Systèmes gazeux

Cet exemple montre comment utiliser les composants gazeux de la Foundation Library pour modéliser un actionneur pneumatique contrôlé. Le sous-système masqué Directional Valve a été créé avec des blocs Variable Local Restriction (G) pour modéliser l’ouverture et la fermeture des trajectoires d’écoulement. Le sous-système masqué Double-Acting Actuator a été créé avec des blocs Translational Mechanical Converter (G) pour modéliser l’interface entre le réseau gazeux et le réseau mécanique de translation.

How a pneumatic vane motor can be modeled using the Simscape™ language. The Pneumatic Motor component is built using the Simscape Foundation gas domain. It inherits from the foundation.gas.two_port_steady base class, which contains common equations that implement the upwind energy flow rate and the gas properties at the ports. The Pneumatic Motor subclass implements equations that describe behaviors specific to the component, such as the motor torque and flow rate characteristics and the mass and energy balance. The Pneumatic Motor block is inserted into the model using the Simscape Component block without the need to generate a separate library.

The choking behavior of a gas orifice modeled by the Local Restriction (G) block. The Controlled Reservoir (G) blocks are used to set up controlled pressure and temperature boundary conditions from the Reservoir Inputs subsystem to test the gas orifice.

Models a gas turbine auxiliary power unit (APU) based on the Brayton Cycle. The Compressor and Turbine blocks are custom components based on the Simscape™ Foundation Gas Library. The power input to the system is represented by heat injection into the combustor; actual combustion chemistry is not modeled. A single shaft connects the compressor and the turbine so that the power from the turbine drives the compressor. The APU is a free turbine that further expands the exhaust stream to produce output power.

Cet exemple présente un modèle du circuit de ventilation d’un bâtiment. Le volume d’air à l’intérieur du bâtiment est divisé en quatre zones. Le système de ventilation insuffle de l’air frais dans la zone 1 et extrait l’air de la zone 3. L’air extrait peut éventuellement être recyclé et réintroduit dans la zone 1. Dans la zone 4, il est possible d’ouvrir une porte pour évacuer l’air dans l’atmosphère.

Model a Gamma Stirling engine using gas, thermal, and mechanical Simscape™ components and domains.

Gas flow through a compressor which is modeled using a simple controlled mass flow rate source. The compressor map that governs this mass flow rate is modeled using the PS Scattered Lookup (2D) block whose data coordinates are the pressure ratio (Pa/Pa) and the engine RPM, and the output is the mass flow rate (kg/s). The scattered lookup block performs delaunay triangulation on the input data (which is shown in plots below), and uses this to interpolate and calculate the mass flow rate based on the input. Scattered lookup allows modeling of the compressor even if the data provided is in an unstructured format.