Raj Ghelani, I. Roumeliotis, C. Saias, C. Mourouzidis, V. Pachidis, Justin Norman, Marko Bacic
An integrated gas turbine cycle design and power management optimization methodology for parallel hybrid electric architectures is shown in this article. The gas turbine cycle design method is extended to both turboprop and turbofan architectures with trade studies performed initially at cycle level. It is shown that the degree of electrification is limited by the surge margin levels of booster for turbofan configuration. An aircraft mission level assessment is then performed using the integrated method initially for an A320 Neo style aircraft case. The results indicate that optimal cycle redesigned hybrid electric propulsion system (HEPS) favor take-off and climb power on-takes while optimal retrofit HEPS favor cruise power on-takes. It is shown that for current battery energy density (250 Wh/Kg), there is no fuel burn benefit. Furthermore, even for optimistic values (750 Wh/kg), the maximum fuel burn benefit for 500 nm mission is 5.5% and 4% for redesigned and retrofit HEPS, respectively. The power management strategies for HEPS configurations also differ based on gas turbine technology with improvement in gas turbine technology showing greater scope for electrification. The method is then extended to ATR 72 style aircraft case, showing greater fuel burn benefits across the flight mission envelope. The power management strategies also change depending on the objective function, and optimum strategies are reported for direct operating cost or fuel burn. Finally, a novel multi-mission approach is shown to highlight the overall fuel burn and direct operating cost benefit across the mission cluster.
{"title":"Integrated Hybrid Engine Cycle Design and Power Management Optimization","authors":"Raj Ghelani, I. Roumeliotis, C. Saias, C. Mourouzidis, V. Pachidis, Justin Norman, Marko Bacic","doi":"10.1115/1.4065020","DOIUrl":"https://doi.org/10.1115/1.4065020","url":null,"abstract":"\u0000 An integrated gas turbine cycle design and power management optimization methodology for parallel hybrid electric architectures is shown in this article. The gas turbine cycle design method is extended to both turboprop and turbofan architectures with trade studies performed initially at cycle level. It is shown that the degree of electrification is limited by the surge margin levels of booster for turbofan configuration.\u0000 An aircraft mission level assessment is then performed using the integrated method initially for an A320 Neo style aircraft case. The results indicate that optimal cycle redesigned hybrid electric propulsion system (HEPS) favor take-off and climb power on-takes while optimal retrofit HEPS favor cruise power on-takes. It is shown that for current battery energy density (250 Wh/Kg), there is no fuel burn benefit. Furthermore, even for optimistic values (750 Wh/kg), the maximum fuel burn benefit for 500 nm mission is 5.5% and 4% for redesigned and retrofit HEPS, respectively. The power management strategies for HEPS configurations also differ based on gas turbine technology with improvement in gas turbine technology showing greater scope for electrification.\u0000 The method is then extended to ATR 72 style aircraft case, showing greater fuel burn benefits across the flight mission envelope. The power management strategies also change depending on the objective function, and optimum strategies are reported for direct operating cost or fuel burn. Finally, a novel multi-mission approach is shown to highlight the overall fuel burn and direct operating cost benefit across the mission cluster.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"263 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140255697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study proposes a new global gas dynamics optimization method which was applied to a multi-objective optimization task of centrifugal compressor performance with the aim of determining the improvement probability for achieving high efficiency across a wide operating range. Initially, the original Nondominated Neighbor Immune Algorithm (NNIA) was extended to solve constrained multi-objective optimization problems for the first time, which mainly incorporated a procedure for handling inequality and equality constraints without additional parameters. Subsequently, an adaptive topological Back-propagation Multilayer Feed-forward Artificial Neural Network (BP-MLFANN) was trained using the modified NNIA to quickly evaluate the fitness value of the centrifugal compressor stage performance during the optimization. The feasibility of the method was validated using the first stage of a refrigeration centrifugal compressor. The results indicated a substantial enhancement in the stage efficiency of the optimized impeller at the Near-stall, Design, and Near-choke operating points, with increasement of 1.8%, 1.9%, and 4%, respectively, as compared to the baseline stage. The flow field analysis shows that the impact loss at impeller leading edge and flow separation in the passage reduced greatly, the mixing process between the leakage flow and mainstream in the channel is significantly weakened, thus the flow field becomes more uniform after optimization. The new global gas dynamics optimization method provides a reference for the development of efficient and rapid optimization techniques for centrifugal compressor.
{"title":"A New Global Gas Dynamics Performance Optimization Method for Refrigeration Centrifugal Compressor Stage Based on the Immune Algorithm","authors":"Lu Liang, Wuqi Gong, Yitong Liu, Fang Wang","doi":"10.1115/1.4064976","DOIUrl":"https://doi.org/10.1115/1.4064976","url":null,"abstract":"\u0000 This study proposes a new global gas dynamics optimization method which was applied to a multi-objective optimization task of centrifugal compressor performance with the aim of determining the improvement probability for achieving high efficiency across a wide operating range. Initially, the original Nondominated Neighbor Immune Algorithm (NNIA) was extended to solve constrained multi-objective optimization problems for the first time, which mainly incorporated a procedure for handling inequality and equality constraints without additional parameters. Subsequently, an adaptive topological Back-propagation Multilayer Feed-forward Artificial Neural Network (BP-MLFANN) was trained using the modified NNIA to quickly evaluate the fitness value of the centrifugal compressor stage performance during the optimization. The feasibility of the method was validated using the first stage of a refrigeration centrifugal compressor. The results indicated a substantial enhancement in the stage efficiency of the optimized impeller at the Near-stall, Design, and Near-choke operating points, with increasement of 1.8%, 1.9%, and 4%, respectively, as compared to the baseline stage. The flow field analysis shows that the impact loss at impeller leading edge and flow separation in the passage reduced greatly, the mixing process between the leakage flow and mainstream in the channel is significantly weakened, thus the flow field becomes more uniform after optimization. The new global gas dynamics optimization method provides a reference for the development of efficient and rapid optimization techniques for centrifugal compressor.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"48 20","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140085631","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Wenfeng Xu, Zeming Wang, Dan Sun, Guozhe Ren, Yu Li, Dezheng Lu
Honeycomb bushing wear has a significant effect on the leakage characteristics of the labyrinth seal. In this paper, four kinds of honeycomb bushing labyrinth seals were designed and processed. The leakage characteristics of honeycomb bushing labyrinth seal were studied experimentally under different inlet and outlet pressure ratios and sealing clearance conditions. At the same time, the numerical model of honeycomb bushing labyrinth seals were established, and the influence of honeycomb bushing wear on the flow field characteristics of labyrinth seals was analyzed by numerical simulation. The existing leakage formula was modified by the correction coefficient method. The results show that the leakage of four kinds of honeycomb bushing labyrinth seals increases with the increase of pressure ratio and sealing clearance, and the sealing effect of unworn honeycomb bushing labyrinth seal is the best. With the increase in wear depth, the leakage of the honeycomb bushing labyrinth seal increases, and the maximum leakage can be increased by 59.59 %. The wear groove weakens the throttling effect of the labyrinth, causing the leakage of the seal to increase. The increase of the depth of the wear groove changes the flow area and the direction of the jet, so that the leakage increases slightly. The theoretical formula of leakage is corrected by the correction coefficient method. The value calculated by the corrected theoretical formula of leakage is in good agreement with the experiment, and the error is within 5%. It meets the practical application of the project.
{"title":"Numerical and Experimental Study On the Influence of Honeycomb Bushing Wear On the Leakage Flow Characteristics of Labyrinth Seal","authors":"Wenfeng Xu, Zeming Wang, Dan Sun, Guozhe Ren, Yu Li, Dezheng Lu","doi":"10.1115/1.4064824","DOIUrl":"https://doi.org/10.1115/1.4064824","url":null,"abstract":"\u0000 Honeycomb bushing wear has a significant effect on the leakage characteristics of the labyrinth seal. In this paper, four kinds of honeycomb bushing labyrinth seals were designed and processed. The leakage characteristics of honeycomb bushing labyrinth seal were studied experimentally under different inlet and outlet pressure ratios and sealing clearance conditions. At the same time, the numerical model of honeycomb bushing labyrinth seals were established, and the influence of honeycomb bushing wear on the flow field characteristics of labyrinth seals was analyzed by numerical simulation. The existing leakage formula was modified by the correction coefficient method. The results show that the leakage of four kinds of honeycomb bushing labyrinth seals increases with the increase of pressure ratio and sealing clearance, and the sealing effect of unworn honeycomb bushing labyrinth seal is the best. With the increase in wear depth, the leakage of the honeycomb bushing labyrinth seal increases, and the maximum leakage can be increased by 59.59 %. The wear groove weakens the throttling effect of the labyrinth, causing the leakage of the seal to increase. The increase of the depth of the wear groove changes the flow area and the direction of the jet, so that the leakage increases slightly. The theoretical formula of leakage is corrected by the correction coefficient method. The value calculated by the corrected theoretical formula of leakage is in good agreement with the experiment, and the error is within 5%. It meets the practical application of the project.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"23 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140435770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Owing to their high specific energy capabilities, ultra micro gas turbines (UMGT) are a high-potential technology to provide portable electric power supply for applications with demand of less than 1 kW. UMGT conceptual design is challenged by small-scale effects augmenting interdisciplinary dependencies leading to highly coupled, non-linear component interactions. This work provides a novel approach to conceptual UMGT design by combining reduced order component and system modelling with constrained multi-objective optimization. Hereby, Part I presents integrated design and performance modelling of compressor, turbine, combustor and generator. In Part II, the heat engine and generator modules are merged into a system framework by establishing conceptual UMGT rotor geometry and engine design. Following bearing selection and lifetime assessment, experimentally validated reduced order models are developed for heat transfer and rotordynamic analysis. Using the elaborated framework, a constrained multi-objective system optimization of a 300W engine is performed based on ten design parameters and comparing SiAlON and Inconel 718 as potential rotor materials available for additive manufacturing. Hereby, bearing lifetime, system efficiency and specific power are maximized while meeting rotordynamic, structural and thermal requirements. Evaluating the results, interdisciplinary effects are highlighted, and two optimum engine configurations are suggested.
{"title":"Multidisciplinary Design Methodology for Micro-Gas-Turbines - Part II: System Analysis and Optimization","authors":"Lukas Badum, B. Cukurel","doi":"10.1115/1.4064826","DOIUrl":"https://doi.org/10.1115/1.4064826","url":null,"abstract":"\u0000 Owing to their high specific energy capabilities, ultra micro gas turbines (UMGT) are a high-potential technology to provide portable electric power supply for applications with demand of less than 1 kW. UMGT conceptual design is challenged by small-scale effects augmenting interdisciplinary dependencies leading to highly coupled, non-linear component interactions. This work provides a novel approach to conceptual UMGT design by combining reduced order component and system modelling with constrained multi-objective optimization. Hereby, Part I presents integrated design and performance modelling of compressor, turbine, combustor and generator. In Part II, the heat engine and generator modules are merged into a system framework by establishing conceptual UMGT rotor geometry and engine design. Following bearing selection and lifetime assessment, experimentally validated reduced order models are developed for heat transfer and rotordynamic analysis. Using the elaborated framework, a constrained multi-objective system optimization of a 300W engine is performed based on ten design parameters and comparing SiAlON and Inconel 718 as potential rotor materials available for additive manufacturing. Hereby, bearing lifetime, system efficiency and specific power are maximized while meeting rotordynamic, structural and thermal requirements. Evaluating the results, interdisciplinary effects are highlighted, and two optimum engine configurations are suggested.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"27 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140435302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ultra micro gas turbines (UMGT) for electric power generation up to 1 kW are a viable replacement technology for lithium batteries in drones due to their high energy density. Previous research has shown that small-scale effects disqualify conceptual design practices applied to larger gas turbines owing to highly coupled, non-linear component interactions. To fill this gap, we propose an interdisciplinary conceptual design and analysis framework based on reduced order models. To this end, the current work is divided into two parts covering component design and system integration, analysis and optimization. In Part I, automated conceptual design of all engine sub-components is elaborated facilitating interdependent reduced order models for compressor, turbine, combustor and high-speed generator, while also considering additive manufacturing constraints. In a second step, the reduced order performance models are compared to CFD RANS simulations of various turbomachinery geometries as well as experimental data of combustor and high-speed generator prototypes, showing good agreement and thus validating the component modules. In conclusion, the first part of this work elaborates an automated and efficient method to conceptual design of all components required for a functional UMGT. Since the strategy is applicable independent of component arrangement and engine layout, the proposed methods offer a universal framework for small gas turbine generators.
{"title":"Multidisciplinary Design Methodology for Micro-Gas-Turbines - Part I: Reduced Order Component Design and Modelling","authors":"Lukas Badum, Felix Schirrecker, B. Cukurel","doi":"10.1115/1.4064825","DOIUrl":"https://doi.org/10.1115/1.4064825","url":null,"abstract":"\u0000 Ultra micro gas turbines (UMGT) for electric power generation up to 1 kW are a viable replacement technology for lithium batteries in drones due to their high energy density. Previous research has shown that small-scale effects disqualify conceptual design practices applied to larger gas turbines owing to highly coupled, non-linear component interactions. To fill this gap, we propose an interdisciplinary conceptual design and analysis framework based on reduced order models. To this end, the current work is divided into two parts covering component design and system integration, analysis and optimization. In Part I, automated conceptual design of all engine sub-components is elaborated facilitating interdependent reduced order models for compressor, turbine, combustor and high-speed generator, while also considering additive manufacturing constraints. In a second step, the reduced order performance models are compared to CFD RANS simulations of various turbomachinery geometries as well as experimental data of combustor and high-speed generator prototypes, showing good agreement and thus validating the component modules. In conclusion, the first part of this work elaborates an automated and efficient method to conceptual design of all components required for a functional UMGT. Since the strategy is applicable independent of component arrangement and engine layout, the proposed methods offer a universal framework for small gas turbine generators.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"29 22","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140435620","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents the experimental leakage and rotordynamic performance for a liquid smooth annular seal operating in the transition regime. The test conditions include pressure differentials up to 64 bars with 1~2 bar increments for 6 rotor speeds (2.5, 3.8, 5, 7.5, 8.8, and 10 krpm), as well as non-rotating rotor case under zero pre-swirl condition. The rotordynamic coefficients for all the test conditions are obtained by pseudo-random excitation of the seal at multiple subsynchronous frequencies. By considering the transition Reynolds number (1000 < Re < 3000) and the Taylor Number (Ta) vs Axial Reynolds Number (Rez), the variations in the direct stiffness coefficients (K) can used as an indicator of the flow regime transition boundaries. The direct stiffness K resulting from the Lomakin and hydrodynamic effects significantly drops until Rez reaches ~1500. For higher Rez, K increases mainly due to hydrodynamic effects. When K drops, the cross-coupled stiffness k, the direct damping C and the cross-coupled virtual mass m increase while the cross-coupled damping c and virtual mass M decrease. None of predictions based on either laminar or turbulent flow show the variations in rotordynamic coefficients obtained from experimental results. The leakage is not highly influenced by rotor speeds for low speed cases crossing laminar boundary as ?P increases, however, results for higher speeds in the superlaminar region show reduced leakage rates as rotor speed increases.
本文介绍了液体光滑环形密封在过渡状态下的试验泄漏和旋转动力性能。试验条件包括 6 种转子速度（2.5、3.8、5、7.5、8.8 和 10 krpm）下最高 64 巴的压差（增量为 1~2 巴），以及零预旋流条件下的非旋转转子情况。所有测试条件下的旋转动力系数都是通过在多个次同步频率下对密封件进行伪随机激励获得的。通过考虑过渡雷诺数（1000 < Re < 3000）和泰勒数（Ta）与轴向雷诺数（Rez）的关系，直接刚度系数（K）的变化可作为流态过渡边界的指标。洛马金效应和流体动力学效应导致的直接刚度 K 在 Rez 达到 ~1500 之前显著下降。Rez 越高，K 越大，这主要是由于流体动力学效应。当 K 下降时，交叉耦合刚度 k、直接阻尼 C 和交叉耦合虚拟质量 m 增加，而交叉耦合阻尼 c 和虚拟质量 M 减少。基于层流或湍流的预测均未显示出实验结果所获得的旋转动力系数的变化。对于穿越层流边界的低速情况，随着 P 的增加，泄漏受转子速度的影响不大，然而，超层流区域的高速结果显示，随着转子速度的增加，泄漏率降低。
{"title":"Dynamic Performance of Liquid Smooth Annular Seal Operating in the Transition Regime","authors":"Seung-Hyeop Hyun, Adolfo Delgado","doi":"10.1115/1.4064805","DOIUrl":"https://doi.org/10.1115/1.4064805","url":null,"abstract":"\u0000 This paper presents the experimental leakage and rotordynamic performance for a liquid smooth annular seal operating in the transition regime. The test conditions include pressure differentials up to 64 bars with 1~2 bar increments for 6 rotor speeds (2.5, 3.8, 5, 7.5, 8.8, and 10 krpm), as well as non-rotating rotor case under zero pre-swirl condition. The rotordynamic coefficients for all the test conditions are obtained by pseudo-random excitation of the seal at multiple subsynchronous frequencies. By considering the transition Reynolds number (1000 < Re < 3000) and the Taylor Number (Ta) vs Axial Reynolds Number (Rez), the variations in the direct stiffness coefficients (K) can used as an indicator of the flow regime transition boundaries. The direct stiffness K resulting from the Lomakin and hydrodynamic effects significantly drops until Rez reaches ~1500. For higher Rez, K increases mainly due to hydrodynamic effects. When K drops, the cross-coupled stiffness k, the direct damping C and the cross-coupled virtual mass m increase while the cross-coupled damping c and virtual mass M decrease. None of predictions based on either laminar or turbulent flow show the variations in rotordynamic coefficients obtained from experimental results. The leakage is not highly influenced by rotor speeds for low speed cases crossing laminar boundary as ?P increases, however, results for higher speeds in the superlaminar region show reduced leakage rates as rotor speed increases.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"77 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140444484","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mohammad F. F. Patwary, Doruk Isik, Song-Charng Kong, Eric Mayhew, Kenneth S. Kim, Chol-Bum M. Kweon
In an internal combustion engine, interactions of fuel droplets and heated walls can significantly affect the combustion process and engine performance. The formation and characteristics of secondary droplets from drop-wall interactions are functions of various factors such as fuel properties, impact velocity, ambient conditions, and wall temperature. Understanding the impact behavior is important to optimize the distribution of the fuel-air mixture for efficient and clean combustion and to develop a comprehensive spray-wall interaction model. In this study, three-dimensional smoothed particle hydrodynamics (SPH) simulations are performed to investigate the interactions of fuel droplets with a heated wall at atmospheric and elevated pressures over a range of Weber numbers (We). The SPH model is validated using available experimental data. Secondary atomization is characterized by using size distributions for different fuels. The resulting droplets vary in size, where secondary droplets are mostly below 7 µm in diameter. Following these cases, this paper qualitatively describes the impact process and proposes empirical correlation relating the mean secondary droplet size to ambient pressure in the film-boiling regime. Post-impingement vaporization characteristics are also analyzed and compared for fuels with drastically different vapor pressures.
{"title":"Characterizing Drop-Wall Interactions of Engine Fuels at Engine-Relevant Conditions Using Smoothed Particle Hydrodynamics","authors":"Mohammad F. F. Patwary, Doruk Isik, Song-Charng Kong, Eric Mayhew, Kenneth S. Kim, Chol-Bum M. Kweon","doi":"10.1115/1.4064802","DOIUrl":"https://doi.org/10.1115/1.4064802","url":null,"abstract":"\u0000 In an internal combustion engine, interactions of fuel droplets and heated walls can significantly affect the combustion process and engine performance. The formation and characteristics of secondary droplets from drop-wall interactions are functions of various factors such as fuel properties, impact velocity, ambient conditions, and wall temperature. Understanding the impact behavior is important to optimize the distribution of the fuel-air mixture for efficient and clean combustion and to develop a comprehensive spray-wall interaction model. In this study, three-dimensional smoothed particle hydrodynamics (SPH) simulations are performed to investigate the interactions of fuel droplets with a heated wall at atmospheric and elevated pressures over a range of Weber numbers (We). The SPH model is validated using available experimental data. Secondary atomization is characterized by using size distributions for different fuels. The resulting droplets vary in size, where secondary droplets are mostly below 7 µm in diameter. Following these cases, this paper qualitatively describes the impact process and proposes empirical correlation relating the mean secondary droplet size to ambient pressure in the film-boiling regime. Post-impingement vaporization characteristics are also analyzed and compared for fuels with drastically different vapor pressures.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"497 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140446617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Gaitanis, Ravi Nath Tiwari, W. De Paepe, M. L. Ferrari, F. Contino, P. Breuhaus
Micro Gas Turbines (mGT) have not yet succeeded in conquering the small-scale combined heat and power (CHP) market. One reason is that their electrical efficiency is not high enough to maintain a cost-effective operation. A two-shaft intercooled mGT has the potential to meet the current market demand. This technology maintains a high electrical efficiency even at part load and coupled with its fuel-flexible combustion chamber, makes it an ideal candidate for CHP concepts in a renewable future. In this paper, performance analysis on 2-spool mGT is carried out with various fuel blends. Attention is given to the low-pressure and high-pressure compressors and the variation of surge margin by adding hydrogen and syngas. Two control strategies of the mGT are adopted. In the first scenario, the two shafts have equal rotational speed while in the second, the speeds are controlled independently. As the engine is operated at equal speeds, the maximum performance with 100 vol.% of syngas is observed at 85% of the nominal load while 100 vol.% of hydrogen shows maximum efficiency at a load of 63.7%. At electric power lower than 60% and for high amounts of syngas in natural gas, the low-pressure compressor (LPC) operates closely to surge line. In the second scenario, the efficiency increases as the load decreases and the LPC runs in an efficient and safe operating region. Moreover, the performance of the 2-spool mGT is influenced by the amount of nitrogen in syngas.
{"title":"Operational Strategies of 2-Spool Micro Gas Turbine with Alternative Fuels: A Performance Assessment","authors":"A. Gaitanis, Ravi Nath Tiwari, W. De Paepe, M. L. Ferrari, F. Contino, P. Breuhaus","doi":"10.1115/1.4064798","DOIUrl":"https://doi.org/10.1115/1.4064798","url":null,"abstract":"\u0000 Micro Gas Turbines (mGT) have not yet succeeded in conquering the small-scale combined heat and power (CHP) market. One reason is that their electrical efficiency is not high enough to maintain a cost-effective operation. A two-shaft intercooled mGT has the potential to meet the current market demand. This technology maintains a high electrical efficiency even at part load and coupled with its fuel-flexible combustion chamber, makes it an ideal candidate for CHP concepts in a renewable future. In this paper, performance analysis on 2-spool mGT is carried out with various fuel blends. Attention is given to the low-pressure and high-pressure compressors and the variation of surge margin by adding hydrogen and syngas. Two control strategies of the mGT are adopted. In the first scenario, the two shafts have equal rotational speed while in the second, the speeds are controlled independently. As the engine is operated at equal speeds, the maximum performance with 100 vol.% of syngas is observed at 85% of the nominal load while 100 vol.% of hydrogen shows maximum efficiency at a load of 63.7%. At electric power lower than 60% and for high amounts of syngas in natural gas, the low-pressure compressor (LPC) operates closely to surge line. In the second scenario, the efficiency increases as the load decreases and the LPC runs in an efficient and safe operating region. Moreover, the performance of the 2-spool mGT is influenced by the amount of nitrogen in syngas.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"85 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140445342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liquid fuelled gas turbines are likely to remain a dominant force in aviation propulsion for the foreseeable future, and therefore understanding the atomisation process is key to meeting future emissions and performance legislation. To make experiments and simulations possible, simplified geometry and boundary conditions are often used, for example, simulations of primary atomisation often use a fixed film height and velocity. This paper aims to quantify the effect of a fully developed unsteady film on the atomisation process. A custom Coupled Level Set & Volume of Fluid (CLSVOF) solver with adaptive meshing built in OpenFOAM v9 is used. A simulation of the atomisation process in the Karlsruhe Institute of Technology atomisation experiment (Warncke et al., 2017) is presented. A precursor simulation of the film development is used to provide accurate, temporally and spatially resolved inlet boundary conditions. These results are compared to previous CLSVOF simulations from Wetherell et al. (2020) using traditional boundary conditions. The unsteady film has doubled the modal ligament length and widened the distribution, and is now in better agreement with experimental measurements. A clear correlation in both time and space is observed between the film, atomisation process, and spray. The SMD is significantly increased, again giving better agreement with the experiment. A discussion of extracting statistical descriptions of the spray is given, outlining the unfeasible computational cost required to converge droplet diameter distributions and other high order statistics for a case such as this.
{"title":"The Effect of Film Development On Primary Breakup in a Prefilming Airblast Atomiser","authors":"Jack R. J. Wetherell, Andrew Garmory","doi":"10.1115/1.4064729","DOIUrl":"https://doi.org/10.1115/1.4064729","url":null,"abstract":"\u0000 Liquid fuelled gas turbines are likely to remain a dominant force in aviation propulsion for the foreseeable future, and therefore understanding the atomisation process is key to meeting future emissions and performance legislation. To make experiments and simulations possible, simplified geometry and boundary conditions are often used, for example, simulations of primary atomisation often use a fixed film height and velocity. This paper aims to quantify the effect of a fully developed unsteady film on the atomisation process. A custom Coupled Level Set & Volume of Fluid (CLSVOF) solver with adaptive meshing built in OpenFOAM v9 is used. A simulation of the atomisation process in the Karlsruhe Institute of Technology atomisation experiment (Warncke et al., 2017) is presented. A precursor simulation of the film development is used to provide accurate, temporally and spatially resolved inlet boundary conditions. These results are compared to previous CLSVOF simulations from Wetherell et al. (2020) using traditional boundary conditions. The unsteady film has doubled the modal ligament length and widened the distribution, and is now in better agreement with experimental measurements. A clear correlation in both time and space is observed between the film, atomisation process, and spray. The SMD is significantly increased, again giving better agreement with the experiment. A discussion of extracting statistical descriptions of the spray is given, outlining the unfeasible computational cost required to converge droplet diameter distributions and other high order statistics for a case such as this.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"33 50","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139781994","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liquid fuelled gas turbines are likely to remain a dominant force in aviation propulsion for the foreseeable future, and therefore understanding the atomisation process is key to meeting future emissions and performance legislation. To make experiments and simulations possible, simplified geometry and boundary conditions are often used, for example, simulations of primary atomisation often use a fixed film height and velocity. This paper aims to quantify the effect of a fully developed unsteady film on the atomisation process. A custom Coupled Level Set & Volume of Fluid (CLSVOF) solver with adaptive meshing built in OpenFOAM v9 is used. A simulation of the atomisation process in the Karlsruhe Institute of Technology atomisation experiment (Warncke et al., 2017) is presented. A precursor simulation of the film development is used to provide accurate, temporally and spatially resolved inlet boundary conditions. These results are compared to previous CLSVOF simulations from Wetherell et al. (2020) using traditional boundary conditions. The unsteady film has doubled the modal ligament length and widened the distribution, and is now in better agreement with experimental measurements. A clear correlation in both time and space is observed between the film, atomisation process, and spray. The SMD is significantly increased, again giving better agreement with the experiment. A discussion of extracting statistical descriptions of the spray is given, outlining the unfeasible computational cost required to converge droplet diameter distributions and other high order statistics for a case such as this.
{"title":"The Effect of Film Development On Primary Breakup in a Prefilming Airblast Atomiser","authors":"Jack R. J. Wetherell, Andrew Garmory","doi":"10.1115/1.4064729","DOIUrl":"https://doi.org/10.1115/1.4064729","url":null,"abstract":"\u0000 Liquid fuelled gas turbines are likely to remain a dominant force in aviation propulsion for the foreseeable future, and therefore understanding the atomisation process is key to meeting future emissions and performance legislation. To make experiments and simulations possible, simplified geometry and boundary conditions are often used, for example, simulations of primary atomisation often use a fixed film height and velocity. This paper aims to quantify the effect of a fully developed unsteady film on the atomisation process. A custom Coupled Level Set & Volume of Fluid (CLSVOF) solver with adaptive meshing built in OpenFOAM v9 is used. A simulation of the atomisation process in the Karlsruhe Institute of Technology atomisation experiment (Warncke et al., 2017) is presented. A precursor simulation of the film development is used to provide accurate, temporally and spatially resolved inlet boundary conditions. These results are compared to previous CLSVOF simulations from Wetherell et al. (2020) using traditional boundary conditions. The unsteady film has doubled the modal ligament length and widened the distribution, and is now in better agreement with experimental measurements. A clear correlation in both time and space is observed between the film, atomisation process, and spray. The SMD is significantly increased, again giving better agreement with the experiment. A discussion of extracting statistical descriptions of the spray is given, outlining the unfeasible computational cost required to converge droplet diameter distributions and other high order statistics for a case such as this.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"233 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139841839","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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