Accession Number : ADA301312

Title :   Separation of a Gas Mixture Flowing Through a Long Tube at Low Pressure,

Corporate Author : TECHNICAL INFORMATION SERVICE (AEC) OAK RIDGE TN

Personal Author(s) : Present, R. D. ; deBethune, A. J.

PDF Url : ADA301312

Report Date : 14 DEC 1948

Pagination or Media Count : 13

Abstract : The separation of a binary gas mixture by diffusion through a capillary of radius r depends on the fact that the molecules have different masses m sub i and mean speeds v sub i. When the inlet pressure is so low that the mean free path lambda is much greater than r, the flow is diffusive and the separation factor (at zero outlet pressure) has its maximum value (m sub 1/m sub 2)(1/2). At high pressures (lambda (less than or equal r) no separation occurs. This paper treats the intermediate case (lambda approx. r) where the transfer of forward momentum from light to heavy molecules in unlike collisions equalizes the transport velocities and decreases the separation factor. As the inlet pressure rises, this effect makes the flow nonseparative before it becomes viscous. Flow equations are derived by equating the momentum acquired by the light component from the pressure gradient to the momentum lost to the wall plus that transferred to the other component. The viscous effects are treated as a small additive perturbation on the flow. The integrated flow equations express the separation factor as a function of the inlet and outlet pressures.

Descriptors :   *LOW PRESSURE, *GASES, *MIXTURES, *SEPARATION, *TUBES, VELOCITY, PRESSURE GRADIENTS, FORWARD AREAS, INTEGRATED SYSTEMS, MOLECULES, LIGHT, HIGH PRESSURE, TRANSPORT, ADDITIVES, PERTURBATIONS, FLOW, VISCOSITY, INLETS, RADIUS(MEASURE), CAPILLARITY, MOMENTUM TRANSFER, MEAN FREE PATH.

Subject Categories : Physical Chemistry
      Inorganic Chemistry
      Fluid Mechanics
      Atomic and Molecular Physics and Spectroscopy
      Optics

Distribution Statement : APPROVED FOR PUBLIC RELEASE