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Consequently, if a liquid has dynamic viscosity of n centiPoise, and its density is not too different from that of water, then its kinematic viscosity is around n centiStokes. For gas, the dynamic viscosity is usually in the range of 10 to 20 microPascal-seconds, or 0.01 to 0.02 centiPoise. The density is usually on the order of 0.5 to 5 kg/m^3.
But SAE also allows designating an oil with two viscosity grades, referred to as a multi-grade oil. For example, 10W-30 designates a common multi-grade oil. A 10W-30 oil must pass the SAE J300 viscosity grade requirements for both 10W and 30, and all limitations placed on the viscosity grades, such as the requirement that a 10W oil must fail ...
Extensional viscosity can be measured with various rheometers that apply extensional stress. Volume viscosity can be measured with an acoustic rheometer. Apparent viscosity is a calculation derived from tests performed on drilling fluid used in oil or gas well development. These calculations and tests help engineers develop and maintain the ...
where U is the oil's kinematic viscosity at 40 °C (104 °F), Y is the oil's kinematic viscosity at 100 °C (212 °F), and L and H are the viscosities at 40 °C for two hypothetical oils of VI 0 and 100 respectively, having the same viscosity at 100 °C as the oil whose VI we are trying to determine.
The dilute gas viscosity contribution to the total viscosity of a fluid will only be important when predicting the viscosity of vapors at low pressures or the viscosity of dense fluids at high temperatures. The viscosity model for dilute gas, that is shown above, is widely used throughout the industry and applied science communities.
Viscotherms is a general name used to describe equipment for control of viscosity and temperature of a fluid, in particular of fuel oil in fuel viscosity control systems. [1] [2] The term originated from a brand name Viscotherm registered by VAF Instruments in 1971 and produced until 2009.
The mini-rotary viscometer is a device used to measure the pumpability of an engine oil at low temperatures. [1] [2] Engine oils must meet viscometric standards including those determined by the MRV in order to be classifiable within SAE J300 viscosity grades. The requirement was added after the winters of 1980-81 and 1981-82 caused major ...
Increasing temperature results in a decrease in viscosity because a larger temperature means particles have greater thermal energy and are more easily able to overcome the attractive forces binding them together. An everyday example of this viscosity decrease is cooking oil moving more fluidly in a hot frying pan than in a cold one.