modelMechanicalPumpLosses
Coulomb and viscous friction in pump
Extends from Modelica.Mechanics.Rotational.Interfaces.PartialTwoFlangesAndSupport (Partial model for a component with two rotational 1-dim. shaft flanges and a support used for graphical modeling, i.e., the model is build up by drag-and-drop from elementary components), Modelica.Mechanics.Rotational.Interfaces.PartialFriction (Partial model of Coulomb friction elements).
Information
This element describes frictional losses in a hydraulic pump or motor.
The model is based on the paper:
- McCandlish, D., and Dorey, R. E.,
- 'The Mathematical Modelling of Hydrostatic Pumps and Motors,' Proceedings of the Institution of Mechanical Engineers, Part B, Vol. 198, No. 10, 1984, pp 165-174.
The model implementation is derived from the bearing friction model in the standard Modelica library.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | useSupport (from PartialTwoFlangesAndSupport) | false | = true, if support flange enabled, otherwise implicitly grounded |
| Real | Cv | 0.1 | Coefficient of viscous drag |
| Real | Cf | 0.01 | Coefficient of Coulomb friction (fraction of full stroke torque) |
| SI.Volume | Dmax | 1e-4 | Full stroke pump Displacement |
| SI.DynamicViscosity | mu | 0.036 | Dynamic Viscosity of liquid |
| Integer | Unknown (from PartialFriction) | 3 | Value of mode is not known |
| Integer | Free (from PartialFriction) | 2 | Element is not active |
| Integer | Forward (from PartialFriction) | 1 | w_relfric > 0 (forward sliding) |
| Integer | Stuck (from PartialFriction) | 0 | w_relfric = 0 (forward sliding, locked or backward sliding) |
| Integer | Backward (from PartialFriction) | -1 | w_relfric < 0 (backward sliding) |
| Advanced | |||
| SI.AngularVelocity | w_small (from PartialFriction) | 1.0e10 | Relative angular velocity near to zero if jumps due to a reinit(..) of the velocity can occur (set to low value only if such impulses can occur) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Flange_a | flange_a (from PartialTwoFlangesAndSupport) | Flange of left shaft | |
| Flange_b | flange_b (from PartialTwoFlangesAndSupport) | Flange of right shaft | |
| Support | support (from PartialTwoFlangesAndSupport) | Support/housing of component | |
| Modelica.Blocks.Interfaces.RealInput | dp |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| SI.AngularVelocity | w_relfric (from PartialFriction) | Relative angular velocity between frictional surfaces | |
| SI.AngularAcceleration | a_relfric (from PartialFriction) | Relative angular acceleration between frictional surfaces | |
| SI.Torque | tau0 (from PartialFriction) | Friction torque for w_relfric=0 and forward sliding | |
| SI.Torque | tau0_max (from PartialFriction) | Maximum friction torque for w_relfric=0 and locked | |
| Boolean | free (from PartialFriction) | = true, if frictional element is not active | |
| Real | sa (from PartialFriction) | Path parameter of friction characteristic tau = f(a_relfric) | |
| Boolean | startForward (from PartialFriction) | = true, if w_relfric=0 and start of forward sliding | |
| Boolean | startBackward (from PartialFriction) | = true, if w_relfric=0 and start of backward sliding | |
| Boolean | locked (from PartialFriction) | = true, if w_rel=0 and not sliding | |
| Integer | mode (from PartialFriction) | Mode of friction (-1: backward sliding, 0: stuck, 1: forward sliding, 2: inactive, 3: unknown) | |
| SI.Torque | tau | ||
| SI.Angle | phi | ||
| SI.AngularVelocity | w | Absolute angular velocity of flange_a and flange_b | |
| SI.AngularAcceleration | a | Absolute angular acceleration of flange_a and flange_b |