Principle: Archimedes method,,andare the system of heavy hammer and immersed melt filament respectively,is the acceleration of gravity,is the additional force caused by the surface tension of the melt, generally, ,is the radius of the hanging wire,is the surface tension of the melt, andis the wetting angle between the melt and the filament.

Advantages: considering the influence of volume expansion and surface tension, the test accuracy is greatly improved, with an accuracy of 0.5%.

Scope of application: stable without volatilization, low viscosity, uniform in liquid state, no precipitation, such as various molten salts and some liquid metals.

Schematic diagram of device principle:

Aid diagram

Result:

NCl experiment result and literature result comparison

Principle: CVCC method, that is, continuously changing conductance cell, that is, changing the length of the capillary conductance cell at a fixed external frequency, and then reading out the total impedance of the circuit at different conductance cell lengths.,is the molten salt resistance,is the length of the conductivity cell,is the cross-sectional area of the conductivity cell,is the constant of the conductivity cell, is the conductivity.

Advantages: during calibration and measurement, the consistency requirements of the conductivity cell are no longer as strict as those of the fixed conductivity cell constant method, which facilitates the test. The measurement accuracy is 5%, and the reproducibility is 3%.

Scope of application: stable without volatilization, low viscosity, uniform in liquid state, no precipitation, such as various molten salts and some liquid metals.

Principle: step cooling curve method

Measurement accuracy:±1℃

Historical data: sodium chloride step cooling curve

Schematic diagram of device principle:

Crystal temperature measurement aid diagram

Result:

Test method: maximum bubble method,,whereis the surface tension,is the radius of the capillary,is the maximum pressure of the bubble,is the gravitational acceleration,is the depth of the capillary immersed in the electrolyte molten salt,For the density of molten electrolyte, the measurement accuracy of this method can reach 3%.

Result:

Schematic diagram of device principle:

5.1 Rotational method

Principle: rotation method,,is the moment generated by rotation,andis the radius of the inner and outer cylinders respectively, is the depth of the inner cylinder immersed in the liquid,is the angular velocity of rotation, is the additional pipe length introduced by the end effect caused by the viscous resistance of the end face of the inner cylinder.

Advantages: the double hanging wire software connection technology realizes the measurement of the viscosity of high-temperature liquid molten salt for the first time, filling the gap in the field of high-temperature and low viscosity measurement.

Viscosity test range:1.6-20cp(low viscosity),50-10⁵ cp (vacuum high viscosity)

Measurement accuracy:＜0.2cp

Schematic diagram of device principle:

Sample(oil) result:

5.2 Torsion cylinder method

Principle: oscillating cup, by rotating and vibrating the sample liquid in the container, internal friction will occur between liquid molecules. The logarithmic decay rate of rotation is measured, and the viscosity data is obtained according to the relationship between the logarithmic decay rate and viscosity.

Advantages: suitable for the measurement of high temperature and low viscosity liquid samples, especially low viscosity samples such as metals / alloys.

Schematic diagram of device principle:

Principle: laser flash method, based on Park formula,,whereandandare the thermal diffusion coefficient of the sample, the thickness of the sample and 1 / 2 of the time when the temperature of the laser pulse emitted to the lower surface rises to steady state, respectively.

Application: isotropic solid samples.

Schematic diagram of device principle:

Method: Short hot wire method

Testing range: molten salt

Schematic diagram of device principle:

Principle: falling isotherm method: take the material with massas the sample, heat it to a constant temperaturein a high-temperature furnace under constant pressure, and then put it into a calorimeter with a constant temperature, causing the temperature of the calorimeter to rise. If the energy equivalent of the calorimeter isand the stable temperature at the end of the calorimeter is, the heatlost by the sample is:

is the average specific heat of the sample betweenand. And the heatobtained by the meter is:

If the calorimeter is kept in an ideal adiabatic state and the heat loss when the sample falls is eliminated, then:

From the above three formulas and according to the definitions of enthalpy, average specific heat and true specific heat, we can get:

Advantages: wide measurement temperature range -150~1700℃, measurement accuracy: 100-800℃（±1.5%），800-1700℃（±3%）