Email Document Reference

Enter your email address below and the reference for this document will be sent to shortly from webmaster@ceesi.com.

Title: Pressure Ror Gas Flow Measurement: When Is The Fill Isothermal?
Author: Thomas O. Maginnis
Source: 2009 Measurement Science Conference
Year Published: 2009
Abstract: The rate of rise of gas pressure in a vacuum tank of known volume has been used to measure the steady flow of gas into the tank. An equation of state for the gas is required to relate gas pressure, tank volume, fill time and gas temperature to the mass of gas collected in the tank. Normally the ideal gas equation (or a simple correction) is used for this purpose. The difficulty of accurately measuring the real-time temperature of a low pressure gas during the fill process has caused much confusion. Many practitioners simply measure the tank wall temperature and assume that it is always equal to the gas temperature. This is certainly not correct when adiabatic compression causes the gas to heat up during the fill, and thermal conduction to the wall makes the gas temperature time dependent and spatially non-uniform. However, the ROR technique appears empirically to work well at sufficiently low gas pressures, for some gases better than others. This gas dependence has until now not been theoretically modeled. This paper will examine the basic physics of the ROR flow measurement process and derive pressure and flow restrictions required for the fill to take place isothermally, as a function of the gas properties

In order to prevent spam and automated file downloads for documents within the Measurement Library, please follow the instructions below and then you will be able to email a reference to this article.