![]() ![]() Fluids that deform at the same rate regardless of the force that causes this deformation are Newtonian. A distinction is usually made between two types: Newtonian and non-Newtonian fluids. Viscosity changes for different types of fluids. To remove most of the oil from the car, they run the engine to warm it up, increasing the flow of the oil. Decreased viscosity of oil with an increase in temperature is a very useful property for auto mechanics who change the oil. When measuring viscosity for machine lubrication purposes, it is commonly measured for 40° C (104° F) and for 100° C (212° F). When measuring kinematic viscosity, it is important to specify which temperature it was measured for, because it differs with temperature for each substance. It is calculated as absolute viscosity divided by the density. Kinematic viscosity measures this resistance, as relative to the density of the substance. Absolute Viscosity and Kinematic ViscosityĪbsolute viscosity, also known as dynamic viscosity, measures the resistance of a fluid to a force that is acting upon it to make it flow. The latter is more often used in the automotive industry. There are two types of viscosity: absolute viscosity that is used more commonly in medicine, cosmetics, and cooking, and kinematic viscosity. Viscosity is a measure of internal resistance of fluid to the force causing the fluid to flow. s) Centipoise is properly abbreviated cP, but the alternate abbreviations cps and cPs are also commonly seen.This is what happens when a metal ball falls into a cup of non-viscous coffee.A centipoise is one millipascal-second (mPa The poise is often used with the metric prefix centi. What is the difference between a poise and A centipoise? Check ASTM D 2161 “Standard Practice for Conversion of Kinematic Viscosity to Saybolt Universal Viscosity or to Saybolt Furol Viscosity”.Ĭentipoise (cP), dynamic viscosity. What is the Saybolt universal Sus viscosity equivalent?ġ) The Saybolt Universal SUS viscosity equivalent (SSU or SUS) to a given kinematic viscosity varies with the temperature at which the determination is made. Note! Viscosity conversions are based on fluids with specific gravity of one. What is the absolute viscosity of water at 1 centipoise?Ģ) Water at 68.4oF (20.2oC) has an absolute viscosity of one – 1 – centiPoise. Usually, centistokes (cSt) is used (1 cSt = 0.01 St = 1 mm2/s). The SI unit for kinematic viscosity is one meter squared per second and is equivalent to 10,000 St. The commonly used kinematic viscosity is defined as a measure of the restrictive flow of a fluid under gravitational force. To find the exact cp of your fluid: cp = cSt x (weight per gallon x 0.120). How do you convert Centipoise to centistokes?Ĭentipoise = centistokes x specific gravity where specific gravity is assumed to be 0.8 (except for water). There are several formulas and equations to calculate viscosity, the most common of which is Viscosity = (2 x (ball density – liquid density) x g x a^2) ÷ (9 x v), where g = acceleration due to gravity = 9.8 m/s^2, a = radius of ball bearing, and v = velocity of ball bearing through liquid. Measurement alternatives Typical Viscosity in cP∗∗ degrees F (degrees C) What is the viscosity of crude oil in Centipoise? The most common unit in the United States is the Sabolt Universal Seconds (SUS) or Sabolt Seconds Universal (SSU), which is measured with a Saybolt Viscosimeter. Saybolt Universal Seconds (SUS), which is the time in seconds for 60 milliliters of oil to flow through a standard orifice at a given temperature. ![]() This viscosity system is still in limited use, although it has been generally replaced by the ISO grading system. Although the two terms are regularly interchanged, which is further complicated due to 1 cP being equal to 1 cSt, they are in fact two slightly different terms. The proper way to identify oil viscosity, in cgs units, is either in centistokes (cSt), or more appropriately, centipoise (cP). 1 cP = 0.01 poise = 0.01 gram per cm second = 0.001 Pascal second = 1 milliPascal second = 0.001 N s/m2.For example: 100 cSt tested at 210 F is equivalent to 466.4 SUS because 100 x 4.664 = 466.4. The result is the cSt value converted to SUS. Multiply the cSt value by 4.664 if the test temperature was 210 F. How do you convert viscosity to centipoise?Īn easy way to convert from kinematic to dynamic viscosity is to multiply the value in centistokes by the specific gravity of the liquid to get the corresponding value in centipoise. ![]()
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