Papers by Keyword: Spark Discharge

Abstract: Varnish now becomes the severe problem of gas turbine, nuclear power plant and other industry which use lubricant oil and hydraulic fluid. The cause of varnish formation is heat, oxidation and contamination. Varnish can cause many turbine problems. The Membrane Patch Colorimetry (MPC) test can be used to measure varnish. Partial or all oil change, Filtration with Cellulose Media and System Chemical Cleaning can be applied to mitigate varnish.

Abstract: A pulsed spark-discharge aerosol generator using air as a carrier gas was successfully applied to the titania nanoparticle production. The titanium vapor evaporated by spark discharge was subsequently supersaturated and condensed to titania nanoparticles by nucleation and condensation. The size and concentration of the particles can be controlled easily using air as a carrier gas by altering the repetition frequency, capacitance, gap distance, and flow rate of the spark-discharge system. TEM observation shows that the generated particles were aggregates, which primary particle sizes are a few nanometers. The element composition of the nanoparticles was titanium and the crystal phase was amorphous. XPS analysis shows that oxidation state of generated particles corresponded to TiO2. These XPS data indicates that some fraction of the evaporated titanium vapor could be oxidized in an air atmosphere by the oxidation with oxygen. However, enough time for crystallization was lacked because of raid cooling.