A Preliminary Study Of The Effect Of Some Pressurising Gasses On The Viscosity Of Dimethyl Ether

Ion Marius Sivebæk, Jørgen Jakobsen

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Abstract

Dimethyl Ether (DME) has been recognised as a clean substitute for diesel oil as it does not form soot during combustion. DME has a vapour pressure of 6 bar at 25 C so pressurisation is necessary to keep DME liquid at ambient temperature. Inert gases are good candidates as pressurising media for DME but their effect on DME viscosity is unknown. Argon (Ar), nitrogen (N2), carbon dioxide (CO2), hydrogen (H2) and Propane (C3H8) have been investigated at pressure levels of 12 – 15 bars. A Cannon-Manning semi-micro capillary glass viscometer, size 25, enclosed in a cylindrical pressure container, of glass, has been used. No significant change of the efflux time was found for all the pressurising gasses, except for the gas CO2. A reduction of efflux times was found for the CO2 of about 9 %   0,6 %. The measurement accuracy for all these series was found for this very low viscosity fluid to be in the range 0,2 % up to more than 1 %. The previously reported viscosity of DME has been corrected for the surface tension effect. Viscosity determination was initially based on a direct comparison of efflux times of DME with efflux times of distilled water. Assuming an upper limit for the variation of an order of magnitude of maximum of 1 %, as found for all the series with pressurising gasses, the calculated correction for surface tension gave a revised, kinematic viscosity of 0,186 cSt   0,002 cSt @ 25 C. The viscosity of pure DME has been determined again with a calibrated Cannon- Manning semi-micro glass viscometers, size 25, submerged completely in a constant temperature bath. A kinematic viscosity of 0,188 cSt  0,001 cSt @ 25 C, was found, consistent with the previous and initial result 0,186 cSt   0,002 cSt. Key words: Dimethyl Ether (DME), a clean substitute for diesel oil. DME viscosity. Influence of pressurising gases on viscosity. Exponential kinematic viscosity – temperature coefficient, kin, values of pure DME.
Original languageEnglish
Title of host publicationProceedings of the 12th Nordic Symposium on Tribology:
EditorsPeder Klit, Jørgen Jakobsen, Svend Eskildsen
Publication date2006
ISBN (Print)87-90416-19-8
Publication statusPublished - 2006
Event12th Nordic Symposium on Tribology - Helsingør, Denmark
Duration: 7 Jun 20069 Jun 2006

Conference

Conference12th Nordic Symposium on Tribology
CountryDenmark
CityHelsingør
Period07/06/200609/06/2006

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