University of Surrey

Test tubes in the lab Research in the ATI Dance Research

The measurement of rotational relaxation times in gas mixtures at elevated temperatures.

Blacker, Stephen G. (1977) The measurement of rotational relaxation times in gas mixtures at elevated temperatures. Doctoral thesis, University of Surrey (United Kingdom)..

[img]
Preview
Text
10797547.pdf
Available under License Creative Commons Attribution Non-commercial Share Alike.

Download (6MB) | Preview

Abstract

The design, construction and use of an apparatus for the measurement of ultrasonic absorption and velocity dispersion in gas mixtures at elevated temperatures is described. The apparatus was used to measure rotational relaxation times in mixtures of normal hydrogen and argon at 293, 473 and 673 °K. The apparatus was capable of operation at temperatures from room up to 1000 °K and at pressures from one atmosphere down to ~ 0.015 of an atmosphere. It operated at a sound frequency of ~1 MHz, giving a frequency to pressure ratio (f/p) of between 1 and 65 MHz per atmosphere. A variable path length technique was employed. Bursts gated from a 1 MHz reference sine wave were amplified and transmitted, via fused quartz buffer rods, through the heated gas. Detection was achieved by mixing the received signal with the reference signal in a Phase-Sensitive Detector, the output of which was sampled and averaged by a Boxcar Integrator. The output of the Boxcar Integrator was digitised and recorded on punched tape for computer analysis which, with a knowledge of the sound frequency, yielded values of absorption coefficient and velocity. These were plotted as functions of f/p with temperature as a parameter. Calibration runs are described. These were performed on pure argon to determine the precision of measurements and, by comparison with other work, the accuracy of results obtained. Finally the results for mixtures of normal hydrogen and argon are presented and discussed. Values of rotational relaxation time and collision number for these mixtures are obtained and compared with available theoretical predictions.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors :
NameEmailORCID
Blacker, Stephen G.
Date : 1977
Contributors :
ContributionNameEmailORCID
http://www.loc.gov/loc.terms/relators/THS
Additional Information : Thesis (Ph.D.)--University of Surrey (United Kingdom), 1977.
Depositing User : EPrints Services
Date Deposited : 22 Jun 2018 09:50
Last Modified : 06 Nov 2018 16:52
URI: http://epubs.surrey.ac.uk/id/eprint/847169

Actions (login required)

View Item View Item

Downloads

Downloads per month over past year


Information about this web site

© The University of Surrey, Guildford, Surrey, GU2 7XH, United Kingdom.
+44 (0)1483 300800