Wenchong Yang, Yifeng Tang, Wenxiang Zhou, Gang Yang, Jinquan Huang, Tao Cui
Turbofan engines exhibit pronounced nonlinearity, so linearization has become a crucial link between turbofan engine control and linear control theory. Among linearization method, non-equilibrium linearization offers enhanced transient tracking accuracy and superior controller performance compared to methods operating near equilibrium points, making it more suitable for systems with rapid acceleration and deceleration, such as turbofan engines. Hardware-in-Loop (HIL) experiments are essential for verifying turbofan engine controller performance. However, time delay in the HIL platform can induce oscillations of state variables with controllers designed using this linearization method. To address this issue, this paper introduces an off-equilibrium linearization-based control strategy. This strategy employs a non-equilibrium linearized linear model to approximate the nonlinear time-delay system, followed by designing an H∞ controller for the linear time-delay system. The effectiveness of this approach applied to turbofan engines, including its anti-delay and robust tracking capabilities, is validated through simulations, HIL experiments, and semi-physical experiments.
{"title":"Off-Equilibrium Linearization-Based Control of Nonlinear Time-Delay System and Application to a Turbofan Engine","authors":"Wenchong Yang, Yifeng Tang, Wenxiang Zhou, Gang Yang, Jinquan Huang, Tao Cui","doi":"10.1115/1.4065993","DOIUrl":"https://doi.org/10.1115/1.4065993","url":null,"abstract":"\u0000 Turbofan engines exhibit pronounced nonlinearity, so linearization has become a crucial link between turbofan engine control and linear control theory. Among linearization method, non-equilibrium linearization offers enhanced transient tracking accuracy and superior controller performance compared to methods operating near equilibrium points, making it more suitable for systems with rapid acceleration and deceleration, such as turbofan engines. Hardware-in-Loop (HIL) experiments are essential for verifying turbofan engine controller performance. However, time delay in the HIL platform can induce oscillations of state variables with controllers designed using this linearization method. To address this issue, this paper introduces an off-equilibrium linearization-based control strategy. This strategy employs a non-equilibrium linearized linear model to approximate the nonlinear time-delay system, followed by designing an H∞ controller for the linear time-delay system. The effectiveness of this approach applied to turbofan engines, including its anti-delay and robust tracking capabilities, is validated through simulations, HIL experiments, and semi-physical experiments.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":" 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141824576","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}
Oussama Chaib, Lee Weller, Anthony Giles, Steve Morris, Benjamin A. O. Williams, Simone Hochgreb
Laser-induced grating spectroscopy (LIGS) is applied, for the first time, to a swirling non-premixed hydrogen-air flame in a high-pressure combustion facility. A portable LIGS unit is used to probe 35 different axial and radial locations in the flame and a new conditioned processing approach based on laminar flame simulation is introduced to infer temperatures from instantaneous LIGS spectra. Thermal and electrostrictive frequencies are used to produce a spatial map of temperatures in the combustor. Temperatures up to 2500 K are measured in this work, which constitute the highest temperatures ever measured using LIGS. Challenges associated with the deployment of the technique in turbulent stratified hydrogen flames are discussed, as are potential measures to overcome them, including the use of data-driven clustering techniques.
{"title":"Spatial Temperature Measurements in a Swirl-Stabilized Hydrogen-Air Diffusion Flame At Elevated Pressure Using Laser-Induced Grating Spectroscopy","authors":"Oussama Chaib, Lee Weller, Anthony Giles, Steve Morris, Benjamin A. O. Williams, Simone Hochgreb","doi":"10.1115/1.4065996","DOIUrl":"https://doi.org/10.1115/1.4065996","url":null,"abstract":"\u0000 Laser-induced grating spectroscopy (LIGS) is applied, for the first time, to a swirling non-premixed hydrogen-air flame in a high-pressure combustion facility. A portable LIGS unit is used to probe 35 different axial and radial locations in the flame and a new conditioned processing approach based on laminar flame simulation is introduced to infer temperatures from instantaneous LIGS spectra. Thermal and electrostrictive frequencies are used to produce a spatial map of temperatures in the combustor. Temperatures up to 2500 K are measured in this work, which constitute the highest temperatures ever measured using LIGS. Challenges associated with the deployment of the technique in turbulent stratified hydrogen flames are discussed, as are potential measures to overcome them, including the use of data-driven clustering techniques.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":" 52","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141825220","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}
Petter Miltén, Isak Jonsson, Anders Lundbladh, C. Xisto
The paper introduces a novel method for generalized heat exchanger design and evaluation, freeing the process from predefined geometries. It aims to facilitate early-stage conceptual exploration, allowing the designer to make informed decisions. The paper explores heat transfer and fluid friction principles in order to set key parameters for estimating aerothermal performance, introduced by LaHaye. Arguing against a single metric, the paper proposes a custom cost function for evaluating the integrated generalized heat exchanger. A case study applies the method to a particular aircraft engine scenario, using cost functions to evaluate intercooler designs based on pressure loss and heat transfer surface weight. The study determines suitable heat exchanger families for further development, considering factors like finned area, compactness and flow distribution.
{"title":"Generalized Method for the Conceptual Design of Compact Heat Exchangers","authors":"Petter Miltén, Isak Jonsson, Anders Lundbladh, C. Xisto","doi":"10.1115/1.4065922","DOIUrl":"https://doi.org/10.1115/1.4065922","url":null,"abstract":"\u0000 The paper introduces a novel method for generalized heat exchanger design and evaluation, freeing the process from predefined geometries. It aims to facilitate early-stage conceptual exploration, allowing the designer to make informed decisions. The paper explores heat transfer and fluid friction principles in order to set key parameters for estimating aerothermal performance, introduced by LaHaye. Arguing against a single metric, the paper proposes a custom cost function for evaluating the integrated generalized heat exchanger. A case study applies the method to a particular aircraft engine scenario, using cost functions to evaluate intercooler designs based on pressure loss and heat transfer surface weight. The study determines suitable heat exchanger families for further development, considering factors like finned area, compactness and flow distribution.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141653388","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}
Meghna Das Chaudhury, Abinash Sahoo, Kaushik Nonavinakere Vinod, Wesley Fisher, S. Ekkad, Venkat Narayanaswamy, Tiegang Fang
Alternative low carbon fuel blends are a promising way towards clean energy transition in the transportation and power generation sectors. In this work, the objective was to study the combustion characteristics of one such low carbon fuel blend (premixed Ammonia, Methane and Air) in a swirl stabilized Gas Turbine Can Combustor under varying % of pilot fuel flow (= 8 % to 10 % of the main fuel flow rate) at atmospheric pressure conditions. Pure Methane was used as the pilot flame which helped in the ignition and stabilization of the main flame and was kept on throughout the experiment. Different volume % of Ammonia and Methane blends were analyzed (starting from 10 to 50 % Ammonia in the fuel blend and the rest being Methane) at Reynolds number of the incoming air ~ 50000, and at equivalence ratio = 0.6 and 0.7. Characteristics such as Combustor liner wall heat load and flame stability were studied using the Infrared Thermography technique and High-Speed flame imaging respectively. Additionally, both carbon and NOx emission trends were estimated for selected cases using the CONVERGE CFD software under steady state conditions incorporating the RANS RNG k-ε and SAGE modeling techniques. Among all cases, wall heat load was observed to be the least for the 50 % Ammonia-50 % Methane case and for cases under reduced pilot %. Also, under reduced pilot %, flames were mostly unstable wherein the manifestation of instabilities at equivalence ratio = 0.6 and 0.7 were markedly different from one another.
{"title":"Characteristics of Premixed Ammonia/Methane/Air Blends as an Alternative Fuel in a Swirl-Stabilized Gas Turbine Combustor Under Varying Pilot Percentage","authors":"Meghna Das Chaudhury, Abinash Sahoo, Kaushik Nonavinakere Vinod, Wesley Fisher, S. Ekkad, Venkat Narayanaswamy, Tiegang Fang","doi":"10.1115/1.4065923","DOIUrl":"https://doi.org/10.1115/1.4065923","url":null,"abstract":"\u0000 Alternative low carbon fuel blends are a promising way towards clean energy transition in the transportation and power generation sectors. In this work, the objective was to study the combustion characteristics of one such low carbon fuel blend (premixed Ammonia, Methane and Air) in a swirl stabilized Gas Turbine Can Combustor under varying % of pilot fuel flow (= 8 % to 10 % of the main fuel flow rate) at atmospheric pressure conditions. Pure Methane was used as the pilot flame which helped in the ignition and stabilization of the main flame and was kept on throughout the experiment. Different volume % of Ammonia and Methane blends were analyzed (starting from 10 to 50 % Ammonia in the fuel blend and the rest being Methane) at Reynolds number of the incoming air ~ 50000, and at equivalence ratio = 0.6 and 0.7. Characteristics such as Combustor liner wall heat load and flame stability were studied using the Infrared Thermography technique and High-Speed flame imaging respectively. Additionally, both carbon and NOx emission trends were estimated for selected cases using the CONVERGE CFD software under steady state conditions incorporating the RANS RNG k-ε and SAGE modeling techniques. Among all cases, wall heat load was observed to be the least for the 50 % Ammonia-50 % Methane case and for cases under reduced pilot %. Also, under reduced pilot %, flames were mostly unstable wherein the manifestation of instabilities at equivalence ratio = 0.6 and 0.7 were markedly different from one another.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"79 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141655569","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 combustion engines are one of the few possible ways forward to drastically reduce climate impact of aviation. While there is many information about the engine performance of hydrogen combustion engines it is not clear to which extend each property of the fuel switch effects the engines thermodynamic cycle and component behavior. The basic architecture is identical for both fuels but it is not known to which extend already existing and fully designed components can be used for the new application. In this work the basic differences between both fuels are presented using a thermodynamic model of simplified turbojet. The archived knowledge is applied to a reference turbofan for an application similar to an Airbus A320 while burning hydrogen. Different effects occurring during the fuel switch, e.g. higher water loading after combustion and lower fuel mass flow, will be looked at separately. A retrofitted engine towards hydrogen combustion will use 1.5% less energy for the same thrust while operating at 60 K lower temperatures. The working line in the compressors will also switch towards higher mass flow rates despite the higher working fluid quality after combustion. Additionally, a new designed turbofan is presented on preliminary level for a constant fan diameter, to address the effects of different thrust requirements and has a 3.6% lower specific energy consumption.
{"title":"Step-by-Step Evaluation of the Fuel Switch From Kerosene to Hydrogen On the Thermodynamic Cycle in Gas Turbine Engines","authors":"Alexander Görtz, Björn Schneider","doi":"10.1115/1.4065926","DOIUrl":"https://doi.org/10.1115/1.4065926","url":null,"abstract":"\u0000 Hydrogen combustion engines are one of the few possible ways forward to drastically reduce climate impact of aviation. While there is many information about the engine performance of hydrogen combustion engines it is not clear to which extend each property of the fuel switch effects the engines thermodynamic cycle and component behavior. The basic architecture is identical for both fuels but it is not known to which extend already existing and fully designed components can be used for the new application. In this work the basic differences between both fuels are presented using a thermodynamic model of simplified turbojet. The archived knowledge is applied to a reference turbofan for an application similar to an Airbus A320 while burning hydrogen. Different effects occurring during the fuel switch, e.g. higher water loading after combustion and lower fuel mass flow, will be looked at separately. A retrofitted engine towards hydrogen combustion will use 1.5% less energy for the same thrust while operating at 60 K lower temperatures. The working line in the compressors will also switch towards higher mass flow rates despite the higher working fluid quality after combustion. Additionally, a new designed turbofan is presented on preliminary level for a constant fan diameter, to address the effects of different thrust requirements and has a 3.6% lower specific energy consumption.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"118 48","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141656922","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}
Tong Su, Boyan Xu, Rob J. M. Bastiaans, Nicholas Worth
The lean blow-off (LBO) behavior of turbulent premixed bluff-body stabilized hydrocarbon flames and ammonia/hydrogen/nitrogen flame is investigated and compared both experimentally and numerically. Simultaneous high-speed PIV and OH-PLIF are employed to resolve temporal flame and flow field information, allowing the curvature and hydrodynamic strain rates along the flame surfaces to be calculated. OH* and NH2* chemiluminescence images are also used to examine flame structures at the same bulk flow velocity but at four equivalence ratios from far away from to near LBO. A NH3/H2/N2 (70%/22.5%/7.5%) flame is slightly more resilient to LBO compared with methane and propane flames at 20 m/s. The hydrocarbon flame structures change from 'V-shape' to 'M-shape' when approaching lean blow-off, resulting in incomplete reactions and finally trigger the LBO. However, the strong OH* intensity in the shear layer near flame root for the ammonia blend flames indicate a robust reaction which can increase flame stability. Widely-distributed positive curvature along the flame surface of the NH3/H2/N2 flames (Le<1) may also enhance combustion. The less strain rates change along NH3/H2/N2 flames fronts due to less dramatic changes to the flame shape and position can extend the stability limits. Furthermore, the faster consumption rates of hydrogen near the flame root for the ammonia blend flames, and the lower temperature loss compared with the adiabatic temperature also contribute to the stabilization of ammonia blends near lean blow-off.
{"title":"Lean Blow-Off Behaviour of Premixed Bluff-Body Stabilized Hydrocarbon-Air Flames and Ammonia/Hydrogen/Nitrogen-Air Flames","authors":"Tong Su, Boyan Xu, Rob J. M. Bastiaans, Nicholas Worth","doi":"10.1115/1.4065908","DOIUrl":"https://doi.org/10.1115/1.4065908","url":null,"abstract":"\u0000 The lean blow-off (LBO) behavior of turbulent premixed bluff-body stabilized hydrocarbon flames and ammonia/hydrogen/nitrogen flame is investigated and compared both experimentally and numerically. Simultaneous high-speed PIV and OH-PLIF are employed to resolve temporal flame and flow field information, allowing the curvature and hydrodynamic strain rates along the flame surfaces to be calculated. OH* and NH2* chemiluminescence images are also used to examine flame structures at the same bulk flow velocity but at four equivalence ratios from far away from to near LBO. A NH3/H2/N2 (70%/22.5%/7.5%) flame is slightly more resilient to LBO compared with methane and propane flames at 20 m/s. The hydrocarbon flame structures change from 'V-shape' to 'M-shape' when approaching lean blow-off, resulting in incomplete reactions and finally trigger the LBO. However, the strong OH* intensity in the shear layer near flame root for the ammonia blend flames indicate a robust reaction which can increase flame stability. Widely-distributed positive curvature along the flame surface of the NH3/H2/N2 flames (Le<1) may also enhance combustion. The less strain rates change along NH3/H2/N2 flames fronts due to less dramatic changes to the flame shape and position can extend the stability limits. Furthermore, the faster consumption rates of hydrogen near the flame root for the ammonia blend flames, and the lower temperature loss compared with the adiabatic temperature also contribute to the stabilization of ammonia blends near lean blow-off.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"96 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141657935","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 optimization of Venturi mixers in burners is critical for enhancing combustion efficiency and minimizing emissions. In this study, we utilize the adjoint method to analyze and refine the design of a Venturi mixer. Our numerical simulations integrate the species transport equation with the Eddy Dissipation Model (EDM) for reacting flow and the generalized k-omega (GEKO) model to simulate turbulence. By solving adjoint equations, we effectively compute the shape sensitivity for various observables, including pressure drop, outlet fuel variance/uniformity deviation index, air and fuel mass flow rates, and outlet CO mass fraction. The shape sensitivity analysis uncovers the interplay between the observables and the appropriate weights for multiple objective optimizations. Subsequently, we perform gradient-based optimizations to enhance the mixer's performance, employing both shape sensitivity and mesh morphing techniques. We conduct a series of case studies focusing on both cold and reacting flows. The optimization of cold flow provides an in-depth exploration of various optimization strategies, encompassing single-objective and multi-objective optimization with diverse weight combinations. Following this, the optimization of reacting flow enhances the mixer's functionality under combustion conditions, emphasizing the reduction of emissions and the increase of combustion efficiency. Our findings showcase the potential of an adjoint-based optimization framework in designing Venturi mixers that are efficient and emit lower levels of pollutants.
{"title":"Adjoint-Based Optimization for the Venturi Mixer of a Burner","authors":"Min Xu, Akram Radwan, Yu Xia","doi":"10.1115/1.4065921","DOIUrl":"https://doi.org/10.1115/1.4065921","url":null,"abstract":"\u0000 The optimization of Venturi mixers in burners is critical for enhancing combustion efficiency and minimizing emissions. In this study, we utilize the adjoint method to analyze and refine the design of a Venturi mixer. Our numerical simulations integrate the species transport equation with the Eddy Dissipation Model (EDM) for reacting flow and the generalized k-omega (GEKO) model to simulate turbulence. By solving adjoint equations, we effectively compute the shape sensitivity for various observables, including pressure drop, outlet fuel variance/uniformity deviation index, air and fuel mass flow rates, and outlet CO mass fraction. The shape sensitivity analysis uncovers the interplay between the observables and the appropriate weights for multiple objective optimizations. Subsequently, we perform gradient-based optimizations to enhance the mixer's performance, employing both shape sensitivity and mesh morphing techniques. We conduct a series of case studies focusing on both cold and reacting flows. The optimization of cold flow provides an in-depth exploration of various optimization strategies, encompassing single-objective and multi-objective optimization with diverse weight combinations. Following this, the optimization of reacting flow enhances the mixer's functionality under combustion conditions, emphasizing the reduction of emissions and the increase of combustion efficiency. Our findings showcase the potential of an adjoint-based optimization framework in designing Venturi mixers that are efficient and emit lower levels of pollutants.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"75 14","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141658078","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}
Tim Sebastian Widera, Bastian Patzer, S. Behre, Peter Jeschke
This study shows that no additional measurement error due to unsteadiness was detected, when measuring in periodic turbomachinery flows at frequencies up to 5 kHz with steady, pneumatic probes. An experiment was designed, which consisted of abstracted rotors placed in the jet of a free stream wind tunnel. Five steady and unsteady probes were compared in the periodic, turbomachinery-like wakes at Mach numbers up to 0.8. The impacts of unsteadiness, probe head size and shape, and distance between probe and rotor were systematically investigated at up to 90 operating points. Within the limits imposed by unsteady pressure transducers, the experiments demonstrated the absence of a frequency-dependent effect on the measurements by comparing the time-averaged measurements of identically shaped steady and unsteady probes. Measurements with hemispherical five-hole probes of two sizes and kielhead probes at the same location deviated significantly due to different interaction with the upstream rotor. Distance variations between probe and rotor showed that each combination of probe and flow should be evaluated individually. The study concludes that pneumatic probes offer a reasonable means to measure the mean flow downstream of a rotor, accurately reproducing time-averaged values. However, careful individual evaluation of probes is essential to minimise measurement uncertainty.
{"title":"Accuracy of Steady Pneumatic Probes in Unsteady Turbomachinery Flows","authors":"Tim Sebastian Widera, Bastian Patzer, S. Behre, Peter Jeschke","doi":"10.1115/1.4065924","DOIUrl":"https://doi.org/10.1115/1.4065924","url":null,"abstract":"\u0000 This study shows that no additional measurement error due to unsteadiness was detected, when measuring in periodic turbomachinery flows at frequencies up to 5 kHz with steady, pneumatic probes. An experiment was designed, which consisted of abstracted rotors placed in the jet of a free stream wind tunnel. Five steady and unsteady probes were compared in the periodic, turbomachinery-like wakes at Mach numbers up to 0.8. The impacts of unsteadiness, probe head size and shape, and distance between probe and rotor were systematically investigated at up to 90 operating points. Within the limits imposed by unsteady pressure transducers, the experiments demonstrated the absence of a frequency-dependent effect on the measurements by comparing the time-averaged measurements of identically shaped steady and unsteady probes. Measurements with hemispherical five-hole probes of two sizes and kielhead probes at the same location deviated significantly due to different interaction with the upstream rotor. Distance variations between probe and rotor showed that each combination of probe and flow should be evaluated individually. The study concludes that pneumatic probes offer a reasonable means to measure the mean flow downstream of a rotor, accurately reproducing time-averaged values. However, careful individual evaluation of probes is essential to minimise measurement uncertainty.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"140 26","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141655836","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}
Post-combustion capture (PCC) by means of mono-ethanolamine (MEA) and hydrogen co-firing, combined with exhaust gas recirculation (EGR), were applied to a typical 2x1 combined cycle (CC) with the goal of reaching net-zero CO2 emissions. The novelty lies in integrating decarbonization solutions into the daily operation of the CC, when power generation is adjusted according to fluctuations in electricity demand, throughout two representative days in summer and winter. More specifically, off-design thermodynamic modelling was adapted to incorporate a multivariable optimization problem to find the maximum power plant efficiency as a function of the following decision variables: - load of each gas turbine (GT), spanning from minimum turndown to full load; - EGR rate, in a range that depends on the fuel type: [0; 0.4] for 100% natural gas (NG) vs. [0; 0.55] when hydrogen is fed to the combustor; with the constraint of net power output equal to electricity demand, for given environmental conditions. Suggestions were made to mitigate the energy penalty due to decarbonization in the load-following operation mode, taking the integration of MEA CO2 capture into the NG-fired CC as a benchmark. The solution in which EGR combines optimally with hydrogen in the fuel mixture, with the addition of PCC to abate residual CO2 emissions, has proven to be the most efficient way to provide dispatchable clean energy, especially in cold climates
通过单乙醇胺（MEA）和氢气联合燃烧（PCC），结合废气再循环（EGR），将燃烧后捕集（PCC）应用于典型的 2x1 联合循环（CC），目标是实现二氧化碳净零排放。其新颖之处在于将脱碳解决方案整合到 CC 的日常运行中，在夏季和冬季的两个具有代表性的日子里，根据电力需求的波动调整发电量。更具体地说，设计外热力学建模经过调整，纳入了一个多变量优化问题，以找到发电厂的最高效率，作为以下决策变量的函数： - 每台燃气轮机（GT）的负荷，从最小降压到满负荷； - EGR 率，范围取决于燃料类型：[在给定的环境条件下，净输出功率等于电力需求。以 MEA 二氧化碳捕集技术融入 NG 燃气 CC 为基准，提出了在负载跟随运行模式下减轻脱碳带来的能量损失的建议。事实证明，EGR 与燃料混合物中的氢优化组合的解决方案，加上 PCC 以减少残余 CO2 排放，是提供可调度清洁能源的最有效方式，尤其是在寒冷气候条件下。
{"title":"Thermodynamic Optimization of Load-Following Operation in a Decarbonized Combined Cycle Power Plant Under Net-Zero Scenarios","authors":"Silvia Ravelli","doi":"10.1115/1.4065920","DOIUrl":"https://doi.org/10.1115/1.4065920","url":null,"abstract":"\u0000 Post-combustion capture (PCC) by means of mono-ethanolamine (MEA) and hydrogen co-firing, combined with exhaust gas recirculation (EGR), were applied to a typical 2x1 combined cycle (CC) with the goal of reaching net-zero CO2 emissions. The novelty lies in integrating decarbonization solutions into the daily operation of the CC, when power generation is adjusted according to fluctuations in electricity demand, throughout two representative days in summer and winter. More specifically, off-design thermodynamic modelling was adapted to incorporate a multivariable optimization problem to find the maximum power plant efficiency as a function of the following decision variables: - load of each gas turbine (GT), spanning from minimum turndown to full load; - EGR rate, in a range that depends on the fuel type: [0; 0.4] for 100% natural gas (NG) vs. [0; 0.55] when hydrogen is fed to the combustor; with the constraint of net power output equal to electricity demand, for given environmental conditions. Suggestions were made to mitigate the energy penalty due to decarbonization in the load-following operation mode, taking the integration of MEA CO2 capture into the NG-fired CC as a benchmark. The solution in which EGR combines optimally with hydrogen in the fuel mixture, with the addition of PCC to abate residual CO2 emissions, has proven to be the most efficient way to provide dispatchable clean energy, especially in cold climates","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"130 47","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141656586","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}
Swirl stabilized combustion is a common technique used in gas turbine engine combustors and is accomplished by introducing swirl into the inlet flow, which enhances mixing and stabilizes the combustion event. Coaxial swirlers introduce the fuel and air axially through concentric inlets and use vanes to impart a tangential component to either the fuel, air, or both flows. The present study conducted a parametric analysis of coaxial swirler design by manufacturing an array of 14 coaxial swirlers scaled for use in low flow, small engine operations which incorporated the same base design but varied the swirl number, Sn, by changing the vane angle between 0° and 63°, vane count between four and ten, and vane shape between traditional and helical. Each design was experimentally evaluated using air and propane at different flow conditions to correlate swirler design with lean blowout limits, pressure loss, and flame liftoff. Lean blowout was primarily influenced by swirl number, while vane count and shape had significant impact at Sn = 0.8 but little impact at Sn = 1.5. Pressure loss was unchanged below a Sn of 0.6, and unlike lean blowout, Sn had little impact at 0.8 but significant impact at 1.5. Finally, flame liftoff was mainly driven by swirl number, with vane count and shape the next significant design parameters.
漩涡稳定燃烧是燃气涡轮发动机燃烧器中常用的一种技术，通过在进气流中引入漩涡来加强混合并稳定燃烧。同轴漩涡器通过同心进气口轴向引入燃料和空气，并使用叶片为燃料流、空气流或两股气流传递切向分量。本研究对同轴漩涡器的设计进行了参数分析，制造了 14 个同轴漩涡器阵列，用于小流量、小型发动机的运行，这些漩涡器采用了相同的基本设计，但通过改变叶片角度（0° 至 63°）、叶片数量（4 至 10）以及叶片形状（传统型和螺旋型）来改变漩涡数（Sn）。在不同的流动条件下，使用空气和丙烷对每种设计进行了实验评估，以确定漩涡设计与贫气喷出极限、压力损失和火焰升腾之间的关系。贫气喷出主要受漩涡数的影响，而叶片数和形状在 Sn = 0.8 时影响很大，但在 Sn = 1.5 时影响很小。压力损失在 Sn = 0.6 以下保持不变，与贫油喷出不同的是，Sn 在 0.8 时影响很小，但在 1.5 时影响很大。最后，火焰升腾主要受漩涡数的影响，叶片数量和形状是下一个重要的设计参数。
{"title":"Swirler Design Parameter Impact On Lean Blowout, Pressure Loss, and Flame Liftoff","authors":"Kevin J. DeMarco, M. Polanka, Brian T. Bohan","doi":"10.1115/1.4065909","DOIUrl":"https://doi.org/10.1115/1.4065909","url":null,"abstract":"\u0000 Swirl stabilized combustion is a common technique used in gas turbine engine combustors and is accomplished by introducing swirl into the inlet flow, which enhances mixing and stabilizes the combustion event. Coaxial swirlers introduce the fuel and air axially through concentric inlets and use vanes to impart a tangential component to either the fuel, air, or both flows. The present study conducted a parametric analysis of coaxial swirler design by manufacturing an array of 14 coaxial swirlers scaled for use in low flow, small engine operations which incorporated the same base design but varied the swirl number, Sn, by changing the vane angle between 0° and 63°, vane count between four and ten, and vane shape between traditional and helical. Each design was experimentally evaluated using air and propane at different flow conditions to correlate swirler design with lean blowout limits, pressure loss, and flame liftoff. Lean blowout was primarily influenced by swirl number, while vane count and shape had significant impact at Sn = 0.8 but little impact at Sn = 1.5. Pressure loss was unchanged below a Sn of 0.6, and unlike lean blowout, Sn had little impact at 0.8 but significant impact at 1.5. Finally, flame liftoff was mainly driven by swirl number, with vane count and shape the next significant design parameters.","PeriodicalId":508252,"journal":{"name":"Journal of Engineering for Gas Turbines and Power","volume":"126 8","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141657130","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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