Column Number Density Expressions Through M = 0 and M = 1 Point Source Plumes Along Any Straight Path

Woronowicz, Michael

Analytical expressions for column number density (CND) are developed for optical line of sight paths through a variety of steady free molecule point source models including directionally-constrained effusion (Mach number M = 0) and flow from a sonic orifice (M = 1). Sonic orifice solutions are approximate, developed using a fair simulacrum fitted to the free molecule solution. Expressions are also developed for a spherically-symmetric thermal expansion (M = 0). CND solutions are found for the most general paths relative to these sources and briefly explored. It is determined that the maximum CND from a distant location through directed effusion and sonic orifice cases occurs along the path parallel to the source plane that intersects the plume axis. For the effusive case this value is exactly twice the CND found along the ray originating from that point of intersection and extending to infinity along the plume's axis. For sonic plumes this ratio is reduced to about 4/3. For high Mach number cases the maximum CND will be found along the axial centerline path. Keywords: column number density, plume flows, outgassing, free molecule flow.

Document ID

20160008956

Acquisition Source

Goddard Space Flight Center

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Conference Paper

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Date Acquired

July 12, 2016

Publication Date

July 10, 2016

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Report/Patent Number

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Meeting: International Symposium on Rarefied Gas Dynamics

Location: Victoria, BC

Country: Canada

Start Date: July 10, 2016

End Date: July 15, 2016

Sponsors: Victoria Univ.

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Public

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