Variable-Displacement Motor (TL)

A variable-displacement hydraulic motor in a heat-conducting fluid network.

blockType: EngeeFluids.ThermalLiquid.Turbomachinery.VariableDisplacementMotor

Path in the library:

/Physical Modeling/Fluids/Thermal Liquid/Pumps & Motors/Variable-Displacement Motor (TL)

Description

Block Variable-Displacement Motor (TL) It is a device that receives energy from a heat-conducting liquid network and transmits it to a mechanical network. The working volume of the hydraulic motor fluid can change during simulation, and is sent as a signal to port D.

Ports A and B represent the inlet and outlet ports of the hydraulic motor. Ports R and C represent the drive shaft and the hydraulic motor housing. The liquid flow can be directed from port A to port B (forward mode) or from port B to port A (reverse mode). Operation in the hydraulic motor mode occurs when the pressure drops in the flow direction. The pump operation mode is realized when the pressure increases in the flow direction.

The operating modes are shown in the diagram.

variable displacement motor il 1

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

Mode 1, direct hydraulic motor mode: the 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: the negative angular velocity of the shaft causes pressure to rise from port B to port A and flow from port B to port A.
Mode 3, reverse hydraulic motor mode: the flow from port B to port A causes a decrease in pressure from port B to port A and a negative angular velocity of the shaft.
Mode 4, Direct pump mode: the positive angular velocity of the shaft causes pressure to rise from port A to port B and flow from port A to port B.
Mode 5, Reverse pump mode: the positive angular velocity of the shaft causes pressure to rise from port B to port A and flow from port B to port A.
Mode 6, direct hydraulic motor mode: the flow from port A to port B causes a decrease in pressure from port A to port B and a negative angular velocity of the shaft.
Mode 7, Direct pump mode: the negative angular velocity of the shaft causes pressure to rise from port A to port B and flow from port A to port B.
Mode 8, reverse hydraulic motor mode: the flow from port B to port A causes a decrease in pressure from port B to port A and a positive angular velocity of the shaft.

The time constant of the hydraulic motor is considered insignificant compared to the time constant of the system. It is assumed that the hydraulic motor reaches a steady state almost instantly and is considered as a quasi-stationary component.

Flow rate and torque

The mass flow rate of the hydraulic motor is:

where

— actual mass consumption;
— ideal mass flow rate;
— mass consumption of internal leakage.

The torque of the hydraulic motor is:

where

— actual torque;
— perfect torque;
— the moment of friction.

The ideal flow rate and ideal torque are calculated as

where

— the average value of the liquid density in the ports of the heat-conducting liquid A and B;
— the working volume supplied as a scalar to the port S;
— angular rotation speed of the shaft;
— pressure drop from inlet to outlet.

Analytical parameterization of leakage and friction moment

If for the parameter Leakage and friction parameterization the value is set Analytical, then the leakage rate is:

and the moment of friction is calculated as:

where

— the Hagen-Poiseuille coefficient for laminar flows. The unit calculates this coefficient from the specified nominal parameters;
— the average dynamic viscosity of the heat-conducting liquid in the ports;
— average density of liquid in ports;
— the coefficient of dependence of the moment of friction on the pressure at the nominal working volume, which is determined by the value of the parameter Mechanical efficiency at nominal conditions, :

where — the moment of friction under nominal conditions:
— the value of the block parameter Nominal displacement;
— parameter value No-load torque;
— parameter value Nominal shaft angular velocity. This is the angular velocity at which the nominal volumetric efficiency is set.;
— parameter value Nominal pressure drop. This value represents the pressure drop at which the nominal volumetric efficiency is set.;

The unit determines the Hagen-Poiseuille coefficient based on the nominal parameters of the liquid and components

where

— parameter value Nominal dynamic viscosity. This value represents the dynamic viscosity at which the nominal volumetric efficiency is set.;
— parameter value Volumetric efficiency at nominal conditions.

Tabular parameterization

When using tabular data for the efficiency or losses of a hydraulic motor, you can specify data for one or more operating modes. The signs of the tabular data determine the operating mode of the block. If data is provided for less than four operating modes, the block calculates additional data for another mode(s), expanding the specified data into the remaining quadrants.

Table data — parameterization of volumetric and mechanical efficiency_

If for the parameter Leakage and friction parameterization the value is set Tabulated data - volumetric and mechanical efficiencies, then the block performs parameterization based on tabular data for volumetric and mechanical efficiency.

The leakage rate is:

and the moment of friction is:

where

— numerical smoothing parameter for the transition process from the hydraulic motor to the pump;
— leakage rate in pump mode;
— leakage rate in hydraulic motor mode;
— the moment of friction in the pump mode;
— the moment of friction in the hydraulic motor mode.

Smoothing parameter is defined by a hyperbolic function

where

— parameter value Pressure drop threshold for motor-pump transition;
— parameter value Angular velocity threshold for motor-pump transition;
— parameter value Displacement threshold for motor-pump transition.

The volumetric flow rate is calculated based on volumetric efficiency, a value that is set in tabular form in the using the Volumetric efficiency table block parameter.

When operating in pump mode, the leakage rate is:

where — volumetric efficiency obtained by interpolation or extrapolation of tabular data.

Similarly, when operating in the hydraulic motor mode, the leakage rate is:

The moment of friction is calculated in a similar way from the mechanical efficiency, a value that is set in tabular form in the area of using the block parameter Mechanical efficiency table, e_m(dp,w,D).

When operating in pump mode, the friction moment is:

where — mechanical efficiency obtained by interpolation or extrapolation of tabular data.

Similarly, when operating in the hydraulic motor mode, the friction moment is:

Table data — parameterization of volume and mechanical losses_

If for the parameter Leakage and friction parameterization the value is set Tabulated data - volumetric and mechanical losses, then the volume flow rate of the leak is set directly in tabular form in the area :

The mass flow rate of the leak is calculated from the volume flow rate:

The moment of friction is:

where and — volumetric and mechanical losses obtained by interpolation or extrapolation of tabular data specified in the parameters Volumetric loss table, q_loss(dp,w,D) and Mechanical loss table, torque_loss(dp,w,D).

Parameterization via the input signal

If for the parameter Leakage and friction parameterization the value is set Input signal - volumetric and mechanical efficiencies, then ports EV and EM are enabled. Internal leakage and shaft friction are calculated in the same way as with parameterization Tabulated data - volumetric and mechanical efficiencies, except that the efficiency values are and They are delivered directly to the EV and EM ports, respectively.

Efficiency is a positive value with a value between 0 and 1'. The values of the input signals outside these boundaries are set equal to the nearest boundary (`0 for inputs less than 0 and 1 for inputs greater than 1). Volumetric and mechanical efficiency vary between user-defined minimum and maximum values. Any values below or above this range will take the minimum and maximum set values, respectively.

If for the parameter Leakage and friction parameterization the value is set Input signal - volumetric and mechanical losses, then ports LV and LM are enabled. These ports receive the values of the leakage current and the moment of friction in the form of positive scalars.

The input values are expected to be positive. The unit automatically sets the signs based on the operating conditions set during the simulation, that is, from the quadrant. , in which the component is running.

Energy conservation

The mechanical work performed by a hydraulic motor is related to the exchange of energy. The energy conservation equation has the form:

where

and — energy flows in ports A and B respectively;
— hydraulic power of the hydraulic motor. It is a function of the pressure difference between the ports of the hydraulic motor: .

The mechanical power of a hydraulic motor is determined based on the torque and angular velocity :

Assumptions and limitations

The compressibility of the liquid can be neglected.
The load on the hydraulic motor shaft due to inertia, friction and springs is negligible.

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 of rotation and torque of the body.

Program usage name

case_flange

# A — thermal liquid port
thermal liquid

Details

The fluid inlet or outlet port in a hydraulic motor.

Program usage name

port_a

# B — thermal liquid port
thermal liquid

Details

The fluid inlet or outlet port of a pump.

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

The mechanical losses of the pump, in N⋅m, given as a scalar.

Dependencies

To use this port, set parameter Leakage and friction parameterization value Input signal - volumetric and mechanical losses.

Data types	`Float64`.
Complex numbers support	No

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 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,D) and Mechanical efficiency table, e_m(dp,w).
Tabulated data - volumetric and mechanical loss - leakage flow rate and friction torque 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 loss table, q_loss(dp,w,D) and Mechanical loss table, torque_loss(dp,w,D).
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` \| `Input signal - volumetric and mechanical efficiencies` \| `Input signal - volumetric and mechanical losses`
Default value	`Analytical`
Program usage name	`leakage_and_friction_parameterization`
Evaluatable	No

Details

The amount of fluid that enters the motor over a given shaft rotation under nominal operating conditions.

Dependencies

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

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` \| `Nm/Pa/rad` \| `Nm/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 the parameters Leakage and friction parameterization 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 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. This value under standard operating conditions can usually be found in the manufacturer’s specification. The unit uses this parameters to calculate the internal leakage flow rate.

Dependencies

To use this parameter, set the parameter Leakage and friction parameterization 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

# Nominal dynamic viscosity — nominal dynamic viscosity for a given volumetric efficiency
P | cP | reyn | s*uPa

Details

The nominal dynamic viscosity of the fluid corresponding to a given volumetric efficiency. This value under standard operating conditions can usually be found in the manufacturer’s specification. The unit uses this parameters to calculate the internal leakage flow rate.

Dependencies

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

Units	`P` \| `cP` \| `reyn` \| `s*uPa`
Default value	`0.9 cP`
Program usage name	`mu_nominal`
Evaluatable	Yes

# Volumetric efficiency at nominal conditions — volumetric efficiency at nominal conditions

Details

The ratio of the actual flow rate to the ideal flow rate under nominal conditions. This value under standard operating conditions can usually be found in the manufacturer’s specification. The unit uses this parameters to calculate the internal leakage flow rate.

Dependencies

To use this parameter, set the parameter Leakage and friction parameterization to 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 the parameter Leakage and friction parameterization 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. This torque is the load-independent component of the total friction torque.

Dependencies

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

Units	`Nm` \| `mNm` \| `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 parameters Leakage and friction parameterization 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 parameters Leakage and friction parameterization 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

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 the parameters Leakage and friction parameterization to . Tabulated data - volumetric and mechanical efficiencies.

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` \| `Nm/Pa/rad` \| `Nm/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) — table of volumetric efficiency values

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 the parameters Pressure drop vector, dp.
- number of vector elements in the parameters Shaft angular velocity vector, w.
- number of vector elements in the parameters Displacement vector, D.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to 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 the parameters Pressure drop vector, dp.
- number of vector elements in the parameters Shaft angular velocity vector, w.
- number of vector elements in the parameters Displacement vector, D.

Dependencies

To use this parameter, set the Leakage and friction parameterization parameters to 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 the parameters Leakage and friction parameterization 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 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 the parameters Leakage and friction parameterization 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

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 the parameters Leakage and friction parameterization to . Tabulated data - volumetric and mechanical losses.

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` \| `Nm/Pa/rad` \| `Nm/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 the parameters Pressure drop vector, dp.
- number of vector elements in the parameters Shaft angular velocity vector, w.
- number of vector elements in the parameters Displacement vector, D.

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	`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 the parameters Pressure drop vector, dp.
- number of vector elements in the parameters Shaft angular velocity vector, w.
- number of vector elements in the parameters Displacement vector, D.

Dependencies

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

Units	`Nm` \| `mNm` \| `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 the parameter Leakage and friction parameterization 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 parameter Leakage and friction parameterization 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 parameters Leakage and friction parameterization 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 parameters Leakage and friction parameterization 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 parameters, 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

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.

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` \| `Nm/Pa/rad` \| `Nm/bar/rad` \| `lbf*ft/psi/rad`
Default value	`0.1 cm^3/rev`
Program usage name	`displacement_threshold`
Evaluatable	Yes

# Cross-sectional area at ports A and B — cross-sectional area of ports A and B
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

Cross-sectional area of ports A and B. It is assumed that the areas are equal.

Units	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`0.01 m^2`
Program usage name	`port_area`
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 the Leakage and friction parameterization parameters to 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 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