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viscosity is when something movs to slow or when something moves really fast like
maple syrup and water
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∙ 14y ago
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What is the effect of adding impurity on viscosty of liquid?
This depends on the type of this impurity.
How do viscosity index improvers work?
these are large sized molecules that have a ball shape when cold. upon heating they then uncoil and become longer. they are also sticky and so interact with each other.the oil fluid with these bulkier compounds is then harder to pump and therefore more viscois. this makes the resulting oil mix thicker at the higher temperature than without the viscosity index improvers. as a result a thinner base oil can be used to lubricate with the advantage of better flow at low temperatures, and in the post strartup warming cycle. this heated oil mix is thicker at higher temps than a heavier oil without viscosity index improvers, and thus can protect better. these compounds ae commonly used in multi viscosty oils.
Why cant one engine oil serve all engines?
If all the engines were the same - then you could use the same oil. But each engine design is slightly different - different power output, different metal structure, cam design, etc - all these put differences add up so that the lubrication requirement for one engine isn't the same as the lubrication requirement for another.Some engines (esp. high performance types) require oils that can transfer heat away from the surfaces more efficiently without oxidising or vapourising, and where the Viscosity Index (not the actual viscosity) is high - for these engines a fully synthetic oil with a relatively low actual viscosity but high VI is needed. Say a 0W10 to 0W30 oil.Other engines, lets take the extreme example of a steam locomotive engine, require an oil that can operate in wet conditions while still rejecting moisture, high sulfur load fuel and "loose" seals - the oil would need to be high viscosty, high Total Base Number to protect the moving parts, high EP factor and low moisture capture. This could be a mono grade 600 weight oil.It all really comes back to engine design.
How does viscosity affect the rate of diffusion?
The higher the viscosity, the slower the rate of diffusion. Think of a liquid trying to diffuse through a plate of water (low viscosity) versus a liquid trying to diffuse through a plate of agar (high viscosity)
