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Impact of 1.5°C and 2.0°C global warming on aircraft takeoff performance in China

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Science Bulletin 2018年第11期63卷 700-707页

作者： Tianjun Zhou Liwen Ren Haiwen Liu Jingwen Lu LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China Department of aviation Meteorology Civil Aviation University of ChinaTianjin 300300China

Associated with global warming, climate extremes such as extreme temperature will significantly increase. Understanding how climate change will impact the airflights is important to the planning of future flight operations. In this study, the impacts of 1.5 and 2 degree's global warming on the aircraft takeoff performance in China are investigated using a unique climate projection data from an international collaboration project named HAPPI. It is found that the mean summer daily maximum temperature, which is a major factor that affects the flight through changing the aircraft's takeoff weight, will increase significantly with magnitude less than 1.5℃ over most parts of China except for the Tibetan Plateau. The half a degree additional global warming will lead to higher extreme temperature in the arid and semi-arid western China, the Tibetan Plateau and the northeastern China, while the change in eastern China is weak. Five airports including Beijing, Shanghai, Kunming, Lasa and Urumqi will see ～1.0°-2.0℃(1.4°-3.0℃) higher daily maximum temperature under 1.5℃(2.0℃) scenario. The half-degree additional warming will lead to a shift toward higher extreme temperature in these five sites. For both1.5° and 2.0℃ scenarios, the number of weight-restriction days will increase significantly at 3 airports including Beijing, Shanghai, and Lasa. Urumqi will witness an increase of weight-restriction days only in 2.0℃ future.

关键词： Extreme temperature 1.5 and 2 degree's global warming Airflight Weight-restriction days

Effects of Heat Transfer on Laminar-to-Turbulent Transition over a Compressor Blade Operating at Low Reynolds Number

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Journal of Thermal Science 2024年第5期33卷 1826-1838页

作者： LU Lehan WANG Mingyang ZHANG Yanfeng SUN Shuang HUANG Zhen WANG Maomao Department of aviation Engineering Civil Aviation University of ChinaTianjin 300300China institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China State Key Laboratory of Aerodynamics CARDCMianyang 621000China

To control the transition process in a laminar separation bubble(LSB)over an ultra-high load compressor blade at a Re of 1.5×10^(5),the effects of wall heat transfer were considered and numerically investigated by large eddy simulations(LES).Compared with the adiabatic wall condition,the local kinematic viscosity of airflow was reduced by wall cooling;thus the effects of turbulent dissipation on the growth of fluctuations were *** such,the transition occurred much earlier,and the size of LSB became *** the cooled surface,the spanwise vortices deformed much more rapidly and the size of hairpin vortex structures was ***,the rolling-up of 3D hairpin vortices and the ejection and sweeping process very close to the blade surface was ***,the aerodynamic losses of the compressor blade were reduced by 18.2%and 38.4%for the two cooled wall *** results demonstrated the feasibility of wall cooling in controlling the transition within an LSB and reducing the aerodynamic loss of an ultra-highly loaded compressor blade.

关键词： heat transfer compressor blade laminar-to-turbulent transition loss generation

Parametric study of turbine NGV blade lean and vortex design

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Chinese Journal of Aeronautics 2016年第1期29卷 104-116页

作者： Zhang Shaowen David G.Mac Manus Luo Jianqiao Department of Turbine Design China Aviation Powerplant Research Institute AVIC School of Aerospace Transport and Manufacturing Cranfield University

The effects of blade lean and vortex design on the aerodynamics of a turbine entry nozzle guide vane （NGV） are considered using computational fluid dynamics. The aim of the work is to address some of the uncertainties which have arisen from previous studies where conflicting results have been reported for the effect on the NGV. The configuration was initially based on the energy efficient engine turbine which also served as the validation case for the computational method. A total of 17 NGV configurations were evaluated to study the effects of lean and vortex design on row efficiency and secondary kinetic energy. The distribution of mass flow ratio is introduced as an additional factor in the assessment of blade lean effects. The results show that in the turbine entry NGV, the secondary flow strength is not a dominant factor that determines NGV losses and therefore the changes of loading distribution due to blade lean and the associated loss mecha- nisms should be regarded as a key factor. Radial mass flow redistribution under different NGV lean and twist is demonstrated as an addition key factor influencin~ row efficiency.

关键词： Blade lean Losses Mass flow radial distribu-tion Parametric study Secondary kinetic energy Turbine Vortex design

Oxidation of a Co-base Superalloy

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Journal of Materials Science & Technology 2008年第6期24卷 883-890页

作者： Guichen HO U Zhiyuan LIU Hua WEI Qi ZHENG Xiaofeng SUN Hengrong G UAN Zhuangqi HU Superalloy Division Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China China aviation Powerplant Research institute Zhuzhou 412002 China

The oxidation behavior of a cast polycrystalline Co-base superalloy was studied at temperatures from 900 to 1050℃ and analyzed by thermogravimetric analysis （TGA）, X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The results indicate that a cast Co-base superalloy follows the subparabolic oxidation kinetics at 900 and 1000℃, which are controlled by the growth of the inner Cr-rich layer, and that after oxidation at 1050℃ for 200 h, it almost exhibits the linear oxidation kinetics possible due to the volatility of Cr-rich oxide. A mixed scale forms on the alloy after prolonged oxidation. The oxide scale formed at 900 and 1000℃ is composed of an outer layer of spinel and an inner continuous Cr-rich layer and at I050℃ is composed of a very discontinuous Cr-rich layer.

关键词： Co-base superalloy Oxidation Kinetics Microstructure

A radar-infrared compatible broadband absorbing surface:Design and analysis

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Chinese Physics B 2021年第7期30卷 605-612页

作者： Qing-Tao Yu Yuan-Song Zeng Guo-Jia Ma aviation Key Laboratory of Science and Technology on Advanced Surface Engineering AVIC Manufacturing Technology InstituteBeijing 100024China

A radar-infrared compatible stealth surface is designed and *** modifying the radar absorbing material(RAM),the design can theoretically achieve radar-infrared compatibility and broadband radar absorption through surface patterns and structures.A transmission-line-based model(TLM)is developed to analyze the radar absorbing performance of the *** of the structure geometries is conducted aiming to maximize the-10 d B absorption bandwidth in 2–18 *** with optimized structure geometries exhibits a superior absorption bandwidth,more than twice the bandwidth of the original 1.5 mm RAM slab,while maintaining a relatively low infrared emissivity.

关键词： stealth infrared-radar compatible broadband absorbing patterned surface

A STUDY ON THE PRECIPITATION CHARACTERISTICS OVER THE SOUTH CHINA SEA BEFORE AND AFTER THE MONSOON ONSET

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Journal of Tropical Meteorology 2012年第1期18卷 1-10页

作者：李耀东宋明坤胡亮 institute of aviation Meteorology institute of Meteorology PLA University of Science and Technology National Satellite Meteorology Center CMA

This paper presents a study on the temporal and spatial variations of the precipitation over the area of the South China Sea (SCS) during the monsoon onset period. The data used are from the Tropical Rainfall Measuring Mission (TRMM) observations between April and June over the nine years from 1998 to 2006. This study focuses on the central and northern part of South China Sea (110-120°E, 10-20°N). Based on the observations, the 27th pentad is selected as the occurrence time of the SCS monsoon onset. The conclusions are as follows. (1) After the monsoon onset, the specific area, defined as the ratio of the number of pixels with certain type of precipitation to the number of total pixels, extends significantly for both convective and stratiform rain, with the latter having a larger magnitude. The specific rainfall, defined as the ratio of the amount of certain type of precipitation to the total amount of precipitation, decreases for convective rain and increases for stratiform rain. (2) Results also show significant increase in heavy rain and decrease in light rain after the monsoon onset. (3) Changes are also observed in the rainfall horizontal distributions over the SCS before and after the monsoon onset, manifested by the relocation of precipitation minima for both convective and stratiform rain. (4) After the monsoon onset, the variability in characteristics of precipitation vertical structure increases significantly, leading to more latent heat release and consequently deeper convection. Meanwhile, the bright-band altitude of stratiform precipitation is also elevated.

关键词： TRMM South China Sea monsoon onset precipitation

Experimental study and analysis on the rising motion of grains in a vertically-vibrated pipe

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Chinese Physics B 2015年第3期24卷 224-229页

作者：刘煜赵俊红 Electric Power Research institute Henan Electric Power Company Luoyang College Civil Aviation Flight University of China

Previous experimental investigations have shown that when a narrow pipe is inserted into a granular bed and is vibrated vertically but the granular bed is kept still, the grains in the bed can enter the pipe and rise against gravity along the pipe and finally stabilized at a certain height. The growth velocity and final stable height of the grain column inside the pipe can be controlled by varying the vibration conditions. In this paper, we discuss those experimental findings. We establish a mathematic relation between the grain column height（h） and time（t）, and by using the relation we discuss the change of the growth velocity（ dh/ dt） and acceleration（ d^2h/ dt^2） with t and h, respectively. We also analyze the mechanism of the rising motion of the grains during vibration. Furthermore, we derive a theoretical expression for describing the final stable height（h st）, which shows that the main factors influencing the height are vibration strength（Γ）, bulk density of grains,inner diameter of the pipe, and vibration frequency, and that h st increases nonlinearly in the presence of air and linearly in a vacuum environment with increasing Γ.

关键词： granular matter vertical vibration theoretical analysis

Unsteady aerodynamic noise prediction of contra-rotating open rotor using meshless method

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Chinese Journal of Aeronautics 2024年第8期37卷 144-165页

作者： Zhiliang HONG Meng SU Haitao ZHANG Zerui XU Lin DU Lingfeng CHEN College of Safety Science and Engineering Civil Aviation University of ChinaTianjin 300300China Civil aviation Administration of China Beijing 100710China Research institute of Aero-Engine Beihang UniversityBeijing 100191China

The Contra-Rotating Open Rotor(CROR)design confronts significant noise challenges despite being one of the possible options for future green *** efficiently estimate the noise emitted from a CROR,a three-dimensional unsteady prediction model based on the meshless method is *** unsteady wake flow and the aerodynamic load fluctuations on the blade are solved through the viscous vortex particle method,the blade element momentum theory and vortex lattice ***,the acoustic field is obtained through the Farassat’s formulation *** of this method is conducted on a CROR,and a mesh-based method,e.g.,Nonlinear Harmonic(NLH)method,is also employed for *** is found that the presented method is three times faster than NLH method while maintaining a comparable precision.A thorough parametric analysis is also carried out to illustrate the effects of rotational speed,rotor-rotor spacing and rear rotor diameter on the noise *** rotor speed is found to be the most influencing factor,and by optimizing the speed difference between the front and rear rotors,a notable noise reduction can be *** current findings not only contribute to a deeper comprehension of the CROR’s aeroacoustic properties but also offer an effective tool for engineering applications.

关键词： Contra-Rotating Open Rotor(CROR) Aerodynamic noise Blade element momentum theory Viscosity vortex particle method Farassat’s formulation 1A

Numerical study on flow fields and aerodynamics of tilt rotor aircraft in conversion mode based on embedded grid and actuator model

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Chinese Journal of Aeronautics 2015年第1期28卷 93-102页

作者： Zhang Ying Ye Liang Yang Shuo aviation Key Laboratory of Science and Technology on Aerodynamics of High Speed and High Reynolds Number AVIC Aerodynamics Research Institute

A method combining rotor actuator disk model and embedded grid technique is presented in this paper, aimed at predicting the flow fields and aerodynamic characteristics of tilt rotor aircraft in conversion mode more efficiently and effectively. In this method, rotor＇s influence is considered in terms of the momentum it impacts to the fluid around it; transformation matrixes among different coordinate systems are deduced to extend actuator method＇s utility to conversion mode flow fields＇ calculation. Meanwhile, an embedded grid system is designed, in which grids generated around fuselage and actuator disk are regarded as background grid and minor grid respectively, and a new method is presented for ‘donor searching＇ and ‘hole cutting＇ during grid assembling. Based on the above methods, flow fields of tilt rotor aircraft in conversion mode are simulated, with threedimensional Navier–Stokes equations discretized by a second-order upwind finite-volume scheme and an implicit lower–upper symmetric Gauss–Seidel（LU-SGS） time-stepping scheme. Numerical results demonstrate that the proposed CFD method is very effective in simulating the conversion mode flow fields of tilt rotor aircraft.

关键词： actuator aircraft rotor searching assembling symmetric coordinate donor stepping Stokes