Particle interactions in engines can be complex phenomena leading to degradation of thermal (TBCs) and environmental barrier coatings (EBCs) meant to protect engine components. Ingestion of particles into the engine can lead to recession of coatings due to particle erosion. Similarly, these particles can become molten, adhere to coatings and result in thermochemical corrosion of coating materials. Erosion testing is often carried out where particles are injected into a gas stream, accelerated within a nozzle, and impinge on samples. Conversely, most molten particle corrosion testing is often done in static furnaces, which does not capture the dynamic nature of deposition. Nevertheless, these damage mechanisms are often tested separately, and no standard exists to test both erosive/corrosive particle interactions with coating materials under relevant turbine operating conditions. Understanding the synergies of particle interactions is crucial in determining operating lifetimes of potential coating materials. Such considerations emphasize the need for realistic approaches in standardizing particle interaction testing in combustion environments. This study outlines efforts at NASA Glenn's Erosion Burner Rig Facility in improving dynamic erosion/corrosion testing methods by assessing the durability of state-of-the-art (SOA) TBC 7 wt.% yttria stabilized zirconia (7YSZ) as a function of particle deposition rate, burner temperature, and particle size. Calibration data to determine particle deposition rate will be presented, and mass and optical profilometry measurements were utilized to estimate mass/volume loss versus deposition per increment of particulate used. Electron microscopy analyses were then carried out to assess coating damage after testing.
发动机中的微粒相互作用是一种复杂的现象，会导致用于保护发动机部件的热防护涂层（TBC）和环境防护涂层（EBC）降解。由于颗粒的侵蚀，发动机中的颗粒摄入会导致涂层脱落。同样，这些颗粒也会熔化，附着在涂层上，导致涂层材料的热化学腐蚀。腐蚀测试通常是将颗粒注入气流，在喷嘴内加速并撞击样品。相反，大多数熔融颗粒腐蚀测试通常在静态熔炉中进行，无法捕捉沉积的动态性质。尽管如此，这些破坏机制通常都是单独测试的，目前还没有在相关涡轮机运行条件下测试颗粒与涂层材料的侵蚀/腐蚀相互作用的标准。了解颗粒相互作用的协同作用对于确定潜在涂层材料的运行寿命至关重要。这种考虑强调了在燃烧环境中标准化颗粒相互作用测试的现实方法的必要性。本研究概述了 NASA 格伦腐蚀燃烧器钻机设施在改进动态侵蚀/腐蚀测试方法方面所做的努力，评估了最先进的（SOA）TBC 7 wt.%钇稳定氧化锆（7YSZ）的耐久性与颗粒沉积率、燃烧器温度和颗粒大小的函数关系。将介绍用于确定颗粒沉积速率的校准数据，并利用质量和光学轮廓测量法来估算每增量颗粒的质量/体积损失与沉积的关系。然后进行电子显微镜分析，以评估测试后的涂层损坏情况。
{"title":"A Dynamic Testing Approach for Particulate Erosion-Corrosion for Gas Turbine Coatings","authors":"Jamesa Stokes, Michael Presby","doi":"10.1115/1.4065886","DOIUrl":"https://doi.org/10.1115/1.4065886","url":null,"abstract":"\u0000 Particle interactions in engines can be complex phenomena leading to degradation of thermal (TBCs) and environmental barrier coatings (EBCs) meant to protect engine components. Ingestion of particles into the engine can lead to recession of coatings due to particle erosion. Similarly, these particles can become molten, adhere to coatings and result in thermochemical corrosion of coating materials. Erosion testing is often carried out where particles are injected into a gas stream, accelerated within a nozzle, and impinge on samples. Conversely, most molten particle corrosion testing is often done in static furnaces, which does not capture the dynamic nature of deposition. Nevertheless, these damage mechanisms are often tested separately, and no standard exists to test both erosive/corrosive particle interactions with coating materials under relevant turbine operating conditions. Understanding the synergies of particle interactions is crucial in determining operating lifetimes of potential coating materials. Such considerations emphasize the need for realistic approaches in standardizing particle interaction testing in combustion environments. This study outlines efforts at NASA Glenn's Erosion Burner Rig Facility in improving dynamic erosion/corrosion testing methods by assessing the durability of state-of-the-art (SOA) TBC 7 wt.% yttria stabilized zirconia (7YSZ) as a function of particle deposition rate, burner temperature, and particle size. Calibration data to determine particle deposition rate will be presented, and mass and optical profilometry measurements were utilized to estimate mass/volume loss versus deposition per increment of particulate used. Electron microscopy analyses were then carried out to assess coating damage after testing.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141677788","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}
The potential of replacing the use of natural gas with biomass gasification syngas through an Externally-Fired Micro-Gas Turbine is the main scope of this study. This includes the performance assessment at various off-design and ambient conditions compared to a reference natural-gas-fired Micro-Gas Turbine. The penetration of biomass use in the decentralized combined heat and power sector can reduce fossil fuel dependency and contribute to the achievement of the net-zero emissions target. For this purpose, an analytical externally-fired thermodynamic model is incorporated and validated with an artificial neural network based on a natural-gas-fired micro-gas turbine unit. An operating strategy is proposed to ensure the system's safe operation under any fuel input conditions. The performance between the investigated cases is compared using an exergetic analysis. The main loss contributors that determine each case's performance are the exit losses. The substantial decrease of the latter results in high externally-fired part-load efficiency, maximizing 110% of design-point efficiency. System performance has a linear dependency on ambient conditions. The increased flexibility introduced by the proposed operating strategy case facilitates the transition from natural gas to biomass, especially for higher heat-to-power ratio demands. The analysis highlights that the current externally-fired configuration lags behind in high electrical demands (> 90 kWel). However, this deficiency is diminished in cold ambient temperatures (<0 °C), indicating that the proposed technology is very opportune for these climatic conditions.
{"title":"On The Potential of Biomass-Fueled Externally-Fired Micro-Gas Turbines In The Energy Transition: Off-Design Performance Analysis","authors":"K. Bollas, R. Banihabib, Mohsen Assadi, A. Kalfas","doi":"10.1115/1.4065884","DOIUrl":"https://doi.org/10.1115/1.4065884","url":null,"abstract":"\u0000 The potential of replacing the use of natural gas with biomass gasification syngas through an Externally-Fired Micro-Gas Turbine is the main scope of this study. This includes the performance assessment at various off-design and ambient conditions compared to a reference natural-gas-fired Micro-Gas Turbine. The penetration of biomass use in the decentralized combined heat and power sector can reduce fossil fuel dependency and contribute to the achievement of the net-zero emissions target. For this purpose, an analytical externally-fired thermodynamic model is incorporated and validated with an artificial neural network based on a natural-gas-fired micro-gas turbine unit. An operating strategy is proposed to ensure the system's safe operation under any fuel input conditions. The performance between the investigated cases is compared using an exergetic analysis. The main loss contributors that determine each case's performance are the exit losses. The substantial decrease of the latter results in high externally-fired part-load efficiency, maximizing 110% of design-point efficiency. System performance has a linear dependency on ambient conditions. The increased flexibility introduced by the proposed operating strategy case facilitates the transition from natural gas to biomass, especially for higher heat-to-power ratio demands. The analysis highlights that the current externally-fired configuration lags behind in high electrical demands (> 90 kWel). However, this deficiency is diminished in cold ambient temperatures (<0 °C), indicating that the proposed technology is very opportune for these climatic conditions.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141678021","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}
S. Karagiannopoulos, Taniguchi Tomoki, David Peral, Silvia Araguás Rodríguez, Ryozo Tanaka, Jim Hickey, Jörg P. Feist
Small and midsize gas turbines for distributed power generation have been widely used in recent years, with designers constantly seeking to improve efficiency by increasing operating temperatures. Therefore, accurate thermal mapping is now more critical than ever for validating new designs, but also very challenging in such a dynamic environment as a gas turbine. A novel advanced offline temperature mapping technology has been developed called thermal history coating (THC). Thermal History technology has distinct advantages including wide temperature measurement range (150 °C to >1600 °C), high durability, high-temperature resolution, single or multicycle operation, high spatial resolution (thousands of measurement points per component), and fully digitized computer-aided design (CAD) compatible data. Additionally, THC materials are REACH-compliant and can be used for both moving and stationary components. High-resolution thermal maps of the surface of three-dimensional (3D) CAD components can be delivered at the end of the process. For the first time ever this paper directly compares Thermal History technology with other methods such as Type-K sheathed thermocouples, uniform crystal temperature sensors (UCTS), and pyrometry on two stage-1 blades of a midsize Kawasaki gas turbine engine test. Temperature data obtained from the different temperature methods were compared qualitatively and quantitatively. Measurement data were also compared with the conjugate heat transfer (CHT) model for the particular internal cooling design of these blades. Further, the application of the THC on two identical blades allowed a direct comparison of component-to-component variations and indicated excellent repeatability of the THC data.
{"title":"Validation of Thermal History Coating Technology on Two Stage-One Turbine Blades","authors":"S. Karagiannopoulos, Taniguchi Tomoki, David Peral, Silvia Araguás Rodríguez, Ryozo Tanaka, Jim Hickey, Jörg P. Feist","doi":"10.1115/1.4065727","DOIUrl":"https://doi.org/10.1115/1.4065727","url":null,"abstract":"\u0000 Small and midsize gas turbines for distributed power generation have been widely used in recent years, with designers constantly seeking to improve efficiency by increasing operating temperatures. Therefore, accurate thermal mapping is now more critical than ever for validating new designs, but also very challenging in such a dynamic environment as a gas turbine. A novel advanced offline temperature mapping technology has been developed called thermal history coating (THC). Thermal History technology has distinct advantages including wide temperature measurement range (150 °C to >1600 °C), high durability, high-temperature resolution, single or multicycle operation, high spatial resolution (thousands of measurement points per component), and fully digitized computer-aided design (CAD) compatible data. Additionally, THC materials are REACH-compliant and can be used for both moving and stationary components. High-resolution thermal maps of the surface of three-dimensional (3D) CAD components can be delivered at the end of the process. For the first time ever this paper directly compares Thermal History technology with other methods such as Type-K sheathed thermocouples, uniform crystal temperature sensors (UCTS), and pyrometry on two stage-1 blades of a midsize Kawasaki gas turbine engine test. Temperature data obtained from the different temperature methods were compared qualitatively and quantitatively. Measurement data were also compared with the conjugate heat transfer (CHT) model for the particular internal cooling design of these blades. Further, the application of the THC on two identical blades allowed a direct comparison of component-to-component variations and indicated excellent repeatability of the THC data.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141678047","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}
Hydrogen is being considered as a possible path towards carbon-neutral aviation. There are additional advantages besides its main benefit of CO2-free combustion. One application is to use it for aero engine heat management due to its cryogenic temperature and high heat capacity, including intercooling and exhaust heat recuperation. The focus of this paper is on the design of a compact heat exchanger integrated into an intermediate compressor duct (ICD), which could decrease compression work and specific fuel consumption (SFC). This compact heat exchanger features curved fins to promote flow turning and decrease pressure losses compared to more conventional straight fin heat exchangers. Conceptual design and duct shape optimization has been carried out which produced integrated ICD heat exchanger designs with significantly lower air-side total pressure losses compared to their conventional straight fin counterparts, which could improve system level integration and engine performance. A direct outcome of this study is a pressure loss correlation which can be used in future engine system level trade studies.
{"title":"Compact Heat Exchangers with Curved Fins for Hydrogen Turbofan Intercooling","authors":"Alexandre Capitao Patrao, Isak Jonsson, C. Xisto","doi":"10.1115/1.4065887","DOIUrl":"https://doi.org/10.1115/1.4065887","url":null,"abstract":"\u0000 Hydrogen is being considered as a possible path towards carbon-neutral aviation. There are additional advantages besides its main benefit of CO2-free combustion. One application is to use it for aero engine heat management due to its cryogenic temperature and high heat capacity, including intercooling and exhaust heat recuperation. The focus of this paper is on the design of a compact heat exchanger integrated into an intermediate compressor duct (ICD), which could decrease compression work and specific fuel consumption (SFC). This compact heat exchanger features curved fins to promote flow turning and decrease pressure losses compared to more conventional straight fin heat exchangers. Conceptual design and duct shape optimization has been carried out which produced integrated ICD heat exchanger designs with significantly lower air-side total pressure losses compared to their conventional straight fin counterparts, which could improve system level integration and engine performance. A direct outcome of this study is a pressure loss correlation which can be used in future engine system level trade studies.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141680655","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}
Research have shown that the use of a continuous detonation afterburner can improve the propulsion performance of aero engine. However, backpropagation pressure waves (BPW) generated by the pressure gain of detonation will affect the internal flow and performance of turbine. This article simulates BPW through a custom function, and investigates the effects of BPW amplitude, rotation frequency, and propagation mode on turbine performance through three-dimensional simulation. The results show that as the pressure amplitude of the BPW increases, the pressure oscillation at each section of the turbine increases and a local subcritical flow state will appear, leading to the decrease of turbine flow rate and turbine power, as well as an intensification of instantaneous turbine power fluctuations. As the rotation frequency of the BPW increases, the pressure oscillation at each section of the turbine gradually decreases. The flow rate and power of the turbine do not change much, but turbine efficiency gradually decreases. Compared to the aligned mode, the turbine performs better under the influence of BPW in misaligned mode. Compared to the single-wave mode, the fluctuation of transient turbine power is lower under the influence of BPW in the multi-wave mode excluding collision mode. Finally, the constraints of equal flow rate region and equal turbine power line on the peak-to-peak value of the BPW were analyzed when the joint operation of the turbine and compressor was not affected. The rotation frequency and mode of BPW will affect the flow region and power line.
{"title":"Numerical Investigation on the Influence of Continuous Rotating Backpropagation Pressure Wave On Turbine Performance","authors":"Hua Qiu, Xiao Wang, Zhi-peng Cao, Cha Xiong, Xi-tao Chen, Minghao Zhao","doi":"10.1115/1.4065885","DOIUrl":"https://doi.org/10.1115/1.4065885","url":null,"abstract":"\u0000 Research have shown that the use of a continuous detonation afterburner can improve the propulsion performance of aero engine. However, backpropagation pressure waves (BPW) generated by the pressure gain of detonation will affect the internal flow and performance of turbine. This article simulates BPW through a custom function, and investigates the effects of BPW amplitude, rotation frequency, and propagation mode on turbine performance through three-dimensional simulation. The results show that as the pressure amplitude of the BPW increases, the pressure oscillation at each section of the turbine increases and a local subcritical flow state will appear, leading to the decrease of turbine flow rate and turbine power, as well as an intensification of instantaneous turbine power fluctuations. As the rotation frequency of the BPW increases, the pressure oscillation at each section of the turbine gradually decreases. The flow rate and power of the turbine do not change much, but turbine efficiency gradually decreases. Compared to the aligned mode, the turbine performs better under the influence of BPW in misaligned mode. Compared to the single-wave mode, the fluctuation of transient turbine power is lower under the influence of BPW in the multi-wave mode excluding collision mode. Finally, the constraints of equal flow rate region and equal turbine power line on the peak-to-peak value of the BPW were analyzed when the joint operation of the turbine and compressor was not affected. The rotation frequency and mode of BPW will affect the flow region and power line.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141681757","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}
The central rod-fastened rotor of gas turbine exhibits pronounced non-continuous characteristics due to the large number of contact interfaces between the compressor and turbine disks. It is necessary to establish an accurate dynamic modeling method for the central rod-fastened rotor that fully considers the contact surface effect. In this work, the contact behavior of the rough surface is characterized by the fractal theory. The normal and tangential contact stiffness models are developed, and the influence of fractal parameters is discussed. Besides, the finite element model for the central rod-fastened rotor is established by developing an improved contact element considering the equivalent stiffness segment of Hirth couplings. Finally, the proposed model is verified by conducting modal testing and measuring the first four modes of natural frequencies and modal shapes of the central rod-fastened rotor. The results show that the numerical results are in good agreement with the experimental ones, and the fractal contact model can effectively predict the connection stiffness of Hirth couplings, which in turn improves the simulation accuracy for the modal characteristics of the central rod-fastened rotor and provides a dynamic modeling approach with high efficiency and less computational complexity.
{"title":"Dynamic modeling and experimental modal analysis for the central rod-fastened rotor with Hirth couplings based on fractal contact theory","authors":"Gancai Huang, Chao Liu, Dongxiang Jiang","doi":"10.1115/1.4065672","DOIUrl":"https://doi.org/10.1115/1.4065672","url":null,"abstract":"\u0000 The central rod-fastened rotor of gas turbine exhibits pronounced non-continuous characteristics due to the large number of contact interfaces between the compressor and turbine disks. It is necessary to establish an accurate dynamic modeling method for the central rod-fastened rotor that fully considers the contact surface effect. In this work, the contact behavior of the rough surface is characterized by the fractal theory. The normal and tangential contact stiffness models are developed, and the influence of fractal parameters is discussed. Besides, the finite element model for the central rod-fastened rotor is established by developing an improved contact element considering the equivalent stiffness segment of Hirth couplings. Finally, the proposed model is verified by conducting modal testing and measuring the first four modes of natural frequencies and modal shapes of the central rod-fastened rotor. The results show that the numerical results are in good agreement with the experimental ones, and the fractal contact model can effectively predict the connection stiffness of Hirth couplings, which in turn improves the simulation accuracy for the modal characteristics of the central rod-fastened rotor and provides a dynamic modeling approach with high efficiency and less computational complexity.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141267467","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}
Ruikai Cai, Mingyang Yang, W. Zhuge, K. Deng, Yangjun Zhang
This paper investigates the mechanism of aerodynamic instability of shrouded SCO2 compressors and accordingly proposes a new method for stability enhancement via the casing treatment in terms of shroud riblets. Firstly, the experimentally validated CFD method is employed to investigate the flow mechanism of the compressor under near-surge condition. The significant backflow phenomena within the impeller were revealed. Further analysis indicated that the imbalance of the Coriolis force and pressure gradient in blade-to-blade direction pushed the low-momentum fluid toward the shroud suction side. Additionally, higher Reynolds number resulted in thinner SCO2 boundary layer at the inlet near end-wall, increasing passage vorticity and further intensifying the aggregation of low-energy fluid on the shroud suction side. Based on the flow mechanisms, the streamwise riblets on shroud were designed to impede the migration of low-energy fluid. The CFD results revealed that under low-flow condition, riblets inhibit the formation of inducer vortices and backflow, enhancing impeller aerodynamic stability and reducing the surge mass-flow rate. Further research indicated that riblets obstruct the migration of low-energy fluid towards shroud suction side, reducing the accumulation of low-energy fluid and blockage, thereby increasing the flow area and aerodynamic stability. Moreover, additional riblets wake and friction losses contributed to the deterioration of compressor performance at middle/large mass-flow-rate conditions. Specifically, riblets reduced the flow area between blades at near choke mass-flow rate, leading to more pronounced shock structures and compressor earlier choke.
{"title":"Aerodynamic Stability Enhancement of a Sco2 Centrifugal Compressor by Riblets of the Shroud","authors":"Ruikai Cai, Mingyang Yang, W. Zhuge, K. Deng, Yangjun Zhang","doi":"10.1115/1.4065524","DOIUrl":"https://doi.org/10.1115/1.4065524","url":null,"abstract":"\u0000 This paper investigates the mechanism of aerodynamic instability of shrouded SCO2 compressors and accordingly proposes a new method for stability enhancement via the casing treatment in terms of shroud riblets. Firstly, the experimentally validated CFD method is employed to investigate the flow mechanism of the compressor under near-surge condition. The significant backflow phenomena within the impeller were revealed. Further analysis indicated that the imbalance of the Coriolis force and pressure gradient in blade-to-blade direction pushed the low-momentum fluid toward the shroud suction side. Additionally, higher Reynolds number resulted in thinner SCO2 boundary layer at the inlet near end-wall, increasing passage vorticity and further intensifying the aggregation of low-energy fluid on the shroud suction side. Based on the flow mechanisms, the streamwise riblets on shroud were designed to impede the migration of low-energy fluid. The CFD results revealed that under low-flow condition, riblets inhibit the formation of inducer vortices and backflow, enhancing impeller aerodynamic stability and reducing the surge mass-flow rate. Further research indicated that riblets obstruct the migration of low-energy fluid towards shroud suction side, reducing the accumulation of low-energy fluid and blockage, thereby increasing the flow area and aerodynamic stability. Moreover, additional riblets wake and friction losses contributed to the deterioration of compressor performance at middle/large mass-flow-rate conditions. Specifically, riblets reduced the flow area between blades at near choke mass-flow rate, leading to more pronounced shock structures and compressor earlier choke.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140966847","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}
Cooled Spray (CS) technology passively reduces particulate matter emissions from diesel engines compared to non-CS-equipped diesel engines. CS inserts are mounted near the injector nozzle and control mixing so that the fuel and air can premix while limiting combustion near fuel-rich zones, thereby reducing formation of particulate matter. CS components contain no moving parts and could be installed as a retrofit or built into new engines. However, CS technology is early in its development and further investigations are needed to understand the overall performance implications and practicality of the technology. In this paper, we investigate several important aspects of CS, providing a clearer picture of some challenges and potential benefits of CS. Two alignment techniques are used to characterize measurement ease and bias, namely an optical alignment and spray-plug impact alignment. While the optical technique facilitates alignment more easily, a bias was measured between the optical and spray-plug techniques, suggesting the optical technique may have insufficient accuracy without additional corrections. We also evaluate engine performance of a well-aligned and poorly aligned CS insert, compared to the baseline configuration. The poorly aligned insert shows slower combustion than the baseline and mixed overall performance. However, the well-aligned insert shows faster combustion than the baseline and PM emission reduction at most operating conditions with some conditions showing PM reduction up to 80%. The results of this paper highlight the alignment challenges of CS technology as well as the potential PM reduction benefit of the technology.
{"title":"Cooled Spray Technology for Particulate Reduction in a Heavy-Duty Engine","authors":"Adam Klingbeil, Tristen Tinar, Scott Ellis","doi":"10.1115/1.4065365","DOIUrl":"https://doi.org/10.1115/1.4065365","url":null,"abstract":"\u0000 Cooled Spray (CS) technology passively reduces particulate matter emissions from diesel engines compared to non-CS-equipped diesel engines. CS inserts are mounted near the injector nozzle and control mixing so that the fuel and air can premix while limiting combustion near fuel-rich zones, thereby reducing formation of particulate matter. CS components contain no moving parts and could be installed as a retrofit or built into new engines. However, CS technology is early in its development and further investigations are needed to understand the overall performance implications and practicality of the technology.\u0000 In this paper, we investigate several important aspects of CS, providing a clearer picture of some challenges and potential benefits of CS. Two alignment techniques are used to characterize measurement ease and bias, namely an optical alignment and spray-plug impact alignment. While the optical technique facilitates alignment more easily, a bias was measured between the optical and spray-plug techniques, suggesting the optical technique may have insufficient accuracy without additional corrections. We also evaluate engine performance of a well-aligned and poorly aligned CS insert, compared to the baseline configuration. The poorly aligned insert shows slower combustion than the baseline and mixed overall performance. However, the well-aligned insert shows faster combustion than the baseline and PM emission reduction at most operating conditions with some conditions showing PM reduction up to 80%. The results of this paper highlight the alignment challenges of CS technology as well as the potential PM reduction benefit of the technology.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140671616","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}
Yue Yang, Junkui Mao, Pingting Chen, Naxian Guo, Feilong Wang
The transient turbine tip clearance (d) throughout the engine process is crucial to modern high-performance aero engines. However, there is still a lack of efficient and accurate transient prediction models of tip clearances with active thermal control (ATC) system, especially for the tip clearances of the complex turbine structures with various parameters. This study develops a transient prediction model for the tradeoff between computational efficiency and accuracy, which includes an offline dataset generation process and an online d prediction process. The offline dataset is first generated using an in-house finite element analysis code, which is validated against a transient tip clearance experiment, and data splicing and sensitivity analysis are applied to enrich the sample features and reduce the input parameters' dimensionality. Then, the long short-term memory neural network is employed to learn the transient tip clearances' timing information. The time consumption for the transient prediction model is significantly shorter than that for the tip clearance calculation method by three orders, and the maximum relative error is as low as 3.59%. In addition, the transient characteristics, including the overshoot value (s) and the response time (ts), are investigated with different jet Reynolds numbers (Rec) and temperatures (Tfc) of ATC cooling flow. The ts decreases with larger Rec and smaller Tfc due to a more significant cooling effect. However, the s increases with the increase of Rec and Tfc due to the different sensitivity of cooling parameters.
{"title":"Prediction and Analysis of Transient Turbine Tip Clearance Using Long Short-Term Memory Neural Network","authors":"Yue Yang, Junkui Mao, Pingting Chen, Naxian Guo, Feilong Wang","doi":"10.1115/1.4065364","DOIUrl":"https://doi.org/10.1115/1.4065364","url":null,"abstract":"\u0000 The transient turbine tip clearance (d) throughout the engine process is crucial to modern high-performance aero engines. However, there is still a lack of efficient and accurate transient prediction models of tip clearances with active thermal control (ATC) system, especially for the tip clearances of the complex turbine structures with various parameters. This study develops a transient prediction model for the tradeoff between computational efficiency and accuracy, which includes an offline dataset generation process and an online d prediction process. The offline dataset is first generated using an in-house finite element analysis code, which is validated against a transient tip clearance experiment, and data splicing and sensitivity analysis are applied to enrich the sample features and reduce the input parameters' dimensionality. Then, the long short-term memory neural network is employed to learn the transient tip clearances' timing information. The time consumption for the transient prediction model is significantly shorter than that for the tip clearance calculation method by three orders, and the maximum relative error is as low as 3.59%. In addition, the transient characteristics, including the overshoot value (s) and the response time (ts), are investigated with different jet Reynolds numbers (Rec) and temperatures (Tfc) of ATC cooling flow. The ts decreases with larger Rec and smaller Tfc due to a more significant cooling effect. However, the s increases with the increase of Rec and Tfc due to the different sensitivity of cooling parameters.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140667602","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}
Dry Low Emissions (DLE) systems are well-known to be susceptible to thermoacoustic instabilities. In particular, transverse, spinning modes of high frequency may appear, and lead to severe damage in a matter of seconds. The thermoacoustic response of an engine is usually specific to the combustor geometry, operating conditions and difficult to reproduce at the lab-scale. In this work, details of high frequency dynamics observed during the early development phase of a new DLE system are provided, where a multi-peaked spectrum was noticed during testing. Beginning with an analysis of the measured pressure spectra from three different concepts, an analytical model of the clockwise and anti-clockwise transverse waves was fitted to the experimental data using a non-linear curve fitting approach to produce a simple yet useful understanding of the phenomena. A flamelet-based Large Eddy Simulation (LES) of the entire combustion system was used to complement this analysis and confirm the mode shapes using dynamic mode decomposition (DMD). Both approaches independently identified a spinning second order mode as the dominant one in the high frequency regime. The LES indicates the coupling of a distortion of swirl profile with a precessing vortex core as a possible cause for the onset of instability. With regard to modeling sensitivities, it is shown that sub-grid scale combustion modeling has a strong impact on predicted amplitudes. Ultimately, a thickened-flame model with a modified efficiency function provided consistent results.
众所周知，干式低排放（DLE）系统容易受到热声不稳定性的影响。特别是，可能会出现高频率的横向旋转模式，并在几秒钟内导致严重损坏。发动机的热声响应通常与燃烧器的几何形状和工作条件有关，很难在实验室尺度上重现。在这项工作中，提供了在新型 DLE 系统早期开发阶段观察到的高频动态细节，在测试过程中发现了多峰频谱。从分析三个不同概念的测量压力频谱开始，使用非线性曲线拟合方法将顺时针和逆时针横波的分析模型与实验数据进行拟合，从而得出对这一现象简单而有用的理解。对整个燃烧系统进行了基于火焰子的大涡流模拟 (LES)，以补充这一分析，并利用动态模式分解 (DMD) 确认模式形状。这两种方法都确定了旋转二阶模式是高频率机制中的主要模式。LES 表明，漩涡剖面的扭曲与前冲漩涡核心的耦合可能是导致不稳定性发生的原因。在建模敏感性方面，研究表明亚网格尺度燃烧建模对预测振幅有很大影响。最终，具有修正效率函数的加厚火焰模型提供了一致的结果。
{"title":"Numerical Analysis of High Frequency Transverse Instabilities in a Can-Type Combustor","authors":"S. Jella, M. Füri, Vasilis Katsapis","doi":"10.1115/1.4065346","DOIUrl":"https://doi.org/10.1115/1.4065346","url":null,"abstract":"\u0000 Dry Low Emissions (DLE) systems are well-known to be susceptible to thermoacoustic instabilities. In particular, transverse, spinning modes of high frequency may appear, and lead to severe damage in a matter of seconds. The thermoacoustic response of an engine is usually specific to the combustor geometry, operating conditions and difficult to reproduce at the lab-scale. In this work, details of high frequency dynamics observed during the early development phase of a new DLE system are provided, where a multi-peaked spectrum was noticed during testing. Beginning with an analysis of the measured pressure spectra from three different concepts, an analytical model of the clockwise and anti-clockwise transverse waves was fitted to the experimental data using a non-linear curve fitting approach to produce a simple yet useful understanding of the phenomena. A flamelet-based Large Eddy Simulation (LES) of the entire combustion system was used to complement this analysis and confirm the mode shapes using dynamic mode decomposition (DMD). Both approaches independently identified a spinning second order mode as the dominant one in the high frequency regime. The LES indicates the coupling of a distortion of swirl profile with a precessing vortex core as a possible cause for the onset of instability. With regard to modeling sensitivities, it is shown that sub-grid scale combustion modeling has a strong impact on predicted amplitudes. Ultimately, a thickened-flame model with a modified efficiency function provided consistent results.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2024-04-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140689008","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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