modelMixingValve
Extends from AixLib.Obsolete.BaseClasses.ObsoleteModel (Icon for classes that are obsolete and will be removed in later versions), Modelica.Fluid.Fittings.BaseClasses.PartialTeeJunction (Base class for a splitting/joining component with three ports).
Information
Overview
This model is a model of a three-way mixing-valve. It mixes two incoming fluid-streams into one resulting fluid-stream. It is based on two seperate SimpleValve from the AixLib Library. The Model features a RealInput which controls the mixture of the streams in a range between 0 and 1. A filtered option is available.
Assumptions
The model assumes that pressure loss and friction phenomena of a mixing-valve correspond to the phenomena of a normal valve. The mixing of both streams is assumed ideal.
Concept
The MixingValve is put together from two single SimpleValves. It is controlled by a RealInput in the range between 0 and 1. Value 0 opens port_1 completely and closes port_3, value 1 closes port_1 completely and opens port_3. The function between those values is linear. The model features a filter which simulates the delay when opening a valve manually. For this see PartialValve.
References
The following sheets can be used for finding apropriate values for Kv:
http://www.armstronginternational.com/files/products/lynnwood/pdf/installation/IOM-442_CPAC0012.pdf
http://www.herzvalves.com/www/downloads/DS_4037_Three_Way_Valve.pdf
Example Results
Verification:
MixingValves.AixLib.Examples.MixingValveForwardDirection
MixingValves.AixLib.Examples.MixingValveBackwardDirection
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November 26, 2014 by Roozbeh Sangi:
Implemented
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Real | Kvs | 1.4 | Kv value at full opening (=1) |
| Real | leakageOpening | 1e-3 | The opening signal is limited by leakageOpening (to improve the numerics) |
| Filtered opening | |||
| Boolean | filteredOpening | false | = true, if opening is filtered with a 2nd order CriticalDamping filter |
| Modelica.Units.SI.Time | riseTime | 1 | Rise time of the filter (time to reach 99.6 % of an opening step) |
Connectors
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.Fluid.Interfaces.FluidPort_a | port_1 (from PartialTeeJunction) | ||
| Modelica.Fluid.Interfaces.FluidPort_b | port_2 (from PartialTeeJunction) | ||
| Modelica.Fluid.Interfaces.FluidPort_a | port_3 (from PartialTeeJunction) | ||
| Modelica.Blocks.Interfaces.RealInput | opening | Valve position in the range 0..1 | |
| Modelica.Blocks.Interfaces.RealOutput | opening_filtered | Filtered valve position in the range 0..1 | |
| Modelica.Blocks.Interfaces.RealOutput | opening_actual | Actual opening dpending if filtered or not. |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| AixLib.Utilities.Sources.BaseParameters | baseParameters | System wide properties | |
| AixLib.Obsolete.Year2021.Fluid.Actuators.Valves.SimpleValve | Valve | ||
| AixLib.Obsolete.Year2021.Fluid.Actuators.Valves.SimpleValve | Valve2 | ||
| Modelica.Blocks.Sources.Constant | Constant | To compute opening of second valve | |
| Modelica.Blocks.Math.Add | add | ||
| Modelica.Blocks.Continuous.Filter | filter | ||
| MinLimiter | minLimiter |
Contents
| Name | Description |
|---|---|
 MinLimiter | Limit the signal above a threshold |