Competitive Environment and Reform Conceptions

There are various signs that indicate the pace of civil aviation reform is quickening withlittle buzz.People hold a common understanding that the air fare hearing, which was held in mid-Julyafter being postponed by SARS, is an important progress of market-oriented reform of civilaviation despite controversies among representatives and different remarks from the society.As a development strategy of Chinese civil aviation, regional aviation has been proposedfor many years. However, few actions…     

Secondary trading of airport slots: Issues and challenges

Most Level 3 airports around the world suffer severe congestion and flight delays. Airlines have to obtain airport slots in order to schedule flights at such airports. The main way for airlines to acquire slots is primary slot allocation, in which a slot coordinator distributes slots to airlines according to certain rules and regulations. Due to excessive demand for slots and restrictions on allocation rules, it is difficult for some airlines to obtain the desired slots in this manner.Another wa...     

Achieving the Stride From "Big" to "Strong

Time flies. Here we come to a new year again.The just-gone 2002 is bound to leave a heavy print in the history of Chinesecivil aviation. The plan of civil aviation system reform was settled and this re-form has entered into the implementation phase. The establishment of three airtransport groups and three aviation support groups was announced, which sym-bolizes an essential step has been taken in the civil aviation system reform. At theend of the year, good news that the Capital Airport Grou…     

THE STUDY OF AIRPORTTERRAIN EFFECTS ON AUTOLAND FOR ANY AIRPLANE

<正> The terrain profile at several airports has caused some difficulty with autolands on the DC-10 and MD-80. Some operators have reported that the pilot had to disconnect the flight guidance system during flare and land manually. At present, the autoland guidance system is not uniquely designed to handle the variations of terrain. Since there is no accurate substitute for radio altitude(h_(rad)) the only variable left to improve is radio altitude rate (h_(rad)).     

A New Page For Shanghai Airports

The Shanghai Airport(Group)Co Ltd,set up onMay28,1998with approval of the ShanghaiMunicipal government,is China's first of the kindgoverned by local governments.In the past eight years,the company has written acolourful page in the history of the development ofShanghai airports.Shanghai airports have made historic achievementsin aviation transport,becoming one of the world's topairports.Their flights have risen from128,000to375,000,passengers from13.71million to41.34million,and cargoand ma…     

Efforts To Build Shanghai Into An Airport Hub

Shanghai is a city that boasts two civil international airportsin Mainland China.One is Pudong International Airportin the east of the city and the other is HongqiaoInternational Airport in the west.In order to suit the new pattern of``one city,two airports,'the Shanghai Airport(Group)Co Ltd was set up on May28,1998upon the approval of the Shanghai government to manage thetwo international airports.In the past years,the two airports have been adhering to theenterprise spirit of``working…     

Vulnerability analysis for airport networks based on fuzzy soft sets: From the structural and functional perspective

Recently,much attention has been paid to the reliability and vulnerability of critical infrastructure.In air traffic systems,the vulnerability analysis for airport networks can be used to guide air traffic administrations in their prioritization of the maintenance and repair of airports,as well as to avoid unnecessary disturbances in the planning of flight schedules.In this paper,the evaluation methods of airport importance and network efficiency are established.Firstly,the evaluation indices of airport importance are proposed from both the topological and functional perspectives.The topological characteristics come from the structure of airport network and the functional features stem from the traffic flow distribution taking place inside the network.Secondly,an integrated evaluation method based on fuzzy soft set theory is proposed to identify the key airports,which can fuse together importance indices over different time intervals.Thirdly,an airport network efficiency method is established for the purpose of assessing the accuracy of the evaluation method.Finally,empirical studies using real traffic data of US and China’s airport networks show that the evaluation method proposed in this paper is the most accurate.The vulnerability of US and China’s airport networks is compared.The similarities and differences between airport geography distribution and airport importance distribution are discussed here and the dynamics of airport importance is studied as well.     

Expansion of Domestic Demandand Civil Aviation Reform

At the recently-closed 5th session of the 9th National People's Congress, Premier Zhu Rongji, in his Government Work Report, put "Expanding and Nurturing Domestic Demand, Promoting Rapid Economic Growth" in first place among eight key tasks this year. It is good news for civil aviation enterprises, which are in a crucial period of reform and reorganization. In early February, Minister Liu Jianfeng publicized civil aviation reform plan, passed at the 121st Premier Work Meeting of the …     

Management Reform, Fundamental to Enterprises'''' Development

When the reorganization of the 5 civil aviation enterprise groups took shapes,China civil aviation industry makes an important step in the enterprise reform.Soon after that, 6 local airlines signed an agreement on establishing Sky AviationGroup, and expansion has been made in the scale of the discounted air fare. Chinacivil aviation reform, once-called "action with no news", draws all the focuses ofthe public.Chinese air transport industry is not very strong in the world air transportmarket,…     

STUDY ON FLAP SIDE-EDGE NOISE BASED ON THE FLY-OVER MEASUREMENTS WITH A PLANAR MICROPHONE ARRAY

After the significant progress that has beenachieved in engine noise reduction in the last twodecades,the airframe noise of civil transportshas now become a major concern for noise certi-fication and environmental considerations.Con-sequently,aircraft manufacturers and researchcenters have been working on airframe noisewith the objectives of developing reliable noiseprediction schemes and reducing aerodynamicnoise generation at the source in recentyears[1～ 2 ] .　　 Of all the airframe noise …     

Unimpeded Routes in the Blue Sky

The air transport in China is developing rapidly with an annual average growth rate of20 %since the reform and open to the outside.The rising air traffic will make ATC more difficult.With questions about China‘s ATC development at present and in the future,the reporters of IA interviewed to Mr.Chen Xuhua,the director general of the Air Traffic Managment Bureau of the CAAC.     

NUMERICAL SIMULATION OF UNSTEADY FLOW AROUND A CIRCULAR CYLINDER AT HIGH REYNOLDS NUMBERS

A Lagrangian-Eulerian hybrid scheme to solve unsteady N-S equation in two-dimensional incompressible fluid at high Reynolds numbers is presented in this paper. A random walk is imposed to simulate the viscous diffusion, the vortex-in-cell method is used to obtain the convection velocity, and nascent vortices are created on a cylinder to satisfy the zero-slip condition. The impulsively started flow around a circular cylinder and the separation induced by a pair of incident vortices symmetrically approaching a circular cylinder have been successfully simulated by the hybrid scheme. The impulsively started flow from rest has been computed at Reynolds numbers 3000 and 9500. Comparisons are made with those results of finite-difference method, vortex method and flow visualization. Agreement is good. The particular attention has been paid to the evolutions of flow pattern. A topological analysis has been proposed in the region of the near wake. The bulge, isolated secondary vortex, a pair of secondary vortices     

OVERSEAS BRIEFS Dec. 1-31

▲Dec. 1 The American Transport Secu-rity Bureau had chosen 6 airports to launch atrial reform of boarding procedures, hoping toeliminate at-the-gate random X-ray scanningcheck in every airport.▲Dec. 1 Austrian Airlines earned a profitof 61.8 million EURO during Jan.to Sept. 2002,a great progress compared with 2001 recordinga loss of 16 million EURO.▲Dec. 2 British Airways announced a pre-tax profit of 245 million pounds for the secondquarter of the 2002-2003 fiscal year ending on…     

Ignition enhancement of ethylene/air by NOx addition

Recently, non-equilibrium plasma assisted combustion (PAC) has been found to be promising in reducing the ignition delay time in hypersonic propulsion system. NO x produced by non-equilibrium plasma can react with intermediates during the fuel oxidation process and thereby has influence on the combustion process. In this study, the effects of NO x addition on the ignition process of both the homogeneous ethylene/air mixtures and the non-premixed diffusion layer are examined numerically. The detailed chemistry for ethylene oxidization together with the NO x sub-mechanism is included in the simulation. Reaction path analysis and sensitivity analysis are conducted to give a mechanistic interpretation for the ignition enhancement by NO x addition. It is found that for both the homogenous and non-premixed ignition processes at normal and elevated pressures, NO 2 addition has little influence on the ignition delay time while NO addition can significantly promote the ignition process. The ignition enhancement is found to be caused by the promotion in hydroxyl radical production which quickly oxidizes ethylene. The promotion in hydroxyl radical production by NO addition is achieved in two ways:one is the direct production of OH through the reaction HO2+NO = NO2+OH, and the other is the indirect production of OH through the reactions NO+O2=NO2+O and C2H4+O = C2H3+OH. Moreover, it is found that similar to the homogeneous ignition process, the acceleration of the diffusion layer ignition is also controlled by the reaction HO2+NO = NO2+OH.     

Numerical simulation of multi-phase combustion flow in solid rocket motors with metalized propellant

Multi-phase flowfield simulation has been performed on solid rocket motor and effect of multi-phases on the performance prediction of the solid rocket motor(SRM) is investigation.During the combustion of aluminized propellant,the aluminum particles in the propellant melt and formliquid aluminum at the burning propellant surface.So the flow within the rocket motor is multi phase or two phase because it contains droplets and smoke particles of Al2O3.Flowsi mulations have been performed on a large scale motor,to observe the effect of the flowfield onthe chamber and nozzle as well.Uniform particles diameters and Rosin-Rammler diameter distribution method that is based on the assumption that an exponential relationship exists betweenthe droplet diameter,dand mass fraction of droplets with diameter greater thandhave been used for the si mulation of different distribution of Al2O3 droplets present in SRM.Particles sizes in the range of 1-100μm are used,as being the most common droplets.In this approachthe complete range of particle sizes is dividedinto a set of discrete size ranges,eachto be defined by single streamthat is part of the group.Roe scheme-flux differencing splitting based on approxi mate Riemann problem has been used to si mulate the effects of the multi-phase flowfeild.This is second order upwind scheme in which flux differencing splitting method is employed.To cater for the turbulence effect,Spalart-All maras model has been used.The results obtained show the great sensitivity of this diameters distribution and particles concentrations to the SRMflowdynamics,primarily at the motor chamber and nozzle exit.The results are shown with various sizes of the particles concentrations and geometrical configurations including models for SRM and nozzle.The analysis also provides effect of multi-phase on performance prediction of solid rocket motor.     

Breakthrough Needed for the Work of Flight Standard

China civil aviation is at present in a crucial time of reform and development, faced with major tasks of separating business operations from government administration, transferring the responsibilities of the administration, and the strategic regroup of enterprises. The rapid growth of the national economy lays a good foundation for China civil aviation. The economy globalization, the trade deregularization, and the regulation integration brought both the opportunity and the challenge to Chin…     

Optimum blade loading for a powered rotor in descent

The optimum loading for rotors has previously been found for hover, climb and wind turbine conditions;but, up to now, no one has determined the optimum rotor loading in descent. This could be an important design consideration for rotary-wing parachutes and low-speed des-cents. In this paper, the optimal loading for a powered rotor in descent is found from momentum theory based on a variational principle. This loading is compared with the optimal loading for a rotor in hover or climb and with the Betz rotor loading (which is optimum for a lightly-loaded rotor). Wake contraction for each of the various loadings is also presented.     

Unsteady Flow Variability Driven by Rotor-stator Interaction at Rotor Exit

Numerical investigation of the unsteady flow variability driven by rotorstator interaction in a transonic axial compressor is performed. Two models with close and far axial gap between rotor and stator rows are studied in the simulation. Particular attention is attached to the analysis of mechanisms involved in driving rotor wake oscillation, rotor wake skewing and flow angle fluctuation at rotor exit. The results show that smaller axial gap is favorable to enhance the interaction in the region between two adjacent rows, and the fluctuation of the static pressure difference between two sides of rotor wake is improved by potential field from down stator, which is the driving force for rotor wake oscillation. The interaction between rotor and stator is weakened by increasing axial distance, rotor wake shifts to suction side of rotor blade with 5%-10% of rotor pitch, the absolute value of flow angle at rotor exit is less than that in the case of close interspace for every time step, and the fluctuation amplitude is also decreased.     

Effects of swirler position on flame response and combustion instabilities

This study is concerned with the experimental and theoretical investigation of the combustion instabilities in a premixed swirl combustor. It is focused on the effects of the swirl mixing distance on the intrinsic thermoacoustic mode. The swirler as an origin of the swirling flow is also the source of the flow disturbance, which has effects on the flame response. The location of the swirler is varied in the experiment to study the effect on combustion instabilities and flame transfer functions. ...     

Multi-scale strength analysis of bolted connections used in integral thermal protection system

Efficient and accurate strength analysis of bolted connections is essential in analyzing the integral thermal protection system(ITPS) of hypersonic vehicles, since the system bears severe loads and structural failures usually occur at the connections. Investigations of composite mechanical properties used in ITPS are still in progress as the architecture of the composites is complex. A new method is proposed in this paper for strength analysis of bolted connections by investigating the elastic behavior and failure strength of three-dimensional C/C orthogonal composites used in ITPS. In this method a multi-scale finite element method incorporating the global–local method is established to ensure high efficiency in macro-scale and precision in meso-scale in analysis.Simulation results reveal that predictions of material properties show reasonable accuracy compared with test results. And the multi-scale method can analyze the strength of connections efficiently and accurately.