Lubricants and Lubrication

All of the below functions can be found in the lubrication module of the package.

This module contains functions related to lubricants and lubrication.

barus(eta_0, alpha_p, pressure)

Calculate the dynamic viscosity at a given pressure based on the dynamic viscosity at atmospheric pressure and the pressure-viscosity coefficient.

Parameters:

• eta_0 (float, ndarray) – The dynamic viscosity at atmospheric pressure.
• alpha_p (float, ndarray) – The pressure-viscosity coefficient of the fluid.
• pressure (float, ndarray) – The pressure at which to calculate the dynamic viscosity.

Returns:

eta_p – The dynamic viscosity at pressure pressure.

Return type:

scalar

dyn2kin(dyn, density)

Convert from dynamic to kinematic viscosity.

Parameters:

• dyn (ndarray, scalar) – The dynamic viscosity of the lubricant.
• density (ndarray, scalar) – The density of the lubricant.

Returns:

kin – The kinematic viscosity of the lubricant.

Return type:

ndarray, scalar

kin2dyn(kin, density)

Convert from kinematic to dynamic viscosity.

Parameters:

• kin (ndarray, scalar) – The kinematic viscosity of the lubricant.
• density (ndarray, scalar) – The density of the lubricant.

Returns:

dyn – The dynamic viscosity of the lubricant.

Return type:

ndarray, scalar

trheomcone(eta, alpha, omega, r_a)

Calculate the torque that occurs during a viscosity measurement using a cone-on-plate rheometer.

Parameters:

• eta (scalar) – The dynamic viscosity of the fluid.
• alpha (scalar) – The cone angle in radians.
• omega (scalar) – The angular velocity of the rotating plate (in radians per second).
• r_a (scalar) – The outer diameter of the rotating plate.

Returns:

torque – The torque required to rotate the rotating plate.

Return type:

scalar

trheomflat(eta, gap_height, omega, r_a)

Calculate the torque that occurs during a viscosity measurement using a plate-on-plate rheometer.

Parameters:

• eta (scalar) – The dynamic viscosity of the fluid.
• gap_height (scalar) – The gap height between the stationary and the rotating plate.
• omega (scalar) – The angular velocity of the rotating plate (in radians per second).
• r_a (scalar) – The outer diameter of the rotating plate.

Returns:

torque – The torque required to rotate the rotating plate.

Return type:

scalar

viscrheomcone(torque, alpha, omega, r_a)

Calculate the dynamic viscosity of a fluid based on the measurement torque in a cone-on-plate rheometer.

Parameters:

• torque (scalar) – The torque required to rotate the rotating plate.
• alpha (scalar) – The cone angle in radians.
• omega (scalar) – The angular velocity of the rotating plate (in radians per second).
• r_a (scalar) – The outer diameter of the rotating plate.

Returns:

eta – The dynamic viscosity of the fluid.

Return type:

scalar

viscrheomflat(torque, gap_height, omega, r_a)

Calculate the dynamic viscosity of a fluid based on the measurement torque in a plate-on-plate rheometer.

Parameters:

• torque (scalar) – The torque required to rotate the rotating plate.
• gap_height (scalar) – The gap height between the stationary and the rotating plate.
• omega (scalar) – The angular velocity of the rotating plate (in radians per second).
• r_a (scalar) – The outer diameter of the rotating plate.

Returns:

eta – The dynamic viscosity of the fluid.

Return type:

scalar

walther(temp_1, nu_1, temp_2, nu_2, temp_3)

Calculate the kinematic viscosity at temperature temp_3 based on the kinematic viscosities at temperatures temp_1 and temp_2. The implementation follows standard ASTM D341.

Parameters:

• temp_1 (scalar) – The temperature in \(^{\circ}\text{C}\) that corresponds to the kinematic viscosity nu_1.
• nu_1 (scalar) – The kinematic viscosity in cSt at temperature temp_1.
• temp_2 (scalar) – The temperature in \(^{\circ}\text{C}\) that corresponds to the kinematic viscosity nu_2.
• nu_2 (scalar) – The kinematic viscosity in cSt at temperature temp_2.
• temp_3 (ndarray) – The temperature in \(^{\circ}\text{C}\) for which to calculate the kinematic viscosity.

Returns:

nu_3 – The kinematic viscosity in cSt at temperature temp_3.

Return type:

ndarray