2007 Vol. 22, No. 1

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Dynamic chaos features auto-extracting technique of non-linear time series
CHEN Guo
2007, 22(1): 1-7.
Abstract PDF(871KB) icon1692 icon431
Abstract:
A new method is put forward,which can implement auto-extracting of chaos features of nonlinear time series.It can directly from non-linear time series compute the chaos features such as delay time,embedded dimensions,correlation dimension,maximum Lyapunov exponents,phase track features and Poincare map features,and the whole features extracting process is carried out automatically without manpower intervention.Finally,examples show the validity and correctness of the new method.The new chaos features extracting method has important meaning to fault diagnosis of nonlinear system by nonlinear chaos feature.
Frequency veering and mode shape interaction for rotating blades
WANG Jian-jun, QING Li-wei, LI Qi-han
2007, 22(1): 8-11.
Abstract PDF(464KB) icon1971 icon425
Abstract:
By the results from direct finite element analyses,frequency veering and mode shape interaction of rotating blade are studied,especially emphasis is placed on the multi-mode frequency veering and shape interaction.Firstly the finite element model of a simple geometry blade is given and the mode shapes and natural frequencies of this simple blade are calculated as a function of rotational speed using the ANSYS finite element program.Then frequency veering and shape interaction for the multi-mode and two-mode of rotating blades are discussed respectively.It is shown that except for the frequency veering problem with two-mode coupling,the multi-mode frequency veering and mode shape interaction of rotating blade are more complicate and must be further researched deeply.
General analysis software of aeroengine lubrication system design
LIU Zhen-xia, HUANG Sheng-qin, Lü Ya-guo, GUO Hui
2007, 22(1): 12-17.
Abstract PDF(992KB) icon1795 icon444
Abstract:
A new General Analysis Software of Aeroengine Lubrication System(GASALS) is presented.The software adopts network algorithm to analyze calculation network of abstracted form for lubrication system.All kinds of aeroengine lubrication systems can be divided into finite correlative elements and nodes from which the calculation network is developed.Typical elements are classified as simple elements and combinative elements,which are convenient for parameter initialization of elements.Graphic modeling and automatic identification technique make complex calculation network easy to be generated.Visual operation interface and backup database are convenient for GASLS users.
Experimental study of real casing containment
FAN Zhi-qiang, GAO De-ping, QIN Zhi-xian, WAN Wei, JI Yong-han
2007, 22(1): 18-22.
Abstract PDF(966KB) icon2131 icon495
Abstract:
In order to investigate an engine casing containment,a casing containment test has been carried out in a spin facility.In this test,interference between adjacent blades has been considered.The rotational speed when the broken blade flings out,and the strain responses of the casing as the broken blade impacts on the casing are described in the paper.At the same time,the impacting process is recorded on the film by a hi-speed camera.The released blade exerted two impacts one after another on the casing.The casing has been broken through at the second impact.The casing is destroyed by shear stress.The casing containment has been calculated using containment-curve methods,and the results are in good agreement with the test results.The study can be used as a reference for the engine casing containment design.
Multidisciplinary optimization design system for turbine blade
WANG Jing-chao, LI Li-zhou, YUE Zhu-feng
2007, 22(1): 23-29.
Abstract PDF(1381KB) icon1904 icon492
Abstract:
An integrated,three-dimensional,multi-disciplinary optimization design system for turbine blades has been set up,which enables the design and analysis of certain blades optimized involving five disciplines.In this system,quintic polynomial is used for parameter modeling of three-dimensional turbine blades,and unit linear interpolation method used for transfer of interdisciplinary load information,while MIGA(Multi-island Genetic Algorithm) and SQP(Sequential Quadratic Programming) are used for overall optimization.The case study shows that, optimization efforts could improve greatly the performance of turbine blades,and the system exhibits higher stability,feasibility and efficiency for engineering applications.
Performance analysis of special cross section rubber seal ring
SUN Jian, CHI Ke-wei, FENG Mao-lin, ZHANG Wen-ming
2007, 22(1): 30-36.
Abstract PDF(1646KB) icon1692 icon446
Abstract:
The response of special cross section rubber seal ring during squeeze and pressurization was studied by non-liner finite element method.A finite element model had been built to approximate the response of an axisymmetric special cross section rubber seal ring in a rectangular joint groove.The deformation and stress distribution during squeeze and pressurization were studied based on the large displacement,incompressible ginite element model with two terms Moone-Rivilin in the strain energy function.Meanwhile,the simulated results were compared with those of general O-ring in the same case.The model is proved to be able to predict the characteristic parameters of deformation and stress of special shape seal rings during pressurization.Deeper understanding of the seal performance is obtained,and it is useful for further designing of this type of sealing structure.
Standardization of description for expert's opinion during weaponreliability evaluation under small sampling test
LIU Qi, WU Xiao-yue, ZHANG Jin-huai
2007, 22(1): 37-40.
Abstract PDF(334KB) icon1860 icon421
Abstract:
Based on the characteristics analysis of expert's opinion in reliability engineering in aerospace field,the article presents the standardization description for three types of fuzzy description,viz.probability description,expert marking method,and subjective language description method.In addition,the prior distribution foundation on expert's opinion was carried out.In this article,the standardization models of general prior distribution,the weighted method based on expert's uncertainty,and maximum entropy method are presented.It is useful for getting the prior distribution from expert's opinion in reliability engineering when filed test data are small samplings and Bayes method is used.
Appl ication of preconditioning method in 3D numericalsimulation of turbomachinery
YAN Ming, ZHAO Qiu-ying, LIANG Lei
2007, 22(1): 41-47.
Abstract PDF(2123KB) icon1861 icon425
Abstract:
A preconditioning technique for solving 3-D compressible Navier-Stokes equations is developed to simulate both transonic and incompressible flows in turbomachinery.Computations over NASA Rotor 67 and a low-speed large-scale compressor stage in Beijing University of Aeronautics and Astronautics were performed and the results are in accordance with experimental data,it shows that the method presented is practical for engineering usage.
Aerodynamic optimization for cascade blade based onNiche GAs and RANS equation
SHU Xin-wei, GU Chuan-gang, YANG Bo, WANG Tong
2007, 22(1): 48-53.
Abstract PDF(758KB) icon1919 icon374
Abstract:
A global optimization method for cascade blade based on Niche GAs(Niche genetic algorithms) coupled with RANS(Reynolds-Averaged Navier-Stokes) equation has been presented.In order to meet the search theory of GAs and the aerodynamic performances of cascade blade,Bezier curve is adopted to parameterize the cascade blade profile in this method,and a fitness function pertaining to optimization is designed.The design variables are the control points' ordinates of Bezier curve representing the cascade blade profile;the object function is the maximum lift-drag ratio of the cascade;the constraint conditions take account of the leading and trailing edge metal angle,and the strength and aerodynamic performers of cascade blade;and the treatment method of the constraint conditions is the flexible penalty function.The lift-drag ratio of optimized cascade is 8.3 percent higher than that of the initial one.
Design and numerical simulation of a transonic swept fan DING Jian2guo,H U Jun
DING Jian-guo, HU Jun
2007, 22(1): 54-59.
Abstract PDF(668KB) icon1715 icon402
Abstract:
The paper employs arbitrary airfoil blade design procedures of turbomachinery to design a transonic wide-chord fan with forward-swept and back-swept blades.In the process of designing,the radial distributions of parameters(such as total pressure ratio,maximum relative thickness and thickness of leading and trailing edges of blade and so on,camber and maximum thickness as a fraction of chord) are adjusted,so that shock intension of blade tip is weakened,the loss of shock is debased,the conflict of high relative Mach number with low loss and high efficiency is overcome.Numerical simulation of core and bypass indicates that,the fan has a higher efficiency over a wider range and better stall margin.
3-D unsteady numerical simulation of fan/compressorwith inlet distortion
ZHENG Ning, ZOU Zheng-ping, XU Li-ping
2007, 22(1): 60-65.
Abstract PDF(1835KB) icon2071 icon430
Abstract:
A fast calculation code for 3-D unsteady inlet distortion was developed for solving 3-D Euler equations with body force.The 3-D unsteady numerical simulation of circumferential fan/compressor with inlet distortion can be achieved through the code.The characteristics of fan with inlet steady total pressure distortion in an aeroengine were simulated and compared with experimental results.It demonstrates that 3-D unsteady inlet distortion of circumferential fan can be simulated by the code with less computer resources.The effects of inlet distortion on fan/compressor can also be simulated accurately.
Preliminary investigation on parametric design method of thetwo dimensional hypersonic inlet
FAN Xiao-qiang, LI Hua, LI Xiao-yu, DING Guo-hao
2007, 22(1): 66-72.
Abstract PDF(634KB) icon1863 icon426
Abstract:
A parametric design method of the two-dimensional hypersonic inlet was established.By analyzing the restriction and sensitivity of the parameters which affect the inlet performance or configuration,five basic geometric parameters were selected for the parametric inlet design.It is indicated that the key performance and the configuration of the inlet are sensitive to the basic parameters selected.The parametric design method provides a practical way for the optimization design of the two-dimensional inlet.
Calculation of airfoil flows using GAO-YONG turbulence equations
REN Xin, LI Bai-he, YIN Xing-yu, GAO Ge
2007, 22(1): 73-78.
Abstract PDF(1032KB) icon2061 icon413
Abstract:
The NACA0012 isolated airfoil at different angels of attack is numerically simulated with SIMPLE algorithm and GAO-YONG turbulence equations.The problem of checkerboard prediction of pressure was cured by evaluating the cell face velocities by the momentum interpolated principle.In order to improve the calculation precision,an orthogonal body fitted coordinate system was selected and a second-order HLAP discretization for the convective part was used.Separated flow structures over the isolated airfoil at different angles of attack and corresponding aerodynamic parameters are presented in details.By comparing with the experimental data and the results of the large-eddy simulation,it shows the GAO-YONG turbulence equations without using empirical coefficients and wall functions successfully simulate the separated flow pattern on the airfoil surface,and accurately predict the location of separation and the aerodynamic force coefficients.In addition,the results of GAO-YONG turbulence equations are better than that of k-ε、k-ω、k-ω sst turbulence models in the software of FLUENT soft.
A mode match method for extracting impedance of liners in flow duct facility
GUAN Ying, WANG Tong-Qing, WANG Li
2007, 22(1): 79-84.
Abstract PDF(659KB) icon1630 icon436
Abstract:
A mode-match method was developed for calculating the sound propagation in two-dimensional lined rectangular flow duct with uniform flow,the prediction results agree well with the data from NASA flow duct facility and CAA calculation.Based on these,an unknown impedance extracting is implemented by applying changed-scales method to optimize object function or by pursuing a minimum of object function in a given region.The two methods are validated by some cases and the effects of random error and the number of input pressure on the results are analyzed.
Building and analysis of ontology based knowledge organizationmodel for aircraft engine design
JIA Di, FAN Xiao-qiang, FENG Ding-hua, LI Hua
2007, 22(1): 85-89.
Abstract PDF(492KB) icon2086 icon429
Abstract:
Firstly configurations of the generic sidewall compression scramjet inlets were introduced and then two kinds of spillage that sidewall compression inlets might occur were introduced.Spillage induced by the back-swept sidewall leading edge is called Configuration Spillage,while spillage evoked by the pressure difference is described as Pressure-Driven Spillage.Parametric analysis of the inviscid effects of leading edge sweep,sidewall compression,width-height ratio,cowl position and inflow Mach number on spillage was carried out.Finally,numerical simulations were performed for a series of inlets at various flight altitude and speed.The research indicates that the area of spillage window,which is mainly determined by the position of the cowl,significantly influences the spillage characteristics of the scramjet inlet.
Design and numerical simulation of a transonic swept fan
CHEN Yong-dang, YANG Hai-cheng, DU Bing-lao
2007, 22(1): 90-95.
Abstract PDF(588KB) icon1789 icon419
Abstract:
In order to realize centralized organizing and management for aircraft engine design knowledge,formulation methods of ontology-based knowledge organization model are presented.This paper studies the structure,design criteria,formulation methods and mapping techniques for knowledge ontology for aircraft engine design and analyzes the characteristics of ontology-based knowledge organization model.The implementation framework of ontology-based knowledge organization model for aircraft engine design was given.The research result is of reference value to application research of knowledge management to aircraft engine design.
Numerical simulation f or tank pressurization system of L RE test-bed
CHEN Yang, ZHANG Zhen-peng, QU Qian, ZHU Zi-huan
2007, 22(1): 96-101.
Abstract PDF(1964KB) icon2117 icon439
Abstract:
A simple model of propellant tank was established by neglecting mass and heat transfer between the propellant and pressurant.Then by employing the modularization modeling and simulation software for liquid rocket engine（LRE） test-bed gas system（LRETBMMSS-GS）,blowdown of a tank and pressurization of a LO2 tank pressurization system during engine firing were simulated.The simulation results are in good agreement with the analytical solution and test data.Accordingly,the software is validated to be effective and versatile.The progress of modeling two systems shows that the method of MMS is suitable for modeling complicated LRE system and can be used to simulate all kinds of working processes of LRE system.The simulation of LO2 tank pressurization system indicates that PID control parameters should be set reasonably and the initial opening of pneumatic diaphragm control valve should be adjusted to nominal pressurant mass rate,which is effective to improve stability of pressurization starting transient.
Bayesian model for missile storage reliability analysisbased on success failure test
LIU Fei, DOU Yi-fang, ZHANG Wei-hua
2007, 22(1): 102-107.
Abstract PDF(510KB) icon1725 icon424
Abstract:
In view of the disadvantages of the classical analysis method for missile storage reliability analysis,a Bayesian model was proposed in this paper.The Dirichlet distribution was taken as prior distribution in the model.The historical information and expert information were synthetically used.Combined with the missile success-failure test data for every stage,the joint posterior distribution of reliability was generated.Then,the Gibbs sampling algorithm was used to compute the posterior inference.The Bayesian estimators and Bayesian lower bound were gained for the reliability of every stage.Furthermore,based on the test data,the model can be used to predict the missile storage reliability.The example shows that the parameters of the Bayesian model have apparent meaning and are convenient to use for engineering applications.
Numerical simulation of f ill ing pipe of cryogenic liquid propellant
GAO Fang, CHEN Yang, ZHANG Zhen-peng
2007, 22(1): 108-113.
Abstract PDF(2109KB) icon2188 icon443
Abstract:
Computational method about the pre-cool filling process in the feed pipe of cryogenic liquid propellant was studied.By using one-dimension homogeneous balance fluid dynamic model and a heat transfer model covering main heat transfer work condition in pre-cooling process,and also taking into account of the compressibility of cryogenic liquid propellant,a finite volume method was used to calculate the pipe flow formula,and a finite difference method used to calculate one-dimension non-steady heat conduction formula of inner pipe-wall.The pre-cool filling process in the feed pipe of cryogenic liquid propellant for a test-bed system of cryogenic liquid rocket engine was computed,while the simulative and experimental results were also analyzed,thus providing a basis for improvement of rocket engine and test-bed system and design of a new system.The simulative results and analytical conclusion have been applied to revamping of existing engine experimental system and design of long-distance liquid hydrogen pipeline.
Effect of aspect ratio on heat transfer and fluid flow in regenerativecool ing channel of liquid rocket engine thrust chamber
WU Feng, ZENG Min, WANG Qiu-wang, SUN Ji-guo
2007, 22(1): 114-118.
Abstract PDF(1729KB) icon1926 icon420
Abstract:
The turbulent fluid flow and heat transfer in a regenerative-cooling channel of liquid propellant rocket engine were numerically investigated by solving three-dimensional elliptical Navier-Stokes equations.The coolant was hydrogen,whose thermal properties such as thermal conductivity,density,dynamical viscidity,etc varied with both temperature and pressure.The specific heat of hydrogen and thermal properties of solid metal varied with temperature.The standard k-ε turbulence model and gas-solid coupled technique were adopted.An optimized calculation scheme was applied so as to find the best design for rocket combustion chamber.In the scheme,the cooling channel aspect ratio varied with the thickness of channel ribs while the channel number is fixed and coolant mass flow rate remains constant.The simulation results show that the heat transfer of rocket chamber will be enhanced when increasing the aspect ratio,but the pressure drop will increase simultaneously.The cooling effect of rocket thrust chamber will to be reach saturated as the aspect ratio becomes large enough.
Object-oriented simulation platform for turbofan engineand its control system
ZHOU Wen-xiang, HUANG Jin-quan, DOU Jian-ping, SHEN Feng
2007, 22(1): 119-125.
Abstract PDF(1641KB) icon1653 icon463
Abstract:
The method of developing object-oriented aeroengine numerical simulation platform is investigated.Basic class hierarchy for turbofan engine and control system performance simulation was designed.These basic classes together with some other assistant classes were coded through object-oriented computer language.The key technology for programming interactive graphical user interface and modular simulation system was introduced.A general numerical simulation platform for turbofan engine and control system was developed.Simulation results show that the platform can simulate turbofan engine dynamic process from near zero to maximal state,and the dynamic simulation error is less than 8%.The control system has quick response with suitable percent overshot.The platform is suitable for aeroengine and control system simulation.
Intelligent perf ormance diagnosis of aeroengine withsensor measurement bias
YUAN Chun-fei, YAO Hua
2007, 22(1): 126-131.
Abstract PDF(962KB) icon1606 icon509
Abstract:
An Intelligent aeroengine performance diagnostic method,based on neural networks,was investigated.Sensor measurement deviations from the nominal condition are the only information for the estimation of engine health parameters.They are often distorted by noise and bias,thereby mask the true engine condition and lead to incorrect diagnostic results.A bank of neural networks and engine models was developed.The errors between the model outputs and sensor measurements can be used to detect and isolate the sensor,which has measurement bias.Then the engine performance can be estimated by the set of measurements without biases.The simulation results show that this approach is promising for reliable aero-engine diagnosis.
Augmented LQL method and its application to aeroengine control
WANG Yong-ting, GUO Ying-qing, WANG Hai-guan
2007, 22(1): 132-136.
Abstract PDF(509KB) icon1670 icon452
Abstract:
LQL（Linear quadratic L2 bounded uncertainties）control method was applied to the aeroengine control system.The augmented LQL method was proposed,then the aeroengine control system was designed by using the method.Simulation of the control system in the flight envelope was performed,and excellent tracking performance and robustness were obtained.
Support vector machines PID adaptive control in aeroengine
LIANG Hua, LI Ying-hong, WEI Xun-kai, LIU Jian-xun
2007, 22(1): 137-141.
Abstract PDF(626KB) icon1810 icon407
Abstract:
The support vector machine principal and the support vector machine return model are introduced first,and the self-adaptive PID support vector machines' controller is established.It makes use of support vector machines' strong nonlinear mapping ability,and network's structure is optimally auto-created.Finally, the aeroengine controller is designed at the design point.Application results in an aeroengine show that the controller possesses much better performance when the work of the aeroengine deviates from the design point.The presented control strategy introduces a new way for nonlinear control.
Performance analysis of aero-valve in pulse detonation engine
FAN Yu-xin, WANG Jia-hua, LI Jian-zhong, ZANG Yi-ning
2007, 22(1): 142-149.
Abstract PDF(1910KB) icon2021 icon457
Abstract:
Two types of aero-valve including bi-swirl and blunt type were designed incorporated with air-blast atomization mechanism.Results of experiments and numerical simulation show that integrate design of aero-valve with air-blast atomizer can improve the distribution of the fuel spray field effectively,and reduce the distance of engendering detonable mixture.Although bi-swirl aero-valve is superior to blunt aero-valve due to its fine atomization and mixing,thrust loss is higher.Numeric simulations results of the process with inlet closed show that large eddies fall off and break into small eddies which increase turbulence intensity greatly.
Study of sub-grid pollutant formation model in combustor
YAN Ying-wen, ZHAO Jian-xing, ZHANG Jing-zhou
2007, 22(1): 150-155.
Abstract PDF(660KB) icon1798 icon436
Abstract:
The NO subgrid-scale formation model and the beta PDF subgrid-scale NO formation model were used for Large-Eddy Simulation(LES) of NO emission in model afterburner with V-gutter flame stabilizer.The k-equation sub-grid scale model was used to simulate the sub-grid eddy viscosity,and the EBU combustion sub-grid scale model was employed to determine the chemical reaction rate.Discrete equations were solved with SIMPLE algorithm and hybrid scheme in staggered grid system.The effects of two different subgrid-scale NO formation models and inlet temperatures on NO formation were calculated.The reasonable agreement of simulation results in comparison with experimental data shows two different subgrid-scale pollutant formation models may predict the NO formation in the combustor.The NO subgrid-scale formation model spends much less calculation time than the Beta PDF(subgrid-scale) NO formation model,and it was more appropriate for engineering application.
Dynamic assessment and diagnosis of vibration of rolling bearings using grey bootstrap
XIA Xin-tao, CHEN Xiao-yang, ZHANG Yong-zhen, WANG Zhong-yu, BAI You-cai, LIU Chun-huao
2007, 22(1): 156-162.
Abstract PDF(916KB) icon1727 icon405
Abstract:
Based on grey prediction and bootstrap resampling,a model of dynamic assessment and diagnosis is proposed to evaluate and improve vibration of rolling bearings.The model characterizes vibration of rolling bearings by developing six parameters,viz.dynamic uncertainty,estimated interval,estimated true value,mean uncertainty,mean true value,and systematic error measure.Experiments on HKRB bearing show that the model can separate systematic errors with a minimum of the mean uncertainty,without any requirements for both the probability distribution of random errors and the type of systematic errors.Reliability of assessment is proved to be 100%.The model also discovers the effect of error character on vibration of rolling bearings and then lays a foundation of control over vibration of rolling bearings in the process of production,by revealing error root from making the parts of rolling bearings.
Heating analysis of the high speed ball bearing
CHEN Guan-ci, WANG Li-qin, GU Le, ZHEN De-zhi
2007, 22(1): 163-168.
Abstract PDF(1041KB) icon1800 icon462
Abstract:
Based on the thermal analysis and the quasi-static analysis,heating by different heat sources is calculated.The local heating between the units of the high speed ball bearing and the total heating are obtained.The influences of the rotational speed,the load and other parameters on the local heating and the total heating are analyzed.The results reveal that a great portion of the heating comes from the spin heating between the ball and the inner ring.Furthermore,the influences of the rotational speed,the axial load and the curvature coefficient of the inner ring on the heating are the greatest of all the parameters which have an effect on the heating.At the same time,the heating is also calculated from the integral bearing.It is found that the result departs from the fact.In comparison with the result by regarding the ball bearing as an integral unit,the result obtained by the local method is consistent with the practice.However,the total heating calculated from the local heat sources of the bearing is more accurate.It can help to investigate three dimensional thermal field of the ball bearing and to choose the lubricant quantity etc.

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