oilman
14-03-2008, 16:30
To kick off Opie Oils new 12 part series of interesting oil facts we thought that we would address the statement “My oil has turned to water!”
Let’s be objective and look at the actual figures involved here, emotional expressions such as ‘turned to water’ just will not do. Engineering is supposed to be a science afterall!
So! Almost all modern jet engines run on 5cst at 100degC synthetic ester oil. Needless to say, some bearings will actually be running at a temperature of perhaps 200degC; so the true oil viscosity in these situations is in fact 1.5cst.
This is really thin, much thinner than any car or bike engine oil even in a race engine.
But is it as thin as water? NO!
At 20degC water has a viscosity of 1.0cst and at 50degC it drops to 0.55cst.
Just for comparison, a 0w-20 oil will have an approximate viscosity of 107cst at 20degC, 32cst at 50degC, 8.9cst at 100degC and 2.3cst at 200degC.
So there you go, it may look like water but it certainly isn’t!
Cheers.
Guy & The Opieoils.co.uk Team
Note:
Centistokes (cst) is the measure of a fluid's resistance to flow (viscosity). It is calculated in terms of the time required for a standard quantity of fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid.
Let’s be objective and look at the actual figures involved here, emotional expressions such as ‘turned to water’ just will not do. Engineering is supposed to be a science afterall!
So! Almost all modern jet engines run on 5cst at 100degC synthetic ester oil. Needless to say, some bearings will actually be running at a temperature of perhaps 200degC; so the true oil viscosity in these situations is in fact 1.5cst.
This is really thin, much thinner than any car or bike engine oil even in a race engine.
But is it as thin as water? NO!
At 20degC water has a viscosity of 1.0cst and at 50degC it drops to 0.55cst.
Just for comparison, a 0w-20 oil will have an approximate viscosity of 107cst at 20degC, 32cst at 50degC, 8.9cst at 100degC and 2.3cst at 200degC.
So there you go, it may look like water but it certainly isn’t!
Cheers.
Guy & The Opieoils.co.uk Team
Note:
Centistokes (cst) is the measure of a fluid's resistance to flow (viscosity). It is calculated in terms of the time required for a standard quantity of fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid.