A novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical coupling
<p>Decarbonising <em>high-temperature</em> industrial processes—steel, cement, and petrochemicals—poses one of the greatest challenges in achieving net-zero emissions. To address this, this thesis introduces a revolutionary turbomachinery concept, the turbo-reactor, which replaces...
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| Format: | Thesis |
| Language: | English |
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2024
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| _version_ | 1817931480448368640 |
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| author | Rubini, DA |
| author2 | Rosic, B |
| author_facet | Rosic, B Rubini, DA |
| author_sort | Rubini, DA |
| collection | OXFORD |
| description | <p>Decarbonising <em>high-temperature</em> industrial processes—steel, cement, and petrochemicals—poses one of the greatest challenges in achieving net-zero emissions. To address this, this thesis introduces a revolutionary turbomachinery concept, the turbo-reactor, which replaces conventional surface heat exchange within furnaces by directly transferring mechanical energy to the fluid through a renewably powered, electric-motor-driven system. This fundamental shift in the energy transfer mechanism offers substantial improvements in power density, scalability, energy efficiency, operability, and reaction performance compared to both traditional technologies and alternative decarbonisation strategies.</p>
<p>Using a combination of high- and low-fidelity computations, this work presents the working principles of the elemental stage design and investigates the uniquely complex aerothermodynamics within both axial and regenerative turbo-reactor architectures. The feasibility of an ultra-high-work-coefficient stage design complemented by rapid dissipation is successfully demonstrated. It is concluded that this universal stage design philosophy can be used effectively across a range of feedstocks and chemical reaction states.</p>
<p>For many applications of the turbo-reactor in the chemical/petrochemical industries, energy is directly supplied to the process gas to drive an endothermic chemical reaction. Therefore, this opens up a new design space for optimising the reaction performance through careful aerodynamic design. The primary objective is to design a reaction-efficient temperature profile by balancing the reaction heat absorption with fine-tuned control of the rate of work input and energy dissipation. Consequently, the physical flow mechanisms responsible for the energy dissipation process are explored in detail. Then, it is outlined how the temperature profile can be tailored by adjusting the distance between stages. From an aerodynamic performance perspective, the minimum distance between stages is determined from high-fidelity computations. This sets a lower bound on the range of control available to the aerochemical designer. Using simple 0D chemical reaction simulations, it is established that there is scope for optimising the temperature profile to improve reaction performance. However, this is difficult to achieve in practise since 3D viscous reacting flow simulations with detailed and accurate kinetic models are prohibitively costly.</p>
<p>Traditional state-of-the-art acceleration strategies for reactive flows are insufficient to bring aerochemical simulations into the design optimisation loop. To address this, a new multi-fidelity machine-learning-enhanced efficiently coupled aerochemical modelling methodology, called <strong>ChemZIP</strong>, is developed. It is demonstrated that <strong>ChemZIP</strong> is nearly two orders of magnitude faster than state-of-the-art acceleration approaches while maintaining accuracy within 10%. For the first time, this enables aerochemical numerical simulations to be brought into the aerodynamic design optimisation outer loop. This will lead to more efficient designs that can be developed quickly and with a reduced reliance on costly physical experiments.</p> |
| first_indexed | 2024-12-09T03:22:41Z |
| format | Thesis |
| id | oxford-uuid:9f87d046-31fe-40f7-a0e8-7370f05cabf8 |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-12-09T03:22:41Z |
| publishDate | 2024 |
| record_format | dspace |
| spelling | oxford-uuid:9f87d046-31fe-40f7-a0e8-7370f05cabf82024-11-21T07:30:35ZA novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical couplingThesishttp://purl.org/coar/resource_type/c_db06uuid:9f87d046-31fe-40f7-a0e8-7370f05cabf8Supersonic compressorsChemical kineticsThermofluid systemsMachine learningEnglishHyrax Deposit2024Rubini, DARosic, B<p>Decarbonising <em>high-temperature</em> industrial processes—steel, cement, and petrochemicals—poses one of the greatest challenges in achieving net-zero emissions. To address this, this thesis introduces a revolutionary turbomachinery concept, the turbo-reactor, which replaces conventional surface heat exchange within furnaces by directly transferring mechanical energy to the fluid through a renewably powered, electric-motor-driven system. This fundamental shift in the energy transfer mechanism offers substantial improvements in power density, scalability, energy efficiency, operability, and reaction performance compared to both traditional technologies and alternative decarbonisation strategies.</p> <p>Using a combination of high- and low-fidelity computations, this work presents the working principles of the elemental stage design and investigates the uniquely complex aerothermodynamics within both axial and regenerative turbo-reactor architectures. The feasibility of an ultra-high-work-coefficient stage design complemented by rapid dissipation is successfully demonstrated. It is concluded that this universal stage design philosophy can be used effectively across a range of feedstocks and chemical reaction states.</p> <p>For many applications of the turbo-reactor in the chemical/petrochemical industries, energy is directly supplied to the process gas to drive an endothermic chemical reaction. Therefore, this opens up a new design space for optimising the reaction performance through careful aerodynamic design. The primary objective is to design a reaction-efficient temperature profile by balancing the reaction heat absorption with fine-tuned control of the rate of work input and energy dissipation. Consequently, the physical flow mechanisms responsible for the energy dissipation process are explored in detail. Then, it is outlined how the temperature profile can be tailored by adjusting the distance between stages. From an aerodynamic performance perspective, the minimum distance between stages is determined from high-fidelity computations. This sets a lower bound on the range of control available to the aerochemical designer. Using simple 0D chemical reaction simulations, it is established that there is scope for optimising the temperature profile to improve reaction performance. However, this is difficult to achieve in practise since 3D viscous reacting flow simulations with detailed and accurate kinetic models are prohibitively costly.</p> <p>Traditional state-of-the-art acceleration strategies for reactive flows are insufficient to bring aerochemical simulations into the design optimisation loop. To address this, a new multi-fidelity machine-learning-enhanced efficiently coupled aerochemical modelling methodology, called <strong>ChemZIP</strong>, is developed. It is demonstrated that <strong>ChemZIP</strong> is nearly two orders of magnitude faster than state-of-the-art acceleration approaches while maintaining accuracy within 10%. For the first time, this enables aerochemical numerical simulations to be brought into the aerodynamic design optimisation outer loop. This will lead to more efficient designs that can be developed quickly and with a reduced reliance on costly physical experiments.</p> |
| spellingShingle | Supersonic compressors Chemical kinetics Thermofluid systems Machine learning Rubini, DA A novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical coupling |
| title | A novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical coupling |
| title_full | A novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical coupling |
| title_fullStr | A novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical coupling |
| title_full_unstemmed | A novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical coupling |
| title_short | A novel turbomachine for decarbonisation of high-temperature chemical reaction processes and fast aerochemical coupling |
| title_sort | novel turbomachine for decarbonisation of high temperature chemical reaction processes and fast aerochemical coupling |
| topic | Supersonic compressors Chemical kinetics Thermofluid systems Machine learning |
| work_keys_str_mv | AT rubinida anovelturbomachinefordecarbonisationofhightemperaturechemicalreactionprocessesandfastaerochemicalcoupling AT rubinida novelturbomachinefordecarbonisationofhightemperaturechemicalreactionprocessesandfastaerochemicalcoupling |