valve

Modules

valve_torch_system module

class ValveTorchSystem(waterFlowRateMax=0.01594896331738437, valveAuthority=1, **kwargs)[source]

Bases: System, Module

A valve system model implemented with PyTorch for gradient-based optimization.

This model represents a valve that controls water flow rate based on valve position. The valve characteristic is modeled using the valve authority equation, which provides a more accurate representation of the valve’s behavior compared to a simple linear relationship.

Parameters:

  • waterFlowRateMax (Optional[float]) – Maximum water flow rate [kg/s]

  • valveAuthority (Optional[float]) – Valve authority (0-1)

  • **kwargs – Additional keyword arguments

Mathematical Formulation

The valve characteristic is calculated using the valve authority equation:

\[u_{norm} = \frac{u}{\sqrt{u^2 (1-a) + a}}\]
where:

  • \(u\) is the valve position (0-1)

  • \(a\) is the valve authority (0-1)

  • \(u_{norm}\) is the normalized valve position

The water flow rate is then calculated as:

\[\dot{m}_w = u_{norm} \cdot \dot{m}_{w,max}\]
where:

  • \(\dot{m}_w\) is the water flow rate [kg/s]

  • \(\dot{m}_{w,max}\) is the maximum water flow rate [kg/s]

param waterFlowRateMax:

Maximum water flow rate [kg/s]

type waterFlowRateMax:

float

param valveAuthority:

Valve authority (0-1), where: - 0: Linear characteristic - 1: Equal percentage characteristic - Values in between: Mixed characteristic

type valveAuthority:

float

Notes

Valve Authority Characteristics:

  • Linear (a = 0): Flow rate is directly proportional to valve position

  • Equal Percentage (a = 1): Flow rate changes exponentially with valve position

  • Mixed (0 < a < 1): Combination of linear and equal percentage characteristics

Implementation Details:

  • The model uses PyTorch tensors for gradient-based optimization

  • All parameters are stored as non-trainable PyTorch parameters

  • The valve authority equation provides better control at low flow rates

  • The model assumes ideal valve behavior (no hysteresis or deadband)

do_step(secondTime, dateTime, step_size, stepIndex)[source]

Perform one step of the valve system simulation.

The valve characteristic is calculated using the valve authority equation: u_norm = u / sqrt(u^2 * (1-a) + a) where: - u is the valve position (0-1) - a is the valve authority (0-1) - u_norm is the normalized valve position

The water flow rate is then calculated as: m_w = u_norm * waterFlowRateMax

Return type:

None

initialize(start_time, end_time, step_size, simulator)[source]

Initialize the valve system.

Return type:

None

property config

Get the configuration of the valve system.

property input: dict

Get the input ports of the valve system.

Returns:

Dictionary containing input ports:

  • ”valvePosition”: Valve position (0-1)

Return type:

dict

property output: dict

Get the output ports of the valve system.

Returns:

Dictionary containing output ports:

  • ”valvePosition”: Valve position (0-1)

  • ”waterFlowRate”: Water flow rate [kg/s]

Return type:

dict

sp = [<twin4build.translator.translator.SignaturePattern object>]
get_signature_pattern()[source]