Engee documentation

Fixed-Displacement Motor (IL)

A constant displacement hydraulic motor in an isothermal liquid network.

fixed displacement motor il

Description

The Fixed-Displacement Motor (IL) unit simulates a constant displacement hydraulic motor. The fluid flow can be from port A to port B (forward mode) or from port B to port A (reverse mode). The hydraulic motor mode is realised when the pressure drops in the direction of flow. The pump mode is realised when the pressure in the flow direction increases.

fixed displacement motor il 1

The unit has four modes of operation. The mode of operation depends on the pressure drop from port A to port B and the angular velocity :

  • Mode 1, forward hydraulic motor mode: flow from port A to port B causes a pressure drop from port A to port B and a positive shaft angular velocity.

  • Mode 2, reverse pump mode: negative shaft angular velocity causes pressure increase from port B to port A and flow from port B to port A.

  • Mode 3, reverse hydraulic motor mode: flow from port B to port A causes pressure decrease from port B to port A and negative shaft angular velocity.

  • Mode 4, forward pump mode: positive shaft angular velocity causes an increase in pressure from port A to port B and flow from port A to port B.

The hydraulic motor block has analytical parameterization, tabular parameterization and parameterization via input signals. When using tabular data or an input signal for the parameterization, it is possible to select a hydraulic motor performance characteristic based on efficiency or volumetric and mechanical losses.

In the parameterization options for table data and input signal, the threshold parameters Pressure drop threshold for motor-pump transition and Angular velocity threshold for motor-pump transition define the areas in which a numerically smoothed flow transition between hydraulic motor modes can occur. Select a transition region that provides some margin for the transition term, but which is small enough with respect to pressure and angular velocity to not affect the calculation results.

Analytical parameterization of leakage and friction torque

If Leakage and friction parameterization is set to `Analytical', the unit calculates leakage and friction torque based on nominal values of shaft speed, mechanical pressure drop and volumetric efficiency. The leakage rate, which depends on the pressure drop across the hydraulic motor, is calculated as:

where

  • ;

  • - is the average density of the liquid;

  • - Hagen-Poiseuille coefficient for calculation of analytical losses:

    where

    • - is the value of the Displacement parameter;

    • - is the value of parameter Nominal shaft angular velocity;

    • - parameter value Volumetric efficiency at nominal conditions;

    • - parameter value Nominal pressure drop.

The friction torque, which depends on the angular speed of the shaft, is calculated as:

where

  • - is the value of the No-load torque parameter;

  • - coefficient of dependence of friction torque on pressure at nominal working volume, which is determined by the value of parameter Mechanical efficiency at nominal conditions, :

    where is the friction torque at nominal conditions:

  • - pressure drop between ports A and B;

  • - shaft angular velocity, or .

Tabular data for parameterization

When using tabular data for efficiency or losses of a hydraulic motor, data for one or more operating modes can be provided. The signs of the tabular data define the operating mode of the unit. If data is provided for less than four operating modes, the unit calculates additional data for the other mode(s) by extending the given data into the remaining quadrants.

*Table data - parameterization of volumetric and mechanical efficiencies.

If Leakage and friction parameterization is set to `Tabulated data - volumetric and mechanical efficiencies', the block performs parameterization using tabulated data for volumetric and mechanical efficiencies.

The leakage flow rate is

where

  • ;

  • ;

  • - volumetric efficiency, which is interpolated from tabular data provided by the user;

  • - transition term, represents

    where

    • ;

    • - is the value of parameter Pressure drop threshold for motor-pump transition;

    • ;

    • - parameter value Angular velocity threshold for motor-pump transition.

The friction torque is equal to

where

  • ;

  • ;

  • - mechanical efficiency, which is interpolated from user-supplied tabular data.

*Table data - parameterization of volumetric and mechanical losses.

If Leakage and friction parameterization is set to Tabulated data - volumetric and mechanical loss, the unit performs parameterization using tabulated data for volumetric and mechanical loss.

The leakage flow rate is

where is an interpolation based on the Volumetric loss table parameter, q_loss(dp,w).

The shaft friction torque is equal to

where is an interpolation based on the parameter Mechanical loss table, torque_loss(dp,w).

Table data - parameterization of torque and speed.

If Leakage and friction parameterization is set to Tabulated data - torque and speed, the block performs parameterization using tabulated data for torque and speed.

The block calculates the volume loss table and the mechanical loss table as follows



where

  • - parameter value Flow rate vector, q;

  • - parameter value Shaft speed table, w(q,dp);

  • - parameter value Pressure drop vector, dp;

  • - parameter value Torque table, T(q,dp).

If the given values of the parameters Shaft speed table, w(q,dp) and Torque table, T(q,dp) do not cover all four quadrants, the block expands the data by:

  • symmetrically mirrored values of the Pressure drop vector, dp and Flow rate vector, q parameters so that they contain negative values;

  • symmetrically expanded values of the volume loss table into additional quadrants. The signs of these expanded values correspond to the sign of in each quadrant;

  • calculated expanded values of the shaft speed vector, from the expanded values of the flow vector and the volume loss table, ;

  • symmetrically expanded values of the mechanical loss table into additional quadrants. The signs of these expanded values correspond to the sign in each quadrant.

If the data tables have unknown values in any of the four corners or parameters Shaft speed table, w(q,dp) or Torque table, T(q,dp), then use NaN instead of these values. The block fills in the NaN elements in the resulting volume loss table and mechanical loss table using the nearest extrapolation relative to the pressure drop. The block corrects the signs in the extrapolated mechanical loss table to match the signs of the corresponding elements in the shaft speed vector , where .

After expanding or filling in unknown values, the block uses linear interpolation and nearest extrapolation to calculate the volumetric and mechanical loss tables during simulation

Where .

parameterization via input signal

If the parameter Leakage and friction parameterization is set to Input signal - volumetric and mechanical efficiencies', the ports EV and EM are enabled. The internal leakage and shaft friction are calculated in the same way as with the `Tabulated data - volumetric and mechanical efficiencies parameterization, except that the values and are fed directly to the EV and EM ports respectively.

If Leakage and friction parameterization is set to Input signal - volumetric and mechanical losses, then the LV and LM ports are enabled. These ports receive the leakage flow and friction torque values as positive scalars. The leakage flow rate is calculated as:

where

  • - is the leakage volume flow rate obtained at the LV port;

  • - is the value of Pressure drop threshold for motor-pump transition.

The friction torque is calculated as:

where

  • - is the friction torque obtained at the LM port;

  • - is the value of parameter Angular velocity threshold for motor-pump transition.

The volumetric and mechanical efficiencies vary between the user defined minimum and maximum values. Any values below or above this range will take the minimum and maximum setpoints respectively.

Hydraulic motor operation

The flow rate of the hydraulic motor is:

where .

The torque of the hydraulic motor is:

where .

The mechanical power developed by the hydraulic motor shaft is:

The hydraulic power of the hydraulic motor is:

If you want to know if the unit is operating outside the range of supplied tabulated data, you can set Check if operating outside the range of supplied tabulated data to `Error' to stop the simulation in this case. When parameterising by input signal for volumetric or mechanical losses, you can be notified if the simulation goes beyond the range of motor operating modes by using the parameter Check if operating outside of motor mode.

The functionality of the hydraulic motor can also be monitored. Set Check if pressures are less than motor minimum pressure to `Error' to stop the simulation when the output pressure is less than the minimum setpoint.

Ports

Conserving

# A — isothermal liquid port
isothermal liquid

Details

The fluid inlet or outlet port in a hydraulic motor.

Program usage name

port_a

# B — isothermal liquid port
isothermal liquid

Details

The fluid inlet or outlet port in a hydraulic motor.

Program usage name

port_b

# R — mechanical port
`rotational mechanics

Details

Angular velocity of rotation and torque of a shaft.

Program usage name

rod_flange

# C — mechanical port
`rotational mechanics

Details

Angular velocity and torque of the body.

Program usage name

case_flange

Input

# EV — volumetric efficiency
scalar

Details

Volumetric efficiency specified as a scalar. The value must be in the range from 0 to 1.

Dependencies

To use this port, set Leakage and friction parameterization to `Input signal - volumetric and mechanical efficiencies'.

Data types

Float64.
Complex numbers support

No

# EM — mechanical efficiency
scalar

Details

The mechanical efficiency of the hydraulic motor, given as a scalar. The value must be in the range from 0 to 1.

Dependencies

To use this port, set Leakage and friction parameterization to `Input signal - volumetric and mechanical efficiencies'.

Data types

Float64.
Complex numbers support

No

# LV — leakage volume flow rate
scalar

Details

Hydraulic motor losses, in m3/s, given as a scalar.

Dependencies

To use this port, set Leakage and friction parameterization to `Input signal - volumetric and mechanical losses'.

Data types

Float64.
Complex numbers support

No

# LM — friction moment
scalar

Details

Mechanical losses of the hydraulic motor, in N⋅m, given as a scalar.

Dependencies

To use this port, set Leakage and friction parameterization to `Input signal - volumetric and mechanical losses'.

Data types

Float64.
Complex numbers support

No

Parameters

Parameters

# Leakage and friction parameterization — method for calculating leakage flow rate and friction torque
Analytical | Tabulated data - volumetric and mechanical efficiencies | Tabulated data - volumetric and mechanical losses | Tabulated data - torque and speed | Input signal - volumetric and mechanical efficiencies | Input signal - volumetric and mechanical losses

Details

Parametrization of leakage and friction characteristics of a hydraulic motor.

  • `Analytical' - leakage flow rate and friction torque are calculated using analytical equations.

  • Tabulated data - volumetric and mechanical efficiencies - volumetric and mechanical efficiencies are calculated from user defined parameters Pressure drop vector, dp and Shaft angular velocity vector, w and interpolated from the corresponding two-dimensional tables Volumetric efficiency table, e_v(dp,w) and Mechanical efficiency table, e_m(dp,w).

  • `Tabulated data - volumetric and mechanical loss' - leakage flow and friction torque are calculated from the user defined parameters Pressure drop vector, dp and Shaft angular velocity vector, w and interpolated from the corresponding two-dimensional tables Volumetric loss table, q_loss(dp,w) and Mechanical loss table, torque_loss(dp,w).

  • `Tabulated data - torque and speed' - it is possible to set the torque and shaft speed as functions of flow and differential pressure using the parameters Torque table T(q,dp) and Shaft speed table w(q,dp).

  • `Input signal - volumetric and mechanical efficiencies' - volumetric and mechanical efficiencies are input as signals to the EV and EM ports respectively.

  • Input signal - volumetric and mechanical loss - leakage flow rate and friction torque are input as signals to ports LV and LM respectively.

Values

Analytical | Tabulated data - volumetric and mechanical efficiencies | Tabulated data - volumetric and mechanical losses | Tabulated data - torque and speed | Input signal - volumetric and mechanical efficiencies | Input signal - volumetric and mechanical losses
Default value

Analytical
Program usage name

leakage_and_friction_parameterization_motor
Evaluatable

No

# Displacement — working volume
l/rad | l/rev | gal/rad | gal/rev | igal/rad | m^3/deg | m^3/rad | m^3/rev | cm^3/rad | cm^3/rev | mm^3/rad | km^3/rad | ft^3/rad | in^3/deg | in^3/rad | in^3/rev | N*m/Pa/rad | N*m/bar/rad | lbf*ft/psi/rad

Details

The amount of fluid displaced when the shaft is rotated by a certain angle.

Units

l/rad | l/rev | gal/rad | gal/rev | igal/rad | m^3/deg | m^3/rad | m^3/rev | cm^3/rad | cm^3/rev | mm^3/rad | km^3/rad | ft^3/rad | in^3/deg | in^3/rad | in^3/rev | N*m/Pa/rad | N*m/bar/rad | lbf*ft/psi/rad
Default value

30.0 cm^3/rev
Program usage name

displacement
Evaluatable

Yes

# Nominal shaft angular velocity — nominal angular speed of the shaft
rpm | deg/s | rad/s

Details

The angular speed of the shaft at rated operating conditions.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Analytical'.

Units

rpm | deg/s | rad/s
Default value

1800.0 rpm
Program usage name

w_nominal
Evaluatable

Yes

# Nominal pressure drop — nominal pressure drop between fluid inlet and outlet
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The pressure drop between the inlet and outlet of the hydraulic motor under nominal operating conditions.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Analytical'.

Units

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar
Default value

10.0 MPa
Program usage name

p_nominal
Evaluatable

Yes

# Volumetric efficiency at nominal conditions — volumetric efficiency

Details

The ratio of the actual flow rate to the ideal flow rate under nominal conditions.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Analytical'.

Default value

0.92
Program usage name

nominal_volumetric_efficiency
Evaluatable

Yes

# Mechanical efficiency at nominal conditions — mechanical efficiency under ideal conditions

Details

The ratio of the actual torque to the ideal torque produced under nominal conditions.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Analytical'.

Default value

0.88
Program usage name

nominal_mechanical_efficiency
Evaluatable

Yes

# No-load torque — rest friction torque
N*m | mN*m | lbf*ft

Details

The minimum torque value to overcome seal friction.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Analytical'.

Units

N*m | mN*m | lbf*ft
Default value

0.0 N*m
Program usage name

no_load_torque
Evaluatable

Yes

# Pressure drop vector; dp — vector of pressure drop values for tabular parameterization
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Vector of pressure drop values for tabular parameterization of leakage and torque friction. The elements of the vector must be listed in ascending order.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical efficiencies'.

Units

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar
Default value

[0.1, 1.0, 2.0] MPa
Program usage name

delta_p_vector_efficiency
Evaluatable

Yes

# Shaft angular velocity vector; w — vector of angular velocity values for tabular parameterization
rpm | deg/s | rad/s

Details

Vector of angular velocity data for tabular parameterization of leakage and friction torque. The elements of the vector must be listed in ascending order.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical efficiencies'.

Units

rpm | deg/s | rad/s
Default value

[250.0, 500.0, 1000.0, 2000.0, 3000.0, 4000.0] rpm
Program usage name

w_vector_efficiency
Evaluatable

Yes

# Volumetric efficiency table; e_v(dp;w) — volumetric efficiency table

Details

Matrix at of volumetric efficiencies at a given fluid pressure drop and shaft angular speed. The block uses linear interpolation between the elements of the table.

The values and are the dimensions of the corresponding vectors:

  • - number of vector elements in the Pressure drop vector parameters, dp.

  • - number of vector elements in the Shaft angular velocity vector parameters, w.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical efficiencies'.

Default value

[0.816 0.908 0.954 0.977 0.981 0.984; 0.325 0.663 0.831 0.916 0.925 0.946; 0.137 0.568 0.78 0.892 0.893 0.910]
Program usage name

volumetric_efficiency_matrix
Evaluatable

Yes

# Mechanical efficiency table; e_m(dp;w) — mechanical efficiency table

Details

Matrix at of mechanical efficiencies at a given fluid pressure drop and angular speed of shaft rotation. The block uses linear interpolation between the elements of the table. The values and are the dimensions of the corresponding vectors:

  • - number of elements in the pressure drop vector Pressure drop vector, dp.

  • - number of elements in the angular velocity vector Shaft angular velocity vector, w.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical efficiencies'.

Default value

[0.996 0.996 0.996 0.996 0.996 0.996; 0.988 0.989 0.989 0.989 0.989 0.990; 0.981 0.981 0.982 0.982 0.983 0.984]
Program usage name

mechanical_efficiency_matrix
Evaluatable

Yes

# Pressure drop vector; dp — vector of pressure drop values for tabular parameterization
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Vector of pressure drop values for tabular parameterization of leakage and torque friction. The elements of the vector must be listed in ascending order.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical losses'.

Units

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar
Default value

[0.1, 1.0, 2.0] MPa
Program usage name

delta_p_vector_loss
Evaluatable

Yes

# Shaft angular velocity vector; w — vector of angular velocity values for tabular parameterization
rpm | deg/s | rad/s

Details

Vector of angular velocity data for tabular parameterization of leakage and friction torque. The elements of the vector must be listed in ascending order.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical losses'.

Units

rpm | deg/s | rad/s
Default value

[250.0, 500.0, 1000.0, 2000.0, 3000.0, 4000.0] rpm
Program usage name

w_vector_loss
Evaluatable

Yes

# Volumetric loss table; q_loss(dp;w) — volumetric loss table
m^3/s | m^3/h | cm^3/s | mm^3/s | ft^3/s | lpm | l/s | gpm | gal/s | gal/h

Details

Matrix at volume losses at a given fluid pressure drop and shaft angular speed. The block uses linear interpolation between the elements of the table.

The values and are the dimensions of the corresponding vectors:

  • - number of elements in the pressure drop vector Pressure drop vector, dp.

  • - number of elements in the angular velocity vector Shaft angular velocity vector, w.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical losses'.

Units

m^3/s | m^3/h | cm^3/s | mm^3/s | ft^3/s | lpm | l/s | gpm | gal/s | gal/h
Default value

1e-3*[0.0230 0.0230 0.0230 0.0230 0.0285 0.0320; 0.0844 0.0842 0.0845 0.0840 0.1125 0.1080; 0.1079 0.1080 0.1100 0.1080 0.1605 0.1800] m^3/s
Program usage name

volumetric_loss_matrix
Evaluatable

Yes

# Mechanical loss table; torque_loss(dp;w) — mechanical loss table
N*m | mN*m | lbf*ft

Details

Matrix at of mechanical losses at a given fluid pressure drop and angular speed of shaft rotation.

The block uses linear interpolation between the elements of the table. The values and are the dimensions of the corresponding vectors:

  • - number of elements in the pressure drop vector Pressure drop vector, dp.

  • - number of elements in the angular velocity vector Shaft angular velocity vector, w.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - volumetric and mechanical losses'.

Units

N*m | mN*m | lbf*ft
Default value

[0.0020 0.0020 0.0020 0.0020 0.0020 0.0020; 0.0607 0.0556 0.0556 0.0556 0.0556 0.0505; 0.1937 0.1937 0.1833 0.1833 0.1729 0.1626] N*m
Program usage name

mechanical_loss_matrix
Evaluatable

Yes

# Flow rate vector; q — vector of volume flow rates
m^3/s | m^3/h | cm^3/s | mm^3/s | ft^3/s | lpm | l/s | gpm | gal/s | gal/h

Details

Vector of volume flow values for tabular parameterization of torque and speed. The elements of the vector must be listed in ascending order.

Dependencies

To use this parameter, set the parameter Leakage and friction parameterization to `Tabulated data - torque and speed'.

Units

m^3/s | m^3/h | cm^3/s | mm^3/s | ft^3/s | lpm | l/s | gpm | gal/s | gal/h
Default value

[0.125, 0.25, 0.5, 1.0, 1.5, 2.0]*1e-3 m^3/s
Program usage name

Vdot_vector_shaft
Evaluatable

Yes

# Pressure drop vector; dp — vector of pressure drop values for tabular parameterization
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Vector of pressure drop values for tabular parameterization of leakage and torque friction. The elements of the vector must be listed in ascending order.

Dependencies

To use this parameter, set the parameter Leakage and friction parameterization to `Tabulated data - torque and speed'.

Units

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar
Default value

[0.1, 1.0, 2.0] MPa
Program usage name

delta_p_vector_shaft
Evaluatable

Yes

# Torque table; T(q; dp) — torque values for tabular parameterization
N*m | mN*m | lbf*ft

Details

Matrix for torque values at a given differential pressure and fluid flow rate. The block uses linear interpolation between the table elements.

The values and are the dimensions of the corresponding vectors:

  • - number of elements in the volume flow rate vector Flow rate vector, q.

  • - number of elements in the pressure drop vector Pressure drop vector, dp.

If the table has unknown values in any of the four corners, use NaN instead of these values.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to Tabulated data - torque and speed.

Units

N*m | mN*m | lbf*ft
Default value

[0.47 4.72 9.35; 0.47 4.70 9.36; 0.47 4.70 9.40; 0.47 4.70 9.41; 0.47 4.70 9.46; 0.47 4.68 9.50] N*m
Program usage name

torque_matrix_shaft
Evaluatable

Yes

# Shaft speed table; w(q;dp) — shaft angular velocity values for tabular parameterization
rpm | deg/s | rad/s

Details

Matrix for shaft speed values at a given differential pressure and fluid volume flow rate. The block uses linear interpolation between the table elements.

The values and are the dimensions of the corresponding vectors:

  • - number of elements in the volumetric flow rate vector Flow rate vector, q.

  • - number of elements in the pressure drop vector Pressure drop vector, dp.

If the table has unknown data in any of the four corners, use NaN instead of these values.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Tabulated data - torque and speed'.

Units

rpm | deg/s | rad/s
Default value

[205.0 80.0 35.0; 455.0 330.0 285.0; 955.0 831.0 780.0; 1950.0 1830.0 1780.0; 2940.0 2775.0 2680.0; 3940.0 3780.0 3640.0] rpm
Program usage name

w_matrix_shaft
Evaluatable

Yes

# Minimum volumetric efficiency — minimum volumetric efficiency

Details

The minimum value of the volumetric efficiency. If the input signal is below this value, the volumetric efficiency is set to the minimum volumetric efficiency value.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Input signal - volumetric and mechanical efficiencies'.

Default value

1e-3
Program usage name

min_volumetric_efficiency
Evaluatable

Yes

# Maximum volumetric efficiency — maximum volumetric efficiency

Details

The maximum value of the volumetric efficiency. If the input signal exceeds this value, the volumetric efficiency is set to the maximum volumetric efficiency value.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Input signal - volumetric and mechanical efficiencies'.

Default value

1.0
Program usage name

max_volumetric_efficiency
Evaluatable

Yes

# Minimum mechanical efficiency — minimum mechanical efficiency

Details

The minimum value of the mechanical efficiency. If the input signal is below this value, the mechanical efficiency is set to the minimum mechanical efficiency value.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Input signal - volumetric and mechanical efficiencies'.

Default value

1e-3
Program usage name

min_mechanical_efficiency
Evaluatable

Yes

# Maximum mechanical efficiency — maximum mechanical efficiency

Details

The maximum value of the mechanical efficiency. If the input signal is higher than this value, the mechanical efficiency is set to the maximum mechanical efficiency value.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Input signal - volumetric and mechanical efficiencies'.

Default value

1.0
Program usage name

max_mechanical_efficiency
Evaluatable

Yes

# Pressure drop threshold for motor-pump transition — threshold pressure for transient operation
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The differential pressure threshold for the transition between pump and motor operation. The transition region is defined in the region of 0 MPa between the positive and negative values of the threshold differential pressure. Within this region, the calculated leakage rate and friction torque are corrected according to the transition term , to ensure a smooth transition from one mode to the other.

Dependencies

To use this parameter, set Leakage and friction parameterization to one of the values:

  • `Tabulated data - volumetric and mechanical efficiencies';

  • `Input signal - volumetric and mechanical efficiencies';

  • Input signal - volumetric and mechanical losses.

Units

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar
Default value

1e-3 MPa
Program usage name

p_threshold
Evaluatable

Yes

# Angular velocity threshold for motor-pump transition — threshold angular velocity for transient mode
rpm | deg/s | rad/s

Details

The angular velocity threshold for the transition between pump and hydraulic motor operation. The transition region is defined around 0 rpm between the positive and negative values of the angular velocity threshold. Within this region, the calculated leakage rate and friction torque are corrected according to the transition term , to ensure a smooth transition from one mode to the other.

Dependencies

To use this parameter, set Leakage and friction parameterization to one of the values:

  • `Tabulated data - volumetric and mechanical efficiencies';

  • `Input signal - volumetric and mechanical efficiencies';

  • Input signal - volumetric and mechanical losses.

Units

rpm | deg/s | rad/s
Default value

100.0 rpm
Program usage name

w_threshold
Evaluatable

Yes

# Check if operating beyond the range of supplied tabulated data — reporting of data overruns
None | Error

Details

Select Error to stop the simulation when the block uses values outside the provided data range.

If the Leakage and friction parameterization parameter is set to Tabulated data - torque and speed, this parameter also checks if the block is running in the NaN value range.

Dependencies

To use this parameter, set the Leakage and friction parameterization to one of the values:

  • Tabulated data - volumetric and mechanical efficiencies;

  • `Tabulated data - volumetric and mechanical losses';

  • `Tabulated data - torque and speed'.

Values

None | Error
Default value

None
Program usage name

supplied_range_assert_action
Evaluatable

No

# Check if operating outside of motor mode — message about unit operation outside the hydraulic motor mode
None | Error

Details

Select Error to stop the simulation when the unit is operating in the forward or reverse pump modes.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to `Input signal - volumetric and mechanical losses'.

Values

None | Error
Default value

None
Program usage name

operating_mode_assert_action
Evaluatable

No

# Check if pressures are less than motor minimum pressure — low fluid pressure message at the hydraulic motor outlet
None | Error

Details

Select Error to stop the simulation when the outlet pressure drops below the minimum setpoint.

This parameters helps to identify potential conditions for cavitation when the fluid pressure falls below the fluid vapour pressure.

Values

None | Error
Default value

None
Program usage name

pressure_assert_action
Evaluatable

No

# Motor minimum pressure — lower threshold of permissible pressure at the hydraulic motor outlet
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Lower threshold of permissible pressure at the inlet or outlet of the hydraulic motor.

Dependencies

To use this parameter, set Check if pressures are less than motor minimum pressure to Error.

Units

Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar
Default value

0.101325 MPa
Program usage name

p_valid_min
Evaluatable

Yes