Born in France, but being a citizen of the world, I had the opportunity to live in China, Romania, the United States, Switzerland and currently in Germany as an EASITrain ESR working at the University of Stuttgart, Institute of Thermal Turbomachinery and Machinery Laboratory (ITSM). This personal path has given me the opportunity to build a strong adaptability and openness of mind that I have been continuously cultivating.
Fascinated by the applications of turbomachines, I am working on advanced technologies that would increase the performance of turbocompressors operating with light gases while also making them financially more viable.
- Assessment and optimisation of turbocompressors for light gases
- Radial compressor design: aerodynamic optimisation of impeller, diffuser and volute. Impeller structural validation. Research on Reynolds number effect
- Experimental test bench: design, assembly and operation of a test rig enabling the performance validation of compressors with different light gas mixtures
- Industrial compressor: architecture optimisation of high speed multi-stage machine
- Training: Theory on superconductivity, cryogenic and project management
- Development of a grid generator based on elliptic PDE
- Development of a throughﬂow solver based on a stream function approach with the implementation of loss models and capable of handling supersonic ﬂows
- Development of a periodic maintenance plan for the axle, braking and diesel motor parts and implementation in SAP
- Elaboration of a daily log book for the monitoring and regular controls of railway machines
- Mechanical engineering in aerospace and aeronautics
- Research major in ﬂuid dynamics and turbomachinery
- Major in ﬂuid mechanics and minor in management and entrepreneurship
This research falls within a larger project with the objective of designing an efficient and sustainable cryogenic cycle for the Future Circular Collider (FCC) with a low acquisition, operating and maintenance cost. One element of this cycle which contributes greatly to this objective is the compressor technology. In fact, to compress light gases required by the cycle, such as helium, the state of the art technology is a screw compressor with the drawback of inherent low efficiencies. Replacing this technology to achieve a higher overall cycle performance is thus the main objective of this research project.
In recent years, relying on a turbocompressor instead is becoming economically viable due to the technological development of high speed motors, new manufacturing processes, affordable light weight materials as well as new bearing technology. To do so, all of the above mentioned novel technologies need to be brought together, adapted and new components have to be developed to successfully build and operate such machine. Hence, the main question which needs to be answered is what are the components of a multi-stage turbocompressor which, after being brought together, would in the end fulfil the operating requirements of the FCC cryogenic cycle?
Hence, the additional technologies and components required which differ from a standard turbocompressor operating with heavier gases need to be identified. Some of these components are already available today but some of them need to be designed for this specific application. Therefore, most of the research will consist in designing a component which is at the heart of the machine, the so-called compressor wheel. Numerical tools are required to optimised its geometry and reach the specifications as well as to ensure its mechanical integrity during operation. Moreover, before it can be used on the real machine its performance need to be validated experimentally, which requires a test rig built for this specific purpose. Finally, technologies that would help improving the performance of the machine and which are expected to become state of the art in the near future should also be identified and their effects quantified.
The machine architecture is developed in cooperation with MAN Energy Solutions. It is based on a sealed compressor operating with high speed motors and allowing a high number of impellers to be stacked one behind the other. Hence, a numerical model has been developed to predict the performance of such machine as well as to obtain an optimised architecture depending on specifications coming from the FCC and its cryogenic cycle operation.
Results of this model are then used to provide boundary conditions for the design of new compressor wheels. To generate these new wheels a second numerical tool has been developed, which gives as an output a first “good guess” geometry. The latter is then optimised further to achieved its highest performance using a Computational Fluid Dynamics (CFD) tool. A stress analysis also has to be conducted to ensure that the impeller can withstand the stresses involved during operation.
Finally, the performance of the newly designed compressor wheels has to be validated experimentally. To do so, a test rig has been designed and build for this specific purpose. It will enable to measure the compressor performance at different gas densities ranging from the density of helium to roughly half the density of air at standard atmospheric condition. Moreover, results of this study will help predicting more accurately the performance variation of compressor when scaled to different sizes.
In order to better understand the implication of operating a turbocompressor with light gases, an exploratory design has been first conceived (picture below on the left). The latter has been developed specifically to cover a wide range of gas mixtures and operating conditions. This enables to gather knowledge and experience on the effect of varying gas properties on the compressor performance. A second impeller (picture below on the right) has then been designed, this time in accordance with the specification of the real machine required for the FCC cryogenic cycle. Later on, this geometry can be altered easily to create variants so that most or even all of the impellers mounted on the final machine would come from this baseline geometry. This compressor design is then scaled to the test rig dimension so that the latter can be mounted on it for performance validation.
This test rig has been designed and is currently being assembled before it can be commissioned and the measurement campaign started. The latter is designed so that different gas properties can be tested by varying the proportion of two gases (helium and neon). A wide range of gas mixture can thus be tested, among which the optimal composition for the cryogenic cycle. A scheme of the test rig is shown below:
Finally, a cost analysis has been conducted to determine the optimal gas composition in the cryogenic cycle leading to its lowest purchasing, maintenance and operational cost. For this obtained gas composition, a machine architecture including the second impeller design and the technology currently available can be derived. The follow-up objective will be to keep this same compact machine while implementing the foreseen technological advancements, which would help compressing even lighter gases and in the end improve the overall cycle efficiency further.
The next short term objective is the commissioning of the test rig after its assembly. The measurement campaign will start with the first exploratory turbocompressor and shortly after with the second design.
In parallel, a third compressor wheel will be designed to help compressing even lighter gases resulting in higher overall cycle efficiency. To do so, the second design geometry will be modified by redistributing its mass along the wheel radius and reducing its total weight while maintaining its aerodynamic performance. Moreover, a study is currently on-going to assess the possibility of adapting the cryogenic cycle architecture to reinforce the compressor integration inside the cycle. This process has for final goal to optimise the cycle architecture and the compressor not separately but together so that a higher overall cycle performance is achieved.
Finally, the real potential of the foreseen technological improvements for the compressor need to be ascertained and quantified.
In this project, a compressor with a specific size and architecture is designed to respect the boundary conditions provided by the FCC cryogenic cycle operation. However, the machine and technology used as well as the novel impeller designs can be scaled to fulfil multiple applications. These applications correspond to all the cases where an efficient compressor is required to operate with light gases. This is mainly the case of cryogenic cycles, which are used in a wide variety of applications such as the production of liquid fuel for space exploration, in the food industry for product conservation, in the treatment of material or as in the EASITrain project, in the superconductivity technology, which is then employed in fundamental research, medical imaging, the transportation industry (train and aeronautic), or in the energy production and transport.