Isothermal Liquid Library

Specialized components for modeling fluid networks in the isothermal liquid domain

Isothermal liquid networks do not undergo temperature or viscosity changes due to any processes occurring in or around the network, but can support elevated or reduced temperatures. The fluid properties are a function of pressure. The available blocks include actuator and actuator forces, flow resistances, pumps and pump components with optional pre-parameterization, and a variety of valves with opening and closing dynamics.

In R2020a, the Isothermal Liquid library was introduced as a mass flow rate-based alternative to the Hydraulics (Isothermal) volumetric flow rate-based library. The Isothermal Liquid library introduces block usability improvements. For more information on converting models with Hydraulics (Isothermal) blocks to use Isothermal Liquid blocks, see: Upgrading Hydraulic Models to Use Isothermal Liquid Blocks.

If a specific component does not yet exist in a domain library, you can build your own using the Simscape™ language. For more information, see Creating Custom Components.

Related Information

Featured Examples

Hydraulic Axial-Piston Pump with Load-Sensing and Pressure-Limiting Control

A test rig designed to investigate the interaction between an axial-piston pump and a typical control unit simultaneously performing the load-sensing and pressure-limiting functions. To increase the fidelity of the simulation, this example uses a detailed model of the pump that accounts for the interaction between the pistons, swash plate, and valve plate.

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Hydraulic Actuator with Dual Counterbalance Valves

An actuator controlled by a 4-way directional valve and loaded with an overriding load, requiring the use of counterbalance valves to prevent the load from creeping when the directional valve is in the neutral position. In the neutral position, the directional valve connects ports A and B to the reservoir while blocking the pressure port P. The counterbalance valves block flow from returning to the reservoir, thus holding the actuator in place.

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Front-Loader Actuation System

A simplified version of an actuation system consisting of the lift and tilt cylinders. Each cylinder is controlled by an open center, 6-way, 3-position directional valve. The valves are connected in series through their unloading branch such that the system pump is unloaded when both command levers are in neutral position. If either tilt or lift command is applied, the unloading path is closed.

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Washing Machine Fault Analysis

Model a washing machine and introduce a fault in its operation. The machine water supply faults at a specific time and this example models the system response under this scenario. The electric motor switches off and the machine operation is aborted by discharging the partially filled outer drum.

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Cylinder Design Parameter Estimation

Parameterize and test a tandem primary cylinder starting from a manufacturer datasheet. This example uses optimization to determine remaining unknown parameters, given the numerical data extracted from the datasheet. After the model is simulated, it compares the resulting push rod force - brake pressure relationship curve to the curve provided on the manufacturer datasheet. Understanding the behavior of the tandem primary cylinder is important when selecting other braking system components.

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Tractor Transmission Energy Flow Chart

Model, parameterize, and test a tractor with a hydrostatic continuously variable transmission (CVT). When you run one of the plot functions, you can view plots of the tractor velocity, engine speed, transmission speed, and pump and motor energy computations.

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