Periodic Reporting for period 1 - TWINECS (Toward a Digital Twin ECS and thermal management architecture models: Improvement of MODELICA libraries and usage of Deep Learning technics)
Reporting period: 2020-09-01 to 2022-02-28
This project deals with the modelling of a VCS system within the framework of a system-oriented simulation of the whole ECS for control and optimization purposes. This work is aligned with the Clean Sky 2 SYS ITD WP6 – Major loads, WP6.1 – Electrical Air System and Thermal Management. Within this work package, this topic is specifically related to the subsection about the New Generation of Cooling Systems.
The aims of the TwinECS project are, on the one hand, to enhance existing Modelica libraries to simulate Environmental Control Systems (ECSs) based on the major challenges underlined in the Clean Sky 2 MALET project, and on the other hand, to develop and integrate surrogate models based on data analytics technics in order to reduce computational costs. The TwinECS specific objectives are summarized as follows:
• Development of thermo-fluid models: VCS heat exchangers and their successful integration in assembled VCS models.
• Development of electrical models for: motor, power inverter, ATRU, IGBT and MOSFET.
• Development of surrogate models of the aforementioned thermo-fluid and electrical components based on data analytics technics.
• Simulation of a complete thermo-fluid-electrical VCS model using both the standard and the surrogate models.
The expected enhanced numerical tool for the ECS simulation will have a crucial role for the design of more efficient ECS within the new More Electrical Approach (MAE). Given the ECS high needs of energy (ECS is the aircraft largest energy consumer without considering the propelling systems) its optimization will contribute to the global CleanSky objectives such as competitiveness improvement, reduction of fuel consumption, etc…
The aims of the TwinECS project are, on the one hand, to enhance existing Modelica libraries to simulate Environmental Control Systems (ECSs) based on the major challenges underlined in the Clean Sky 2 MALET project, and on the other hand, to develop and integrate surrogate models based on data analytics technics in order to reduce computational costs. The TwinECS specific objectives are summarized as follows:
• Development of thermo-fluid models: VCS heat exchangers and their successful integration in assembled VCS models.
• Development of electrical models for: motor, power inverter, ATRU, IGBT and MOSFET.
• Development of surrogate models of the aforementioned thermo-fluid and electrical components based on data analytics technics.
• Simulation of a complete thermo-fluid-electrical VCS model using both the standard and the surrogate models.
The expected enhanced numerical tool for the ECS simulation will have a crucial role for the design of more efficient ECS within the new More Electrical Approach (MAE). Given the ECS high needs of energy (ECS is the aircraft largest energy consumer without considering the propelling systems) its optimization will contribute to the global CleanSky objectives such as competitiveness improvement, reduction of fuel consumption, etc…
The work performed during this first period of the project has been focused on:
1) System Themo-Fluid modelling
- Heat exchanger modelling. A new flexible modelling approach has been implemented in order to satisfy the requirements in terms of numerical robustness and CPU time consumption.
- Heat exchanger calibration procedure. A calibration procedure based on reference data has been implemented to reach the expected accuracy levels.
- Heat exchanger numerical tests. A full set of numerical tests has been implemented to assess the model numerical robustness with respect to many configuration and operational aspects such as initialization, boundary conditions, input signals types, numerical parameters, null mass flow rates, reversed mass flow rates, reversed heat direction etc…
2) System electrical modelling
- Development of motor, power converters and transistors models. All the models developed were tested rigorously with various operating conditions and simulation time steps.
- Generation of electrical database. An electrical database has been generated based on the electrical models to be used for surrogate modelling.
- Surrogate models for electrical components. Surrogate models have been built using Gaussian Process Regression. Their performance has been evaluated with K-fold cross-validation techniques.
1) System Themo-Fluid modelling
- Heat exchanger modelling. A new flexible modelling approach has been implemented in order to satisfy the requirements in terms of numerical robustness and CPU time consumption.
- Heat exchanger calibration procedure. A calibration procedure based on reference data has been implemented to reach the expected accuracy levels.
- Heat exchanger numerical tests. A full set of numerical tests has been implemented to assess the model numerical robustness with respect to many configuration and operational aspects such as initialization, boundary conditions, input signals types, numerical parameters, null mass flow rates, reversed mass flow rates, reversed heat direction etc…
2) System electrical modelling
- Development of motor, power converters and transistors models. All the models developed were tested rigorously with various operating conditions and simulation time steps.
- Generation of electrical database. An electrical database has been generated based on the electrical models to be used for surrogate modelling.
- Surrogate models for electrical components. Surrogate models have been built using Gaussian Process Regression. Their performance has been evaluated with K-fold cross-validation techniques.
The library to simulate ECS based on the Modelica/Dymola framework is being optimized in terms of numerical robustness, CPU time consumption and accuracy. The main focus is placed on the VCS and the electrical components.
Compared to the state of the art, this enhanced ECS simulation tool will contribute to study and introduce new ECS architectures including supplemental cooling systems.
The library characteristic will allow to reproduce a large amount of cases (good numerical robustness) with significantly low CPU time (optimized time consumption based on appropriate modelling methods) that will support the activities needed to comply the high level objectives at demonstrator/technology level. Among them:
- Selection of new generation fluid compliant with environmental future rules and aerospace certification constrains.
- Study of variable and non-variable speed compressor centrifugal technologies.
- Design and development of optimized valve for dynamic regulation of VCS.
-Control capabilities. Improvement and definition of an optimized control strategy (introduction of the surrogate modelling approach to accelerate and stabilize the non-linear and complex nature of VCS systems).
- Design and optimization of heat Exchanger optimized for VCS application.
Compared to the state of the art, this enhanced ECS simulation tool will contribute to study and introduce new ECS architectures including supplemental cooling systems.
The library characteristic will allow to reproduce a large amount of cases (good numerical robustness) with significantly low CPU time (optimized time consumption based on appropriate modelling methods) that will support the activities needed to comply the high level objectives at demonstrator/technology level. Among them:
- Selection of new generation fluid compliant with environmental future rules and aerospace certification constrains.
- Study of variable and non-variable speed compressor centrifugal technologies.
- Design and development of optimized valve for dynamic regulation of VCS.
-Control capabilities. Improvement and definition of an optimized control strategy (introduction of the surrogate modelling approach to accelerate and stabilize the non-linear and complex nature of VCS systems).
- Design and optimization of heat Exchanger optimized for VCS application.