Block Substitutions for Simscape Fluids Hydraulics (Isothermal) Blocks

The hydraulicToIsothermalLiquid conversion tool replaces hydraulic blocks in your model with the corresponding isothermal liquid blocks. This table lists the Hydraulics (Isothermal) library blocks and their associated Isothermal Liquid library blocks. To match the Hydraulics (Isothermal) block configuration, some converted models may include a subsystem with additional Simscape Fluids or Simscape blocks. Some blocks in the Hydraulics (Isothermal) library do not have an equivalent Isothermal Liquid library block. In this case, you can reconstruct the functionality from a collection of Simscape and Simscape Fluids blocks.

Accumulators

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Gas-Charged Accumulator	Gas-Charged Accumulator (IL)
Spring-Loaded Accumulator	Spring-Loaded Accumulator (IL) The isothermal liquid block does not model hard-stop damping.

Hydraulic Cylinders

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Centrifugal Force in Rotating Cylinder	Rotating Cylinder Force (IL) The Fluid density parameter is replaced with port X, which senses the network density.
Cylinder Cushion	Cylinder Cushion (IL) The Cylinder Cushion (IL) block is parameterized by plunger diameter, area, and length. The Hydraulics (Isothermal) block is parameterized by tabulated area and displacement. The conversion tool calculates the plunger length, or the orifice control member travel, from the Hydraulics (Isothermal) block as opening(end) - opening(1).
Cylinder Friction	Cylinder Friction (IL) The Cylinder Friction (IL) block does not assign beginning values to variables.
Single-Acting Rotary Actuator	Single-Acting Rotary (IL) The conversion tool converts the Single-Acting Rotary Actuator block to a subsystem. If the Hydraulics (Isothermal) block models leakage, or the Leak coefficient is nonzero, port A of the Single-Acting Rotary (IL) connects to port A of a Laminar Leakage (IL) block, which connects to a Reservoir (IL) block at atmospheric pressure.
Double-Acting Rotary Actuator	Double-Acting Rotary Actuator (IL) The conversion tool converts the Double-Acting Rotary Actuator to a subsystem. If the Hydraulics (Isothermal) block models leakage, or the Leak coefficient is nonzero, ports A and B of the Double-Acting Rotary Actuator (IL) block connect in parallel to ports A and B, respectively, of a Laminar Leakage (IL) block.
Single-Acting Hydraulic Cylinder	Single-Acting Actuator (IL)
Single-Acting Hydraulic Cylinder (Simple)	Single-Acting Actuator (IL) The conversion tool sets the Hard stop model parameter to Stiffness and damping applied smoothly through transition region, damped rebound, with default hard stop parameters.
Double-Acting Hydraulic Cylinder	Double-Acting Actuator (IL)
Double-Acting Hydraulic Cylinder (Simple)	Double-Acting Actuator (IL) The conversion tool sets the Hard stop model parameter to Stiffness and damping applied smoothly through transition region, damped rebound, with default hard stop parameters.

Utilities

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Hydraulic Fluid	Isothermal Liquid Predefined Properties (IL)
Reservoir	Reservoir (IL)

Hydraulic Resistances

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Elbow	Elbow (IL)
Gradual Area Change	Area Change (IL) The conversion tool converts the Gradual Area Change block to a subsystem to maintain the original port orientation.
Local Resistance	Local Resistance (IL)
Pipe Bend	Pipe Bend (IL) The Initial liquid pressure parameter in the Pipe Bend block is in gauge. In the Pipe Bend (IL) block, this parameter is in absolute pressure. The conversion tool converts the Critical Reynolds number parameter into two internally fixed threshold Reynolds numbers in the Pipe Bend (IL), where 2000 indicates a fully laminar flow and 4000 indicates a fully turbulent flow.
Sudden Area Change	Area Change (IL)
T-Junction	The conversion tool converts the T-Junction block to a subsystem with Local Resistance (IL) blocks.

Low Pressure Blocks

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Hydraulic Pipe LP Resistive Pipe LP Resistive Pipe LP with Variable Elevation Segmented Pipe LP	Pipe (IL)
Hydraulic Pipe LP with Variable Elevation	Pipe (IL) Port EL is exposed for elevation change as a physical signal input.
Partially Filled Vertical Pipe LP	Partially Filled Pipe (IL) The Partially Filled Pipe (IL) block receives a liquid level instead of a liquid volume at its physical signal port. The conversion tool add a PS Constant block to divide the original fluid volume by a constant tank cross-section within a subsystem. Modify the assumed tank cross-section in the added PS Constant block.
Constant-Head Tank	The conversion tool converts the Constant-Head Tank block to a subsystem that includes Reservoir (IL), Orifice (IL), PS Integrator, and Flow Rate Sensor blocks.
Tank	The conversion tool converts the Tank block to a subsystem that includes a Tank (IL) block and a Flow Resistance (IL) block for each inlet port.

Orifices

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Annular Orifice	Annular Leakage (IL)
Fixed Orifice Fixed Orifice With Fluid Inertia Fixed Orifice Empirical Variable Orifice	Orifice (IL)
Journal Bearing Pressure-Fed	The conversion tool converts the Journal Bearing Pressure-Fed block to a subsystem that includes two Annular Leakage (IL) blocks.
Orifice With Variable Area Round Holes Orifice With Variable Area Slot	Spool Orifice (IL)
Variable Orifice Between Round Holes	Variable Overlapping Orifice (IL)

Pipes

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Rotating Pipe	Rotating Channel (IL)
Hydraulic Pipeline	Pipe (IL)
Segmented Pipeline	Pipe (IL)

Pumps and Motors

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Angle Sensor	The conversion tool converts the Angle Sensor block to a subsystem that contains an Ideal Rotational Motion Sensor block.
Centrifugal Pump	Centrifugal Pump (IL)
Fixed-Displacement Motor	Fixed-Displacement Motor (IL) The Fixed-Displacement Motor (IL) block uses the network fluid properties. You may need to modify the Volumetric efficiency at nominal conditions parameter to match the Hydraulics (Isothermal) block functionality.
Fixed-Displacement Pump	Fixed-Displacement Pump (IL) The Fixed-Displacement Pump (IL) block uses the network fluid properties. You may need to modify the Volumetric efficiency at nominal conditions parameter to match the Hydraulics (Isothermal) block functionality.
Jet Pump	Jet Pump (IL)
Porting Plate Variable Orifice	Valve Plate Orifice (IL)
Swash Plate	Swash Plate
Variable-Displacement Motor	Variable Displacement Motor (IL) The Variable Displacement Motor (IL) block uses the network fluid properties. You may need to modify the Volumetric efficiency at nominal conditions parameter to match the Hydraulics (Isothermal) block functionality.
Variable-Displacement Pressure-Compensated Pump	Pressure-Compensated Pump (IL) The conversion tool converts the Variable-Displacement Pressure-Compensated Pump block to a subsystem. The Pressure-Compensated Pump (IL) block uses the network fluid properties. You may need to modify the Volumetric efficiency at nominal conditions parameter to match the Hydraulics (Isothermal) block functionality.
Variable-Displacement Pump	Variable Displacement Pump (IL) The Variable Displacement Pump (IL) block uses the network fluid properties. You may need to modify the Volumetric efficiency at nominal conditions parameter to match the Hydraulics (Isothermal) block functionality.

Directional Valves

Hydraulics (Isothermal) Block	Isothermal Liquid Block
2-Way Directional Valve	2-Way Directional Valve (IL) The 2-Way Directional Valve (IL) block behavior and parameterization are based on the spool position at the maximum orifice area and the maximum spool travel distance, while the 2-Way Directional Valve uses initial spool position. Changing the valve parameterization after conversion can lead to inconsistencies. See Upgrade Considerations When Converting Hydraulic to Isothermal Liquid Models.
3-Way Directional Valve	3-Way Directional Valve (IL) The 3-Way Directional Valve (IL) block behavior and parameterization are based on the spool position at the maximum orifice area and the maximum spool travel distance, while the 3-Way Directional Valve uses initial spool position. Changing the valve parameterization after conversion can lead to inconsistencies. See Upgrade Considerations When Converting Hydraulic to Isothermal Liquid Models.
4-Way Ideal Valve	4-Way 3-Position Directional Valve (IL) The 4-Way 3-Position Directional Valve (IL) block behavior and parameterization are based on the spool position at the maximum orifice area and the maximum spool travel distance, while the 4-Way Ideal Valve uses initial spool position. Changing the valve parameterization after conversion can lead to inconsistencies. See Upgrade Considerations When Converting Hydraulic to Isothermal Liquid Models.
4-Way Directional Valve	4-Way 3-Position Directional Valve (IL) The 4-Way 3-Position Directional Valve (IL) block behavior and parameterization are based on the spool position at the maximum orifice area and the maximum spool travel distance, while the 4-Way Directional Valve uses initial spool position. Changing the valve parameterization after conversion can lead to inconsistencies. See Upgrade Considerations When Converting Hydraulic to Isothermal Liquid Models.
4-Way Directional Valves A-K	4-Way 3-Position Directional Valve (IL) The 4-Way 3-Position Directional Valve (IL) block behavior and parameterization are based on the spool position at the maximum orifice area and the maximum spool travel distance, while the 4-Way Directional Valves A-K use initial spool position. Changing the valve parameterization after conversion can lead to inconsistencies. See Upgrade Considerations When Converting Hydraulic to Isothermal Liquid Models.
Cartridge Valve Insert Cartridge Valve Insert With Conical Seat	Cartridge Valve Insert (IL)
Check Valve	Check Valve (IL) When you set Opening dynamics to Include valve opening dynamics for the Check Valve block, the setting affects the valve area. However, when Opening dynamics is On for the Check Valve (IL) block, the setting affects only the valve pressure.
Hydraulically Operated Remote control Valve	Pressure Compensator Valve (IL)
Pilot-Operated Check Valve	Pilot-Operated Check Valve (IL)
Shuttle Valve	Shuttle Valve (IL)

Flow Control Valves

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Ball Valve	Poppet Valve (IL)
Counterbalance Valve	Counterbalance Valve (IL)
Flow Divider	The conversion tool converts the block to a subsystem.
Flow Divider-Combiner	The conversion tool converts the block to a subsystem.
Gate Valve	Variable Overlapping Orifice (IL)
Needle Valve	Needle Valve (IL)
Poppet Valve	Poppet Valve (IL)
Pressure-Compensated 3-Way Flow Control Valve	Pressure-Compensated 3-Way Flow Control Valve (IL)
Pressure-Compensated Flow Control Valve	Pressure-Compensated Flow Control Valve (IL)

Pressure Control Valves

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Pressure Compensator	Pressure Compensator Valve (IL) When you set Opening dynamics to Include valve opening dynamics for the Check Valve block, the setting affects the valve area. However, when Opening dynamics is On for the Check Valve (IL) block, the setting affects only the valve pressure.
Pressure Reducing Valve	Pressure-Reducing Valve (IL) When you set Opening dynamics to Include valve opening dynamics for the Check Valve block, the setting affects the valve area. However, when Opening dynamics is On for the Check Valve (IL) block, the setting affects only the valve pressure.
Pressure Relief Valve	Pressure Relief Valve (IL) When you set Opening dynamics to Include valve opening dynamics for the Check Valve block, the setting affects the valve area. However, when Opening dynamics is On for the Check Valve (IL) block, the setting affects only the valve pressure.
Pressure Reducing 3-way Valve	Pressure-Reducing 3-Way Valve (IL) When you set Opening dynamics to Include valve opening dynamics for the Check Valve block, the setting affects the valve area. However, when Opening dynamics is On for the Check Valve (IL) block, the setting affects only the valve pressure.

Valve Actuators

Hydraulics (Isothermal) Block	Isothermal Liquid Block
2-Position Valve Actuator 3-Position Valve Actuator	Multiposition Valve Actuator
Double-Acting Servo Cylinder	Double-Acting Servo Valve Actuator (IL) The conversion tool sets the Hard stop model parameter to Stiffness and damping applied smoothly through transition region, damped rebound, with default hard stop parameters.
Hydraulic 4-Port Cartridge Valve Actuator	Cartridge Valve Actuator (IL) The conversion tool converts the block to a subsystem. The Cartridge Valve Actuator (IL) block calculates area at port B as the sum of the area at ports X and Y minus the area at port A. The hydraulics block calculates the difference between the areas at port X and port A.
Hydraulic Cartridge Valve Actuator	Cartridge Valve Actuator (IL)
Hydraulic Single-Acting Valve Actuator Hydraulic Double-Acting Valve Actuator	Pilot Valve Actuator (IL)
Proportional and Servo-Valve Actuator	The conversion tool converts the block into a subsystem that contains physical signal blocks.
Valve Actuator	Proportional Valve Actuator

Valve Forces

Hydraulics (Isothermal) Block	Isothermal Liquid Block
Spool Orifice Hydraulic Force	Spool Orifice Flow Force (IL)
Valve Hydraulic Force	The conversion tool converts the Valve Hydraulic Force block to a subsystem.

Fluid Network Interfaces Library

Interface (TL-IL)	Interface (TL-IL) The conversion tool sets the Interface (TL-IL) parameter Fluids domain interface to Thermal Liquid (TL) - Isothermal Liquid (IL). Note In R2020a and R2020b, this block is named Interface.
Double-Acting Actuator (H-G)	Double-Acting Actuator (G-IL) The conversion tool converts the Double-Acting Actuator (H-G) block to a subsystem.

SimHydraulics Legacy Library

Variable-Displacement Hydraulic Machine	Variable-Displacement Motor (IL) The conversion tool converts the Variable-Displacement Hydraulic Machine block to a subsystem and sets the Variable-Displacement Motor (IL) Leakage and friction parameterization to Input signal - volumetric and mechanical losses.
Variable-Displacement Hydraulic Machine (External Efficiencies)	Variable-Displacement Motor (IL) The conversion tool converts the Variable-Displacement Hydraulic Machine (External Efficiencies) block to a subsystem and sets the Variable-Displacement Motor (IL) Leakage and friction parameterization parameter to Input signal - volumetric and mechanical efficiencies.