Turbine
Turbine for boosted engines
Libraries:
Powertrain Blockset /
Propulsion /
Combustion Engine Components /
Boost
Description
The Turbine block uses the conservation of mass and energy to calculate mass and heat flow rates for turbines with either fixed or variable geometry. You can configure the block with a wastegate valve to bypass the turbine. The block uses two-way ports to connect to the inlet and outlet control volumes and the drive shaft. You can specify the lookup tables to calculate the mass flow rate and turbine efficiency. Typically, turbine manufacturers provide the mass flow rate and efficiency tables as a function of corrected speed and pressure ratio. The block does not support reverse mass flow.
If you have Model-Based Calibration Toolbox™, click Calibrate Performance Maps to virtually calibrate the mass flow rate and turbine efficiency lookup tables using measured data.
The mass flows from the inlet control volume to outlet control volume.
The Turbine block implements equations to model the performance, wastegate flow, and combined flow.
Virtual Calibration
If you have Model-Based Calibration Toolbox, click Calibrate Performance Maps to virtually calibrate the corrected mass flow rate and turbine efficiency lookup tables using measured data. The dialog box steps through these tasks.
Task | Description | ||||||||||||||||||||||||||||||||||||||||||||||||||
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Import turbine data | Import this turbine data from a file. For more information, see Using Data (Model-Based Calibration Toolbox).
Model-Based Calibration Toolbox limits the speed and pressure ratio breakpoint values to the maximum values in the file. To filter or edit the data, select Edit in Application. The Model-Based Calibration Toolbox Data Editor opens. | ||||||||||||||||||||||||||||||||||||||||||||||||||
Generate response models | Model-Based Calibration Toolbox fits the imported data and generates response models.
To assess or adjust the response model fit, select Edit in Application. The Model-Based Calibration Toolbox Model Browser opens. For more information, see Model Assessment (Model-Based Calibration Toolbox). | ||||||||||||||||||||||||||||||||||||||||||||||||||
Generate calibration | Model-Based Calibration Toolbox calibrates the response model and generates calibrated tables.
To assess or adjust the calibration, select Edit in Application. The Model-Based Calibration Toolbox CAGE Browser opens. For more information, see Calibration Lookup Tables (Model-Based Calibration Toolbox). | ||||||||||||||||||||||||||||||||||||||||||||||||||
Update block parameters | Update these corrected mass flow rate and efficiency parameters with the calibration.
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Thermodynamics
The block uses these equations to model the thermodynamics.
Calculation | Equations |
---|---|
Forward mass flow | |
First law of thermodynamics | |
Isentropic efficiency | |
Isentropic outlet temperature, assuming ideal gas, and constant specific heats | |
Specific heat ratio | |
Outlet temperature | |
Heat flows | |
Drive shaft torque |
The equations use these variables.
, | Inlet control volume total pressure |
, | Inlet control volume total temperature |
, | Inlet control volume total specific enthalpy |
, | Outlet control volume total pressure |
Outlet control volume total temperature | |
Outlet control volume total specific enthalpy | |
Drive shaft power | |
Temperature exiting the turbine | |
Outlet total specific enthalpy | |
Turbine mass flow rate | |
Turbine inlet heat flow rate | |
Turbine outlet heat flow rate | |
Turbine isentropic efficiency | |
Isentropic outlet total temperature | |
Isentropic outlet total specific enthalpy | |
Ideal gas constant | |
Specific heat at constant pressure | |
Specific heat ratio | |
Drive shaft torque |
Performance Lookup Tables
The block implements lookup tables based on these equations.
Calculation | Equation | |
---|---|---|
Corrected mass flow rate | ||
Corrected speed | ||
Pressure expansion ratio | ||
Efficiency lookup table | Fixed geometry (3-D table) | |
Variable geometry (3-D table) | ||
Corrected mass flow lookup table | Fixed geometry (3-D table) | |
Variable geometry (3-D table) |
The equations use these variables.
Inlet control volume total pressure | |
Pressure expansion ratio | |
Outlet control volume total pressure | |
Lookup table reference pressure | |
Inlet control volume total temperature | |
Lookup table reference temperature | |
Turbine mass flow rate | |
Drive shaft speed | |
Corrected drive shaft speed | |
Variable geometry turbine rack position | |
Efficiency 3-D lookup table for fixed geometry | |
Corrected mass flow rate 3-D lookup table for fixed geometry | |
Efficiency 3-D lookup table for variable geometry | |
Corrected mass flow rate 3-D lookup table for variable geometry |
Wastegate
To calculate the wastegate heat and mass flow rates, the Turbine block uses a Flow Restriction block. The Flow Restriction block uses the wastegate flow area.
The equation uses these variables.
Wastegate valve area percent command | |
Wastegate valve area | |
Wastegate valve area when fully open |
Combined Flow
To represent flow through the wastegate valve and turbine, the block uses these equations.
Calculation | Equations | |
---|---|---|
Blocks not configured with a wastegate valve | ||
Total mass flow rate | ||
Total heat flow rate | ||
Combined temperature exiting the wastegate valve and turbine |
The block uses the internal signal FlwDir
to track the direction of the flow.
The equations use these variables.
Total mass flow rate through the wastegate valve and turbine | |
Turbine mass flow rate | |
Mass flow rate through the wastegate valve | |
Total inlet heat flow rate | |
Total outlet heat flow rate | |
Turbine inlet heat flow rate | |
Turbine outlet heat flow rate | |
Wastegate valve heat flow rate | |
Temperature exiting the turbine | |
Total temperature exiting the block | |
Temperature exiting the wastegate valve | |
Mass flow rate threshold to prevent dividing by zero | |
Specific heat at constant pressure |
Power Accounting
For the power accounting, the block implements these equations.
Bus Signal | Description | Equations | ||
---|---|---|---|---|
|
| PwrDriveshft | Power transmitted from the shaft | |
| Heat flow rate at port A | |||
PwrHeatFlwOut | Heat flow rate at port B | |||
| PwrLoss | Power loss | ||
| Not used |
The equations use these variables.
Drive shaft power | |
Total outlet heat flow rate | |
Total inlet heat flow rate |
Examples
Ports
Input
Output
Parameters
References
[1] Heywood, John B. Internal Combustion Engine Fundamentals. New York: McGraw-Hill, 1988.
[2] Eriksson, Lars and Lars Nielsen. Modeling and Control of Engines and Drivelines. Chichester, West Sussex, United Kingdom: John Wiley & Sons Ltd, 2014.
Extended Capabilities
Version History
Introduced in R2017a