The real-time capability of integrated flight/propulsion optimal control （IFPOC） is studied. An appli- cation is proposed for IFPOC by combining the onboard hybrid aero-engine model with sequential quadratic pro- gr...The real-time capability of integrated flight/propulsion optimal control （IFPOC） is studied. An appli- cation is proposed for IFPOC by combining the onboard hybrid aero-engine model with sequential quadratic pro- gramming （SQP）. Firstly, a steady-state hybrid aero-engine model is designed in the whole flight envelope with a dramatic enhancement of real-time capability. Secondly, the aero-engine performance seeking control including the maximum thrust mode and the minimum fuel-consumption mode is performed by SQP. Finally, digital simu- lations for cruise and accelerating flight are carried out. Results show that the proposed method improves real- time capability considerably with satisfactory effectiveness of optimization.展开更多
In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling perfor...In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling performances of the aircraft. The eigenvalue sen sitivity approach is employed to study the effect of coupling parameters on system stability and gain sensitivity approach is used to direct the reduced states feedback suboptimal control system design. Simulation results show that the integrated flight propulsion control system designed by sensitivity approaches is of good performance.展开更多
This paper aims at investigating the effectiveness of squeeze oil film in suppressing the longitudinal vibration of propulsion shaft systems through a novel integral axial squeeze film damper(IASFD).After designing th...This paper aims at investigating the effectiveness of squeeze oil film in suppressing the longitudinal vibration of propulsion shaft systems through a novel integral axial squeeze film damper(IASFD).After designing the IASFD,a propulsion shafting test rig for the longitudinal vibration control is built.Longitudinal vibration control experiments of the propulsion shafting are carried out under different magnitude and frequency of the excitation force.The results show that both IASFD elastic support and IASFD elastic damping support have excellent vibration attenuation characteristics,and can effectively suppress the longitudinal vibration of the shaft system in a wide frequency range.However,IASFD elastic damping support has a more significant vibration reduction effect than the other supports,and increasing the damping of the system has obvious effect on reducing the shafting vibration.For an excitation force of 45 N,the maximum reduction of the vibration amplitude is 89.16%.Also,the vibration generated by the resonance phenomenon is also significantly reduced.展开更多
The core of the healthy and orderly operation of the existing residential building energy-saving renovation market lies in the exploration of the implementation mechanism of multi-subject and multi-objective integrate...The core of the healthy and orderly operation of the existing residential building energy-saving renovation market lies in the exploration of the implementation mechanism of multi-subject and multi-objective integrated optimization.The multi-agent and multi-objective integrated optimization system framework is a powerful tool to guide the scientific decision-making of the market core structural entities in the future market practice. This paper analyzes the practical dilemma of energy-saving renovation of theexisting residential buildings in China, summarizes the practical experience of multi-subject and multi-objective integrated optimization of energy-saving renovation of the existing residential buildings in foreign countries, and puts forward beneficial practical enlightenment on the basis of comparison at home and abroad;The design principles of the target integrated optimization system have established a multi-subject and multi-objective integrated optimization system framework for the energy-saving renovation of the existing residential buildings, from six aspects: government guidance, trust consensus, value co-creation, risk sharing, revenue sharing, and social responsibility sharing. This paper proposes a multi-subject and multi-objective integrated practice strategy, in order to promote the efficient and orderly development of China's existing residential building energy-saving renovation market.展开更多
This paper proposes the modem passive integrated energy-saving technology of the residential buildings under green building background. The essence of green building is to build a healthy and general environmentally f...This paper proposes the modem passive integrated energy-saving technology of the residential buildings under green building background. The essence of green building is to build a healthy and general environmentally friendly living environment under the premise of reducing the consumption of resources and improving the efficiency of resource utilization in the whole life cycle of construction activities. Green building bearing function is further diversified, integrated, and has a self-initiative. The development of the green building, local isolated from the original single building greening, greening, landscaping site platform, gradually developed for construction area and the surrounding green ecological system of comprehensive, three-dimensional stratified construction and network connection. Its model gradually shows the micro area of the construction of the ecological system and architectural space integration. This paper integrates the passive integrated energysaving technology to construct the novel construction paradigm.展开更多
High power Hall electric propulsion technology is a very competitive electric propulsion technology for future large space missions such as large GEO satellites,manned space programs,deep space explorations,cargo ship...High power Hall electric propulsion technology is a very competitive electric propulsion technology for future large space missions such as large GEO satellites,manned space programs,deep space explorations,cargo ships,space tugs.Based on the experience of more than 20 years in research and development of Hall electric propulsion,the Shanghai Institute of Space Propulsion(SISP)has developed 3 high power Hall thrusters,i.e.,the 10 k W class HET-500,20 k W class HET-1000,and 50 k W class HET-3000.This paper presents the development status of the high power(≥10 k W)Hall electric propulsion at SISP,including tests of 3 high power Hall thrusters in the power range from 10 k W to 50 k W,the qualification of a single string of a 10 k W Hall electric propulsion system,and the study of a cluster of two 1.35 k W HET-80 Hall thrusters to understand the technical issues related to multi-thruster high power electric propulsion systems.展开更多
As the development tends towards high-speed, large-scale and high-power, power of the ship main engine becomes larger and larger. This make the engine design and cabin arrangement become more and more difficult. Ship ...As the development tends towards high-speed, large-scale and high-power, power of the ship main engine becomes larger and larger. This make the engine design and cabin arrangement become more and more difficult. Ship maneuverability becomes bad. A new ship propulsion system, integrated hydraulic propulsion （IHP）, is put forward to meet the development of modem ship. Principle of IHP system is discussed. Working condition matching characteristic of IHP ship is studied based on its matching characteristic charts. According to their propulsion principle, dynamic mathematic models of IHP ship and direct propulsion （DP） ship are developed. These two models are verified by test sailing and test stand data. Based on the software Matlab/Simulink, comparison research between IHP ship and DP ship is conducted. The results show that cabin arrangement of IHP ship is very flexible, working condition matching characteristic of IHP ship is good, the ratio of power to weight of IHP ship is larger than DP ship, and maneuverability is excellent. IHP system is suitable for engineering ship, superpower ship and warship, etc.展开更多
A comprehensive energy-saving sail (CES) has been proposed in order to promote energy saving and emission reduction from shipping. Wind energy is harvested for propulsion and electrical generator at the same time by a...A comprehensive energy-saving sail (CES) has been proposed in order to promote energy saving and emission reduction from shipping. Wind energy is harvested for propulsion and electrical generator at the same time by a unique structure of CES. A CFD (Computational Fluid Dynamics) code is verified by a case of arc wind sail, and it is used to simulate the pressure and velocity around the CES. The results show that the outlet velocity of air tunnel V<sub>o</sub> and wind velocity V<sub>i</sub> serve as an equation V<sub>o</sub> ≈ 1.31V<sub>i</sub>, which means the CES can effectively improve the conversion efficiency. In addition, it is found that V<sub>o</sub> increases with the tunnel diameter to some extend over which it will keep almost constant.展开更多
The two-dimensional coupled implicit Navier-Stokes equations and standard k-ε viscous models are used to simulate the angle of attack characteristics of an inte- grated hypersonic vehicle with a hark head configurati...The two-dimensional coupled implicit Navier-Stokes equations and standard k-ε viscous models are used to simulate the angle of attack characteristics of an inte- grated hypersonic vehicle with a hark head configuration under three kinds of working conditions： inlet cut-off, engine through-flow, and engine ignition. Influence of each com- ponent on aero-propulsive performance of the vehicle is discussed. It is concluded that the longitudinal static stability of the vehicle is good, and there is enough lift-to-drag ratio to satisfy the flying requirement of the vehicle. At the same time, it is important to change configurations of engine and upper surface of airframe to improve aero-propulsive ~erformance of the vehicle.展开更多
Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust ran...Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.展开更多
Aiming at the serious heat and cold loss of the building glass curtain wall in the field of amusement and tourism,and the need to meet the landscape requirements of the building facade,this paper put forward the idea ...Aiming at the serious heat and cold loss of the building glass curtain wall in the field of amusement and tourism,and the need to meet the landscape requirements of the building facade,this paper put forward the idea of integrating the shading and consumption reduction of glass curtain wall with the landscape requirements,that is,the water curtain was set outside the glass curtain wall to form a landscape energy-saving integrated water curtain wall system,while meeting the needs of landscape and shading.By establishing the numerical calculation model of the system,the corresponding relationship between the thickness of water film and the weakening of solar radiation intensity was revealed,as well as the influence of wind speed and wind direction on the nozzle exit angle and velocity selection;and the synergistic law of air flow rate and air temperature drop amplitude.The results showed that the water film thickness at 3-4 cm can reduce the solar radiation by 65%-80%.The temperature of the air layer between the water film and the curtain wall decreased as the air flow rate decreased,when the thickness of water film was 2 cm and the air velocity was 0.5-1.5 m/s,the air temperature dropped to 2.47-3.6°C.Finally,through the analysis of the actual project-ICE World&WATER Park,the system can reduce 66.8%of solar radiation,and reduce the air layer temperature by 3.9°C.展开更多
The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requir...The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requirements.However,the blades of the conventional rotor have poor conformality with the nacelle profile,which will greatly increase the drag of the UAV after folding.This paper proposes an integrated method for the design of rotor and nacelle considering geometric compatibility to reduce the drag of the folded rotor and nacelle,so as to further improve the aerodynamic efficiency in cruise while ensuring the rotor efficiency in the vertical flight mode.A geometric mapping model based on nacelle design parameters and rotor design parameters is established,and a parametric model and aerodynamic optimization model of the outer arc airfoil family are developed.In addition,a rotor performance analysis model and a neural network response surface model for nacelle drag prediction that meet the requirements of confidence level are established.Based on the oblique inflow blade element momentum theory method,numerical simulation method,and genetic algorithm,an integrated optimization framework of the design of the conformal rotor and nacelle is built.Then,a geometrically compatible integrated optimization for the rotor and nacelle is carried out with the objective of maximizing energy efficiency in the full mission profile.Finally,a conformal rotor and nacelle design solution is obtained,which satisfies geometric compatibility and thrust constraints while providing high thrust efficiency and low cruising drag.A comparison of the results of the integrated design and the conventional rotor optimization design shows that the drag of the conventional rotor is 3.45 times that of the conformal integrated design in the cruising state,which proves the effectiveness and necessity of the proposed method.展开更多
Fundamental features of aerodynamic interference and integration of airframes and air-breathing jet engines for high-speed flight vehicles are studied within the framework of supersonic small perturbation theory.Both ...Fundamental features of aerodynamic interference and integration of airframes and air-breathing jet engines for high-speed flight vehicles are studied within the framework of supersonic small perturbation theory.Both the influence of airframe components on air intakes performance and influence of intakes on vehicle external aerodynamics are under consideration.Analytical relations and specific examples show that significant favorable interference between airframes and air intakes can be realized by using preliminary compression of the flow in front of intakes at flight Mach numbers exceeding approximately 3.展开更多
基金Supported by the Aeronautical Science Foundation of China(2010ZB52011)the Funding of Jiangsu Innovation Program for Graduate Education(CXLX11-0213)the Nanjing University of Aeronautics and Astronautics Research Funding(NS2010055)~~
文摘The real-time capability of integrated flight/propulsion optimal control （IFPOC） is studied. An appli- cation is proposed for IFPOC by combining the onboard hybrid aero-engine model with sequential quadratic pro- gramming （SQP）. Firstly, a steady-state hybrid aero-engine model is designed in the whole flight envelope with a dramatic enhancement of real-time capability. Secondly, the aero-engine performance seeking control including the maximum thrust mode and the minimum fuel-consumption mode is performed by SQP. Finally, digital simu- lations for cruise and accelerating flight are carried out. Results show that the proposed method improves real- time capability considerably with satisfactory effectiveness of optimization.
文摘In this paper, sensitivity approaches are taken to analyze and design an integrated flight propulsion control system where the interaction between subsystems direitly affects the stability property and handling performances of the aircraft. The eigenvalue sen sitivity approach is employed to study the effect of coupling parameters on system stability and gain sensitivity approach is used to direct the reduced states feedback suboptimal control system design. Simulation results show that the integrated flight propulsion control system designed by sensitivity approaches is of good performance.
基金Supported by the National Science and Technology Major Project(No.2017-Ⅳ-0010-0047)Key Laboratory Fund for Ship Vibration and Noise(No.614220406020717)+1 种基金China Postdoctoral Science Foundation Funded Project(No.2020M670113)the Fundamental Research Funds for the Central Universities(No.JD2003)。
文摘This paper aims at investigating the effectiveness of squeeze oil film in suppressing the longitudinal vibration of propulsion shaft systems through a novel integral axial squeeze film damper(IASFD).After designing the IASFD,a propulsion shafting test rig for the longitudinal vibration control is built.Longitudinal vibration control experiments of the propulsion shafting are carried out under different magnitude and frequency of the excitation force.The results show that both IASFD elastic support and IASFD elastic damping support have excellent vibration attenuation characteristics,and can effectively suppress the longitudinal vibration of the shaft system in a wide frequency range.However,IASFD elastic damping support has a more significant vibration reduction effect than the other supports,and increasing the damping of the system has obvious effect on reducing the shafting vibration.For an excitation force of 45 N,the maximum reduction of the vibration amplitude is 89.16%.Also,the vibration generated by the resonance phenomenon is also significantly reduced.
基金supported by the National Natural Science Foundation of China (Grant No.71872122)Late-stage Subsidy Project of Humanities and Social Sciences of the EducationDepartment of China (Grant No. 20JHQ095)。
文摘The core of the healthy and orderly operation of the existing residential building energy-saving renovation market lies in the exploration of the implementation mechanism of multi-subject and multi-objective integrated optimization.The multi-agent and multi-objective integrated optimization system framework is a powerful tool to guide the scientific decision-making of the market core structural entities in the future market practice. This paper analyzes the practical dilemma of energy-saving renovation of theexisting residential buildings in China, summarizes the practical experience of multi-subject and multi-objective integrated optimization of energy-saving renovation of the existing residential buildings in foreign countries, and puts forward beneficial practical enlightenment on the basis of comparison at home and abroad;The design principles of the target integrated optimization system have established a multi-subject and multi-objective integrated optimization system framework for the energy-saving renovation of the existing residential buildings, from six aspects: government guidance, trust consensus, value co-creation, risk sharing, revenue sharing, and social responsibility sharing. This paper proposes a multi-subject and multi-objective integrated practice strategy, in order to promote the efficient and orderly development of China's existing residential building energy-saving renovation market.
文摘This paper proposes the modem passive integrated energy-saving technology of the residential buildings under green building background. The essence of green building is to build a healthy and general environmentally friendly living environment under the premise of reducing the consumption of resources and improving the efficiency of resource utilization in the whole life cycle of construction activities. Green building bearing function is further diversified, integrated, and has a self-initiative. The development of the green building, local isolated from the original single building greening, greening, landscaping site platform, gradually developed for construction area and the surrounding green ecological system of comprehensive, three-dimensional stratified construction and network connection. Its model gradually shows the micro area of the construction of the ecological system and architectural space integration. This paper integrates the passive integrated energysaving technology to construct the novel construction paradigm.
文摘High power Hall electric propulsion technology is a very competitive electric propulsion technology for future large space missions such as large GEO satellites,manned space programs,deep space explorations,cargo ships,space tugs.Based on the experience of more than 20 years in research and development of Hall electric propulsion,the Shanghai Institute of Space Propulsion(SISP)has developed 3 high power Hall thrusters,i.e.,the 10 k W class HET-500,20 k W class HET-1000,and 50 k W class HET-3000.This paper presents the development status of the high power(≥10 k W)Hall electric propulsion at SISP,including tests of 3 high power Hall thrusters in the power range from 10 k W to 50 k W,the qualification of a single string of a 10 k W Hall electric propulsion system,and the study of a cluster of two 1.35 k W HET-80 Hall thrusters to understand the technical issues related to multi-thruster high power electric propulsion systems.
基金supported by National Natural Science Foundation of China(Grant No. 50575027)Ministry of Transportation and Communications Foundation of China (Grant No. 200332922502)
文摘As the development tends towards high-speed, large-scale and high-power, power of the ship main engine becomes larger and larger. This make the engine design and cabin arrangement become more and more difficult. Ship maneuverability becomes bad. A new ship propulsion system, integrated hydraulic propulsion （IHP）, is put forward to meet the development of modem ship. Principle of IHP system is discussed. Working condition matching characteristic of IHP ship is studied based on its matching characteristic charts. According to their propulsion principle, dynamic mathematic models of IHP ship and direct propulsion （DP） ship are developed. These two models are verified by test sailing and test stand data. Based on the software Matlab/Simulink, comparison research between IHP ship and DP ship is conducted. The results show that cabin arrangement of IHP ship is very flexible, working condition matching characteristic of IHP ship is good, the ratio of power to weight of IHP ship is larger than DP ship, and maneuverability is excellent. IHP system is suitable for engineering ship, superpower ship and warship, etc.
文摘A comprehensive energy-saving sail (CES) has been proposed in order to promote energy saving and emission reduction from shipping. Wind energy is harvested for propulsion and electrical generator at the same time by a unique structure of CES. A CFD (Computational Fluid Dynamics) code is verified by a case of arc wind sail, and it is used to simulate the pressure and velocity around the CES. The results show that the outlet velocity of air tunnel V<sub>o</sub> and wind velocity V<sub>i</sub> serve as an equation V<sub>o</sub> ≈ 1.31V<sub>i</sub>, which means the CES can effectively improve the conversion efficiency. In addition, it is found that V<sub>o</sub> increases with the tunnel diameter to some extend over which it will keep almost constant.
基金supported by the Excellent Graduate Student Innovative Project of National University of Defense Technology (No. B070101)Hunan Provincial Innovation Foundation for Postgraduate(No. 3206)
文摘The two-dimensional coupled implicit Navier-Stokes equations and standard k-ε viscous models are used to simulate the angle of attack characteristics of an inte- grated hypersonic vehicle with a hark head configuration under three kinds of working conditions： inlet cut-off, engine through-flow, and engine ignition. Influence of each com- ponent on aero-propulsive performance of the vehicle is discussed. It is concluded that the longitudinal static stability of the vehicle is good, and there is enough lift-to-drag ratio to satisfy the flying requirement of the vehicle. At the same time, it is important to change configurations of engine and upper surface of airframe to improve aero-propulsive ~erformance of the vehicle.
基金the National Key R&D Program of China (No. 2020YFC22 01000)the National Natural Science Foundation of China (No. 11927812)。
文摘Many high-precision space missions need thrusters to produce thrust with low noise to compensate for disturbances and ensure satellite platform stability. Microwave ion thruster is characterized with a wide thrust range and potential for these missions. A cost-effective and accurate mathematical model is crucial for mHz-frequency thrust noise analysis and feedback controller design. The Particle-In-Cell(PIC) and global models are two common simulation tools. The PIC model is characterized with high accuracy but huge computation cost, which is difficult to analyze long-time performance characteristics. Now, the global model is only used for the discharge chamber with low accuracy and cannot reflect ion extraction properties. In this paper, an integrative mathematical model is built for a 1-cm microwave ion thruster and can reflect ion beamlet divergence and impingement on the Accelerator Grid(AG). Simulation results show good agreement with experiments at 0.06 sccm. However, the model demonstrates worse consistency with experiments when the flux increases to 0.1 sccm, which may be because the influence of neutral gas on the Electron Cyclotron Resonance(ECR) is not considered in the model. A long-time(1000 s) simulation is conducted with this model under 35 μN. It takes 3 hrs, and the thrust noise reaches 1 μN/Hz^(0.5) at 1 mHz.
基金project Xiangjiang Happy City — Ice World & Water Park, which is constructed by Ltd of China Construction Fifth Engineering
文摘Aiming at the serious heat and cold loss of the building glass curtain wall in the field of amusement and tourism,and the need to meet the landscape requirements of the building facade,this paper put forward the idea of integrating the shading and consumption reduction of glass curtain wall with the landscape requirements,that is,the water curtain was set outside the glass curtain wall to form a landscape energy-saving integrated water curtain wall system,while meeting the needs of landscape and shading.By establishing the numerical calculation model of the system,the corresponding relationship between the thickness of water film and the weakening of solar radiation intensity was revealed,as well as the influence of wind speed and wind direction on the nozzle exit angle and velocity selection;and the synergistic law of air flow rate and air temperature drop amplitude.The results showed that the water film thickness at 3-4 cm can reduce the solar radiation by 65%-80%.The temperature of the air layer between the water film and the curtain wall decreased as the air flow rate decreased,when the thickness of water film was 2 cm and the air velocity was 0.5-1.5 m/s,the air temperature dropped to 2.47-3.6°C.Finally,through the analysis of the actual project-ICE World&WATER Park,the system can reduce 66.8%of solar radiation,and reduce the air layer temperature by 3.9°C.
基金the Fundamental Research Funds for the Central Universities(No.56XCA2205402).
文摘The inner rotors of distributed propulsion tilt-wing Unmanned Aerial Vehicles(UAVs)are often folded in the cruising state and deployed in vertical take-off and landing to cope with the huge difference in thrust requirements.However,the blades of the conventional rotor have poor conformality with the nacelle profile,which will greatly increase the drag of the UAV after folding.This paper proposes an integrated method for the design of rotor and nacelle considering geometric compatibility to reduce the drag of the folded rotor and nacelle,so as to further improve the aerodynamic efficiency in cruise while ensuring the rotor efficiency in the vertical flight mode.A geometric mapping model based on nacelle design parameters and rotor design parameters is established,and a parametric model and aerodynamic optimization model of the outer arc airfoil family are developed.In addition,a rotor performance analysis model and a neural network response surface model for nacelle drag prediction that meet the requirements of confidence level are established.Based on the oblique inflow blade element momentum theory method,numerical simulation method,and genetic algorithm,an integrated optimization framework of the design of the conformal rotor and nacelle is built.Then,a geometrically compatible integrated optimization for the rotor and nacelle is carried out with the objective of maximizing energy efficiency in the full mission profile.Finally,a conformal rotor and nacelle design solution is obtained,which satisfies geometric compatibility and thrust constraints while providing high thrust efficiency and low cruising drag.A comparison of the results of the integrated design and the conventional rotor optimization design shows that the drag of the conventional rotor is 3.45 times that of the conformal integrated design in the cruising state,which proves the effectiveness and necessity of the proposed method.
文摘Fundamental features of aerodynamic interference and integration of airframes and air-breathing jet engines for high-speed flight vehicles are studied within the framework of supersonic small perturbation theory.Both the influence of airframe components on air intakes performance and influence of intakes on vehicle external aerodynamics are under consideration.Analytical relations and specific examples show that significant favorable interference between airframes and air intakes can be realized by using preliminary compression of the flow in front of intakes at flight Mach numbers exceeding approximately 3.
