Periodic Reporting for period 3 - PHP2 (Pulsating Heat Pipes for Hybrid Propulsion systems)
Período documentado: 2021-11-01 hasta 2022-10-31
Pulsating heat pipes (PHP) are a new and promising technology for the thermal management of electrical aircrafts. However, the technical challenges are numerous due to an incomplete understanding of their complex behavior and the lack of simulation tools to describe their performance.
The aim of this project is to study PHPs and develop predesign tools to push this solution to an industrial level. This is achieved by following three main objectives:
- To design, build and test PHPs on an experimental test bench
- To develop a 1D physical tool
- To develop a mathematical tool for predesign purpose
The present project offers cooperation between JJ Cooling Innovation and Provides, leaders in the modelling, design and fabrication of high-performance micro-two-phases cooling systems using state-of-the-art components and heat-exchangers, and Altran, world leader in engineering solutions and outsourced R&D.
During the project, 9 tubular PHP and 1 flat plate PHP have been built and tested and a large experimental database (over 1000 operating points) has been gathered. This database has been used to validate the 1D physical model and to train a mathematical model capable of predicting the thermal resistance of PHP from geometrical and operational parameters.
The TRL achieved for the overall project is TRL 6: the tools and technologies developed during the project have been showed to be relevant in industrial environment. The numerical tools are capable of predicting the performance of the PHP within the expected error and can be therefore used for predesign purpose in Liebherr’s workflow. The experimental campaign has demonstrated the relevance of the use of PHPs for electronics cooling in electrical aircrafts.
The aim of this project is to study PHPs and develop predesign tools to push this solution to an industrial level. This is achieved by following three main objectives:
- To design, build and test PHPs on an experimental test bench
- To develop a 1D physical tool
- To develop a mathematical tool for predesign purpose
The present project offers cooperation between JJ Cooling Innovation and Provides, leaders in the modelling, design and fabrication of high-performance micro-two-phases cooling systems using state-of-the-art components and heat-exchangers, and Altran, world leader in engineering solutions and outsourced R&D.
During the project, 9 tubular PHP and 1 flat plate PHP have been built and tested and a large experimental database (over 1000 operating points) has been gathered. This database has been used to validate the 1D physical model and to train a mathematical model capable of predicting the thermal resistance of PHP from geometrical and operational parameters.
The TRL achieved for the overall project is TRL 6: the tools and technologies developed during the project have been showed to be relevant in industrial environment. The numerical tools are capable of predicting the performance of the PHP within the expected error and can be therefore used for predesign purpose in Liebherr’s workflow. The experimental campaign has demonstrated the relevance of the use of PHPs for electronics cooling in electrical aircrafts.
An experimental campaign has been carried out. The test bench has been designed and built by Provides. The Design of Experiments (DoE) has been created by Altran, based on the applications targeted by Liebherr. The number of prototypes and of experiments have been chosen to be the best compromise between the needs to train the mathematical model, the time allowed to the campaign (two years) and need for a better understanding of the physical phenomena occurring in PHPs. Therefore, nine prototypes have been designed, built and tested according to the DoE. The result is the creation of a database containing more than 1000 operating points with 9 different geometries, which is a very important databased compared to those available in the literature. In addition, during the last year, a transparent flat plate prototype has been studied (similar to prototype 2) to study the differences between flat plate and tubular PHPs and have an insight into the physical phenomena occurring in the PHP.
A detailed bibliography dedicated to the state of the art on PHP modelling methods and recent achievements has been achieved. An advanced 1D numerical tool capable of describing the behaviour and performances of a PHP has been developed and validated over the experimental database. Complex models and correlations for the prediction of the physical phenomena in PHPs have been implemented. The model if now capable of predicting the operating mode and the transient characteristics of a PHP in a few hours. This tool has been used to generate a numerical database to validate the mathematical model.
The experimental database has been used to train, test, and validate mathematical models. Six different algorithms have been compared and artificial neural networks have been chosen. After several iterations, the final tool if composed of five different models:
- One model predicts the operating mode of the PHP (pulsation or conduction)
- Two models predict the thermal resistance of the PHP depending on the operating mode
- Two models predict the error on the thermal resistance depending on the operating mode.
The tool is delivered as an FMU/FMI module compatible with Liebherr predesign standards.
All this work as led to the publication of an article in the Applied Thermal Engineering Journal and to publications and communications in several conferences during 4 years. Each year, all partners have gathered for a workshop. Each partner also communicated internally in workshops and internal websites and newsletters, or externally in workshops with customers and partners, social networks, and websites. The PHP2 website has been created and it is currently available: http://php2-project.eu/.
A detailed bibliography dedicated to the state of the art on PHP modelling methods and recent achievements has been achieved. An advanced 1D numerical tool capable of describing the behaviour and performances of a PHP has been developed and validated over the experimental database. Complex models and correlations for the prediction of the physical phenomena in PHPs have been implemented. The model if now capable of predicting the operating mode and the transient characteristics of a PHP in a few hours. This tool has been used to generate a numerical database to validate the mathematical model.
The experimental database has been used to train, test, and validate mathematical models. Six different algorithms have been compared and artificial neural networks have been chosen. After several iterations, the final tool if composed of five different models:
- One model predicts the operating mode of the PHP (pulsation or conduction)
- Two models predict the thermal resistance of the PHP depending on the operating mode
- Two models predict the error on the thermal resistance depending on the operating mode.
The tool is delivered as an FMU/FMI module compatible with Liebherr predesign standards.
All this work as led to the publication of an article in the Applied Thermal Engineering Journal and to publications and communications in several conferences during 4 years. Each year, all partners have gathered for a workshop. Each partner also communicated internally in workshops and internal websites and newsletters, or externally in workshops with customers and partners, social networks, and websites. The PHP2 website has been created and it is currently available: http://php2-project.eu/.
Pulsating heat pipes are a promising disruptive passive heat transfer technology ready to emerge but have been hindered in industrial applications by the lack of a suitable thermal-fluidic design method. The results obtained in this project allows to take a new step and push the use of PHPs for industrial applications. The mathematical model allows to include PHPs in the pre-design of complex systems by computing their performance instantly. The 1D physical model allows the simulation of the transient behavior of PHPs in a few hours. In addition, an experimental database with more than 1000 experimental points on 9 prototypes has been gathered, which is the widest observed in the literature.