Engee documentation

Variable-Displacement Motor (TL)

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Variable displacement hydraulic motor in a thermal liquid network.

variable displacement motor tl

Description

Unit Variable-Displacement Motor (TL) is a device that receives energy from the thermal liquid network and transfers it to the mechanical network. The working volume of the hydraulic motor fluid can be varied during the simulation and is input 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 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 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 time constant of the hydraulic motor is considered negligible compared to the time constant of the system. The hydraulic motor is assumed to reach steady state almost instantaneously and is considered as a quasi-stationary component.

Flow rate and torque

The mass flow rate of the hydraulic motor is:

where

  • - is the actual mass flow rate;

  • - ideal mass flow rate;

  • - mass flow rate of internal leakage.

The torque of the hydraulic motor is:

where

  • - is the actual torque;

  • - ideal torque;

  • - friction torque.

The ideal flow rate and ideal torque are calculated as




where

  • - is the average value of liquid density in thermal liquid ports A and B;

  • - working volume entering as a scalar on the port S;

  • - angular speed of shaft rotation;

  • - pressure drop from inlet to outlet.

Analytical parameterization of leakage and friction torque

If the parameters Leakage and friction parameterization is set to Analytical, then the leakage flow rate is:

and the friction torque is calculated as:

where

  • - is the Hagen-Poiseuille coefficient for laminar flows. The unit calculates this coefficient from the specified nominal parameters;

  • - average dynamic viscosity of thermal liquid in the ports;

  • - average density of the fluid in the ports;

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

    where is the friction torque under nominal conditions:

  • - block parameter value Nominal displacement;

  • - parameter value No-load torque;

  • - parameter value Nominal shaft angular velocity. This is the angular velocity at which the nominal volumetric efficiency value is set;

  • - parameter value Nominal pressure drop. This value represents the differential pressure at which the nominal volumetric efficiency is set;

The block determines the Hagen-Poiseuille coefficient based on the nominal fluid and component parameters

where

  • - parameter value Nominal dynamic viscosity. This value represents the dynamic viscosity at which the nominal volumetric efficiency value is given;

  • - parameter value Volumetric efficiency at nominal conditions.

Tabular parameterization

When usage of tabular data for efficiency or losses of the hydraulic motor, data for one or more operating modes can be specified. 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 specified data into the remaining quadrants.

Table data - parameterization of volumetric and mechanical efficiency

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

The leakage flow rate is:

and the friction torque is:

where

  • - is the numerical smoothing parameter for the transient process from the hydraulic motor to the pump;

  • - leakage flow rate in pump mode;

  • - leakage flow rate in the hydraulic motor mode;

  • - friction moment in the pump mode;

  • - friction torque in the hydraulic motor mode.

Smoothing parameters is given by 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 the volumetric efficiency, a value that is set in tabular form in the area using the Volumetric efficiency table block parameters.

When operating in pump mode, the leakage flow rate is:

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

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

The friction torque is similarly calculated from the mechanical efficiency, a value that is tabulated in the area using the block parameter Mechanical efficiency table, e_m(dp,w,D).

When operating in pump mode, the friction torque is:

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

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

Table data - parameterization of volumetric and mechanical losses

If the parameters Leakage and friction parameterization is set to Tabulated data - volumetric and mechanical losses, the leakage volume flow rate is entered directly in tabular form in the area :

The leakage mass flow rate is calculated from the volumetric flow rate:

The friction torque is equal to:

where and are volume and mechanical losses obtained by interpolation or extrapolation of tabulated data given in parameters Volumetric loss table, q_loss(dp,w,D) и Mechanical loss table, torque_loss(dp,w,D).

Parametrization through the 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 efficiency values and are fed directly to the EV and EM ports respectively.

The efficiencies are positive values with a value between 0 and 1. The values of input signals outside these limits are set equal to the nearest limit (0 for inputs less than 0 and 1 for inputs greater than 1). Volumetric and mechanical efficiencies vary between a user-defined minimum and maximum value. Any values below or above this range will take the minimum and maximum setpoints respectively.

If the parameters Leakage and friction parameterization is set to Input signal - volumetric and mechanical losses, the LV and LM ports are enabled. These ports receive the leakage flux and friction torque values as positive scalars.

The input values are expected to be positive. The block automatically sets the signs based on the operating conditions set during the simulation, i.e. from the quadrant , in which the component operates.

Energy conservation

The mechanical work performed by the hydraulic motor involves the exchange of energy. The energy conservation equation is of the form:

where

  • and are energy flows in ports A and B respectively;

  • - hydraulic power of the hydraulic motor. It is a function of the pressure difference between the hydraulic motor ports: .

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

Assumptions and limitations

  • The compressibility of the fluid 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

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 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 и Shaft angular velocity vector, w and interpolated from the corresponding two-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 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

# 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 fluid that enters the motor over a given shaft rotation under nominal operating conditions.

Dependencies

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

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 parameter Leakage and friction parameterization value 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 parameter Leakage and friction parameterization value 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 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. This torque is the load-independent component of the total friction torque.

Dependencies

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

# 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.

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, -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 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.

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 parameter Leakage and friction parameterization value 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

# 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.

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, -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.

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 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.

Units

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.

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 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.

Units

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.

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

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 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