In order to evaluate the heating performance of gas engine heat pump（GEHP） for air-conditioning and hot water supply, a test facility was developed and experiments were performed over a wide range of engine speed（1...In order to evaluate the heating performance of gas engine heat pump（GEHP） for air-conditioning and hot water supply, a test facility was developed and experiments were performed over a wide range of engine speed（1400-2600 r/min）, ambient air temperature（2.4-17.8 ℃） and condenser water inlet temperature（30-50℃）. The results show that as engine speed increases from 1400 r/min to 2600 r/min, the total heating capacity and energy consumption increase by about 30% and 89%, respectively; while the heat pump coefficient of performance（COP） and system primary energy ratio（PER） decrease by 44% and 31%, respectively. With the increase of ambient air temperature from 2.4 ℃ to 17.8 ℃, the heat pump COP and system PER increase by 32% and 19%, respectively. Moreover, the heat pump COP and system PER decrease by 27% and 15%, respectively, when the condenser water inlet temperature changes from 30 ℃ to 50 ℃. So, it is obvious that the effect of engine speed on the performance is more significant than the effects of ambient air temperature and condenser water inlet temperature.展开更多
A variable nozzle turbocharger （VNT） was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in whic...A variable nozzle turbocharger （VNT） was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in which VNT adjustment is carried out through pre-calibrated VNT handling rod position,combined with a closed-loop target boost pressure feedback using proportional-integral-derivative（PID） algorithm.Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT,increase engine volumetric efficiency over a wide speed range,improve engine dynamic characteristics and upgrade economic performance.展开更多
Research on dual-fuel(DF)engines has become increasingly important as engine manufacturers seek to reduce carbon dioxide emissions.There are significant advantages of using diesel pilot-ignited natural gas engines as ...Research on dual-fuel(DF)engines has become increasingly important as engine manufacturers seek to reduce carbon dioxide emissions.There are significant advantages of using diesel pilot-ignited natural gas engines as DF engines.However,different combustion modes exist due to variations in the formation of the mixture.This research used a simulation model and numerical simulations to explore the combustion characteristics of high-pressure direct injection(HPDI),partially premixed compression ignition(PPCI),and double pilot injection premixed compression ignition(DPPCI)combustion modes under a low-medium load.The results revealed that the DPPCI combustion mode provides higher gross indicated thermal efficiency and more acceptable total hydrocarbon(THC)emission levels than the other modes.Due to its relatively good performance,an experimental study was conducted on the DPPCI mode engine to evaluate the impact of the diesel dual-injection strategy on the combustion process.In the DPPCI mode,a delay in the second pilot ignition injection time increased THC emissions(a maximum value of 4.27g/(kW·h)),decreased the emission of nitrogen oxides(a maximum value of 7.64 g/(kW·h)),increased and then subsequently decreased the gross indicated thermal efficiency values,which reached 50.4%under low-medium loads.展开更多
Natural gas is transported to thousands of households by long-distance natural gas pipeline. To some extent, the overall quality of the pipeline is related to the safety and stability of natural gas transportation, bu...Natural gas is transported to thousands of households by long-distance natural gas pipeline. To some extent, the overall quality of the pipeline is related to the safety and stability of natural gas transportation, but affected by uncontrollable factors, various problems are easy to appear in the operation of natural gas pipeline, which requires us to do a good job in the process of pipeline welding and improve the welding quality and ensure the stability of pipeline operation. Taking the gas pipeline welding as the research object, this paper analyzes the measures to improve the welding quality of gas pipeline engineering, so as to improve the welding quality of gas pipeline and meet people's requirements for engineering quality.展开更多
In modern urban life, gas is the necessary material basis of people's life. The quality of gas engineering is related to the stability and safety of people's gas use. It is necessary to strengthen the construc...In modern urban life, gas is the necessary material basis of people's life. The quality of gas engineering is related to the stability and safety of people's gas use. It is necessary to strengthen the construction technology management of gas engineering. In the process of urban gas engineering pipeline installation, the installation quality directly determines the follow-up operation of urban gas engineering. Scientific and reasonable gas engineering pipeline installation can effectively improve the operation quality of gas engineering, give play to the performance of gas engineering, and bring convenience to the daily life of urban residents. This paper focuses on the use of gas operation technology standardization measures to avoid gas operation tragic accident of some practices, for readers' reference.展开更多
Gas engineering construction site supervision work involves a wide range of aspects, including construction design, safety supervision and quality supervision and other links, so gas engineering construction site supe...Gas engineering construction site supervision work involves a wide range of aspects, including construction design, safety supervision and quality supervision and other links, so gas engineering construction site supervision work standardized management is the inevitable trend of the development of modern gas engineering. With the rapid development of gas engineering in China and the fierce market competition, the healthy development of gas engineering is hindered by various problems in the process of gas engineering construction. Therefore, the gas engineering construction units must strengthen the on-site supervision management in the field management process, especially on the site construction safety and construction quality supervision and management must develop the corresponding supervision plan, to provide safety and quality assurance for the construction of gas engineering.展开更多
At present, China is entering the stage of high-quality development in an all-round way, and the social economy continues to deepen the reform, and the urbanization process begins to slow down gradually. Improving inf...At present, China is entering the stage of high-quality development in an all-round way, and the social economy continues to deepen the reform, and the urbanization process begins to slow down gradually. Improving infrastructure has become the priority of current social construction. Gas engineering is a very important component in the process of urban infrastructure construction, and the quality of gas engineering construction is a concern of all sectors of society. Urban gas engineering construction has certain particularity, which is shown in the gas construction site. Due to objective factors such as rainfall and debris flow and human factors such as low safety awareness, there are many safety threats in urban natural gas projects. Therefore, it is very important to improve the site construction technology management of urban gas engineering and improve the safety performance of grass-roots engineering.展开更多
Urban gas projects play an important role in the development of urbanization in China. The safe construction and management of urban gas production and operation have great influence on the safe use and quality of urb...Urban gas projects play an important role in the development of urbanization in China. The safe construction and management of urban gas production and operation have great influence on the safe use and quality of urban gas. In the process of urbanization, the continuous construction and development of gas engineering not only greatly promotes the development of society, but also greatly facilitates people's daily production and life. However, it also has some security risks. Therefore, it is necessary to give high priority to urban gas engineering construction and safe production operation management, comprehensively utilize daily operation management, institutional safety and high-tech capabilities, and effectively improve the safety of urban gas production operation.展开更多
Application of a DFIG （doubly-fed induction generator）, which is one of adjustable speed generators, to a gas engine cogeneration system has been investigated. To operate during a blackout as an emergency power supp...Application of a DFIG （doubly-fed induction generator）, which is one of adjustable speed generators, to a gas engine cogeneration system has been investigated. To operate during a blackout as an emergency power supply is one of important roles for the gas engine eogeneration system. In the case of conventional constant speed of synchronous generator, the amount of the allowed step load is limited to around 30% of the rated power. On the other hand, DFIG is expected to increase the amount of step load during the stand-alone operation. In this paper, it has been demonstrated that an increase in the gas engine speed resulted in an increase in the maximum amount of step load using experimental equipment with a real gas engine. It has been concluded that the proposed system can improve the performance of an emergency power supply at step-loading.展开更多
Urban gas engineering is a high risk industry. Because of its industry characteristics, the construction management of urban gas project must play a key role in the operation process. However, in recent years, gas ope...Urban gas engineering is a high risk industry. Because of its industry characteristics, the construction management of urban gas project must play a key role in the operation process. However, in recent years, gas operation accidents occur frequently in the society, and the safety management of gas operation has come into people's eyes again. In the construction of gas projects, there are often some problems in the operation process, which makes it difficult to carry out the operation smoothly, and even restricts people's production and life. Therefore, we must apply scientific and efficient management methods to the whole gas project operation process, gradually enhance the gas operation technology level, and increase the economic and social efficiency of the enterprise on the basis of ensuring the quality benefit.展开更多
In recent years, in order to improve the atmospheric environment and implement the national air pollution prevention and control action plan, the government has vigorously promoted the construction of key projects suc...In recent years, in order to improve the atmospheric environment and implement the national air pollution prevention and control action plan, the government has vigorously promoted the construction of key projects such as "replacing coal with coal" and "replacing coal with gas". Facing the new situation, how to complete the gas engineering construction task safely, high quality and efficiently is an important topic in front of the gas industry, and establish a scientific, reasonable and feasible construction quality management mode is the top priority of gas engineering construction under the new situation. Next, the article discusses the quality management of gas engineering construction.展开更多
The safe transportation of natural gas is a systematic work. Relevant technical personnel need to have safety awareness, strengthen construction safety management and operation safety management, fundamentally elimina...The safe transportation of natural gas is a systematic work. Relevant technical personnel need to have safety awareness, strengthen construction safety management and operation safety management, fundamentally eliminate the occurrence of accidents, and ensure the safety and quality of natural gas production and operation.展开更多
Based on the analysis of the advantages of the Natural Gas Engine with Direct Injection （NGEDI） and the state of the art of the research in this area, the authors point out that, the NGEDI with high pressure is one ...Based on the analysis of the advantages of the Natural Gas Engine with Direct Injection （NGEDI） and the state of the art of the research in this area, the authors point out that, the NGEDI with high pressure is one potential selection and will have a good application prospects. Through investigation experiment and simulation results, the key techniques are put foreword for deployment of the NGEDI and some solutions are given.展开更多
Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel perf...Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel performance-based fault detection and identification(FDI)strategy for twin-shaft turbofan gas turbine engines and addresses these uncertainties through a first-order Takagi-Sugeno-Kang fuzzy inference system.To handle ambient condition changes,we use parameter correction to preprocess the raw measurement data,which reduces the FDI’s system complexity.Additionally,the power-level angle is set as a scheduling parameter to reduce the number of rules in the TSK-based FDI system.The data for designing,training,and testing the proposed FDI strategy are generated using a component-level turbofan engine model.The antecedent and consequent parameters of the TSK-based FDI system are optimized using the particle swarm optimization algorithm and ridge regression.A robust structure combining a specialized fuzzy inference system with the TSK-based FDI system is proposed to handle measurement biases.The performance of the first-order TSK-based FDI system and robust FDI structure are evaluated through comprehensive simulation studies.Comparative studies confirm the superior accuracy of the first-order TSK-based FDI system in fault detection,isolation,and identification.The robust structure demonstrates a 2%-8%improvement in the success rate index under relatively large measurement bias conditions,thereby indicating excellent robustness.Accuracy against significant bias values and computation time are also evaluated,suggesting that the proposed robust structure has desirable online performance.This study proposes a novel FDI strategy that effectively addresses measurement uncertainties.展开更多
Natural gas engines have become increasingly important in transportation applications,especially in the commercial vehicle sector.With increasing demand for high efficiency and low emissions,new technologies must be e...Natural gas engines have become increasingly important in transportation applications,especially in the commercial vehicle sector.With increasing demand for high efficiency and low emissions,new technologies must be explored to overcome the performance limitations of natural gas engines such as limits on lean or dilute combustion,unstable combustion,low burning velocity,and high emissions of CH_(4) and NO_(x).This paper reviews the progress of research on natural gas engines over recent decades,concentrating on ignition and combustion systems,mixture preparation,the development of different combustion modes,and after-treatment strategies.First,the features,advantages,and disadvantages of natural gas engines are introduced,following which the development of advanced ignition systems,organization of highly turbulent flows,and the preparation of high-reactivity mixtures in spark ignition engines are discussed with a focus on pre-chamber jet ignition,combustion chamber design,and H_(2)-enriched natural gas combustion.Third,the progress in natural gas dual-fuel engines is highlighted,including the exploration of new combustion modes,the development of novel pilot fuels,and the optimization of combustion control strategies.The fourth section discusses after-treatment systems for natural gas engines operating in different combustion modes.Finally,conclusions and future trends in the development of high-efficiency and clean combus-tion in natural gas engines are summarized.展开更多
In order to obtain the surge margin of an aero-engine during its operation,an engine surge experiment is required.A multi-dimensional simulation method for an aero-engine is established in this paper.The simulation of...In order to obtain the surge margin of an aero-engine during its operation,an engine surge experiment is required.A multi-dimensional simulation method for an aero-engine is established in this paper.The simulation of a surge experiment using high-pressure air-injection is then carried out on a turbo-shaft engine to obtain the surge boundary using this method.More specifically,firstly,a body-force model is employed to calculate the compressor performance owing to its capability of capturing the main three-dimensional features of compressor surge and avoiding excessive simulation time required by the traditional fully-three-dimensional Reynolds Averaged Navier-Stokes(RANS)method.Then,a one-dimensional model combining a lumped-parameter plenum model is used for the combustor to account for the propagation of pressure waves and the heat-release process,and a zero-dimensional throttle model is used to mimic the choking effect at the turbine nozzle.Finally,the air-injection system is modeled by imposing an injection boundary condition,which can be used conveniently in changing injection parameters.Based on the established method,the influences of different test parameters,such as the air-injection location,the pressure,the orifice size,the number of injection orifices,and the injection time duration on the surge characteristics and boundary are further studied,which offer effective guidance to optimize an actual experimental design.展开更多
This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas p...This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas production engineering in terms of technological adaptability,digital construction,energy-saving and emission reduction,and points out the future development direction.During the"Thirteenth Five-Year Plan"period,series of important progresses have been made in five major technologies,including separated-layer injection,artificial lift,reservoir stimulation,gas well de-watering,and workover,which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields.Under the current complex international political and economic situation,oil and gas production engineering is facing severe challenges in three aspects:technical difficulty increases in oil and gas production,insignificant improvements in digital transformation,and lack of core technical support for energy-saving and emission reduction.This paper establishes three major strategic directions and implementation paths,including oil stabilization and gas enhancement,digital transformation,and green and low-carbon development.Five key research areas are listed including fine separated-layer injection technology,high efficiency artificial lift technology,fine reservoir stimulation technology,long term gas well de-watering technology and intelligent workover technology,so as to provide engineering technical support for the transformation,upgrading and high-quality development of China’s oil and gas industry.展开更多
NiCoCrAlYTa coatings have been deposited onto an aircraft gas turbine engine blade using a LPPS unit equipped with a computerized robot. Optimal processing conditions, including spray parameters, the trajectory of the...NiCoCrAlYTa coatings have been deposited onto an aircraft gas turbine engine blade using a LPPS unit equipped with a computerized robot. Optimal processing conditions, including spray parameters, the trajectory of the robot, and the synchronized movements between the torch and the blade, have been developed for superior coating properties. Transferred arc treatment, providing a preheating and a cleaning of the substrate surface, enhances the adherence of the coatings to the substrate. The resulting LPPS coatings show dense and uniform characteristics with ideal hardness, and good corrosion resistance to cycle oxidation.展开更多
Control technologies are innovated to satisfy increasingly complicated control demands of gas turbine engines.In terms of limit protection control,a novel model-based multivariable limit protection control method,whic...Control technologies are innovated to satisfy increasingly complicated control demands of gas turbine engines.In terms of limit protection control,a novel model-based multivariable limit protection control method,which is achieved by adaptive command reconstruction and multiplecontrol loop selection and switch logic,is proposed in this paper to address the problem of balancing smaller thrust loss and safe operations by comparing with widely-used Min-Max logic.Five different combination modes of control loops,which represent the online control loop of last time instant and that of current time instant,is analyzed.Different command reconstructions are designed for these modes,which is based on static gain conversion of amplitude beyond limits by using an onboard model.The double-prediction based control loop selection and switch logic is developed to choose a control loop appropriately by comparing converted amplitude beyond limits regardless of one or more parameters tending to exceed limits.The proposed method is implemented in a twin-spool turbofan engine to achieve limit protection with direct thrust control,and the loss of thrust is improved by about 30% in comparison with the loss of thrust caused by Min-Max logic when limit protection control is activated,which demonstrates the effectiveness of the proposed method.展开更多
A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted ...A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted in improved activities of the fresh and aged catalyst by lowering the light-off temperature for methane in natural gas engines exhaust.展开更多
基金Project(hx2013-87)supported by the Qingdao Economic and Technology Development Zone Haier Water-Heater Co.Ltd.,China
文摘In order to evaluate the heating performance of gas engine heat pump（GEHP） for air-conditioning and hot water supply, a test facility was developed and experiments were performed over a wide range of engine speed（1400-2600 r/min）, ambient air temperature（2.4-17.8 ℃） and condenser water inlet temperature（30-50℃）. The results show that as engine speed increases from 1400 r/min to 2600 r/min, the total heating capacity and energy consumption increase by about 30% and 89%, respectively; while the heat pump coefficient of performance（COP） and system primary energy ratio（PER） decrease by 44% and 31%, respectively. With the increase of ambient air temperature from 2.4 ℃ to 17.8 ℃, the heat pump COP and system PER increase by 32% and 19%, respectively. Moreover, the heat pump COP and system PER decrease by 27% and 15%, respectively, when the condenser water inlet temperature changes from 30 ℃ to 50 ℃. So, it is obvious that the effect of engine speed on the performance is more significant than the effects of ambient air temperature and condenser water inlet temperature.
基金Sponsored by the Ministerial Advanced Research Foundation (C2002AA002)
文摘A variable nozzle turbocharger （VNT） was applied to a 2.2-liter L4 natural gas engine,and a VNT control system was designed to operate it.Based on VNT matching test results,a VNT control strategy was studied,in which VNT adjustment is carried out through pre-calibrated VNT handling rod position,combined with a closed-loop target boost pressure feedback using proportional-integral-derivative（PID） algorithm.Experimental results showed that the VNT control system presented in this thesis can lead to optimized performance of VNT,increase engine volumetric efficiency over a wide speed range,improve engine dynamic characteristics and upgrade economic performance.
基金Project(2017YFE0102800)supported by the National Key R&D Program of ChinaProject(19JCYBJC21200)supported by the Tianjin Natural Science Foundation,China。
文摘Research on dual-fuel(DF)engines has become increasingly important as engine manufacturers seek to reduce carbon dioxide emissions.There are significant advantages of using diesel pilot-ignited natural gas engines as DF engines.However,different combustion modes exist due to variations in the formation of the mixture.This research used a simulation model and numerical simulations to explore the combustion characteristics of high-pressure direct injection(HPDI),partially premixed compression ignition(PPCI),and double pilot injection premixed compression ignition(DPPCI)combustion modes under a low-medium load.The results revealed that the DPPCI combustion mode provides higher gross indicated thermal efficiency and more acceptable total hydrocarbon(THC)emission levels than the other modes.Due to its relatively good performance,an experimental study was conducted on the DPPCI mode engine to evaluate the impact of the diesel dual-injection strategy on the combustion process.In the DPPCI mode,a delay in the second pilot ignition injection time increased THC emissions(a maximum value of 4.27g/(kW·h)),decreased the emission of nitrogen oxides(a maximum value of 7.64 g/(kW·h)),increased and then subsequently decreased the gross indicated thermal efficiency values,which reached 50.4%under low-medium loads.
文摘Natural gas is transported to thousands of households by long-distance natural gas pipeline. To some extent, the overall quality of the pipeline is related to the safety and stability of natural gas transportation, but affected by uncontrollable factors, various problems are easy to appear in the operation of natural gas pipeline, which requires us to do a good job in the process of pipeline welding and improve the welding quality and ensure the stability of pipeline operation. Taking the gas pipeline welding as the research object, this paper analyzes the measures to improve the welding quality of gas pipeline engineering, so as to improve the welding quality of gas pipeline and meet people's requirements for engineering quality.
文摘In modern urban life, gas is the necessary material basis of people's life. The quality of gas engineering is related to the stability and safety of people's gas use. It is necessary to strengthen the construction technology management of gas engineering. In the process of urban gas engineering pipeline installation, the installation quality directly determines the follow-up operation of urban gas engineering. Scientific and reasonable gas engineering pipeline installation can effectively improve the operation quality of gas engineering, give play to the performance of gas engineering, and bring convenience to the daily life of urban residents. This paper focuses on the use of gas operation technology standardization measures to avoid gas operation tragic accident of some practices, for readers' reference.
文摘Gas engineering construction site supervision work involves a wide range of aspects, including construction design, safety supervision and quality supervision and other links, so gas engineering construction site supervision work standardized management is the inevitable trend of the development of modern gas engineering. With the rapid development of gas engineering in China and the fierce market competition, the healthy development of gas engineering is hindered by various problems in the process of gas engineering construction. Therefore, the gas engineering construction units must strengthen the on-site supervision management in the field management process, especially on the site construction safety and construction quality supervision and management must develop the corresponding supervision plan, to provide safety and quality assurance for the construction of gas engineering.
文摘At present, China is entering the stage of high-quality development in an all-round way, and the social economy continues to deepen the reform, and the urbanization process begins to slow down gradually. Improving infrastructure has become the priority of current social construction. Gas engineering is a very important component in the process of urban infrastructure construction, and the quality of gas engineering construction is a concern of all sectors of society. Urban gas engineering construction has certain particularity, which is shown in the gas construction site. Due to objective factors such as rainfall and debris flow and human factors such as low safety awareness, there are many safety threats in urban natural gas projects. Therefore, it is very important to improve the site construction technology management of urban gas engineering and improve the safety performance of grass-roots engineering.
文摘Urban gas projects play an important role in the development of urbanization in China. The safe construction and management of urban gas production and operation have great influence on the safe use and quality of urban gas. In the process of urbanization, the continuous construction and development of gas engineering not only greatly promotes the development of society, but also greatly facilitates people's daily production and life. However, it also has some security risks. Therefore, it is necessary to give high priority to urban gas engineering construction and safe production operation management, comprehensively utilize daily operation management, institutional safety and high-tech capabilities, and effectively improve the safety of urban gas production operation.
文摘Application of a DFIG （doubly-fed induction generator）, which is one of adjustable speed generators, to a gas engine cogeneration system has been investigated. To operate during a blackout as an emergency power supply is one of important roles for the gas engine eogeneration system. In the case of conventional constant speed of synchronous generator, the amount of the allowed step load is limited to around 30% of the rated power. On the other hand, DFIG is expected to increase the amount of step load during the stand-alone operation. In this paper, it has been demonstrated that an increase in the gas engine speed resulted in an increase in the maximum amount of step load using experimental equipment with a real gas engine. It has been concluded that the proposed system can improve the performance of an emergency power supply at step-loading.
文摘Urban gas engineering is a high risk industry. Because of its industry characteristics, the construction management of urban gas project must play a key role in the operation process. However, in recent years, gas operation accidents occur frequently in the society, and the safety management of gas operation has come into people's eyes again. In the construction of gas projects, there are often some problems in the operation process, which makes it difficult to carry out the operation smoothly, and even restricts people's production and life. Therefore, we must apply scientific and efficient management methods to the whole gas project operation process, gradually enhance the gas operation technology level, and increase the economic and social efficiency of the enterprise on the basis of ensuring the quality benefit.
文摘In recent years, in order to improve the atmospheric environment and implement the national air pollution prevention and control action plan, the government has vigorously promoted the construction of key projects such as "replacing coal with coal" and "replacing coal with gas". Facing the new situation, how to complete the gas engineering construction task safely, high quality and efficiently is an important topic in front of the gas industry, and establish a scientific, reasonable and feasible construction quality management mode is the top priority of gas engineering construction under the new situation. Next, the article discusses the quality management of gas engineering construction.
文摘The safe transportation of natural gas is a systematic work. Relevant technical personnel need to have safety awareness, strengthen construction safety management and operation safety management, fundamentally eliminate the occurrence of accidents, and ensure the safety and quality of natural gas production and operation.
文摘Based on the analysis of the advantages of the Natural Gas Engine with Direct Injection （NGEDI） and the state of the art of the research in this area, the authors point out that, the NGEDI with high pressure is one potential selection and will have a good application prospects. Through investigation experiment and simulation results, the key techniques are put foreword for deployment of the NGEDI and some solutions are given.
文摘Robustness against measurement uncertainties is crucial for gas turbine engine diagnosis.While current research focuses mainly on measurement noise,measurement bias remains challenging.This study proposes a novel performance-based fault detection and identification(FDI)strategy for twin-shaft turbofan gas turbine engines and addresses these uncertainties through a first-order Takagi-Sugeno-Kang fuzzy inference system.To handle ambient condition changes,we use parameter correction to preprocess the raw measurement data,which reduces the FDI’s system complexity.Additionally,the power-level angle is set as a scheduling parameter to reduce the number of rules in the TSK-based FDI system.The data for designing,training,and testing the proposed FDI strategy are generated using a component-level turbofan engine model.The antecedent and consequent parameters of the TSK-based FDI system are optimized using the particle swarm optimization algorithm and ridge regression.A robust structure combining a specialized fuzzy inference system with the TSK-based FDI system is proposed to handle measurement biases.The performance of the first-order TSK-based FDI system and robust FDI structure are evaluated through comprehensive simulation studies.Comparative studies confirm the superior accuracy of the first-order TSK-based FDI system in fault detection,isolation,and identification.The robust structure demonstrates a 2%-8%improvement in the success rate index under relatively large measurement bias conditions,thereby indicating excellent robustness.Accuracy against significant bias values and computation time are also evaluated,suggesting that the proposed robust structure has desirable online performance.This study proposes a novel FDI strategy that effectively addresses measurement uncertainties.
基金This work is supported by the Key Program of National Natural Science Foundation of China(21761142012)the National Key Research and Development Program of China[2016YFB0101402][2017YFE0102800].
文摘Natural gas engines have become increasingly important in transportation applications,especially in the commercial vehicle sector.With increasing demand for high efficiency and low emissions,new technologies must be explored to overcome the performance limitations of natural gas engines such as limits on lean or dilute combustion,unstable combustion,low burning velocity,and high emissions of CH_(4) and NO_(x).This paper reviews the progress of research on natural gas engines over recent decades,concentrating on ignition and combustion systems,mixture preparation,the development of different combustion modes,and after-treatment strategies.First,the features,advantages,and disadvantages of natural gas engines are introduced,following which the development of advanced ignition systems,organization of highly turbulent flows,and the preparation of high-reactivity mixtures in spark ignition engines are discussed with a focus on pre-chamber jet ignition,combustion chamber design,and H_(2)-enriched natural gas combustion.Third,the progress in natural gas dual-fuel engines is highlighted,including the exploration of new combustion modes,the development of novel pilot fuels,and the optimization of combustion control strategies.The fourth section discusses after-treatment systems for natural gas engines operating in different combustion modes.Finally,conclusions and future trends in the development of high-efficiency and clean combus-tion in natural gas engines are summarized.
基金supported by the National Science and Technology Major Project(Nos.J2019-I-0011 and 2017-II0004-0016)。
文摘In order to obtain the surge margin of an aero-engine during its operation,an engine surge experiment is required.A multi-dimensional simulation method for an aero-engine is established in this paper.The simulation of a surge experiment using high-pressure air-injection is then carried out on a turbo-shaft engine to obtain the surge boundary using this method.More specifically,firstly,a body-force model is employed to calculate the compressor performance owing to its capability of capturing the main three-dimensional features of compressor surge and avoiding excessive simulation time required by the traditional fully-three-dimensional Reynolds Averaged Navier-Stokes(RANS)method.Then,a one-dimensional model combining a lumped-parameter plenum model is used for the combustor to account for the propagation of pressure waves and the heat-release process,and a zero-dimensional throttle model is used to mimic the choking effect at the turbine nozzle.Finally,the air-injection system is modeled by imposing an injection boundary condition,which can be used conveniently in changing injection parameters.Based on the established method,the influences of different test parameters,such as the air-injection location,the pressure,the orifice size,the number of injection orifices,and the injection time duration on the surge characteristics and boundary are further studied,which offer effective guidance to optimize an actual experimental design.
基金Supported by the Basic Science Center Project of National Natural Science Foundation of China(72088101)National Natural Science Funded Project(52074345)CNPC Scientific Research and Technology Development Project(2020D-5001-21)。
文摘This paper summarizes the important progress in the field of oil and gas production engineering during the"Thirteenth Five-Year Plan"period of China,analyzes the challenges faced by the current oil and gas production engineering in terms of technological adaptability,digital construction,energy-saving and emission reduction,and points out the future development direction.During the"Thirteenth Five-Year Plan"period,series of important progresses have been made in five major technologies,including separated-layer injection,artificial lift,reservoir stimulation,gas well de-watering,and workover,which provide key technical support for continuous potential tapping of mature oilfields and profitable production of new oilfields.Under the current complex international political and economic situation,oil and gas production engineering is facing severe challenges in three aspects:technical difficulty increases in oil and gas production,insignificant improvements in digital transformation,and lack of core technical support for energy-saving and emission reduction.This paper establishes three major strategic directions and implementation paths,including oil stabilization and gas enhancement,digital transformation,and green and low-carbon development.Five key research areas are listed including fine separated-layer injection technology,high efficiency artificial lift technology,fine reservoir stimulation technology,long term gas well de-watering technology and intelligent workover technology,so as to provide engineering technical support for the transformation,upgrading and high-quality development of China’s oil and gas industry.
文摘NiCoCrAlYTa coatings have been deposited onto an aircraft gas turbine engine blade using a LPPS unit equipped with a computerized robot. Optimal processing conditions, including spray parameters, the trajectory of the robot, and the synchronized movements between the torch and the blade, have been developed for superior coating properties. Transferred arc treatment, providing a preheating and a cleaning of the substrate surface, enhances the adherence of the coatings to the substrate. The resulting LPPS coatings show dense and uniform characteristics with ideal hardness, and good corrosion resistance to cycle oxidation.
基金supported by China Scholarship Council(No.201906830081)。
文摘Control technologies are innovated to satisfy increasingly complicated control demands of gas turbine engines.In terms of limit protection control,a novel model-based multivariable limit protection control method,which is achieved by adaptive command reconstruction and multiplecontrol loop selection and switch logic,is proposed in this paper to address the problem of balancing smaller thrust loss and safe operations by comparing with widely-used Min-Max logic.Five different combination modes of control loops,which represent the online control loop of last time instant and that of current time instant,is analyzed.Different command reconstructions are designed for these modes,which is based on static gain conversion of amplitude beyond limits by using an onboard model.The double-prediction based control loop selection and switch logic is developed to choose a control loop appropriately by comparing converted amplitude beyond limits regardless of one or more parameters tending to exceed limits.The proposed method is implemented in a twin-spool turbofan engine to achieve limit protection with direct thrust control,and the loss of thrust is improved by about 30% in comparison with the loss of thrust caused by Min-Max logic when limit protection control is activated,which demonstrates the effectiveness of the proposed method.
基金the National Natural Science Foundation of China(No:20273043)the Ministry of Education of China for providing financial support for this project
文摘A three-way catalyst comprised novel oxygen storage components for emission control in natural gas powered engines was prepared. The addition of novel oxygen storage components to the Pd/γ-Al2O3 catalysts resulted in improved activities of the fresh and aged catalyst by lowering the light-off temperature for methane in natural gas engines exhaust.
