ID 58

High Pressure Measurements of Interfacial Tension in Methanol-CO2 using Capillary Waves

 

Abstract:

Interfacial tension measurements are crucial in the design and operation of many systems that function at high pressure and temperatures such as rocket and diesel engines. An experimental study has been conducted to determine the effects of pressure on interfacial tension very near the critical point. Interfacial tension for a CH3OH-CO2 mixture was measured by the capillary wave method and extended up to pressures of 5.6 MPa and taken at 298K. The experimental setup consists of a pool methanol placed inside a pressure vessel which was pressurized with CO2. Capillary waves are generated on the liquid surface using a metal rod and driven by a function generator. The waves act as a diffraction grating for the HeNe light to reflect off the surface and generate a diffraction pattern. Interfacial tension measurements of pure methanol are compared with published data and significant scatter is found among various techniques. Experimental uncertainties associated with the technique are described. Interfacial tension measurements with increasing pressure are made in CH3OH-CO2 mixtures and show a linear decrease very near the critical point.