modelPolytropicFlow
Extends from ThermofluidStream.Idealized.Examples.TUMExercisesThermodynamicCycles.Exercise3OttoEngine.BaseModel.
Information
Example of an Otto cycle engine model. See TUMExercisesThermodynamicCycles.Exercise3OttoEngine for the problem description.
This example makes use of the following components and settings:
-
SimpleAir medium model
(ideal gas with
R = 287 J/(kg·K)andgamma = 1.40) - PolytropicPerfectGas process model
-
systemSpec = Flow(SystemModel)
This setup is based on the fact that the specific work of a thermodynamic cycle is given by the closed integral in the p–v diagram (pressure - specific volume).
Therefore, integrating with respect to volume, p*dv (boundary work as typically transferred in a piston–cylinder system),
and integrating with respect to pressure, v*dp (“artificial” shaft work of a dual stationary-flow process),
yield the same net cycle work, even though the individual contributions of each process step differ.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Medium.AbsolutePressure | p1 (from BaseModel) | 100000 | Pressure before compression |
| Medium.Temperature | T1 (from BaseModel) | 300 | Temperature before compression |
| Real | compressionRatio (from BaseModel) | 10 | Compression ratio |
| Medium.Temperature | T3 (from BaseModel) | 2200 | Temperature after combustion |
| SI.MassFlowRate | m_flow (from BaseModel) | 1 | Mass flow rate |
| Medium.Density | rho1 (from BaseModel) | Medium.density_pTX(p1, T1, Medium.X_default) | Density before compression |
| Medium.Density | rho2 (from BaseModel) | rho1*compressionRatio | Density after compression |
| SI.SpecificVolume | v1 (from BaseModel) | 1/rho1 | Specific volume before compression |
| SI.SpecificVolume | v2 (from BaseModel) | 1/rho2 | Specific volume after compression |
Components
| Type | Name | Default | Description |
|---|---|---|---|
| ThermofluidStream.DropOfCommons | dropOfCommons (from BaseModel) | ||
| ThermofluidStream.Idealized.Processes.PolytropicPerfectGas | compression | ||
| ThermofluidStream.Idealized.Processes.Isochoric | combustion | ||
| ThermofluidStream.Idealized.Processes.PolytropicPerfectGas | expansion | ||
| ThermofluidStream.Idealized.Processes.Isochoric | gasExchange | ||
| ThermofluidStream.Idealized.Boundaries.LoopBreaker_m | loopBreaker | ||
| ThermofluidStream.Idealized.EnergyFlow.Components.Sum | shaftPower | ||
| ThermofluidStream.Utilities.showRealValue | maximumPressure | ||
| ThermofluidStream.Utilities.showRealValue | efficiency | ||
| ThermofluidStream.Utilities.showRealValue | netWork |
Revisions
-
2026, by Raphael Gebhart (raphael.gebhart@dlr.de):
Initial version.