viscosity

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One of the main problems with biodiesel is its viscosity. The viscosity of diesel fuel is 2.5 to 3.2 cSt at 40 ° C and the viscosity of biodiesel made from soybean oil is 4.2 to 4.6 cSt. The viscosity of the diesel must be high enough to provide sufficient lubrication to the engine parts, but it must be low enough to operate at operating temperature. High viscosity may clog the fuel filter and injection system inside the engine. Vegetable oil is composed of lipids containing long chain hydrocarbons. Long chain hydrocarbons are broken down into smaller ester molecules in order to lower the viscosity. This is achieved by using transesterification to convert vegetable oils and animal fats to alkyl esters to lower their viscosity. However, biodiesel viscosity is still higher than diesel, and because of the slow flow rate, the engine may not be able to use fuel at low temperatures. Fuel filter

Depending on the application, kinematic viscosity is more convenient than absolute or dynamic viscosity. Kinematic viscosity is the absolute viscosity of a fluid divided by its mass density. The magnitude of the kinematic viscosity is the area divided by the time, the appropriate unit is square meters per second. A unit of kinematic viscosity in the centimeter - gram - second (CGS) system known as Stokes in the UK and Stokes in the United States. It is from British physicist Sir George Gabriel Stokes. Give your name. The stroke is defined as 1 square centimeter per second

Actually there are two quantities called viscosity. The amount defined above may be referred to as dynamic, absolute or simple viscosity to distinguish it from other quantities, but in many cases it is called viscosity. Another quantity called kinematic viscosity (represented by the Greek letter ν "nu") is the ratio of the viscosity of the fluid to its density. Kinematic viscosity is a measure of the resistance flow of a fluid under the influence of gravity. It is usually measured using a device called a capillary viscometer - basically a calibrated can with a thin tube at the bottom. When two equal volumes of fluid are placed in the same capillary viscometer and flow under the influence of gravity, it takes time for the more viscous fluid to flow through the tube than the non-viscous fluid. Capillary viscometer is explained in detail later in this section.