scholarly journals Discussion: “An Experimental and Analytical Study of Vortex-Flow Temperature Separation by Superposition of Spiral and Axial Flow: Parts 1 and 2” (Lay, J. E., 1959, ASME J. Heat Transfer, 81, pp. 202–211 and pp. 213–221)

1959 ◽  
Vol 81 (3) ◽  
pp. 221-222
Author(s):  
F. Kreith
Keyword(s):  
Heat Transfer ◽  
Analytical Study ◽  
Vortex Flow ◽  
Axial Flow ◽  
Flow Temperature ◽  
Temperature Separation

An Experimental and Analytical Study of Vortex-Flow Temperature Separation by Superposition of Spiral and Axial Flow: Part 2

1959 ◽  
Vol 81 (3) ◽  
pp. 213-221 ◽  
Author(s):  
J. E. Lay
Keyword(s):  
Analytical Study ◽  
Vortex Motion ◽  
Axial Flow ◽  
Experimental Program ◽  
Stagnation Temperature ◽  
Spiral Flow ◽  
Free Vortex ◽  
Temperature Separation ◽  
Flow Part

Part 2 reports on the analytical study. The free vortex motion of the gas upon entrance to the tube is mathematically superposed to a compressible sink to give a spiral flow in the plane. The characteristic existence of limit circles is corroborated by the experimental flow visualization. The solution in space is obtained by addition of a uniform axial velocity to the spiral flow. When viscosity effects are considered, the free vortex is shown to change into a forced vortex. The latter flow is one of minimum kinetic energy and maximum entropy. Energy considerations enable the determination of an optimum cold air radius to give largest stagnation temperature separation. Significantly, this was the radius that gave best performance in the experimental program.

An Experimental and Analytical Study of Vortex-Flow Temperature Separation by Superposition of Spiral and Axial Flows: Part 1

1959 ◽  
Vol 81 (3) ◽  
pp. 202-211 ◽  
Author(s):  
J. E. Lay
Keyword(s):  
Analytical Study ◽  
Vortex Flow ◽  
Vortex Tube ◽  
Radial Distance ◽  
Sink Strength ◽  
Stagnation Temperature ◽  
Spiral Flow ◽  
Temperature Separation ◽  
Forced Vortex ◽  
Potential Vortex

This paper reports on an experimental and analytical study of compressible flow in a uniflow vortex tube. Part 1 deals with an experimental study, Part 2 with the analytical study. Its purpose is to provide a better understanding of the separation of a gas stream into regions of high and low stagnation temperatures, there being at present little agreement as to the theory of operation. The problem is first approached from the experimental standpoint. A large, multipurpose vortex tube is so designed and built that pressure, temperature, and velocity traverses can be taken at six different stations throughout the length of the tube. Pressure, temperature, and velocity traverses are taken by means of hypodermic probes. Velocities are checked by means of a miniature hot-wire anemometer. Data are taken for different runs of inlet pressures and plotted against radial distance. Flow visualization is obtained by means of liquid injection. The analytical study consists of using superposition for the solution of the flow equations. It begins with potential vortex flow in the plane. The solution of this flow is characterized by the existence of sonic or limit circles. Superposition of a sink flow to the vortex solution yields a spiral flow in the plane. The general solution in space is obtained by addition of a uniform axial velocity to the spiral flow. When viscosity effects are considered, the potential vortex changes into a forced vortex, and the solution becomes a superposition of a viscous compressible sink to a forced vortex. Performance or stagnation temperature separation is expressed as function of the ratio of vortex strength to sink strength.

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