Transcription of FLOW OF GASES THROUGH TUBES AND ORIFICES
{{id}} {{{paragraph}}}
Example: biology
FLOW OF GASES THROUGH TUBES AND ORIFICES
2 FLOW OF GASES THROUGH TUBES AND ORIFICES R. Gordon Livesey The nature of gas flow in pipes and ducts changes with the gas pressure and its description is generally divided into three parts or regimes. The flow dynamics are characterized by A, the molecular mean free path, in relation to some characteristic dimension such as the diameter of a pipe. The flow regime cannot be determined from the mean free path alone but only from the relation of this parameter to the characteristic dimension. The relation is known as the Knudsen number, defined as* 1 Kn=d' Three regimes are generally identified: ( ) 1. Free Molecular Flow. The mean free path is of the same order as, or greater than, the characteristic dimension (the range of relatively large Knudsen numbers)~ and gas dynamics are dominated by molecular collisions with the walls of the retaining vessel or pipe. 2. Continuum Flow. The mean free path is small compared with the characteristic dimension (the range of small Knudsen numbers), and intermolecular collisions are much more frequent than wall collisions.
molecular flow. In continuum flow, conductance depends in a complicated way on the flow conditions, and a better approach is to calculate the pressure ratio (Kp) across a component or series of components. It is usually assumed that continuity applies through a system; that is, the through put is the same through all sections.
Tags:
Information
Domain:
Source:
Link to this page:
Please notify us if you found a problem with this document: