Cunningham coefficient

Within the precipitation field, a particle experiences the following forces acting upon it a momentum force, /v = ma an electrical force, = QpE and a drag force, Ed = ReACo (Re is the Reynolds number and Co the Cunningham coefficient). 

Nanoaerosol particles interact with the carrier gas molecules and consequently affect their dynamics. Nanoaerosol particles are small enough to approach the mean free path of air, which is about 67 nm under standard conditions. For nanoaerosol the continuum assumption is no longer valid and can attain free molecular flow there is a noncontinuum interaction between the particles and the carrier gas. The corresponding slipping effect is quantified by the Cunningham coefficient in terms of gas mean free path (A) and particle diameter ... 

Cooper, D.L., Cunningham, T.P., Allan, N.L., McCulloch, A. (1992) Tropospheric lifetimes of potential CFC replacements Rate coefficients for reaction with the hydroxyl radical. Atmos. Enrivon. 26A, 133-1334. 

Here, the numerator is called the Stokes-Cunningham factor. The coefficient A is... 

Stokes-Cunningham correction factor for terminal settling velocity Elooding coefficient Discharge coefficient Diameter Bubble diameter Hole diameter Orifice diameter Cut size of a particle collected in a device, 50% mass efficiency Mass median size particle in the pollutant gas... 

Figure 1 Relationship of the mass attenuation coefficient for the photoelectric process versus photon energy. The lower inset shows in greater detail the change in the attenuation coefficient at the K absorption edge for lead. (Reproduced with permission from Johns HE and Cunningham JR (1983) The Physics of Radiology. Courtesy of Charles C. Thomas Publisher, Ltd., Springfield, Illinois.)...

Here APgas is the gas pressure drop across the Venturi in cm H2O, Pp is the particle density in g/cm Pg is the gas viscosity in poise, P( is the liquid density in g/cm, dp is the particle diameter in micron, Cc is the Cunningham correction factor and / is an experimental coefficient varying between 0.1 and 0.4. 

Cunningham correction factor, Eq. 3.19 slip correction factor, Eq. 3.20 drag coefficient, Eq. 3.4... 

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