Double vortex heat exchanger

Abstract

An improved heat exchanger with two counter-flow passages, a first passage through a round, central tube and a second passage which is annular to the first flow passage. The fluids enter the passages tangentially or past swirl-generating foils at the tube entrance such that fluids are driven to flow in a vortex. The central tube contains a swirling flow of cooler fluid. The annular passage contains warmer swirling fluid flowing in the opposite axial direction from the cooler fluid. The purpose of the heat exchanger is to heat the cooler swirling fluid as it flows through the central tube or to cool the warmer swirling fluid as it flows through the annulus. In some embodiments, fins or other projections on the wetted surfaces of the tubes will be oriented to sustain vortex flow throughout the passages. In some embodiments the outlets may be tangential to recover the some of the kinetic energy of the vortex flow. The tangential outlets may be enlarged for still greater kinetic energy recovery. Heat transfer between the two fluids is stimulated because warmer portion of warm fluid in the annular passage will be driven inward toward the inner surface between annular passage and the inner tube and wherein colder, denser, portion of the colder fluid is forced outward by centrifugal force against the outer wall of the central tube to maintain the maximum temperature difference across the tube wall. Thus, heat transfer is enhanced in an energy efficient manner.

I claim:  
     
         1 . A double vortex heat exchanger comprising an outer tube and an inner tube within said outer tube with tangential inlet to said outer tube with tangential inlet to said inner tube and with higher temperature fluid flowing tangentially into said outer tube and flowing in a swirling motion toward the outlet of said outer tube such that swirling motion generates a centrifugal force to drive the cooler, denser portion of the higher temperature fluid outward and which permits the warmer portion of the higher temperature fluid to flow inward toward the outer wall of said inner tube, and with lower temperature fluid flowing tangentially into said inner tube and flowing in a swirling motion toward the outlet of said inner tube such that swirling motion generates a centrifugal force to drive the cooler, denser portion of the lower temperature fluid outward toward outer wall of said inner tube and which permits the warmer portion of the lower temperature fluid to flow inward away from outer wall of said inner tube such that cooler portion of lower temperature fluid and the warmer portion of higher temperature fluid to both flow toward the outer wall of said inner tube whereby a maximum temperature difference and, consequently, a maximum rate of heat transfer is established between the two fluids as desired.  
     
     
         2 . A double vortex heat exchanger as claimed in  claim 1  further including tangential outlets from said tubes whereby some of kinetic energy of swirling fluid is and pumping energy is conserved as desired.  
     
     
         3 . A double vortex heat exchanger as claimed in  claim 1  further including fins on surfaces of said inner tube whereby heat transfer surface is increased and heat transfer is augmented as desired.  
     
     
         4 . A double vortex heat exchanger as claimed in  claim 2  with said tubes being enlarged in vicinity of said tangential outlets.  
     
     
         5 . A double vortex heat exchanger as claimed in  claim 3  with said fins being so oriented and so shaped as to divert fluid into a swirling flow path within said tubes.  
     
     
         6 . A double vortex heat exchanger as claimed in  claim 1  wherein the fluids within said tubes flow in relative counterblow.  
     
     
         7 . A method of augmenting heat transfer between two fluids whereby the higher temperature fluid flows in a spiral path within an annulus around a circular tube or pipe wherein a lower temperature fluid is also flowing in a spiral path wherein centrifugal force in higher temperature fluid flowing in annulus causes cooler, denser portion of higher temperature fluid to flow outward away from outer surface of said tube or pipe and which permits warmer portion of higher temperature fluid to flow inward toward outer surface of said tube or pipe and such that lower temperature fluid flowing within said tube or pipe by reason of spiral flow path experiences centrifugal force which causes cooler, denser portion of lower temperature fluid to flow outward toward surface of said tube or pipe such that cooler portion of lower temperature fluid and warmer portion of higher temperature are adjacent on opposite sides of said tube or pipe whereby temperature difference is maximized and, heat transfer between higher temperature fluid and lower temperature fluid is maximized as desired.  
     
     
         8 . A double vortex heat exchanger comprising an exterior circular duct, an interior circular duct centrally placed within said exterior circular duct, a vortex generating means at entrance of said exterior circular duct, a vortex generating means at entrance of said interior circular duct, a means of supply of higher temperature fluid to entrance of said exterior circular duct, a means of supply of lower temperature fluid to said interior circular duct, a means of removing cooled fluid from said exterior circular duct and a means of removing heated fluid from said interior circular duct.  
     
     
         9 . A double vortex heat exchanger as claimed in  claim 8  with said vortex generating means being in the form of turning vanes at entrance of said exterior circular duct and at entrance of said interior circular duct.  
     
     
         10 . A double vortex heat exchanger as claimed in  claim 8  with additional vortex generating means within said exterior circular duct and within said interior circular duct such that vortex flow is reenergized within said exterior circular duct and within said interior circular duct whereby vortex flow generated heat transfer augmentation will persist throughout double vortex heat exchanger as desired.