Critical Orifice Theory, Design and Implementation

Abstract

If flow through an orifice's minimum area is maintained at Mach 1, the volume flow rate is only a function of the temperature and the pressure upstream of the orifice. Such a critical orifice is useful in air sampling when ambient conditions do not change rapidly. Under those conditions, a critical orifice will passively keep the volume flow rate constant at a known value. This can eliminate measuring sampler flow rates in the field during field tests. This paper presents substantiating laboratory and field test data and makes recommendations for the use of critical orifices in vacuum driven sampling lines.

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Document Details

Document Type
Technical Report
Publication Date
Nov 17, 2004
Accession Number
ADA449633

Entities

People

  • Dirk Plante
  • Leo W. Stockham

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Flow
  • Barometric Pressure
  • Biological Sciences
  • Equations
  • Field Tests
  • Filter Paper
  • Flow
  • Flow Rate
  • Fluid Flow
  • Mass Flow
  • Materials
  • Measurement
  • Paper
  • Standards
  • Test Facilities
  • Vacuum Pumps
  • Wind Tunnels

Readers

  • Aerosol Science/Aerosol Physics
  • Systems Analysis and Design