3 , wherein the length of the second segment is defined by the equation 5D h <L<4D h Pr wherein L is the length of the second segment, D h  is the hydraulic diameter of the second segment, and Pr is the expected steady state Prandtl number of the first fluid at a location along the second segment. 
     
     
         6 . The heat exchanger of  claim 1 , wherein the segments of the first flow pattern are aligned in the same direction. 
     
     
         7 . The heat exchanger of  claim 1 , wherein the segments of the first flow pattern are straight. 
     
     
         8 . The heat exchanger of  claim 1 , wherein the first pattern flow disruptor narrows the flow channel. 
     
     
         9 . The heat exchanger of  claim 1 , wherein the first pattern flow disruptor changes a direction of flow of the first fluid. 
     
     
         10 . The heat exchanger of  claim 1 , wherein the first pattern flow disruptor includes multiple disruptors. 
     
     
         11 . The heat exchanger of  claim 10 , wherein at least one of the flow disruptors includes a longer length than another disruptor. 
     
     
         12 . The heat exchanger of  claim 1 , further comprising a second series of channels for passing a second fluid therethrough for transferring energy to the first fluid. 
     
     
         13 . A method of transferring heat between fluids comprising:
 directing a fluid through a heat exchanger channel; and   developing a thermal boundary layer between the fluid and a surface of the channel and a momentum boundary layer between the fluid and the surface of the channel, wherein the thermal boundary layer of the fluid includes a different thickness than a thickness of the momentum boundary layer.   
     
     
         14 . The method of  claim 13 , wherein the fluid includes a Pradntl number greater than 1. 
     
     
         15 . The method of  claim 13 , wherein the fluid includes a Prandtl number greater than 7. 
     
     
         16 . The method of  claim 13 , wherein the thermal boundary layer of the fluid is thinner than the momentum boundary layer. 
     
     
         17 . The method of  claim 13 , wherein a ratio of thermal boundary thickness to momentum boundary layer thickness decreases along a flow direction of the fluid. 
     
     
         18 . The method of  claim 17 , wherein the ratio of thermal boundary thickness to momentum boundary layer thickness is greater than 1. 
     
     
         19 . The method of  claim 13 , further comprising directing a second fluid through a second channel adjacent to the first channel and transferring heat from the first fluid to the second fluid.