Rotating Cylinder Force (IL)

R2026b

Centripetal pressure gradient for components in an isothermal liquid system

• 

Rotating Cylinder Force (IL) block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simscape / Fluids / Isothermal Liquid / Actuators / Auxiliary Components

Description

The Rotating Cylinder Force (IL) block models the axial force due to a centripetal pressure gradient in a rotating shaft about its symmetry axis, which is found in applications such as friction clutches, square-jaw positive clutches, dog clutches, and brakes. Connect this block in parallel to a Single-Acting Actuator (IL) or a Translational Mechanical Converter (IL) block to model a rotating actuator. The fluid density is recorded at the isothermal liquid port X. The angular velocity is received as a physical signal at port W. Port R is associated with the piston velocity, relative to the case at port C.

The angular velocity of the shaft is assumed to be constant or nearly-constant, and therefore the fluid is considered to be in rigid-body rotation.

The centripetal force is due solely to the fluid angular momentum induced by shaft rotation. Removing the contribution of the static pressure in the fluid channel, the contribution of the rotation of the shaft to the axial force is:

$$F_{rotational}=\frac{\rho \pi W^2}{4}\left(r_o^4-r_i^4-2r_p^2\left(r_o^2-r_i^2\right)\right),$$

where:

• ρ is the fluid density at port X.

• W is the angular velocity of the rotating pipe, received as a physical signal at port W.

• r_o is the Piston outer radius.

• r_i is the Piston inner radius.

• r_p is the Fluid entry radius.

Ports

Conserving

X — Liquid density port

isothermal liquid

Liquid port associated with fluid density. There is no mass flow through port X. Connect port X to port A of the Single-Acting Actuator (IL) or Translational Mechanical Converter (IL) blocks.

Programmatic Use

Port: X

C — Cylinder casing

mechanical translational

Mechanical translational conserving port associated with the cylinder casing reference velocity and force.

Programmatic Use

Port: C

R — Piston

mechanical translational

Mechanical translational conserving port associated with the piston velocity and force induced by the pressure differential.

Programmatic Use

Port: R

Input

W — Angular velocity, rad/s

physical signal

Angular velocity in rad/s, specified as a physical signal.

Programmatic Use

Port: W

Parameters

Piston outer radius — Piston outer radius

0.1 m (default) | positive scalar

Piston outer radius.

Programmatic Use

Parameter: r_outer

Piston inner radius — Piston inner radius

0.05 m (default) | positive scalar

Piston inner radius.

Programmatic Use

Parameter: r_inner

Fluid entry radius — Fluid channel radius

0.06 m (default) | positive scalar

Radius of the fluid opening in the cylinder casing, measured from the rotational axis. This value must be greater than or equal to the Piston inner radius and less than or equal to the Piston outer radius.

Programmatic Use

Parameter: r_fluid

Actuator mechanical orientation — Piston displacement direction

Pressure at A causes positive displacement of R relative to C (default) | Pressure at A causes negative displacement of R relative to C

Piston displacement direction of the connected actuator block. Pressure at A causes positive displacement of R relative to C corresponds to positive displacement, or actuator shaft extension, when R – C is positive. Pressure at A causes negative displacement of R relative to C corresponds to negative displacement, or actuator shaft retraction, when R – C is positive.

Programmatic Use

Parameter:	mech_orientation
Values:	"foundation.enum.MechOrientationTranslational.Positive" | "foundation.enum.MechOrientationTranslational.Negative"

Programmatic Use: Add Block

To add the block programmatically, use the add_block function with one of these library block paths as the source.

"SimscapeFluids_lib/Isothermal Liquid/Actuators/Auxiliary Components/Rotating
    Cylinder Force (IL)"

Example: add_block("SimscapeFluids_lib/Isothermal Liquid/Actuators/Auxiliary Components/Rotating Cylinder Force (IL)","myModel/myBlock",MakeNameUnique="on")

For information about programmatic access to individual block parameters, see the Programmatic Use section of parameter descriptions on this page.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2020a