2004 Vol. 19, No. 3

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The Calculation of Wall Boundary Layer Using GAO-YONG Turbulence Equations
GAO Ge, REN Xin
2004, 19(3): 289-293.
Abstract PDF(385KB) icon2124 icon418
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Two-dimensional,stationary,compressible boundary layer with zero pressure gradient is numerically simulated with GAO-YONG turbulence model.Employing staggered grid arrangement,SIMPLE/SIMPLER code and a second-order QUICK scheme are used.All the results verify that the GAO-YONG equations,without using empirical coefficients and wall functions,may successfully simulate the compressible turbulent boundary layer (Ma=0.2～2.4).The calculation successfully simulates the flow,including the natural transition process,and predicts the fundamental properties of the boundary layer,such as C_f,the logarithmic law, and the defect law,etc,which are finely close to the experimental data.All the results further verify the adaptability of the turbulence model to real turbulent flow.
Performance of Mechanical Axisymmetric Vectoring Nozzle During Dynamic Deflection
ZHANG Qun-feng, LU Zhi-yong
2004, 19(3): 294-299.
Abstract PDF(478KB) icon1672 icon431
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To study the internal flow characteristics of an axisymmetric vectoring nozzle with external flow at the geometric deflective angle varying from 0° to 14.2° with deflective angle rate of 40°/s,the numerical simulation has been conducted with collocated finite volume scheme and Pressure Implicit Split-Operator (PISO) method.The influence of different Nozzle Pressure Ratio (NPR) and the external flow on the performance of the axisymmetric vectoring nozzle,the relation between the gemeotric deflective angle and thrust vectoring angle have been analyzed.The thrust vectoring angle oscillates after the separation flow occurs on internal wall.The results will afford the reference for designing these nozzles and their control.
The Effect of Thrust Vector Control on the Performance of Turbofan Engine
QU Yu-an, XIE Shou-sheng, SONG Zhi-ping
2004, 19(3): 300-304.
Abstract PDF(632KB) icon2211 icon491
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A mathematical model of turbofan engine with thrust vector control was established.By employing certain turbofan engine as a sample,the effects of vector thrust control on turbofan engine performance and co-operation were studied.Under certain conditions,the results show that the operation line of low-pressure spool moves towards the surge margin when the thrust vector nozzle deflected.But the operation line of high-pressure spool does not change,and the total thrust increases.When combining deflection of the thrust vector nozzle with increasing the nozzle area,the original operation situation of the turbofan engine can be kept.But the total thrust of the turbofan engine is decreased.
Performance of Magnetorheological Damper with its Application to Vibration Control
XIA Pin-qi, YUE Hai-long
2004, 19(3): 305-309.
Abstract PDF(348KB) icon1815 icon427
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Magnetorheological (MR) fluid damper is a relatively new type of device for application to semi-active vibration control.The essential characteristic of the fluid is its ability to reversibly change from a free-flowing,linear viscous fluid to semisolid with a controllable yield strength in milliseconds when exposed to an magnetic field.External energy required by the adjustable fluid damper is minuscule and the damping force produced by the damper is large,while speed of its response is on the order of milliseconds.In this paper,the performance and equivalent linear damping coefficient of MR damper are analyzed based on the Bouc-Wen model,the energy dissipation method and the trapezoidal rule.Applying the MR damper model to an oscillator with signal degree of freedom harmonically excited through its support,the transmissibility which is the degree of relative isolation and defined as the ratio of amplitude of motion of the oscillator to amplitude of motion of the support is determined,and the phase angle of steady response as well.
Parallel Computing for Buckling Load of Thin Shell Structure
LI Li-jun, JIN Xian-long, Li Yuan-yin, LI Gen-guo
2004, 19(3): 310-313.
Abstract PDF(657KB) icon2037 icon442
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This paper describes the study and implementation of parallel algorithm and software for static buckling analysis.The research takes advantage of advanced serial finite element analysis code,MSC.NASTRAN as development platform,and massively parallel computer as parallel environment.The dominating computing work of elastic structure static buckling analysis was parallelized,and the parallel solver was implemented in Fortran90 and MPI.Moreover,the parallel solver was embedded into the original solution sequence as a sub-module,and could be called directly.For convenient use,the development for friendly interface was implemented.The integrated software,which includes serial pre-and postprocessors with parallel solver,can improve the scale and speed of linear buckling analysis for thin shell structure.
Theoretical Model of Metal-Rubber
GUO Bao-ting, ZHU Zi-gen, CUI Rong-fan, PANG Wei
2004, 19(3): 314-319.
Abstract PDF(330KB) icon1764 icon460
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Metal-Rubber (MR) is a metal material,and its elasticity is similar to that of rubber.The paper,based on MR traits of forming technics and spring theory,demonstrates the mechanic model of MR and studies the rigidity characteristics through theoretic method.Besides,the paper presents the constitutive relation of MR,which is significant for the MR product designs and applications.
A Model of Aeroengine Reliability Prediction Based on Fuzzy Number
ZHAO De-zi, WEN Wei-dong, DUAN Cheng-mei
2004, 19(3): 320-325.
Abstract PDF(877KB) icon1433 icon377
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According to the property of fuzzy number which is suited for quantifing fuzzy information,an approach to multi-stage fuzzy synthetical assessment based on fuzzy number is proposed by use of fuzzy sets and interval analysis, which can make a fuzzy decision well in terms of fuzzy information.A model of reliability prediction for an aeroengine is developed by applying the approach and considering the reliability properties of an aeroengine.By means of the model,the reliability level of an aeroengine can be assessed more objectively because a variety of the factors influencing aeroengine reliability can be synthetically considered in the model.Therefore the model is particularly adaptable to the reliability prediction in initial design stage for an aeroengine.
Static Characteristics of Metal-Rubber
MA Yan-hong, GUO Bao-ting, ZHU Zi-gen
2004, 19(3): 326-331.
Abstract PDF(318KB) icon1716 icon408
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Metal-Rubber (MR) is a new damping material,and its characteristics are affected by many parameters.In the paper,based on constitutive relations of MR,theoretical analysis and experimental approaches are presented to study the effects of various MR parameters,such as shape,and size on the characteristics of MR.Some general variation patterns of characteristics of MR were found,which were helpful for better designing and make use of the MR.
The Effect of Flow Field and Fuel Spray of Combustor with Swirl Cup on Lean Blowout Limit at Idle Condition
YUAN Yi-xiang, LIN Yu-zhen, LIU Gao-en
2004, 19(3): 332-337.
Abstract PDF(811KB) icon2129 icon487
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Two kinds of combustor domes were investigated,of which one was that with three swirlers (A model),and the other with two swirlers (B model).Computation was conducted for flow field of these combustors.Flow field and fuel spray of the two designs were measured by Phase Doppler Analysis (PDA).The lean blowout fuel air ratio and flame photo were obtained.The results showed that the A model had better Sauter Mean Diameter (SMD) & uniformity than B model,but it had a worse lean blowout performance,and the flow rate in the inner swirler of A model should decrease to establish a low pressure stagnation region which would be helpful to improve the lean blowout fuel air ratio.
Computational Method for Open Degree Characteristics of Radial Direction Variable Geometry Swirl
LI Gong, LI Chang-lin
2004, 19(3): 338-341.
Abstract PDF(253KB) icon1502 icon529
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The paper describes a computational method for open degree characteristics of radial direction variable geometry swirl.With the increase of aero-engine's propulsive-weight ratio (p/w),the temperature ahead of turbine has increased yearly. Now this temperature of advanced engine is as high as 1800 K and at the same time the fuel-air ratio (F/A) of combustion chamber increases up to 0.03 from 0.02.To ensure the best combustion performance when the chamber works in wide range of F/A,one of the effective technical approaches is to adopt variable geometry swirl.In this paper a mathematical relationship for the open degree characteristics of the swirl is formulated and examples are presented.All these can be used as reference to the combustion chamber designs.
Critical Heat Flux during Natural Convective Boiling in Inclined Tubes
LIU Zhen-hua, YANG Rong-hua, QIU Yu-hao
2004, 19(3): 342-345.
Abstract PDF(251KB) icon1777 icon488
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An experimental study was carried out to investigate the critical heat flux (CHF) during natural convective boiling in the uniformly heated,inclined tubes submerged in the saturated liquids at atmospheric pressure.The inner diameters of the test tubes varied from 100 mm to 400 mm;the heated lengths of the tubes ranged from 0.9 mm to 8 mm;the inclination angles varied from 90° to 30°. The test fluids were pure water and R-11.A semi-theoretical correlation used originally for predicting of the critical heat flux during natural convective boiling in vertical tubes was modified to predict the critical heat flux which occurs in the inclined tubes.The modified correlation agrees reasonably well with the present experimental data.
Experimental Investigation of Unsteady Heat Transfer Between Counter-Rotating Disks
CAI Yi, XU Guo-qiang, TAO Zhi, DING Shui-ting, HE Ya-jun
2004, 19(3): 346-350.
Abstract PDF(290KB) icon2133 icon413
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The contra-rotating turbine disks of an aero-engine were simplified as a counter-rotating plan disk system.The unsteady effects of the coolant flow rate and rotating speed on fluid flow and heat transfer were investigated experimentally by employing a rotating heat transfer test rig.Experimental results indicated that:(1) The inlet Reynolds number is the key factor influencing the average Nusselt number.When the inlet Reynolds number varies,the Nusselt number responds simultaneously.The heat transfer of two disk surfaces was both enhanced due to the increase of the inlet Reynolds number.(2) The effect of the rotating speed variation on heat transfer is,however,limited that it only influences,to some extent,the disk under rotating variation and little effect was observed for the other disk.
Thermal Performance Analysis of Heat Pipe Receiver for Solar Dynamic Space System
CUI Hang-ting, XU Wei-qiang, YUAN Xiu-gan, ZHU Yu-feng
2004, 19(3): 351-355.
Abstract PDF(864KB) icon1724 icon396
Abstract:
In order to reduce the mass and improve the thermal performance of the heat receiver,heat pipe receiver is used for the space solar dynamic power system.A corresponding mathematical and physical model is built,and a method for numerical solution is given by which the temperature of the containment canister outer wall,heat pipe wall temperature,working fluid exit temperature,liquid Phase Change Material (PCM) fraction of the total heat transfer tube are calculated and compared with those obtained from the baseline heat receiver.The results show it is possible to promote receiver performance,to reduce the fluctuation of working fluid temperature and the weight of heat receiver.All results of the calculations can be used to guide the heat receiver design.
Influence of the rib pitch on flow resistance in a U-shaped variable cross-section channel with transverse ribs
GUAN Zhi-hua, DING Shui-ting, TAO Zhi, XU Guo-qiang
2004, 19(3): 356-360.
Abstract PDF(270KB) icon1777 icon414
Abstract:
The turn-over channel of turbine blade is an important part of the internal cooling structure of the turbine blade. Its flow performance is important for the design of cooling structure of the turbine blade.A real turn-over channel of turbine blade is simplified as an object to be studied in the present paper which studies flow performance in a 180° turn-over channel with 90° parallel different height ribs.The efficient pressure distribution in the inner part of the turn-over channel along the channel,including 90° parallel different height ribs,is shown in the paper.The result shows that the efficient pressure distribution in the inner part of these two turn-over channels with 90° parallel rib along the process is similar.Some efficient pressure increases along the channel because of the irregular changing of the channel shape.Correlation formulas of the coefficient of the efficient pressure are obtained in the paper.Resistance coefficient increases with the increase of the rib height to diameter ratio.
Numerical Simulation of Flow and Heat Transfer in Rectangular Channel with Staggered Arrays of Droplet-Type Pin Fins
YANG Cheng-feng, ZHANG Jing-zhou, TAN Xiao-ming
2004, 19(3): 361-365.
Abstract PDF(315KB) icon1928 icon450
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Three-dimensional numerical computation of flow and heat transfer in rectangular channel with staggered arrays of droplet-type pin fins is conducted to investigate the effects of the shape of pin fins on flow and heat transfer characteristics.As a conventional enhanced heat transfer method,the rectangular channel with staggered arrays of column-type pin fins with the same cross-areas to droplet-type pin fins is also considered.Both type pin fins have the same cross-areas.The velocity fields,pressure fields in the channel and local convective heat transfer coefficients on the wall are obtained.The results indicate that in the present research range of Re number and constructional parameters,the enhanced heat transfer capability of droplet-type pin fins about 15% less than that of the conventional column-type pin fins,and the pressure drop of droplet-type pin fins is only about 50% of the conventional column-type pin fins.
Numerical Research of Infrared Characteristics of Axial-Symmetrical Vectored Nozzle
ZHANG Xiao-ying, WANG Xian-wei
2004, 19(3): 366-369.
Abstract PDF(266KB) icon1521 icon443
Abstract:
Numerical simulation methods of infrared characteristics of vectored nozzle in the spectrum range of 2 100～5 260 cm-1 are studied and corresponding Three Dimension (3-D) program was developed.The program can compute infrared characteristics of nozzle both in after-burning condition and non-after-burning condition.Spectral emission and absorption of water vapor and carbon dioxide,and soot after-burning condition were also considered in computation.The simulated results of axial-symmetrical vectored nozzle on wall and in the exit plane in after-burning condition and non-after-burning condition in the spectrum range of 2 100～5 260 cm-1 are presented in the paper.The numerical calculation results obtained by applying the present simulation approach to a real engine show general agreement with the experiments.
Numerical Investigation of Flow and Heat Transfer Performances in Pre-Swirl Rotor-Stator Cavity
YE Ping, ZHANG Jing-zhou
2004, 19(3): 370-374.
Abstract PDF(304KB) icon2010 icon476
Abstract:
In order to investigate the flow and heat transfer performances in a pre-swirl rotor-stator cavity with two air inflows (central air inflow and pre-swirl inflow at stator rim respectively) and two outflows (radial outflow at ourter shroud and axial outflow at rotor rim respectively),a numerical study is conducted by using RNG turbulent model.In the cavity,there are stator septa and rotor septa dividing the inner rotor-stator cavity from the outer pre-swirl cavity.Because of the periodic feature of the flow structure,one thirtieth of the cavity is considered as the computational field.The results show that the rotating Reynolds number,non-dimensional flow velocities,and pre-swirl ratio have different effects on the flow and heat transfer characteristics in the rotor-stator cavity.The synergism of pre-swirl and septa makes satisfactory shroud seals preventing the ingress of hot gas from flowing into the inner rotor-stator cavity and providing the cooling air flowing into blade-cooling holes.
A Review of Aeroengine Control System
ZHANG Shao-ji
2004, 19(3): 375-382.
Abstract PDF(1064KB) icon2425 icon675
Abstract:
The paper reviews and analyses the recent research and development of aeroengine fuel control systems.The technical features,the technical mode selection and the research trend of main fuel control,afterburner fuel control,nozzle control,anti-surge control and engine condition monitoring system are discussed.Recently great progresses have been acheived in the areas of aeroengine fuel and control systems,especially in terms of the research and application of Full Authority Digital Electronic Control System (FADEC) technology.The development of above technology proves that the aeroengine fuel control system is very important for the modern aeroengine in the future.
Hardware in the Loop Simulation of Minitype Turbojet Engine Digital Control Regulator
CHENG Tao
2004, 19(3): 383-386.
Abstract PDF(291KB) icon1910 icon446
Abstract:
This paper covers the designs of Hardware in the Loop Simulation (HILS) testing of minitype turbojet engine digital control regulator,and hardware and software configurations.The HILS tests check up the transient and steady state performances of the engine control system.The tests correct and verify the capability of engine digital control regulator ground start and air start,stopping,automatic accelerating and decelerating,and steady state regulation.Also the tests evaluate the adjusting capability of air start,and flying along the ballistic trajectory.Finally some test results are presented.
LMI Based Multivariable H_∞Fixed-Order Control for an Aero-Engine
SUN Hu-guo, FAN Si-qi, LI Hua-cong, WU Dan
2004, 19(3): 387-391.
Abstract PDF(731KB) icon1677 icon430
Abstract:
A new design method of multivariable static output feedback H_∞fixed-order PI controller for aero-engine is presented.The synthesis of H_∞fixed-order controller can be formulated as a Bilinear Matrix Inequality (BMI) optimization problem which is hard to solve.But under certain aero-engine conditions,the BMIs raised in the H∞fixed-order design problem can be converted into standard Linear Matrix Inequalities (LMIs).Then the existence condition of H_∞fixed-order controller is deduced and the design procedures of the controller are proposed.The approach proposed in the paper has been successfully applied to turbo-engine fixed-order PI controller design.The simulation results show that the performance and robustness of controlled system are satisfied.
Aeroengine Lubrication Monitoring Analysis Via Support Vector Machines
WEI Xun-kai, LI Ying-hong, WANG Shuo, LU Jian-ming, WANG Cheng
2004, 19(3): 392-397.
Abstract PDF(828KB) icon2061 icon445
Abstract:
A novel aeroengine lubrication monitoring method based on support vector machines is presented in this paper.Basic theory analysis of support vector regression in time series forecasting is introduced in detail and a multi-step forecasting formula is presented,Final Prediction Error (FPE) principle is suggested to select the embedding dimension.Compared with general autoregressive forecasting method it adopts new type of structural risk minimization principle and thus it owns excellent generalization ability.During numerical simulations,we infer that Auto-Regressive (AR) forecasting method is suitable to short intervals while Support Vector Machines (SVM) still possesses good robustness and fault-tolerant virtue in metaphase intervals forecasting.Finally,some typs of aeroengine's lubrication metal content have been monitored for feasibility validation and test results are satisfactory.
Steady Pressure Model of the Aeroengine Oil System
MA Zhuang, CHENG Li
2004, 19(3): 398-401.
Abstract PDF(567KB) icon2386 icon425
Abstract:
Taking the oil system of certain aero-engine as a study object,the paper analyzes in-depth the working principles of the oil system and the structure characteristics of its components.Formulas for calculating the oil pressure losses in the pipelines and the mathematical model of the components are established by using fluid dynamics,engineering thermo-dynamics and numerical calculation and experimental data.Finally,the steady pressure model of the oil system is established according to the data acquired in the aero-engine oil system in good conditions,and the results by using this model provide the reference for judging the performance attenuation and the fault of the oil system.The method of this paper can also be used for other aero-engines and its application value bears universality.
An Application of Data Acquisition Technique to Turbomachinery Experiments
YUAN Wei, LU Ya-jun, ZHOU sheng, LI Zhi-ping
2004, 19(3): 402-407.
Abstract PDF(414KB) icon1610 icon426
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A system for measuring and control of some compressor experiments in a test cell is described.An economical scheme,which is effective for the steady data acquisition for turbomachinery,has been demonstrated forward.By dint of the analysis of sources and influencing modes from the dynamic interferential signals,a method that can estimate the jam source is developed,and accordingly the remedies are taken.All this work provides the basis for the further experiments.
Prospects of Numerical Analysis of an Aspirated Transonic Fan Rotor
ZHOU Hai, LI Qiu-shi, LU Ya-jun
2004, 19(3): 408-412.
Abstract PDF(760KB) icon1845 icon438
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The efficiency and pressure ratio in a fan stage can be affected,by means of removal of mass flow from the passage.With properly chosen positions and with holes or slots on the suction side of the blades,the fan rotor behaves better in terms of performance.Calculations of a transonic fan rotor,ATS-2,show that the separated-flow area has been observably reduced,and that positive impacts have been observed even with small bleeding mass flow on the rotor.The results also indicate that the bleeding location has a significant impact on the performance.And with adequate air removal,the effect becomes more distinct.
Numerical and Experimental Study of a Plug Nozzle with two Rectangular Inner cells
WANG Yi-bai, LIU Yu, WANG Chang-hui, QIN Li-zi
2004, 19(3): 413-418.
Abstract PDF(501KB) icon2069 icon452
Abstract:
In order to exactly understand the high performance of the plug nozzle with two-dimensional rectangular inner cells,a two-cell test plug nozzle was designed,and numerical and experimental studies were conducted for such a model.The numerical simulation was based on an Non-Oscillatory and Non-Free Parameters Dissipation Difference （NND） scheme to solve the three-dimensional Navier-Stokes equations,and the cold flow experimental studies using air were performed to evaluate the nozzle performances.The model studied has a nozzle throat area of 4×60 mm2,with the inner nozzle area ratio of 4 and total area ratio of 24.05.The nozzle was designed for the pressure ratio about 500.The flow field and plug pressure profiles were obtained.The results show a good agreement with experimental data,and the maximum discrepancy is by 1%.The model has high nozzle performance with the maximum thrust coefficient efficiency of 0.995,and has good altitude compensation characteristic comparing with the bell nozzle that the nozzle efficiency is in the range of 0.97～0.995 with the pressure ratio changing from 45 to 600.The plug surface pressure profiles for the full-length plug nozzle at different NPR can provide valuable data for researching the truncated plug nozzle.
The Reliability Growth Analysis for Liquid Rocket Engine According to The Gompertz Model
LIU Qi, FENG Jing, ZHOU Jing-lun
2004, 19(3): 419-423.
Abstract PDF(680KB) icon1755 icon430
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In this paper,the Gompertz model and linear statistical method are used to analyze the growth factor of batch experiments for a liquid rocket engine.The reliability distribution of a new product is also forecasted.Then,Bayesian method is used to evaluate the reliability parameters of the products.In the article,first,the reliability growth analysis model is presented.Then with the reliability growth test data, a dynamic parameter iterative evaluation model is built.With the iterative model and field test data,the reliability evaluation of every stage can be calculated by Bayesian formula.Based on the distribution of function of the random variable,the reliability evaluation is given.An example is shown to illustrate this method.
On Relationship between Vibration and Noise of Rolling Bearing Using Grey System Theory
XIA Xin-tao, WANG Zhong-yu, SUN Li-ming, ZHAO Lian-chun
2004, 19(3): 424-428.
Abstract PDF(342KB) icon2129 icon428
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Based on grey system theory,the relationship of the vibration and noise of rolling bearings is studied.Two types of rolling bearing,6201 and 6203,were used in experimentation.The vibration is characterized by the virtual value of acceleration,and the noise is indicated by the sound-pressure-level.The results of data processing demonstrate that,the relationship between vibration and noise of rolling bearings is not obvious,and it has significant uncertainty.Therefore,the vibration can not be in stead of the noise.The problem of the noise of rolling bearings must be studied independently,the standards of the noise and the corresponding technology of rolling bearings must be established.

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