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MESYS Calculation Software

The pressure viscosity coefficient α is used for the calculation of lubricant film thickness. If the film thickness should not be calculated, you can just enter zero.

According (ISO/TR 1281-2, 2008) pressure viscosity coefficient α can be calculated by the kinematic viscosity ν0 in cm2/s as

all_img271

To calculate the reference viscosity ν1 a value of all_img272 using ν in mm2/s and α in mm2/N is used according (Baalmann, 1994).

In the software, the proposal according (AGMA 925, 2003) is used, because different oil types are considered. The pressure viscosity coefficient is calculated as all_img273, where ηM is the dynamic viscosity at operating temperature. The factors k and s are given for different lubricant types as shown in the following table:

Oil type

k

s

Mineral oil

0.010471

0.1348

PAO based synthetic non-VI improved oil

0.010326

0.0507

PAG based synthetic

0.0047

0.1572

 

This formula is used if a lubricant from the list is selected. If ‘own input’ is selected, either the formula according to (ISO/TR 1281-2, 2008) 11.8 or according to (AGMA 925, 2003) or a direct input can be selected using the all_img3-button next to the input field.