VISCOSITY MEASUREMENT WITH DOUBLE-WIRE TORSION PENDULUM

A new method of measuring the viscosity of liquid, which is named the double-wire torsion pendulum method in contrast to the conventional to rsion pendulum method, is described in this paper. It was found that t he damping factor alpha(l) changes nearly linearly with the kinematica l viscosity eta/rho of the standard oil in the range from 1.55 to 1.15 X10(4) cp. An empirical formula is derived for the damping factor alph a(l) and the viscosity eta/rho, and which factors can influence this e mpirical formula are also presented. The apparatus as constructed is c apable of measuring the viscosity and its activation energy over a wid e range of temperatures, and is especially suitable for melts at high temperatures with a wide, accurate, dynamic viscosity range. Applying this method, we have observed that the viscous activation energy of a supercooled Li2BBO13 melt is obviously different from that of the norm al melt. (C) 1995 American Institute of Physics.