Fluid mechanics help mechanical engineering

[apamnani1]

Fluid mechanics help! mechanical engineering

Hi people!

I have been doing some fluid questions and got stuck ont he following two;


1) A Casson plastic fluid is subjected to a shear force of 5.5 Pa. If the fluid obeys a law of the form T =1.5 +0.2^0.45u, determine the shear rate and apparent viscosity under these conditions

2) Oil of dynamic viscosity 0.12 Nsm-2 is used to lubricate the space between the plain journal bearing with the shaft. The shaft and bearing are concentric and the space between them is filled with an oil of dynamic viscosity of 0.15Nsm^-2.

Determine the torque required to overcome viscous resistance and the power loss when the shaft is rotating at a speed of 3000rpm.


Any help would be amazing!

Cheers

 

[AvroArrow]

,Answer 1:Shear rate = (5.5 / (1.5 + 0.2^0.45)) Apparent viscosity = (1.5 + 0.2^0.45) * shear rate Answer 2: Torque required to overcome viscous resistance = (π * (shaft radius)^3 * dynamic viscosity) / (2 * bearing radius)Power loss = (torque required * angular velocity) / (60 * 1000000)