dynamic viscosity coefficient iso vg 32

[Mr_Curious]

Hello dear friends.

Please, share an information of dynamic viscosity coefficien for iso vg 32 oil for various temperature.

 

[electricpete]

I posted a spreadsheet that will get you started, here.
thread391-314986
It requires input of viscosity at two different temperatures.
You have viscosity = 32 cSt at 40C.
We need viscosity index to figure out figure out viscosity at 100C... do you have a viscosity index for your oil?

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(2B)+(2B)' ?

 

[Mr_Curious]

I dont have viscosity index.

 

[romke]

How accurate do you want the data to be? A ISO VG 32 fluid will have a kinematic viscosity of 32 +/- 10% mm2/s at 40 deg C. It thus should have a kinematic viscosity somewhere between 28.8 and 35.2 mm2/s when fresh...a range far greater then what in other forms of engineering would be acceptable. Given that large spread each subsequent batch may differ considerably in viscosity, all be it within the 20% range specified.

The suggested spreadsheet will give you a useful indication of the dynamic viscosity at other temperatures - if you want the dynamic viscosity you will need to multiply the outcome with the density of the fluid at the same temperature of the viscosity measured.

You do not need the viscosity-index to get the viscosity data at various temperatures. However, if you want the VI, it can be calculated - in the appendix of ASTM D2270 you can find how to. If you do have the viscosity at 40 and 100 deg C you can also find a calculation tool on the internet:

https://wiki.anton-paar.com/nl-en/astm-d2270-viscosity-index-vi-from-40c-and-100c/

If you only want to know the dynamic viscosity at a certain non-standard temperature the easiest way is to have that measured in a laboratory.

 

[Mr_Curious]

I have got it.

 

[electricpete]

Not every vg32 oil has the same viscosity variation with temperature.

It follows a predictable pattern which can be determined only if you know the viscosity index or the viscosity at one other temperature (besides 40C where viscosity is 32 cSt).

The further you are projecting away from the reference temperature 40C, the larger the error you might encounter from some arbitrary assumption embodied in the chart.




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(2B)+(2B)' ?

 

[Mr_Curious]

Ok. Thank you. I didn't know about it. i will keep in mind