한국윤활학회:학술대회논문집 (Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference)
- 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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- Pages.355-356
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- 2002
Viscosity Prediction of Synthetic Lubricants from Temperature and Pressure Dependence of Dielectric Relaxation Time
- Suzuki, A. (Department of Chemical Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology) ;
- Masuko, M. (Department of Chemical Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology)
- 발행 : 2002.10.21
초록
The dielectric permittance and the dielectric loss factor of several lubricating oils were measured at frequencies from 100 Hz to 1.5 MHz. The measurements were carried out under atmospheric pressure as a function of temperature and under fixed temperature as a function of pressure. Temperature and pressure dependence of dielectric relaxation time were investigated. The temperature dependence of relaxation time obeyed the Vogel-Fulcher-Tammann (VFT) law. We modified the VFT equation in order to express the dielectric relaxation time as a function of temperature and pressure. Furthermore. by taking into consideration the similarity of the temperature and pressure dependence between dielectric relaxation and mechanical relaxation. the prediction of high-pressure viscosity were conducted. The predicted results were compared with the viscosity data obtained from the falling-sphere type viscometer.