Engee documentation

Variable-Displacement Motor (IL)

Variable displacement hydraulic motor in isothermal liquid network.

variable displacement motor il

Description

Block Variable-Displacement Motor (IL) simulates a hydraulic motor with variable displacement. 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.

The shaft rotation corresponds to the sign of the working volume flowing through the hydraulic motor, which is input as a scalar signal to port D. A positive displacement at port D corresponds to positive shaft rotation in forward mode. A negative displacement at port D corresponds to a negative angular velocity of the shaft in forward mode.

The operating modes are shown in the diagram.

variable displacement motor il 1

The unit has eight operating modes. The mode of operation depends on the pressure drop from port A to port B , the angular velocity and the working volume. In the diagram above, these modes are shown as octants of the diagram :

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

  • 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 pressure increase from port A to port B and flow from port A to port B.

  • Mode 5, reverse pump mode: positive shaft angular velocity causes pressure increase from port B to port A and flow from port B to port A.

  • Mode 6, direct hydraulic motor mode: flow from port A to port B causes a decrease in pressure from port A to port B and a negative shaft angular velocity.

  • Mode 7, forward pump mode: negative shaft angular velocity causes pressure increase from port A to port B and flow from port A to port B.

  • Mode 8, reverse hydraulic motor mode: flow from port B to port A causes a decrease in pressure from port B to port A and a positive shaft angular velocity.

The hydraulic motor block has analytical parameterization, tabular parameterization and parameterization via input signals. With usage of tabular data or input signal for parameterization, the performance characteristic of the hydraulic motor can be selected based on efficiency or volumetric and mechanical losses.

In the parameterization variants for table data and input signal, the threshold parameters are as follows Pressure drop threshold for motor-pump transition, Angular velocity threshold for motor-pump transition и Displacement threshold for motor-pump transition define the regions in which a numerically smoothed flow transition between the hydraulic motor operating 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 not to affect the calculation results. For the displacement threshold, select a threshold value that is smaller than the typical displacement during normal operation.

Analytical parameterization of leakage and friction torque

If the parameters Leakage and friction parameterization is set to Analytical, the unit calculates the leakage and friction torque based on the nominal values of shaft speed, pressure drop, mechanical efficiency 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

    • - parameter value Nominal displacement;

    • - parameter value Nominal shaft angular velocity;

    • - parameter value Volumetric efficiency at nominal conditions;

    • - parameter value Nominal pressure drop.

The friction torque, which depends on the pressure drop in the hydraulic motor, is calculated as:

where

  • - parameter value No-load torque;

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

    where is the friction torque under nominal conditions:

  • - pressure drop between ports A and B;

  • - shaft angular velocity, or .

Tabular parameterization

In usage of 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 eight operating modes, the unit calculates additional data for the other mode(s) by extending the given data into the remaining octants.

Table data - parameterization of volumetric and mechanical efficiencies

If the parameters Leakage and friction parameterization is set to Tabulated data - volumetric and mechanical efficiencies, the unit performs the parameterization using the tabular data for volumetric and mechanical efficiency.

The leakage flow rate is

where

  • ;

  • ;

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

  • - transition term, represents

    where

    • ;

    • - parameter value 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 the parameters Leakage and friction parameterization is set to `Tabulated data - volumetric and mechanical loss', the block performs parameterization using tabulated data for volumetric and mechanical losses.

The leakage flow rate is

where is an interpolation based on the Volumetric loss table parameter, q_loss(Δp,w,D), which is based on user-supplied data on pressure drop, shaft angular velocity, and fluid working volume.

The shaft friction torque is

where is an interpolation based on the Mechanical loss table parameter, torque_loss(Δp,w,D), which is based on user-supplied data on pressure drop, shaft angular velocity, and fluid working volume.

Parametrization via input signal

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

If the parameters Leakage and friction parameterization is set to Input signal - volumetric and mechanical losses, the ports LV and LM are switched on. 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 port LV;

  • - parameter value Pressure drop threshold for motor-pump transition.

The friction torque is calculated as:

where

  • - is the friction torque obtained at port LM;

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

Volumetric and mechanical efficiencies vary between the user-defined minimum and maximum setpoints. 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 whether the block works beyond the provided tabular data, you can set the parameters to Check if operating beyond the range of supplied tabulated data value `Error`to stop the simulation in this case. When parameterising by input signal for volumetric or mechanical losses, it is possible to be notified if the simulation goes outside of motor operating modes using the parameter Check if operating outside of motor mode.

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

Ports

Conserving

# 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

# 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

Input

# D — working volume
scalar

Details

The volume of fluid in m3/rad passing through a hydraulic motor, as a scalar.

Data types

Float64.
Complex numbers support

No

# 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 parameters Leakage and friction parameterization value 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 parameters Leakage and friction parameterization value 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 the parameters to Leakage and friction parameterization value 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 the parameters to Leakage and friction parameterization value 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 | 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 by analytical equations.

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

  • Tabulated data - volumetric and mechanical losses - leakage flow rate and friction torque are calculated using user-defined parameters Pressure drop vector; dp и Shaft angular velocity vector; w и Displacement vector; D and interpolated from the corresponding three-dimensional tables Volumetric loss table; q_loss(dp;w;D) и Mechanical loss table; torque_loss(dp;w;D).

  • Input signal - volumetric and mechanical efficiencies - volumetric and mechanical efficiencies are signalled to the EV and EM ports respectively.

  • Input signal - volumetric and mechanical losses - leakage flow and friction torque are signalled at ports LV and LM respectively.

Values

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

Analytical
Program usage name

leakage_and_friction_parameterization
Evaluatable

No

# Nominal displacement — nominal displacement
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 liquid displaced by the pump under rated operating conditions.

Dependencies

To use this parameter, set parameter Leakage and friction parameterization value Analytical.

Values

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

nominal_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 parameter Leakage and friction parameterization value Analytical.

Values

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 parameter Leakage and friction parameterization value Analytical.

Values

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 parameter Leakage and friction parameterization value Analytical.

Default value

0.92
Program usage name

nominal_volumetric_efficiency
Evaluatable

Yes

# Mechanical efficiency at nominal conditions — mechanical efficiency at rated conditions

Details

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

Dependencies

To use this parameter, set parameter Leakage and friction parameterization value 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 parameter Leakage and friction parameterization value Analytical.

Values

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 parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical efficiencies.

Values

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 values 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 parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical efficiencies.

Values

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

# Displacement vector; D — vector of work volume values for tabular parameterization
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

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

Dependencies

To use this parameter, set parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical efficiencies.

Values

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, -19.0, 19.0, 30.0] cm^3/rev
Program usage name

displacement_vector_efficiency
Evaluatable

Yes

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

Details

Array to to of volumetric efficiencies at a given fluid pressure drop, shaft angular speed and working volume. 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 parameters Pressure drop vector; dp.

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

  • - number of elements of the vector in the parameters Displacement vector; D.

Dependencies

To use this parameter, set parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical efficiencies.

Default value

repeat([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], 1, 1, 4)
Program usage name

volumetric_efficiency_matrix
Evaluatable

Yes

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

Details

Array to to of mechanical efficiencies at a given fluid pressure drop, shaft angular speed and working volume. 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 parameters Pressure drop vector; dp.

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

  • - number of elements of the vector in the parameters Displacement vector; D. Dependencies

To use this parameter, set parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical efficiencies.

Default value

repeat([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], 1, 1, 4)
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 parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical losses.

Values

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 values 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 parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical losses.

Values

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

# Displacement vector; D — vector of work volume values for tabular parameterization
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

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

Dependencies

To use this parameter, set parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical losses.

Values

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, -19.0, 19.0, 30.0] cm^3/rev
Program usage name

displacement_vector_loss
Evaluatable

Yes

# Volumetric loss table; q_loss(dp;w;D) — 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

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

The values , and are the dimensions of the corresponding vectors:

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

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

  • - number of elements of the vector in the parameters Displacement vector; D.

Dependencies

To use this parameter, set parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical losses.

Values

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

repeat(1.0e-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], 1, 1, 4) m^3/s
Program usage name

volumetric_loss_matrix
Evaluatable

Yes

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

Details

Array to to of mechanical losses at a given fluid pressure drop, shaft angular speed and working volume. The block uses linear interpolation between the table elements.

The values , and are the dimensions of the corresponding vectors:

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

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

  • - number of elements of the vector in the parameters Displacement vector; D. Dependencies

To use this parameter, set parameter Leakage and friction parameterization value Tabulated data - volumetric and mechanical losses.

Values

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

repeat([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], 1, 1, 4) N*m
Program usage name

mechanical_loss_matrix
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 parameter Leakage and friction parameterization value 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 parameters to Leakage and friction parameterization value 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 parameter Leakage and friction parameterization value 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 parameter Leakage and friction parameterization value 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 this parameter to Leakage and friction parameterization one of the values:

  • Tabulated data - volumetric and mechanical efficiencies;

  • Input signal - volumetric and mechanical efficiencies;

  • Input signal - volumetric and mechanical losses.

Values

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 the value for Leakage and friction parameterization one of the values:

  • Tabulated data - volumetric and mechanical efficiencies;

  • Input signal - volumetric and mechanical efficiencies;

  • Input signal - volumetric and mechanical losses.

Values

rpm | deg/s | rad/s
Default value

100.0 rpm
Program usage name

w_threshold
Evaluatable

Yes

# Displacement threshold for motor-pump transition — operating volume threshold value for transient mode
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 threshold displacement value for the transition between pump and hydraulic motor operation. The transition region is defined around 0 cm3/s between the positive and negative values of the displacement threshold. Within this region, the calculated leakage flow rate and friction torque are adjusted according to the transition term , to ensure a smooth transition from one mode to the other.

Values

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

0.1 cm^3/rev
Program usage name

displacement_threshold
Evaluatable

Yes

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

Details

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

Dependencies

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

  • Tabulated data - volumetric and mechanical efficiencies;

  • Tabulated data - volumetric and mechanical losses;

Values

None | Error
Default value

None
Program usage name

supplied_range_assert_action
Evaluatable

No

# Check if operating beyond 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 forward or reverse pump modes.

Dependencies

To use this parameter, set the parameters to Leakage and friction parameterization value 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 identify potential cavitation conditions when the fluid pressure drops below the vapour pressure of the fluid.

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 this value to Check if pressures are less than motor minimum pressure value Error.

Values

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

0.101325 MPa
Program usage name

p_valid_min
Evaluatable

Yes