2006 Vol. 21, No. 6

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Display Method:
Integral inference method for ε-N and P-ε-N curves
FU Hui-min, LIU Cheng-rui
2006, 21(6): 957-961.
Abstract PDF(298KB) icon1625 icon438
Abstract:
As the strain fatigue data scatter in lgΔεe-lgN or lgΔεp-lgN coordinates,and their standard deviation increases with reducing of elasticity and plasticity components,ε-N and P-ε-N curves cannot be obtained by group experiment method and homoscedasticity regression analysis method.The mean value method and Wissching method are commonly used in engineering.But they are both approximation methods with significant error.Therefore,an integral inference method for ε-N and P-ε-N curves is presented based on the heteroscedasticity regression analysis theory.It can analyze scattered and heteroscedastic data through treating all the experiment data in different strain levels as an integration.Compared with traditional methods,the presented method can not only save specimens,but also increase precision in ε-N and P-ε-N curve tests effectively.
Preliminary experimental study of pulse detonation combustion efficiency
HUANG Xi-qiao, YAN Chuan-jun, FAN Wei, QIU Hua, WANG Zhi-wu
2006, 21(6): 962-966.
Abstract PDF(916KB) icon1709 icon438
Abstract:
A sampling system with a variable pressure check valve was designed to investigate the combustion efficiency of pulse detonation combustion process on the basis of the pulse detonation engine(PDE) operating principle analysis.With the designed sampling system,the combustion efficiencies of the pulse detonation combustion processes using gasoline as fuel and compressed air as oxidizers at operating frequency of 5 Hz were measured both at conditions that the steady and fully developed detonation waves were formed and not formed.The experimental results indicate that the pulse detonation combustion efficiency can be measured successfully using the designed sampling system.The combustion efficiency where the detonation waves have fully developed is higher than that of not fully developed. The highest combustion efficiency is up to 99.6%.
Gas sampling & analysis in the high enthalpy flow
ZHENG Bi-ke, CHEN Li-hong, LIN Ran, CHANG Xin-yu
2006, 21(6): 967-971.
Abstract PDF(657KB) icon1648 icon495
Abstract:
It was proved that the chemical reaction of the flow in the sampling probe was quenched by the analysis of 1-D.A gas sampling/chromatography analysis system had been established and it was checked for vacuum packaging.The system was used to sample and analyze the exhaust of scramjet.The combustion efficiency was acquired through the experimental results,which were agreed with the observation and the measurement results of static pressure on the combustor wall.
Effect of different porosity on thermally driven heat transfer in a centrifugal force field
XIA Jie, CHANG Hai-ping
2006, 21(6): 972-977.
Abstract PDF(875KB) icon1646 icon484
Abstract:
Based on the background of the turbine blade super-cooling technology,porous medium was installed in a new kind of cooling configuration with cooling tunnels. Experiments and numerical simulations were carried out to investigate the thermally driven heat transfer rules in the new kind of cooling configuration with different porosity in a centrifugal force field.The results of experiments are basically consistent with that of the numerical simnlalions.Study shows that the heat transfer processes of the new cooling configuration are identical under different porosity.The thermally driven heat transfer of the cooling configuration filled with porous medium can be enhanced by increasing rotating speed,heat flux and cooling air speed.At the same time,the heat transfer effect is weakened with the increase of the porosity.
Experimental study on convective heat transfer characteristics of film cooling with tab
YANG Wei-hua, MA Guo-feng, ZHANG Jing-zhou
2006, 21(6): 978-983.
Abstract PDF(1617KB) icon1687 icon516
Abstract:
In order to study the effect of tab on film cooling,three kinds of test pieces with different geometrical parameters were designed,and the heat transfer characteristics of them were experimentally studied.The results show that the convective heat transfer coefficient of film cooling with tab is better than that without the tab.While the area ratio is 0.1,the convective heat transfer coefficient of film cooling is the best at the blow ratio of 0.50.78;while the area ratio is 0.27,the convective heat transfer coefficient gets its maximum value at the blow ratio of 1.221.5.However,because of the existence of tabs,the flow friction loss in the film hole will be increased.
Experimental investigation of the rotating multiple jets impingement heat transfer chracteristic in semi-limited space
YANG Min, CHANG Hai-ping, WU Pei-guang
2006, 21(6): 984-988.
Abstract PDF(716KB) icon1671 icon445
Abstract:
The effects of jet Reynolds number(Rej),rotation Reynolds number(Reω),the jet-holes array and the distance of jet-to-plate on multiple jets impingement cooling were studied by experiments.The results show that:(1) The average Nu number of heat transfer of multiple jets impingement cooling increases significantly with the increasing of jet Reynolds number but have less increment with that of rotation Reynolds number.(2) The jet-holes array has certain effect on the average heat transfer of multiple jets impingement,cross jet-hole array is somewhat better than that of the ordinal array.(3) When the distance of jet-to-plate is four times the jet-hole diameter,the average heat transfer effect of impingement cooling is the best.
Experimental study of heat transfer effect of a new cooling technique based on thermally driven theory
YANG Min, CHANG Hai-ping, WU Pei-guang
2006, 21(6): 989-994.
Abstract PDF(909KB) icon1541 icon432
Abstract:
A New Super Cooling Technique based on thermally driven theory was studied further at the background of turbine blade’s cooling by Experiments.Experimental results show that the heat transfer effect of this new cooling technique is enhanced with increasing in buoyancy,rotational Reynolds number and cooling air Reynolds number,its cooling ability is better than those of the other two kinds of current blade cooling techniques.
Heat transfer in the rectangular passage with 60-degree ribs and film holes
LI Guang-chao, ZHU Hui-ren, Guo Tao
2006, 21(6): 995-1000.
Abstract PDF(983KB) icon1750 icon476
Abstract:
Numerical simulation was conducted to investigate heat transfer in a rectangular channel with both 60-degree rib-roughened wall and film hole suctions with Reynolds number of 9×104 and suction ratio of 0.22.A finite volume method with unstructured meshes was used to solve the three dimensional compressible Navier-Stokes equations.The realizable k-ε model was used carefully and the enhanced wall function was utilized for near wall treatment.The numerical results agree well with the experimental data of the surface with both ribs and film holes.Based on this,investigation was focused on the heat transfer of three other surfaces.The numerical result shows that the flow of the passage is very complex.Heat transfer is enhanced because of the ribs.Maximum Heat transfer coefficient is found on the smooth right surface but not the surfaces with ribs.
Experimental investigation of dynamic evaporation characteristics of liquid droplet on heated surface
WANG Xiao-dong, LU Gui, PENG Xiao-feng, ZHANG Xin-xin, WANG Bu-xuan
2006, 21(6): 1001-1007.
Abstract PDF(1007KB) icon1710 icon490
Abstract:
Using high-speed video imaging system,the evaporation and nucleation of 5ml water droplet on copper,aluminum and stainless steel plates with temperature from 50℃ up to 112℃ were observed.The time-dependent height,wetting radius and contact angle of the droplet were measured.In film evaporation regime,the evaporation process could be divided into two stages.In the fist stage,the height and contact angle of the droplet continuously decrease,but the wetting radius of the droplet hardly alters.In the second stage,the contact angle remains constant as the preceding one,and the wetting radius rapidly approaches zero.In nucleate boiling regime,the nucleation and dynamics of the bubbles inside the droplet are strongly dependent on the surface superheat.It was found that the linear relationship between the mean heat flux of the surfaces and the temperature of the heated surfaces holds true for both regimes,and their different slopes indicate their different heat transfer mechanism.
Experimental investigation on frictional loss in shrouded rotating disk with high-positioned air inflow
WU Hong, LEI Bin, CAI Yi, LUO Xiang
2006, 21(6): 1008-1011.
Abstract PDF(858KB) icon1705 icon483
Abstract:
The experimental results of the friction effect on shrouded rotating disk with high positioned air flow are presented.The result shows that the dimensionless moment coefficient(NMC) of the rotor decreases with the increase of rotational Reynolds number,but the extent decreases with the increase of rotational Reynolds number.The NMC of the rotor increases with the increase of dimensionless cooling flow rate and differs with different structure of the cooling system.When the rotational Reynolds number reaches a certain value or the dimensionless cooling flow rate is zero,the NMC of the rotor is less than that of the free disk.
Experimental study of laminar flow heat transfer with microencapsulated phase change material suspensions in rectangular mini-channels
RAO Yu, Frank Dammel, Peter Stephan, LIN Gui-ping
2006, 21(6): 1012-1020.
Abstract PDF(810KB) icon1956 icon415
Abstract:
A series of comparative experiments was conducted to investigate the laminar flow heat transfer characteristics with microencapsulated phase change material(MEPCM) suspensions in water flowing through rectangular mini-channels with a hydraulic diameter of 2.71 mm.MEPCM particles with an average size of 4.97 μm were used to form suspensions with mass concentrations ranging from 0% to 20%.The comparative experiments were done under the same mass flow rates and the same thermal conditions using water and water-based MEPCM suspensions.The cooling characteristics of MEPCM suspension strongly depend on the mass flow rate and the MEPCM mass concentration.The 5% suspension always shows better cooling performance than water with lower wall temperatures and enhanced heat transfer coefficient within the whole range of mass flow rates.At higher mass concentrations,however,the cooling performance is more effective only at low mass flow rates.At relatively higher mass flow rates,it shows less effective cooling performance than water at higher wall temperatures and lower Nusselt numbers.
Aeroelastic dynamic modeling of the Electrically Controlled Rotor
LU Yang, WANG Hao-wen, GAO Zheng
2006, 21(6): 1021-1026.
Abstract PDF(595KB) icon1734 icon443
Abstract:
For the purpose of aeroelastic analysis of the Electrically Controlled Rotor(ECR),an aeroelastic dynamic model is built in this paper.Firstly,a synthetic unsteady aerodynamic model in time domain is presented,which can take account of the unsteady effect of the flap nose overhang.The inertia effect of the flap is introduced into the structural dynamic model as an independent mass.According to the Hamilton principle,the nonlinear motion equation of the blade with flap is deduced with the form of generalized forces.Then,based on the finite element aeroelastic analysis code LORA01,the implicit equation of ECR blade motion is solved by an improved Newmark numerical integration method.At last,the ECR aeroelastic dynamic model is validated through comparison with the test results of the Active Control Flap(ACF) rotor.
Effect of finite-length casing treatment on cascade aero-elastic stability
YANG Zi-feng, WANG Xiao-yu, SUN Xiao-feng
2006, 21(6): 1027-1032.
Abstract PDF(813KB) icon1578 icon467
Abstract:
The application of casing treatment to the control of blade flutter may have advantages particularly compared with the existing methods of suppressing blade flutter.In the present paper,a novel method,which is called transfer element method,has been proposed to establish an aero-elastic model,which considers the effect of finite-length casing treatment on the blade flutter inception. The present model avoids the difficulty of solving eigenvalue due to impedance wall condition effectively.In particular,the numerical results show that the value of impedance of lining wall has a marked effect on the aero-elastic stability.The possibility of using finite-length casing treatment to suppress the blade flutter has been concluded.
Research on RCS of airplane duct based on SBR method
WAN Shun-sheng, LUO Yi-jie, GUO Ron-wei
2006, 21(6): 1033-1036.
Abstract PDF(660KB) icon1777 icon458
Abstract:
RCS of engine duct was calculated and analyzed using SBR method.EM scattering characteristics of the pipe with arbitrary section and shape were studied by the methods of shooting and bouncing rays,field intensity track and aperture integral.In the ways of vertical polarization and horizontal polarization,real measurement at the frequency of X wave band was done in the anechoic chamber.The calculation was compared with the experimental result for a real engine duct.It proves that this method is very effective.Compared with other methods,its physical conception is clear,mathematical models can be set up more easily and it also meets practical needs in engineering.
Influence of the plate on the cavity flow-induced oscillations and the modification of the oscillation frequency equation
SI Hai-qing, WANG Tong-guang, ZONG Hui-Ying
2006, 21(6): 1037-1042.
Abstract PDF(711KB) icon2177 icon485
Abstract:
A numerical solution of the three-dimensional URANS equation was presented using the fully implicit unfactored methods,where the turbulent coefficient was calculated based on the revised B-L turbulence model,and numerical simulations were implemented for supersonic three-dimensional open cavities.The self-sustained oscillatory motion of the shear layer was studied for plates with different lengths.The plate in the cavity isolates the shear layer and the cavity,and therefore reduces the coupling between the cavity pressure fluctuations and the shear layer.The oscillation of the shear layer decreases with the increase of the plate length.Based on the different characteristic lengths,Heller’s frequency equation was modified.The frequencies predicted by the modified equation agree with those by the close-box acoustic model;several comparisons demonstrate the validity of the modified equation.
Structure and numerical simulation of high order two steps scheme
WANG Yin-yue, JU Yin
2006, 21(6): 1043-1047.
Abstract PDF(568KB) icon1401 icon469
Abstract:
Basing on the flux-vector splitting,a space 3-order accuracy total variation diminishing(TVD) scheme by applying the Taylorseries theory and the control of the limiter was constructed.The scheme was 1-order in time.In the region of the shock wave the scheme changed into 1-order upwind scheme,Then the simple linear differential equation was spread nonlinear equation.It was applied in solving typical numerical experiments.The present results were compared with those results computed by the 2 nd order TVD scheme.It testifys that the scheme has high order accuracy and high resolution for shocks waves,therefore they are non-oscillatory
Flow analysis and the improvement of axial fan support strut
ZANG Xia, CHU Wu-li, DENG Wen-jian, ZHANG Hao-guang, YANG Yong
2006, 21(6): 1048-1052.
Abstract PDF(1133KB) icon1632 icon450
Abstract:
Three-dimensional numerical investigation were carried out to investigate the flow-field in the passage between support struts in front of the axial-flow fan with the help of the commercial code EURANUS,which is an integral part of the software package NUMECA FINE.It was found that the support strut had significant impact on the axial-flow fan performance.The optimization design was performed for the support strut based on numerical result and flow analysis.In addition,three-dimensional flow analysis was carried out to verify the performance improvement of the newly optimized support strut.It was found that with the new strut the efficiency of the fan is improved over the entire range of mass flow,the losses are locally reduced and the flow in the passage between the support struts becomes more reasonable.
Unsteady flow analysis of a single-stage compressor with splitter vane using numerical method
LI Hai-peng, LIU Huo-xing, JIANG Hao-kang
2006, 21(6): 1053-1057.
Abstract PDF(938KB) icon1560 icon478
Abstract:
The numerical method was applied to the unsteady flow analysis of a single-stage compressor with splitter vane.The result shows that because of the separation effect of the splitter vane,the unsteady pressure fluctuation and unsteady blade load fluctuation are strengthened greatly,and it hastens the pressure wave spreading upstream,while the torque and axial force fluctuation of the rotor and stator unit are reduced.The pressure wave at the rotor inlet in the absolute coordinate is the integration of the potential disturb of the rotor,the pressure wave of the rotor-stator interaction and the circumferential distribution of this pressure wave.The magnitude of pressure wave in different circumferential position differs greatly,splitter vane strengthens this difference.
Analysis of the difference between reviews of overseas and domestic aero-engine in developing process
YANG Rui, HAO Yong, ZHANG En-he, LI Qi-han
2006, 21(6): 1059-1063.
Abstract PDF(475KB) icon1569 icon451
Abstract:
The review is absolutely necessary matter and phase in the developing process of an aero-engine.The pertinent and effective review is a great help to the aero-engine being developed.The concept review of a HP Compressor which carried out broadly according to the formal Rolls-Royce technical review was introduced and a domestic aero-engine concept review was introduced also.The two review process and mechanism and etc.were analyzed according to the comparing with the review committee,prepared data,and review conclusions as well as tracicing examination.
Numerical simulation of flow field for supersonic S-shaped inlet
LIU Zhen-xia, GUO Dong-ming, CHANG Li-fen, WU Ding-yi, WANG Xiao-feng, HUANG Chen-sheng
2006, 21(6): 1064-1068.
Abstract PDF(1175KB) icon2314 icon512
Abstract:
Outer flow of the inlet was computed in consideration of inner flow.Three-dimensional Navier-Stokes equations were solved by finite volume method.The predictions were compared with experimental data.Also the influence of airframe/head on entrance of inlet flow fields,the distribution of shock-wave and the behavior of the inner flow were analyzed.The results showed that air can be effectively introduced into inlet by the second and third control plans,avoiding large area reverse flow at first bent,but the loss of the inlet was large,the highest of the total pressure recovery coefficient was 0.96.
Quasi-static analysis of cylindrical roller intershaft bearing
HU Xuan, LUO Gui-huo, GAO De-ping
2006, 21(6): 1069-1074.
Abstract PDF(657KB) icon1860 icon466
Abstract:
Intershaft bearings are often used in gas turbine engines for better performance.The intershaft bearing has great influence upon the dynamic performance of engine rotor systems,but few research results about it are available.A cylindrical roller intershaft bearing analysis model is established by using the quasi-static method,and the calculation results of roller slip ratio are compared with the experimental data in this paper.An intershaft bearing with counter rotating inner ring and outer ring is analyzed.The inner ring of the bearing is mounted on the high pressure rotor,and the outer ring is mounted on the low pressure rotor.The cage speed,the speed of the rollers and the contact forces between the rollers and the cage,are calculated and results are obtained under different radial forces.It shows that,the values of the cage speed,the roller speed and the contact forces between the rollers and the cage all increase as the radial force increases.
The Simulation of active control of FGM plates/shells via a solid shell element
ZHENG Shi-jie, WANG Xiao-xue
2006, 21(6): 1075-1079.
Abstract PDF(1844KB) icon1363 icon447
Abstract:
By using assumed natural strain and enhanced assumed strain method,a solid shell element formulation was developed for the static and dynamic control of FGM(functionally graded material) shells with piezoelectric sensor and actuator layers.This element could be used as solid element and could also be used to model thin curved shell structures.Even for a thin plate/shell with very small thickness to length ratio,the predictions of this element were satisfactory.The properties of the FGM shell were graded in the thickness direction according to a volume fraction power-law distribution and possessed temperature-dependent properties.The effects of the constituent volume fractions on the static and dynamic responses of FGM structures were examined.A velocity feedback control algorithm coupling the direct and inverse piezoelectric effects was applied in a closedloop system to provide feedback control of the integrated FGM plate/shell structures.Both static and dynamic controls of FGM shells were simulated.Computing examples show that the proposed active control scheme is effective.
An analysis of strength reliability of the Vectoring Exhaust Nozzle Machine
GUO Zhi-wei, BAI Guang-chen, GAO yang
2006, 21(6): 1080-1084.
Abstract PDF(527KB) icon1673 icon412
Abstract:
A random process model of structural functional function of components attached to vectoring thrust nozzle was employed,in which strength and stress of components were respectively taken as random variable and stochastic process.By minimizing structural functional function,the problem of dynamic reliability on functional function was converted into static problem.Moreover,according to characteristics of stress random process,minimum variance unbiased estimate of structural reliability of components were employed on the condition that stress process was simplified into Gumber-stationary binomial random process and strength obeyed normal distribution which parameters were unknown.
Investigation of the effect of combined distortion on engine stability
HUANG Shun-zhou, HU Jun
2006, 21(6): 1085-1091.
Abstract PDF(991KB) icon1731 icon478
Abstract:
The calculated effect of combined distortion on the engine stability shows that the critical values of pressure and temperature distortion are 8.82% and 8.60% respectively.The pressure distortion coefficient of the fan is 2.608 and the temperature distortion coefficient of the compressor is 2.442.The magnitude of pressure distortion and temperature distortion determines the severity of the combined distortion effect on the fan or compressor stability.When the relative peak intensity of distortion appears at the fan section,the fan falls into instability first,otherwise the compressor does.The effect of the combined distortion on engine stability can’t be calculated by superposing the effect of the pressure distortion to the temperature distortion simply,but in a complex nonlinear manner.
Nonlinear monitoring of the centrifugal compressor surge process based on the correlation integral method
SUN Tao, XU Guang-hua, ZHANG Chun-mei
2006, 21(6): 1092-1097.
Abstract PDF(587KB) icon1922 icon478
Abstract:
The reference distance in the correlation integral formula affects the computational value of correlation integral dramatically.In this paper,the method of setting values for the reference distance was presented on the basis of the physical meaning of the correlation integral value and the distribution of all inter-points distances at different operating conditions.Relative degree of unsteadiness based on the reference distance and intensity of surge based on the correlation integral value were defined to analyze the degree of instability and surge in centrifugal compressors quantitatively.By means of applying these measuring parameters to a case of our experiment,it demonstrates that the correlation integral value,etc.are effective for the nonlinear monitoring of operating condition,identification of surge intensity and measuring of pressure unsteadiness in centrifugal compressors.
Study of design method for the zero-stage compressor in an expendable gas turbine engine
LIU Ke-hui, SHAN Peng, LI Na, ZHENG Yan
2006, 21(6): 1098-1102.
Abstract PDF(652KB) icon1941 icon489
Abstract:
Analyzing the evolvement from TRI60-2 engine to TRI60-20 engine developed by France MicroTurbo Inc,the technical characteristic and design method of adding zero-stage compressor were researched.Taking obtaining the compressor’s structure and characteristics as the primary concern,the process of adding zero-stage compressor was discussed,and using CFD software validated by test data the flow field was numerically simulated in full three dimensions and analyzed through computation.The result indicates that the method of adding zero-stage compressor discussed in this paper is basically successful.
Model reduction method based on optimization shaping for aero-engine controller
LI Qiu-hong, SUN Jian-guo, XU Guang-hua
2006, 21(6): 1103-1108.
Abstract PDF(1898KB) icon1833 icon457
Abstract:
The model reduction method for aero-engine controller based on the optimization output shaping is presented in this paper.Using the LQG/LTR controller as an example,the 8~(th) order LQG/LTR controller is successfully reduced to a 3~(th) order system with this method.First the controller is divided into the integral part and the stable part.A lower order system is used to approach the stable part.With the optimization output shaping method,the lower order system parameters can be calculated using genetic algorithm(GA).Then the step response of them is very close to each other.At last,combining the optimized lower order system with the separated integral part,the reduced order controller can be obtained.Compared with the balanced truncation Schur model reduction method,this method can make the system with lower order and get better dynamic performance.
Mechanism investigation and numerical simulation of slag deposition for submerged nozzle
WEI Chao, HOU Xiao
2006, 21(6): 1109-1115.
Abstract PDF(861KB) icon1745 icon454
Abstract:
In order to explore the mechanism and the model of slag generation in solid propellant rocket motor,the two phase flowfield has been simulated using a combined Eulerian-Lagrangian analysis.The motion of the particulate phase was tracked with a stochastic model.The droplet size distribution in the chamber and the two captive rules were considered.Finally,the influence of different coefficients of restitution on slag calculation was investigated.The calculated result shows that the lowest slag weight is 0.201% and the highest slag weight is 0.287% of the total weight of Al2O3.The results are accurate and credible compared to the experimental data.
Heat transfer characteristics of expander cycle thrust chamber with different cooling routing
HAN Fei, LIU Yu
2006, 21(6): 1116-1122.
Abstract PDF(1358KB) icon2034 icon478
Abstract:
To study the heat transfer characteristics of expander cycle regeneratively-cooled thrust chamber,three dimension computational models of a referenced thrust chamber and two expander cycle thrust chambers with different area ratio were established.The coolant heat pick-up,pressure loss in the cooling circuit,wall temperature and heat flux distribution were calculated by numerical simulation.Influence of increased length of chamber cylinder,different cooling routing and area ratio were investigated.Governing equations were discrete with two order upstream scheme.Numerical results show that when a converse cooling is taken,the area of hot gas wall surface of chamber is increased 70% by increased length of chamber cylinder and the coolant heat pick-up is increased about as much as one time;while the selected co-flow cooling routing is employed,the pressure loss is decreased in cooling circuit but the coolant heat pick-up is less than the converse cooling and this cooling routing leads higher wall temperature at the throat.

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