2010 Vol. 25, No. 12

  Previous Issue | Next Issue 
Display Method:
Numerical simulation of the effect of blade tip blowing on a low speed axial compressor tip clearance flow
DAI Li-ping, ZHANG Hui, KANG Shun
2010, 25(12): 2643-2649.
Abstract PDF(1169KB) icon1761 icon413
Abstract:
To understand the comprehensive effects of blade tip blowing,the flow fields of a low speed axial compressor cascade with/without blade tip blowing were simulated and analyzed.The results show that both blowing positions and blowing directions have important effects on tip leakage flows.Though blowing in radial and circumferential direction can change the distribution of tip leakage flow rate density,it is little beneficial to the stability improvement;blowing in axial direction can suppress the separation due to tip leakage vortex and then improve stall margin effectively.
Experimental research on unsteady blade surface pressure of axial compressor
WANG Ying-feng, HU Jun
2010, 25(12): 2650-2655.
Abstract PDF(949KB) icon1894 icon408
Abstract:
The unsteady surface pressure on stator blade of an axial compressor was measured by means of mounting micro-sensors onto blades surface.The unsteady blade surface pressure was analyzed.There are different factors to play decisive roles on the unsteady surface pressure and unsteady force with the decrease of flow coefficient.Before stall,unsteady blade surface pressure depends on the wake and potential perturbation of adjacent blade row.But after stall,unsteady blade surface pressure depends on the stall cells.Before stall,maximum amplitude of unsteady blade surface pressure and unsteady force occurs at the flow coefficient of maximum total pressure rise.However,after stall,the amplitude of unsteady surface pressure and unsteady force will be much greater than at the maximum total pressure rise.On the other hand,the frequencies of unsteady surface pressure and unsteady force change with the decrease of flow coefficient.Before stall,the dominant frequencies are represented by blade-passing frequency and its harmonics,but after stall,the dominant frequencies are represented by stall cell passing frequency.
Surge detection of an axial compressor based on statistical characteristics
LI Chang-zheng, XIONG Bing, HAN Wei
2010, 25(12): 2656-2659.
Abstract PDF(788KB) icon2360 icon430
Abstract:
By analyzing 36 groups test data of four models axial compressors, it’s found statistically that the root mean square (RMS) of pulsation of compressors outlet total pressure is subject to normal distribution;the RMS and its standard deviation vary from different models and/or working speeds.An automatic threshold surge-detecting on-line system was designed based on statistical characteristics.Experiments demonstrate that alarm signals can be given at the time of surge.This method is simple in calculation,and has great value in engineering application.
Three-dimensional aerodynamic optimization for the two-stage axial-flow fan based on work distribution
HE Liu, SHAN Peng
2010, 25(12): 2660-2672.
Abstract PDF(1675KB) icon1687 icon463
Abstract:
By integrating genetic algorithm with response surface methodology,this paper developed an optimization system,with introduction of a quasi-three-dimensional through-flow design code and a blade formatting code.While a three-dimensional CFD (computational fluid dynamics) solver was involved,this paper established a numerical aerodynamic optimization platform for three-dimensional blades of axial-flow compressors.The optimization in this paper mainly has four features.First,it applies the conventional inverse design method instead of common CAGD (computer aided geometric design) parameterization method to generate a three-dimensional blade.Second,it chooses aerodynamic parameters with physical meaning as optimization design variables instead of purely geometrical parameters.Third,it presents a stage-by-stage optimization strategy about the multistage turbomachinery optimization.Fourth,it introduces the visual analysis method into optimization.The above techniques were applied,first,to a two-stage axial-flow fan for its maximum mass flow rate,and then,to the reformed two-stage axial-flow fan for its maximum adiabatic efficiency.The work distributions were taken as design variables,which were parametrically represented by means of Bézier curves.The two examples elucidate that not only the techniques mentioned above are appropriate and effective in engineering,but also the design guidance for similar inverse design problems can be obtained from the optimization results.
Development of tip leakage flow in NASA Rotor 37 and casing treatment
HUANG Xu-dong, CHEN Hai-xin, FU Song
2010, 25(12): 2673-2682.
Abstract PDF(1785KB) icon2155 icon398
Abstract:
Based on the detailed computational fluid dynamics (CFD) study on the structure and development of tip leakage flow in NASA(National Aeronautics and Space Administration) Rotor 37,the stall mechanism was discussed.A study of the circumferential grooves casing treatment with different locations,depth and width was also performed.The simulation reveals that the large separation zone at the trailing edge near the blade tip is directly attributable to the compressor stall at the configuration studied in this paper.As a result,the circumferential grooves at the mid-chord and the trailing edge appear to be effective on the extension of the stall margin.Meanwhile,it is found that the depth of the grooves does not influence obviously its effect,while the width seems to be a more important parameter.
Influence of turbulence models on simulation of a compressor
YIN Song, JIN Dong-hai, ZHU Fang, GUI Xing-min
2010, 25(12): 2683-2689.
Abstract PDF(1240KB) icon2143 icon430
Abstract:
A three-dimensional numerical simulation code was developed as a standard three-dimensional viscous flow solver in a compressor.Three turbulence models frequently used in turbomachinery,including:k-ε model,k-ω model and Spalart-Allmaras(S-A) model,were employed in the code to simulate the National Aeronautics and Space Administration (NASA) Rotor 37.The performance parameters,three-dimensional flowfield and hub corner flow structures were compared with the experiment data.The influences of these three turbulence models for simulating compressors in the condition of the same calculating algorithm were compared.The present study demonstrates that k-ω model is superior among these three models for the complicated flowfield with separated,shear flow in a turbomachinery.
Improvement of a micro-turbine nozzle
XUAN Jian-guang, QIU Jian, XIA Chen, HUANG Guo-ping
2010, 25(12): 2690-2696.
Abstract PDF(970KB) icon1834 icon404
Abstract:
The compact configuration and small size of the micro-turbine engine (MTE) cause the large flow loss in the micro-turbine nozzle,so the micro-turbine nozzle has been modified to reduce the flow loss and improve the performance.The numerical simulation of the original turbine nozzle was completed by NAPA program,and the reasons for the low performance were acquired by flow field analysis.The vaned turbine nozzle was improved and the performance comparison between original and improved turbine nozzles was completed.The efficiency of turbine stage at designing point increases by 15%,and the flow rate and efficiency of turbine stage are enhanced remarkably within a wide working range.
Effect of compound boundary layer suction on the performance of a high-load diffusion compressor cascade with a large camber angle
GUO Shuang, CHEN Shao-wen, LU Hua-wei, SONG Yan-ping, CHEN Fu, WANG Zhong-qi
2010, 25(12): 2697-2703.
Abstract PDF(1129KB) icon1748 icon416
Abstract:
The effect of compound boundary layer suction on the aerodynamic performance of a high-load diffusion compressor cascade with a large camber angle was experimentally investigated through ink-trace flow visualization and outlet flow field measurement.Experimental results show that suction on the endwall mainly influences the suction surface corner;suction on the suction surface not only shrinks the endwall corner region,but also delays the transition of the suction surface boundary layer,and improves the flow field around the midspan;the whole flowfield is improved in the case of compound boundary layer suction,and the performance is superior to each of the former two at high suction flow rates as the interaction between the boundary layer of endwall and suction surface is better controlled.
Application of optical pressure sensitive paint measurement technique in internal flow fields
ZHENG Li-xin, HAO Chong-yang, ZHOU Qiang, LIU Bo, CHEN Liu-sheng, JIN Xi-gao
2010, 25(12): 2704-2710.
Abstract PDF(1077KB) icon1694 icon380
Abstract:
A series of experimental pressure measurements inside internal flow fields employing the intensity-based method of pressure sensitive paint technique were depicted based on self-established optical pressure measurement system and indigenously developed pressure sensitive paint.These experimental measurements include the applications inside both the transonic cascade wind tunnel and the nationally unique axial dual counter-rotate compressor facility (ADCCF) of Northwest Polytechnical University (NPU).The test articles involved a single vane of a large bending angle in transonic cascade wind tunnel and the oriented vane inside ADCCF,and both the surfaces of interest were correlated with the suctions.The traditional pressure measurement using electronic pressure scanning has been simultaneously conducted in the cascade wind tunnel for comparison.The contrast of both results from optical pressure measurement and electronic pressure scanning has revealed that the feasible application of optical pressure measurement system in internal flow fields and in practical industrial engineering.
Effect of inlet wake angle on compressor stator loading
YANG Rong-fei, LI Qiu-shi, LI Zhi-ping, ZHOU Sheng
2010, 25(12): 2711-2715.
Abstract PDF(922KB) icon1673 icon380
Abstract:
With increase of the compressor loading,the blade surface boundary layer was easily separated but suppressed by unsteady upstream wake.In this paper,moving cylinder was used to produce unsteady wake,and different inlet wake angles were acquired by changing moving speed.This shows that the performance of stator will be improved on high blade loading while it varies little on low blade loading as the inlet wake angle increases.During the interaction of wake and boundary on high blade loading,increasing inlet wake angle will enhance the energy exchange between wake and boundary layer,which is a main factor to suppress the separated boundary layer and reduce the stator loss.
Effect of numerical dissipation and extended-grid on sound propagation in computational fluid dynamics
ZHAO Lei, QIAO Wei-yang
2010, 25(12): 2716-2720.
Abstract PDF(858KB) icon1451 icon403
Abstract:
A sinusoidal acoustic wave with known dispersion-relation was propagated through a two-dimensional duct using a finite-volume scheme,showing that a rough estimate of around 40 points per wavelength under second order accuracy was sufficient to preserve the wave.Adding an extended coarse grid out of the computational region could reduce the unwanted boundary reflection.A guideline of the extended- grids length and axial size for the good effect of absorbing the boundary reflection with less computation was provided.
Kinematic analysis and digital visualization of secondary flow in curved square passage
LIU Qing-long, DAI Bin, DAI Ren, CHEN Kang-min
2010, 25(12): 2721-2727.
Abstract PDF(1164KB) icon1643 icon392
Abstract:
The equation between secondary flow and vorticity was established through kinematic analysis.One method of digital visualization for secondary flow in curved passage was presented.Secondary flow velocity can be obtained from cross section normal vorticity.Some advantages of this method are below:the equation describes secondary flow as vortices.The influence of potential flow is eliminated.Quantizing secondary flow field can be figured out.More complicated secondary structure is observed.The visualization is more accurate than representation of velocity vector,and doesn ’t depend on the normal direction of cross section.
Method based on wavelet sigularity analysis for complicated flow and its application
WANG Bao-guo, WU Jun-hong, ZHU Jun-qiang
2010, 25(12): 2728-2747.
Abstract PDF(2647KB) icon1635 icon423
Abstract:
Three-dimensional and two-dimensional wavelet sigularity analysis was introduced in complicated flow and a high-order,high-resolution numerical method was developed.The core of this new method is the analysis of Hlder exponent α of complicated flow.The Hlder exponent α depends on wavelet transform and multi-dimensional wavelet analysis.In order to complete the multi-resolution analysis in two-dimensional and three-dimensional Euclidean space,scale basis and wavelet basis have been introduced in scale space and wavelet space.For two-dimensional and three-dimensional cases,scale basis and wavelet basis were constructed by one scale function and by three wavelet functions and seven wavelet functions respectively.High-resolution,high-order WENO (weighted essential non-oscillatory) scheme and high-order central difference scheme can be chosen adaptively according to the results of wavelet sigularity analysis.A series of examples in two-dimensional ( (1) forward facing step problem, (2) double Mach reflection of a strong shock problem, (3) two-dimensional Riemann problem, (4) two-dimensional transonic flow past RAE2822 airfoil problem, (5) two-dimensional transonic VKI-LS 59 turbine cascade flow problem) and three-dimensional ( (6) transonic axial compressor,NASA (National Aeronautics and Space Administration) Rotor 37 three-dimensional viscous flow and (7) NASA Rotor 67 three-dimensional viscous flow) were computed.The computation results have been compared with the experiment results in related references and showed that this new numerical method can not only improve the computation efficiency significantly(the efficiency can be increased by 3~5 times for most examples),but also capture the shock with high-resolution and vortices with an acceptable order.
High enthalpy wind tunnel tests of hypersonic inlets with rectangular section
YUAN Hua-cheng, GUO Rong-wei
2010, 25(12): 2748-2755.
Abstract PDF(1076KB) icon1803 icon488
Abstract:
Preliminary test study was conducted for hypersonic inlets with rectangular section at Mach number of 6,5 and 4 in a high enthalpy wind tunnel.The inlet could be started within the range of the Mach number 4.5 and 6.5.The performance and static-pressure distributions of the inlet under different back-pressure conditions were obtained.Results indicate that,at design condition(Ma=6,α=0°),the mass flow capture rate and mass-averaged total pressure recovery coefficient are 0.97 and 0.41,respectively;at the exit section of the isolator,the average Mach number is less than 2.6,the pressure rise and maximum back-pressure are 35 and 141.52 times of upstream pressure.The shock train formed by back-pressure rising can be kept in the inner tunnel,without affecting the mass flow capture rate.The mass flow capture rate is not less than 0.77,and the mass-averaged total pressure recovery coefficient varies between 0.49 and 0.67 at Mach number of 5 and 0° angle of attack.In the non-back-pressure status,there is no obvious flow separation in the flow inlet field of the inlet.
Study of modifying helicopter inlet containing output shaft
WANG Ming-sheng, HUANG Guo-ping, FU Xin, YOU Yan-cheng
2010, 25(12): 2756-2762.
Abstract PDF(1293KB) icon2051 icon408
Abstract:
A typical helicopter inlet containing output shaft was studied by three-dimensional turbulent numerical calculation code NAPA in this paper.The inlet was redesigned by modifying the curvature of upwind side of the inlet and adding an optimal spike on the backward of output shaft,and then simulated using NAPA program.The results show that,as output shaft blocks the flow path in the original inlet,there is a large separation zone behind the shaft and a turn loss in upwind of the shaft,thus inducing a serious distortion in the inlet.By modification,the separation zone behind the shaft and turn loss at upwind side are reduced.Modifying inlet maintains high pressure recovery,and the distortion index is reduced by 74% at most.
Numerical simulation on flow field of the clamshell thrust reverser with landing flap deployed
LIU Chun-yang, WANG Zhan-xue, WANG Jia-qi, YIN Fang, KONG De-ying
2010, 25(12): 2763-2769.
Abstract PDF(1564KB) icon2026 icon409
Abstract:
Computational fluid dynamics (CFD) technology was used to investigate the flow field distribution characteristic of a clamshell thrust reverser with landing flap deployed.The computational grid was generated with unstructured tetrahedron and hexahedron meshes,and Spalart-Allmaras (S-A) turbulent model based on solving Reynolds-averaged Navier-Stokes (RANS) equations was adopted.The results show that,in the range of landing speed,the hot reverse exhaust flow from the clamshell thrust reverser is not re-injected into the engine inlet,but it impinges on part of the aerofoil and pylon.As landing speed decreases,the hot reverse exhaust flow spreads forward and laterally deeper,so it may be re-injected by near engine inlet if the aerofoil sweepback is large enough,resulting possibly in inlet distortion.When landing speed decreases down to 34m/s,the hot reverse exhaust flow starts to impinge on the ground,which may wind up some dross to the inlet.At last,the reverse thrust decreases as landing speed decreases.
Characteristic of double-jet film cooling tested by pressure sensitive paint
HAN Chang, LI Jia, LI Xue-ying, REN Jing, JIANG Hong-de
2010, 25(12): 2770-2778.
Abstract PDF(1240KB) icon1724 icon420
Abstract:
The characteristics of the film cooling system with double-jet,round and shaped holes were investigated under the condition of mainstream turbulence 6% and blowing ratio 0.5,0.8,1.0,1.2,1.5 in the study.The pressure sensitive paint (PSP) was implemented in the tests as the main measurement technique.The film cooling effectiveness decreases between blowing ratio 0.8 and 1.5 in the case of round holes,but increases in the whole experimental blowing ratio in the case of shaped holes and double-jet.It indicates that the double-jet restrains the lift-off of the cooling jet.The film cooling effectiveness of double-jet is better than that of the round holes,but poor than that of the shaped holes in the same conditions.Meanwhile,the vortex structures near the three focused holes obtained from the corresponding computations are major causes of the characteristics of the investigated film cooling systems.
Experimental investigation of heat transfer and pressure drop in a two-pass internal coolant passages of gas turbine airfoil
CHEN Wei, KAN Rui, REN Jing, JIANG Hong-de
2010, 25(12): 2779-2786.
Abstract PDF(1144KB) icon1959 icon377
Abstract:
An experimental investigation was conducted to assess the heat transfer and pressure drop distribution of a two-pass channel with a round turn.The Reynolds numbers investigated varied from 30000 to 55000.This demonstrates that the secondary flow induced by ribs is the main factor to enhance the heat transfer before turn region.Under different Reynolds numbers,the trend of heat transfer and pressure drop distribution in the duct is consistent.However,the heat transfer in the after turn region is different.Moreover,the largest pressure drop occurs in the turn region.As the Reynolds number increases,the loss coefficient of the turn and the whole duct will decrease.Compared with two-pass channel with a sharp turn,the heat transfer in the turn region and after turn region in this study is lower,because the acceleration effect in the round turn region is not as strong as that in sharp turn.
Effect of ratio of height to width of lobe on the performance of a lobed mixer in a forced mixing exhaust system
XIE Yi, LIU You-hong
2010, 25(12): 2787-2794.
Abstract PDF(1083KB) icon1960 icon410
Abstract:
Geometric and numerical simulation models of lobed mixer with variation of the ratio of height to width (h/b) of lobe were created based on a lobed mixer in the forced mixing exhaust system of turbofan engine with constant lobe number and lobe length.Though three-dimensional numerical simulation,the principle of the effect of different ratios of height to width in a forced mixing exhaust system was obtained.The results show that at the exit section of the force mixing exhaust system,when the width of lobe is constant,the thermal mixing efficiency rises as h/b increases;however,when the height of lobe is constant,the mixing efficiency declines with rise of h/b.Besides,as h/b augments,the total-pressure recovery coefficient decreases if the width of lobe is unchanged,or increases if the height of lobe is invariable.
Investigation on heat transfer of confined and submerged water jet array impingement on pin-fin heat sinks
YANG Rui-bo, XIA Guo-dong, CHAI Lei
2010, 25(12): 2795-2801.
Abstract PDF(1011KB) icon1655 icon389
Abstract:
The thermal performance of pin-fin heat sinks with confined and submerged liquid water jet array impingement was investigated experimentally.The experimental results indicate that:the performance of heat sinks is closely related to the height of the pin-fin,but not the higher the better;Nusselt number is represented by pyramidal distribution in 0.625≤W/G≤1.000 ;for the confined and submerged jet arrays a strong dependence on both jet-to-target and jet-to-jet spacing can be observed,and Nusselt number falls continu ously between 2.5≤H/d≤10.0 ;an increment in jet-to-jet spacing between 3.00~4.50 can be found to decrease Nusselt number when Re<4000;a reduction in jet-to-jet spacing between 4.50~7.00 can be found to decrease Nusselt number rapidly,especially for high Reynolds number.The thermal resistance of heat sinks will decline with the increase of pump power,but then change slowly.
Creep of Ni-based single crystal superalloy: finite element analysis of blade creep
YANG Xiao-guang, BAI Lu, SHI Duo-qi, YU Hui-chen
2010, 25(12): 2802-2806.
Abstract PDF(866KB) icon1690 icon420
Abstract:
This paper is the third part of the research on creep behavior of single crystal superalloy. A UMAT subroutine of ABAQUS based on the creep model was developed. The first order blade of a turbine was chosen as the simulating model. The DD3 creep data and the real temperature field was used to analyze the influence of crystal orientations to the blade creep behavior though defining different crystal orientations. At the same time the influence of the deviation of secondary crystal orientation was also analyzed. Consequently the influence of crystal orientations to the blade creep behavior was found. Unlike the material creep behaviors, the dispersion of blade creep behavior is great though 10° deviation of the crystal orientation is controlled.
Method of reliability analysis for time truncated zero-failure data based on Weibull distribution
FU Hui-min, ZHANG Yong-bo
2010, 25(12): 2807-2810.
Abstract PDF(730KB) icon2050 icon414
Abstract:
It is an outstanding problem in engineering application to solve problems related to time truncated zero-failure data. In this paper, a method of reliability analysis for time truncated zero-failure data based on Weibull distribution was presented, which can making an high confidence assessment for the reliability of product with time truncated zero-failure data when the lower limit of shape parameter and the one-side lower confidence limits of reliability and life were provided. Large mount of Monte Carlo simulation results show that this method can combine the zero-failure data that contributing to Weibull distribution together and make full use of information of time truncated zero-failure data, the precision of forecasting is obviously improved. The method introduced in this paper was used for analyzing the time truncated zero-failure data provide by the life test of one kind of high pressure vessel.
Real-time performance reliability prediction for civil aviation aircraft engines based on multiple performance measures
REN Shu-hong, ZUO Hong-fu
2010, 25(12): 2811-2815.
Abstract PDF(805KB) icon1810 icon479
Abstract:
The civil aviation aircraft engine was studied in this paper,and the performance reliability of the engine was also studied by use of performance degradation theory.Firstly,by analyzing the performance degradation process of the engine,the time-varying performance degradation model based on state space method was built,and the performance trends were predicted by using Kalman filtering.Then,considering the correlation of multiple performance parameters,the real-time performance reliability prediction model was developed by using stochastic process theory to predict the degradation time of engines.These models were applied to practical situations.It shows that the proposed methods are feasible and the prediction accuracy meets the needs of the project.Also,it provides a foundation for scientific management of engine fleet of airlines.
Simulation of turbofan engine main fuel control system based on AMESim
REN Xin-yu, WANG Jian-li, ZHAO Xiao-long
2010, 25(12): 2816-2820.
Abstract PDF(872KB) icon2208 icon420
Abstract:
Based on the AMESim simulation environment,a turbofan engine control system simulation platform was developed.Using the modularization modeling method,the system was subdivided into different subsystems,such us sensors,fuel system,electronic controller,actuators and the engine itself.Every module was built,tested and encapsulated into the aero-engine control system module library.With the module library,the engine system model could be established easily.Taking main fuel control system,for example,the modularity modeling methods was described.The results show that system model can reflect the complex integration and coupling of subsystem.Combinatorial optimization using system model can improve the system capability.
Terminal sliding mode controller for aero-engine based on RBF neural network
MIAO Zhuo-guang, XIE Shou-sheng, WANG Hai-tao, ZHAI Xu-sheng, ZHANG Zi-yang, SUN Xiao-dong
2010, 25(12): 2821-2826.
Abstract PDF(969KB) icon1726 icon381
Abstract:
A method of terminal sliding mode control was put forward for aero-engine with uncertainty and strong nonlinearity based on radical basis function (RBF) neural network.The method integrated neural network control into sliding mode control.Shortage of traditional exponent reaching law was analyzed,and an improved exponent reaching law was proposed to weaken the chattering.Controller was devised using terminal sliding mode surface.And influence caused by unknown disturbance and uncertainty was compensated by RBF neural network in a real-time manner.Simulation results show that the devised controller has good effect,effectively restrains the influence and weakens the chattering.
Performance simulation analysis for a hydrogen-rich / oxygen-rich shear coaxial gas-gas injector
LI Mao, JIN Ping, CAI Guo-biao
2010, 25(12): 2827-2833.
Abstract PDF(783KB) icon1599 icon367
Abstract:
Based on orthogonal experiment design method,the design parameters of a hydrogen-rich/oxygen-rich shear coaxial gas-gas injector,including the ratio of the oxidizer pressure drop to the combustor pressure(Dp),the ratio of the fuel velocity to the oxidizer velocity(Rv),and the oxidizer post tip wall thickness(Wo),were combined.The flow field of the single injector combustor was simulated.The influences of the injector design parameters and the interaction of the parameters on the combustion performance and heat load performance were studied.Evaluation indexes include:combustion length (Lc),average gas temperature on combustion chamber wall (Tw) and average gas temperature on the injection faceplate (Tf).The results show that,the influence of Rv on the combustion performance and the heat load performance is remarkable.The influence of the interaction of Dp and Rv on the combustion performance and heat load is obvious.The results can provide reliable criterion for the gas-gas injector experiment design.
Effects of hot-gas wall nickelage and cooling channel inflow on regenerative cooling
KANG Yu-dong, SUN Bing
2010, 25(12): 2834-2838.
Abstract PDF(821KB) icon2146 icon392
Abstract:
Three-dimensional numerical simulation was carried out for coupled flow and heat transfer of regenerative cooling channel and coolant in consideration of the cooling channel inflow and hot-gas wall nickelage.The empirical method was used to simulate hot-gas convective and radiative heat transfer;the coolant was methane,whose thermophysical properties varied with both temperature and pressure.The results show that,the secondary flow plus sudden expansion flow field at inflow could lead to increase of local pressure lose and affect the flow and heat transfer situation at a large downstream region;nickelage on hot-gas wall can improve its capacity to endure high temperature and reduce the copper-alloy temperature.
Study and experiments of dynamic mechanism of excited gear lapping of spiral bevel gear
YANG Jian-jun, DENG Xiao-zhong, WEI Bing-yang, FANG Zong-de
2010, 25(12): 2839-2845.
Abstract PDF(965KB) icon1705 icon365
Abstract:
A ten-freedom-degrees dynamic model of spiral bevel gear lapping system was established with the consideration of tooth backlash,transmission error and time-varying meshing stiffness.For the disadvantages of conventional gear lapping method,the excited gear lapping method was introduced in this paper.The dynamic lapping force and normal vibration displacement at meshing point between conventional gear lapping and excited gear lapping were analyzed.The results show that both the drive side and non-drive side of the tooth can be lapped at the same time by applying excited gear lapping method.The results of ultrasonic gear lapping experiment show that the quality of gear face is improved and the gear lapping efficiency is increased.
Study on surface flash temperature for spiral bevel gears under condition of mixed elasto-hydrodynamic lubrication
GU Jian-gong, FANG Zong-de, FU Bi-bo, ZHU Xiao-yuan
2010, 25(12): 2846-2850.
Abstract PDF(895KB) icon1929 icon391
Abstract:
The average friction coefficient in the mixed elasto-hydrodynamic lubrication state was derived from Block flash temperature formula,and the calculation precision was improved.In combination with tooth contact and loaded tooth contact analysis of spiral bevel gears,the flash temperature formula under the condition of actual lubrication state was proposed by calculating the surface curvature radiuses and tangential velocities along the contact point.The results show that,its maximum flash temperature locates in the middle of the approach path,but decreases obviously and the scuffing load capacity is enhanced significantly as the inclination and length of the contact path increase,the actual coincidence degree rises and the load at the contact point reduces.

Copyright © 《Journal of Aerospace Power》 All Rights Reserved.

Supported by: Beijing Renhe Information Technology Co., Ltd.