2000 Vol. 15, No. 4

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Display Method:
Relationship between Sweep Leading Edges and the Flow Field Structure in Transonic Fans
XING Xiu-qing, ZHOU Sheng, ZHAO Xiao-lu
2000, 15(4): 337-341.
Abstract PDF(164KB) icon1355 icon454
Abstract:
An improved design method of transonic fan is presented. In order to control shock structure,migration of the low momentum fluid,and therefore to improve the performance of the transonic fan,the leading edges of sweep blades are considered as design freedoms in this method.Three high loaded transonic fans with low aspect ratio were used to prove the practicability of this method.The numerical study of the three transonic fans demonstrates the effect of the sweep leading edge on the flow field structure.
Three-Dimensional Turbulent Flow of the Endwall Region inside a Centrifugal Compressor Impeller
MA Hong-wei, JIANG Hao-kang, XU Yue-ting, YANG Jian, XUE Lin
2000, 15(4): 342-346.
Abstract PDF(356KB) icon1758 icon438
Abstract:
Three-dimensional turbulent flow of the endwall region inside a centrifugal compressor impeller was studied using a Laser Doppler Velocimetry.The flow was surveyed across the entire passage at seven radial locations (leading edge to trailing edge) and ten axial locations.Data obtained include three-dimensional mean and turbulent characteristics.The measurement results indicated that a corner vortex existed along the suction surface near the endwall,leading to obvious flow blockage and turbulence.The suction-side horse-shoe vortex of the blade leading edge developed towards the pressure surface with the flow downstream,resulting in the flow mixing between the endwall boundary layer and the main flow.Interaction of the two sides of the horse-shoe vortex occured at the corner of the pressure surface at about half chord,causing more flow blockage and turbulence.The variations of axial,tangential and radial turbulence intensities were similar,and the tangential turbulence intensity was the highest of the three components.
3-D Turbulent Characteristics of the Tip Leakage Vortex inside an Axial Compressor Rotor Passage at a Low Mass-Flow Condition
MA Hong-wei, JIANG Hao-kang
2000, 15(4): 347-352.
Abstract PDF(383KB) icon2007 icon423
Abstract:
Three-dimensional turbulent characteristics of the tip leakage vortex inside an axial-flow compressor rotor passage were studied using a 3-Component Laser Doppler Velocimetry.The measurements were conducted in a low-speed large-scale compressor at a low mass-flow condition.The flow was surveyed across the entire passage at fifteen axial locations (leading edge to trailing edge) and twelve radial locations (0.985 to 0.700 spans).The measurement results indicated that strong interactions of the tip leakage vortex and the annulus-wall boundary layer produce high turbulence.The region of high turbulence develops with the leakage vortex.The radial turbulence intensity is the largest of the three components,and the axial-radial Reynolds stress is the largest of the three shear stresses.Breakdown of the leakage vortex happens at about 80% axial chord and makes the downstream flow more turbulent in the larger region.The corner vortex contributes to the high turbulence level at the corner of the tip suction surface.
Numerical Simulation of Meridional Divergence on Vortex Structure in Turbomachinery
WU Meng, WANG Song-tao, WANG Zhong-qi, FENG Guo-tai
2000, 15(4): 353-356.
Abstract PDF(282KB) icon2197 icon416
Abstract:
The flow field in low pressure turbine guide vane was simulated by third order accuracy Godunov scheme with TVD property.The turbulence model was the combination of B-L algebraic model and MML model.A feature of this guide vane was existence of a long inlet duct with big meridional divergent angle in order to fulfill the requirements of the structure.The numerical simulation and analysis of the vortex structure in flow field indicated that a large separated zone resulted from the divergence of meridional profile.The separated zone not only increased loss before the stator but also increased the size and strength of horseshoe vortex and passage vortex.
Mathematical Model to Simulate Centrifugal Compressor Performance in Design and off-Design Regimes
YANG Ce, MA Chao-chen, LAO Da-zhong
2000, 15(4): 357-360.
Abstract PDF(271KB) icon2392 icon412
Abstract:
A rapid and simplified mathematical model used to simulate the centrifugal compressor was developed.In the mathematical model,the compressor is divided into several sections,and the parameters in the sections are calculated using iterative method.The stagger grid is used in the region between the impeller exit and diffuser inlet to guarantee accurate simulation.Predicted compressor performance is compared with experimental data for Krain's compressor.The predicted results using 3-D Navier-Stokes equations are also presented for comparison.It is shown that the mathematical model can properly simulate the centrifugal compressor performance.
Effects of Meridional Divergence on Vortex Evolution in Annular Cascades
AN Bai-tao, HAN Wan-jin, LU Wen-cai, WANG Zhong-qi
2000, 15(4): 361-365.
Abstract PDF(340KB) icon1937 icon472
Abstract:
The flow process of concentrated vortex occurrence and development was investigated in the meridian with considerable divergence.The distributions of aerodynamic parameters along pitch and span in the 12 measurement sections were surveyed.The results show that the divergence of the diffused meridian passage thickens the inlet boundary layer,so saddle point separation intensifies,and pressure side and suction side branches of high-strength and large-scale horseshoe vortex are formed,low energy gas around them enhances the paired effect,delays the formation and development of passage vortex.The strength and scale of passage vortex are proportional to the divergent angle of the passage.Due to the influence of radial positive pressure gradient,low-energy gas moves along trailing area to hub.That causes rapid dissipation and weakening of downstream passage vortex.
Experimental Study of Two-Phase Flow Field in Combustor Head
GU Chong-bin, XU Hang, GUO Zhi-hui, LI Ji-bao, XU Hua-sheng
2000, 15(4): 366-370.
Abstract PDF(321KB) icon1895 icon412
Abstract:
Characteristics of Two-phase flow in combustor head have been researched experimentally with the help of Phase Doppler Analyzer.The distributions of mean velocity and fluctuating velocity,drop size and flux of spray have been measured.The detailed structure of spray in primary zone of combustor has been analysed.The results reveal the real flow field in the combustor head.
Application of Characteristics Method to Aerospike Nozzle
DAI Wu-ye, LIU Yu
2000, 15(4): 371-374,380.
Abstract PDF(321KB) icon1962 icon491
Abstract:
The Method of Characteristics (MOC) was applied to the aerospike nozzle.Some particular cases of the aerospike nozzle boundary conditions,expansive wave,oblique shock wave,and so on were considered.Typical flow fields of the aerospike nozzle were obtained.A method of thrust calculation was proposed.The results computed were compared with the experimental data.It is shown that the method is reliable and effective.
Experiments of Impinging Cooling in Leading Edge of Rotating Blades with Outflow Film
WU Hong, TAO Zhi, XU Guo-qiang, DING Shui-ting
2000, 15(4): 375-380.
Abstract PDF(387KB) icon1859 icon394
Abstract:
The heat transfer characteristics of turbine blade model with outflow film under rotating state were researched experimentally.The experimental results indicated that the heat transfer was enhanced with increasing of Reynolds number obviously,but the increases in the blade leading and trailing edges were different.The effect of buoyancy force was complicated in the process of heat transfer.The effect of rotation is inconspicuous at small Reynolds number,but at high Reynolds number,the effect of rotation weakened the heat transfer.The interaction of the factors in the flow field affected the heat transfer,so the rule of the heat transfer was complicated.
Experimental and Numerical Investigation of Internal-Flow Resistance Characteristics in Laminate Porous Plate
DONG Zhi-rui, YU Xing-hua, LIU Song-ling, YOU Sao-kun, XU Du-chun
2000, 15(4): 381-386.
Abstract PDF(599KB) icon1821 icon435
Abstract:
The internal flow resistance of 12 amplified model laminate plates was tested in a small-size suction-type wind tunnel.The influences of some factors,such as single/double-layer,the patterns of pin fin arrays and internal flow patterns (including open-hole ratio),on internal flow resistance were studied.The calculation method of internal flow resistance in laminate porous plates was researched to satisfy the design requirement.The test conditions were taken into account.The comparison of the calculated results with the test data shows consistency of the both.The test data and the calculation method can be used for the cooling construction design of laminate porous plates.
The Adiabatic Film Effectiveness of the Double Wall with Inclined Multihole and Discrete-hole for Combustor Liner
XU Quan-hong, ZHANG Bao-hua, LIN Yu-zhen, LIU Gao-en
2000, 15(4): 387-390.
Abstract PDF(278KB) icon2262 icon436
Abstract:
The adiabatic wall film cooling effectiveness of double wall with impingement of cooling air through discrete-hole wall to the inclined multihole wall were investigated experimentally,on the basis of the heat-mass transfer analogy.The mass transfer measurements were conducted for film cooling mass flow ratios ranging from 0.5 to 2.0,different hole pitch-to-diameter ratios,and the spacing of double wall.Finally,the formulas for five different structures of double wall were fitted by the least square method according to the distribution of average lateral adiabatic wall film cooling effectiveness.The results of the investigation show that the adiabatic wall film cooling effectiveness is affected very little by the distance between the double wall for the same blowing ratio and the same geometry of the inclined multihole wall.But its distribution is determined mainly by the blowing ratio and the hole arrangement of the inclined multihole wall.The long rhombus hole arrangement of the inclined multihole wall is a better way in view of the adiabatic wall film cooling effectiveness.
Experimental Study on Performance of Air Cooling/Atomizing Fuel Injector Bar in Afterburner
BAI Xing-yan, ZHANG Pin-jie, YUE Lian-jie, YANG Mao-lin
2000, 15(4): 391-396.
Abstract PDF(365KB) icon1771 icon428
Abstract:
An air cooling/atomizing fuel injector bar is developed for afterburner.It not only can lower the wall temperature of the fuel injector bar,but also has the ability of air atomizing.Its comprehensive performance in cooling,atomizing and combustion was studied experimentally.The temperature indicating paint and thermal infrared imager were used to measure the wall temperature of the fuel injector bar.The cooling experiment shows that a very good cooling effect can be reached with this new design.When less than 2% of the compressor outlet air is used for cooling,the bar's surface temperature can be decreased by 100 K to 200 K in 1300 K high temperature gas flow.Results of the atomizing experiment obtained from the PDA measuring system show that a much better fuel spray quality can be achieved with the new design.The SMD is obviously decreased and the spray uniformity is considerably improved.Due to its matching with the V type flame holder,the combustion experiment demonstrates that flame lean extinguishing limit can be widened two or three times and the combustion efficiency is much higher too.Therefore its comprehensive performance is enhanced,and the new design is effective and feasible.
Numerical Simulation of Two-Phase Turbulent Combustion in a 3-D Afterburner
ZHANG Cheng, YE Tao-hong, CHEN Yi-liang, HE Jia-de, ZHAO Zhou-bing
2000, 15(4): 397-400.
Abstract PDF(292KB) icon2151 icon433
Abstract:
The two-phase turbulent combustion in a three dimensional afterburner for a turbofan aeroengine was numerically investigated.The afterburner had two ring flame stabilizers and two rows of radial flame stabilizer.The two-fluid model was used for the two-phase flow.The standard k-ε turbulence model was employed.The average chemical reaction rate was approximated by the Eddy-Break-Up (EBU) model.The calculation was performed using the LEAGAP algorithm. The results indicated that the afterbuner was designed reasonably,and the combustion in it was quite good.
Coupling Vibration Analysis of a Particular Turbine Rotor
CHENG Tao, ZHANG Jin
2000, 15(4): 401-404.
Abstract PDF(274KB) icon1298 icon421
Abstract:
The coupling vibration behaviors of a particular turbine rotor have been analyzed.The blades of the system were made of single-crystal nickel-based alloy and the disc was made of high temperature alloy of powder metallurgy.Therefore,the properties of these two kinds of materials were considered.The multi-coupling vibration of the rotor was studied comprehensively and the unique modal shapes were exhibited by the post-processing.Useful conclusions were derived for engineering application.
Experiments of Partial and Full Rotor/Stop Rubbing
DAI Xing-jian, ZHANG Xiao-zhang, JIN Zhao-xiong
2000, 15(4): 405-409.
Abstract PDF(324KB) icon1914 icon418
Abstract:
The vibration of a flywheel rotor with rotor/stop rubbing was investigated experimentally.The large amplitude of the rotor vibration was excited by the electromagnetic harmonic excitation force and thus caused the rubbing between the rotor and the stop.The rubbing force and its effects on the rotor were analyzed.The partial rubbing rotor vibration indicated that the inner type stop can limit the amplitude of asynchronous precession effectively.During the partial rubbing,the rotor/stop collision and rubbing appear occasionally.The partial rubbing has little effect on the rotating speed of the rotor.The partial rubbing will expand to full rubbing as the amplitude of the excitation becomes great enough.During the full rubbing,the rotor keeps contact with the stop and whips in a high frequency.The continuous friction makes rotating speed of the rotor drop sharply.
Dynamic Optimum Design of Power Shared out Equally Among the Planetary Gears
YUAN Ru, WANG San-min, SHEN Yun-wen
2000, 15(4): 410-412,418.
Abstract PDF(415KB) icon2167 icon480
Abstract:
The supporting stiffness of the floating parts has great effects on the power shared out among planetary gears and on the dynamic load on the meshing gears.A dynamic model of 2K-H planetary gear train has been developed.The factor Kc and factor Kd are introduced for measuring the unbalance of power and dynamic load.For the purpose of reducing the unbalance of power and the dynamic load,a dynamic optimum method is used to determine the supporting stiffness of the floating parts.The dynamic characteristics of planetary transmission designed by optimum method have been analyzed.It is found that the values of Kc and Kd are fairly small.
Study on Nonlinear Dynamic Behavior of Rotor-Non-Circular Bearing System
JIAO Ying-hou, CHEN Zhao-bo, XIA Song-bo, CHEN Ming, HUANG Wen-hu, ZHANG Zhi-ming
2000, 15(4): 413-418.
Abstract PDF(535KB) icon1650 icon487
Abstract:
The nonlinear dynamic bifurcation behavior of a rigid Jeffcott rotor-non-circular bearing system was investigated in a wide rang of parameters based with the help of Runge-Kutta method,Poincaré map and frequency spectrum.The journal bearing oil film forces were obtained from database.The diagrams of bifurcation,time course,frequency spectrum,phase and Poincaré map diagrams with some typical system parameters were numerically worked out.The results show that there exist abundant nonlinear dynamic behaviors such as double-period bifurcation,Hopf bifurcation,jump phenomenon,K-T periodic solution,quasi-periodic and chaotic motions and so on.The database method can provide the journal bearing oil film forces accurately and effectively for nonlinear dynamic analysis of rotor-non-circular bearing system.
An Experimental Investigation on Acoustically Excited Jet Flow
ZHAO Hong, WU Nai-ming, ZHENG Ke-yang
2000, 15(4): 419-422.
Abstract PDF(283KB) icon1342 icon427
Abstract:
The mechanism of acoustically excited jet flow has been investigated experimentally.The variation rule of jet parameters was derived from various operating conditions of jets excited by different acoustical wave parameters.The flow-visualization images were obtained.The result indicated that the length of jet core section was decreased,the width of mixing section was increased,and the ambient air was entrained strongly by the jet due to the pulsed jet with acoustic waves.These effects are beneficial to the augmentation of ejector thrust and to decreasing of temperature on the nozzle wall,also to the distribution of infrared radiation intensity.
CANG Zeng-chan, JIANG Yong, KONG Wei-dong, ZHANG Bai-ling, ZHANG Fa-qi, LI Jun, ZHUANG Chuan-xin
2000, 15(4): 423-426.
Abstract PDF(479KB) icon1657 icon460
Abstract:
Simulation of Vector Thrust Control Flight
WANG Li-feng, ZHANG Jin, TANG Hai-long
2000, 15(4): 427-430.
Abstract PDF(99KB) icon1706 icon413
Abstract:
A simulation about vector thrust control flight was completed.On the basis of aircraft model and propulsion model, post stall flight simulation on routine engine control and engine stability control was accomplished.The results verify feasibilily of the vector thrust control flight.
Stability of a Rotor System on Support of Anisotropical Rigidity and Partially Filled with an Inviscid Fluid
ZHU Chang-sheng
2000, 15(4): 431-434.
Abstract PDF(266KB) icon1633 icon432
Abstract:
The stability of rigid rotor on support of anisootropical rigidity with a cavity chamber partially filled with fluid was studied on the basis of a two-dimensional inviscid rotating fluid model.The effects of the system parameters,such as fluid fill ratio,mass ratio,external damping and support anisotropical rigidity ratio,on the instability of the rotor system were considered.It is shown that there probably exist two unstable regions of the rotational speeds that correspond to the two critical speeds of the rigid rotor system.However,the anisotropical rigidity of the support does not always result in occurring two unstable regions of rotational speeds.The possibility of their occurrence also depends on other system parameters.Since the anisotropical rigidity of support always makes the unstable region of rotational speeds increase,it is suggested that the support of anisotropical rigidity should be avoided as possible.
A Gear System Identification Method Based on Higher Order Cumulants
SHAO Ren-ping, CHEN Li-qun, SUN Jin-cai, SHEN Yun-wen
2000, 15(4): 435-438.
Abstract PDF(274KB) icon1668 icon442
Abstract:
A gear transmission system exhibits a coupling nonlinear vibration due to the nonlinearity of gear meshing,bearing and gearbox supporting system stiffnesses incorporated with the modulating of gear and bearing as well as the nonlinear coupling of rotary wings.The dynamic signals of the system appear of complicated non-Gauss and nonlinear characteristics.A new method of modern signal processing-the higher order cumulant was adopted.The nonlinear modulating characteristics of the system were monitored by determining the dynamic response of the transmission system and helicopter rotary wings.The dynamic natural frequencies of the transmission system and the rotary wings were obtained by analyzing in the cumulant domain.Its comparison with the power spectrum method and the time-series analysis (ARMA) identification Method shows that the higher order cumulant method is supperior in noise inhibiting,higher identification accuracy and nonlinear characteristic extracting of the system.
Experimental Investigation of Ejector with Main Flow Inclined
ZHANG Kun-yuan, XU Hui, SHEN Ping-yuan, XU Qi-qiang, NIU Yan-yun
2000, 15(4): 439-441,438.
Abstract PDF(273KB) icon1802 icon410
Abstract:
Four ejector models designed with changeable main flow angles were investigated experimentally under four back pressure and five flow angles.The results indicated that the ejection coefficient N of the model with constant cross section was higher than the model with diffusion inlet.The maximum N of 3.379 was measured from model 4.It was found that the model 4 has a favorable performance among the tested four models.

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