GB/T 18856.4-2008Test methods for coal water mixture - Part 4: Determination of apparent viscosity (English PDF)

1 Scope

This Part of GB/T 18856 specifies the terms and definitions, method summary, reagents and materials, instruments and equipment, test conditions, test procedures, result calculation, method precision, and test report for the determination of apparent viscosity of coal water mixture using a coaxial cylindrical rotational viscometer.

This Part applies to various types of coal water mixture.

2 Terms and Definitions

The following terms and definitions are applicable to this Part of GB/T 18856.

2.1 rate of shear

The change in flow velocity of a fluid per unit distance is called the rate of shear, which is represented as Ds , in the unit of s

-1

.

2.2 apparent viscosity

For a fluid subjected to shear between two parallel planes, when the normal gradient per unit contact surface area is 1, the magnitude of the internal friction or shear force caused by the fluid’s viscosity is called viscosity. The viscosity of a non-Newtonian fluid at a given rate of shear is called the apparent viscosity at that rate of shear.

2.3 apparent viscosity of coal water mixture

In this Part,eta100 s ^-^1 is used to represent the apparent viscosity of coal water mixture at a rate of shear of 100 s^-^1, in the unit of (mPa - s). The subscript indicates the rate of shear at the time of determination.

3 Method Summary

Put a suitable amount of coal water mixture in the outer cylinder of a coaxial cylindrical rotational viscometer. At a specified temperature, the inner cylinder rotates at a certain angular velocity. Determine the viscous torque experienced by the cylinder during rotation, thereby obtaining the apparent viscosity at the corresponding rate of shear.

4 Reagents and Materials

Dynamic viscosity approximately 300 mPa - s ~ 2,500 mPa - s (20 °C); one set of four certified standard viscosity solutions.

5 Instruments and Equipment

6 Test Conditions

6.1 Ambient temperature: 18 °C ~ 28 °C.

6.2 Test temperature: (20 ± 0.1) °C.

6.3 Rate of shear: 100 s^-^1. Apparent viscosity determination at other rates of shear can be performed with reference to this Part.

7 Test Procedures