2001 Vol. 16, No. 3

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Consideration on the Basic Design and Application of Counter-Rotating Turbines
CAI Rui-xian
2001, 16(3): 193-198.
Abstract PDF(961KB) icon1509 icon505
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According to the comprehensive basic analysis of counter rotating turbines given by the author ten years ago,some aero thermodynamic design problems, which have not yet attracted enough attention of turbine designers,are raised and discussed.The possibilities for application of various counter rotating elementary stages and their cascades are elaborated from the viewpoint of the required matchings of the loads,rotating speeds and pressure ratios between the high pressure and low pressure counter rotating shafts,and then the turboengine systems suitable for utilization of the counter rotating turbines are proposed.Finally the possibility and necessity for designing the ultra high turning angle cascades and the ultra high inlet and outlet angle (related to axial direction) low turning angle cascades are considered.Therefore the consideration on integration of the requirements for both the engine systems and turbomachinery gasdynamic designs will be beneficial to the development of the counter rotating turbines.
A Review of Vortex Model Development for Rectangular Turbine Cascades
ZHOU Xun, HAN Wan-jin
2001, 16(3): 199-204,198.
Abstract PDF(861KB) icon1739 icon549
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Six valuable vortex models for the rectangular turbine cascades are considered and the mechanisms of their evolution are discussed.The review comes to a conclusion that the substance of the vortex controlling technology in aerodynamic field is an attempt to construct or reconstruct the vortex structure.Therefore the future improvement in the flow efficiency of the turbine cascades is the optimum matching between cutting and expansion of the gas curved flow by controlling the strength,length and location of the passage vortex at outlet plane.
Development and prospect of Controlled Diffusion Airfoils for Multistage Compressor Part Ⅰ:Design and Development of Controlled Diffusion Airfoils
ZHONG Jing-jun, WANG Hui-she, WANG Zhong-qi
2001, 16(3): 205-211.
Abstract PDF(961KB) icon2050 icon497
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The optimum design of Controlled Diffusion Airfoils (CDA) is one of the main research fields in subsonic and transonic profile design for multistage compressor.This paper reviews the necessity of CDA research,the background of CDA development,the features and design methods of first generation CDA and the second generation CDA with consideration of cascade endwall flow.The CDA is originated from the supercritical airfoil.Controlling the diffusion on the suction surface of an airfoil,can eliminate or decrease the shock wave,reduce the loss and enlarge the range of incidence.Around this criterion of airfoil design,many design methods have been proposed,which can be classified into inverse method and direct method.The CDA research in China started later than many other countries,and concentrated mainly on its principles and design methods.
Research and Development of Pulse Detonation Engines
YAN Chuan-jun, HE Li-ming, FAN Wei, LEI Heng-ren, HUANG Xi-qiao, ZHANG Qun
2001, 16(3): 212-217.
Abstract PDF(1046KB) icon2380 icon654
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This paper reviews the principles and primary characteristics of Pulse Detonation Engine (PDE),the prospect of its application and trends of its development.The results of our recent theoretical,experimental and numerical researches of pulse detonation engines are summaried.The experiments of a two phase PDE with three different diameters were carried out successfully.The gasoline/air mixture was used in the PDE.The ignition frequency can vary in the range of 5～117 Hz.The ignition energy of the spark igniter used in these experiments is approximately 50 mJ.The PDE research areas,key technology and development stages in 21 century are foreseen.
Application and Development of Platform Friction Damper for depressing Resonant Vibration of Blades
SHAN Ying-chun, HAO Yan-ping, ZHU Zi-gen, YAN Li-tang
2001, 16(3): 218-223.
Abstract PDF(838KB) icon2102 icon597
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Utilization of dry friction has been recognized to be an effective and simple means to increase the damping level and reduce blade vibratory stresses of the bladed disk system.The platform damper is a kind of such application.During the last twenty years,a great deal of researchers has been working on structural models for the blade/friction damper system and the nonlinear analytical methodology to predict the dynamic behaviors of the frictionally constrained blade system.In result certain theoretical principles have been provided for designing the platform damper.This paper reviews recent works in three aspects:simplified structure models,nonlinear analytical approach and damper design optimization.The authors make attempts to indicate the advantages and constraints of the models and methods in common use and present the problems worthy to research in the future.
Calculation of Turbulent Flow over Three-Dimensional Turbine Rotor Blade Rows with Film Cooling on Unstructured Grids
WANG Bao-guo, LI Rong-xian, MA Zhi-mingqe, LUO Xiao-yong
2001, 16(3): 224-231.
Abstract PDF(1135KB) icon1521 icon460
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A high resolution finite volume scheme for the Reynolds averaged Navier Stokes solutions on unstructured Grids has been developed and tested in rotating Cartesian coordinates.A Godunov type upwind method was used for inviscid flux computations.The second order smoothing operator and the minmod limiter were developed for shock capturing.A finite volume formulation was applied to computations of viscous terms.The turbulence models for suction and pressure surfaces of turbine rotor blade rows with film cooling were established,respectively.Initial conditions in calculation procedure of N S equations were given by a new method.The rotor region had a tip clearance grid system that contained about 7 grid points in the spanwise direction.The computed results obtained from the proposed scheme are compared with experiment in a good agreement and show a dramatic improvement in the convergence and in the resolution of flowfield.
Improvement for Unstructured Grid Generation and Calculations of Three-Dimensional Turbulent Flow around Turbine Stator Blade Rows with Film Cooling
WANG Bao-guo, LI Rong-xian, MA Zhi-ming, GE Zhao-sheng
2001, 16(3): 232-237.
Abstract PDF(363KB) icon1671 icon443
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The generation of prismatic unstructured grid for complex3 D geometries and the application of a new high resolution algorithm for the unstructured grids have been developed in consideration of the engineering background.The unstructured grids are generated on one given S1 surface (i.e.a surface of constant x3 in a three dimensional curved coordinate ( x1,x2,x3),while the grids on the other S1 surfaces are constructed by a space mapping.The final grids obtained in this way become unstructured on S1 surfaces and structured in x3 direction.Therefore they are composed of pentahedrons.In the generation of the grid on the S1 surface,the triangle elements of 0 type grid are created near the walls.By improving Bowyer Watson method,a scheme of high efficiency is developed to produce unstructured grids in the region far from the walls.The new algorithm consists of a high resolution finite volume scheme for the 3 D Navier Stokes turbulent flow equations.Spatial discretization uses a finite volume.High order Taylor series expansion is employed to march the solution in time.Spacial volume and time step weighting of the residual are employed to produce a stable scheme.A second order smoothing operator and the minmod limiter are developed for shock capturing.The operator retains its order with unstructured grids.Some typical numerical examples, including a turbine stator blade row with film cooling,demonstrate the ability of the algorithm to resolve local flow features.
Determination of Similarity Criteria for Flow and Heat Transfer of Rotor-Stator Disks System
CAI Yi, XU Guo-qiang, DING Shui-ting, TAO zhi
2001, 16(3): 238-241.
Abstract PDF(631KB) icon1699 icon491
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Characteristic parameters, qrR/λD are introduced as the temperature difference to non dimensionalize the governing equations,and then the similarity criteria for flow and heat transfer of rotor stator disks system are established.It is concluded that the study of cooling effects in the turbine disks should comprise not only Nusselts number for disk surface convective heat transfer,but also the non dimensional excessive averaged body temperature for total disk temperature level and the non dimensional radial temperature difference for the disk radial thermal stress.With resort to the concept of turbine blade cooling efficiency,an expression is derived for calculating the cooling efficiency of a turbine disk.
Unsteady Numerical Simulation on the Effects of Hot Streak Phenomena on Turbine Stage
DONG Su-yan, LU Song-ling, ZHU Hui-ren
2001, 16(3): 242-248.
Abstract PDF(914KB) icon2011 icon533
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The unsteady numerical simulation is completed by means of two dimensional,Navier Stokes analysis to predict unsteady flow and temperature fields with inlet temperature distortions in a turbine stage.Because of relative movement of blade rows,the pressure distributions on the blade and the flow field in the cascade vary periodically.When the distribution of inlet flow temperature becomes non uniform,the inlet hotter gas in the hot streak will migrate to the pressure surface of the rotor blade and causes the hot spot on it.The location of the hot streak has a significant effect on the surface temperature distribution.However the presence of hot streak has little effect on the pressure distribution on the blade surface.
Endwall Heat Transfer and Film Cooling Measurements in a Turbine Cascade with Injection Upstream of Leading Edge
LIU Gao-wen, LIU Song-ling, ZHU Hui-ren, Lapworth B L, Forest A E`
2001, 16(3): 249-255.
Abstract PDF(1096KB) icon2083 icon578
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Detailed heat transfer measurements were conducted on the endwall surface of a large scale low speed turbine cascade with single and double row injection on the endwall upstream of leading edge.Local film cooling effectiveness and heat transfer coefficient with coolant injection were determined at blowing ratio 1,2 and 3.In conjuction with the previous measurement flow field,the behaviours of endwall film cooling and heat transfer were studied.The results show that endwall film cooling effectiveness is influenced to a great extent by the secondary flow and the coverage of the coolant on the endwall is mainly determined by blowing ratio.An uncovered triangle shaped area with low effectiveness close to pressure side could be observed at low blowing ratio injection.The averaged effectiveness increases significantly when injecting at medium and high blowing ratio,and quite uniform coverage of coolant on the endwall could be achieved.The averaged effectiveness could be doubled in case of double row injection.It was also observed that coolant injection made the overall averaged heat transfer rate increase remarkably with blowing ratio and then made the thermal loads on the endwall decrease effectively.Large increments of heat transfer rate could be happened at cascade entrance and exit and in the area near suction surface.
Investigation on Compressor Blade Load Distribution in Endwall Regions
ZHOU Zheng-gui, WU Guo-chuan
2001, 16(3): 256-261.
Abstract PDF(794KB) icon1775 icon505
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In order to find out the effects of blade load distribution on the flow in endwall boundary layers,three sets of planar cascades were designed,in which the blade loads tending to blade front,middle and rear parts,are numbered as No 1,No 2 and No 3 respectively.The static pressure on the blades and the cascade outlet flow fields are investigated by experiments and three dimensional Navier Stokes equation methods.The following conclusions were drawn:The performance of the No cascade #3 is inferior to that of 2 cascades #1 and #2;In the endwall region of cascade #2,the flow outlet loss is smaller but the deviation angles are larger and the pressure elevating ability is weaker than those of cascade #1;In a given inlet endwall boundary layer,the variation of the blade force defect is positively correlative to the blade force variation;In the corner region formed by the blade suction surface and the endwall,corner vortex does not induce obvious decrease of pressure on the suction surface of blade rear part in the endwall region;The outlet vortex strength of cascade #2 is smallest.
The Solution of Round-Jet/plane-jet Anomaly Using GAO-YONG Incompressible Turbulence Equations
LI Wei-bing, GAO Ge
2001, 16(3): 262-266.
Abstract PDF(298KB) icon3409 icon440
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The round-jet/plane-jet anomaly remains as a long unsolved problem in turbulence,and it is the touchstone of a turbulence model of differential equations.In this paper,axisymmetric round-jet is numerically simulated with GAO YONG turbulence model.The calculation successfully simulates the flow and predicts a spreading rate of 0.086,which is close to the measured range of 0.086 to 0.093 and thus solves the round-jet/plane-jet anomaly problem.All the results further verify the adaptability and generality of the equations to real turbulent flow.
A Non-Linear k-ε-kp Two-Phase Turbulence Model
GU Hong-xia, ZHOU Li-Xing
2001, 16(3): 267-272.
Abstract PDF(839KB) icon1706 icon474
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A nonlinear k-ε-kp two phase turbulence model is proposed for simulating anisotropic turbulent two phase flows,such as swirling and buoyant flows.Non linear relationships of two phase stresses and two phase fluctuation velocity correlations with the strain rates are derived based on the two phase algebraic Reynolds stress expressions.The nonlinear k-ε-kp model is applied to simulating two phase sudden expansion flows and the results are compared with those obtained from the second order moment model,linear k-ε-kp model and experimental data.It is shown that the nonlinear k-ε-kp model is almost as good as the second order moment model but with much less computation time,and is obviously better than the linear k-ε-kp model in simulating anisotropic two phase turbulence.
A Study on the Two-Dimensional Thrust Vectoring Nozzle with Secondary Flow Injection
QIAO Wei-yang, CAI Yuan-hu
2001, 16(3): 273-278.
Abstract PDF(331KB) icon2154 icon480
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The new type of two dimensional thrust vectoring nozzle with the secondary flow injection was studied by using experimental method and CFD method.The experiments were finished in a supersonic wind tunnel in NPU.The wall pressure and the thrust vector angle were measured for the different secondary flow pressure under the constant main flow pressure.The flow field and performance of the nozzle were also analyzed by the computation of Reynolds averaging N S equations with the time marching finite volume method.The computed results were compared to experimental data in a good agreement.Both the experimental and computational results showed that the pressure of secondary injection flow should be large enough to create a vectoring thrust.In our case the threshold ratio of the total pressure of the second flow to that of main flow was 0 32 and the maximum deflection of the thrust vector was 46°.
An Inverse Aeroacoustic Problem on Rotor/Stator Interaction
LUO Jun, LI Xiao-dong
2001, 16(3): 279-282.
Abstract PDF(759KB) icon1491 icon495
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An inverse aeroacoustic problem on rotor/stator interaction is investigated,which aims at reproduction of the unsteady pressure distributions on the stator blade according to the sound pressures at a limited number of points in space.On basis of the linearized Euler equation,the sound pressure is correlated with the unsteady pressure distributions on stator blade surface in the form of the Fredholm integral equation of the first kind.In order to solve this kind of typical ill posed problem,the least square method,which combines singular value decomposition technique and Tikhonov regularization method,is used,and the discrete Picard condition is employed to analyze the ill posed problem.The regularization parameter is chosen by Generalized Cross Validation method.The numerical results show that the reproductions are feasible on the conditions that the signal to noise ratio is not very low.
Effects of Non-Smooth Blades on the Cascade Exit Streamwise Vortex Systems
WEN Jie, ZHAO Gui-lin, HE Long-de, PENG Hui
2001, 16(3): 283-286.
Abstract PDF(287KB) icon1235 icon453
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An experimental investigation on the cascades equipped with conventional smooth blades and non smooth blades was carried out in the low speed plane cascade wind tunnel,so as to study the effects of non smooth blades on the exit streamwise vortex systems.The experimental results show that the non smooth blades exert a distinct influence on the exit streamwise vortex systems.The locations of the passage vortex and trailing vortex shift toward the centre of cascade passage,and the intensity of the trailing vortex weakens.
Numerical Method for Calculating the Burst Speed of Axial-Flow-Type Discs
GU Ai-jun, ZHANG Xue-ren, WANG Ping, LIU Si-yong
2001, 16(3): 287-290.
Abstract PDF(695KB) icon1914 icon468
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Two dimension non linear finite element calculation has been done for three kinds of axial flow type discs at normal and high temperatures.A burst criterion is presented for calculating the burst speed of rotating disc using finite element method,and the burst speed of the rotating discs is obtained. The results are compared with experimental data and analytic results according to large deformation theory.
Experimental Investigation on Thin Shell Random Vibration Excited by Noise
CAO Mao-guo, LI Lin
2001, 16(3): 291-294.
Abstract PDF(243KB) icon2012 icon504
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An experimental scheme was designed for investigation on the random vibration of the thin shell under excitation of the noise.A cylindrical shell with length 640 mm inner radius 253 2 mm,and thickness 0 8 mm was tested.The experimental installation consisted of three parts:noise generation system,noise pressure measurement system and vibration response measurement system.The time history of noise load and the shell responses were measured by microphones and acceleration sensors,and then the noise load spectrum and response spectrum were analyzed qualitatively.The characteristics of the noise load distribution in frequency domain and the vibration response under the inner random noise were obtained.Therefrom the conclusion was drawn that every vibration model of the thin shell could be excited in the frequency domain of the noise.
A Design Method for Aeroengine Robust Multivariable Digit Controller
WANG Xi, MENG Qing-ming
2001, 16(3): 295-299,304.
Abstract PDF(853KB) icon1627 icon462
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A method is provided for designing robust multivariable digit controller of turbojet engine,in which the forwardback and feedback control structure is adopted in the divided flight envelope,the μ structurization is used to deal with the structured uncertainty and unstructured uncertainty,so that the problem for solving robust controller is transformed into standard H∞ control problem.The robust disturbance rejection and tracking performance is verified by simulation on a nonlinear model of the twin spool turbojet engine aerothermodynamics.
Study on Non-Augmented Supersonic Cruise of the 4th Generation Engines
TU Qiu-ye, TANG Di-yi
2001, 16(3): 300-304.
Abstract PDF(321KB) icon1641 icon457
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In order to improve the non augmented supersonic cruise performance of the 4th generation engine,an idea for designing is proposed,which consists in rational matching of the high pressure rotor physical speed to the throttle ratio at ground design point and utilization of the "cold overrun" and "gas temperature storage" techniques for performance optimization.A realization of the ides is carried out.It is proven that the velocity characteristics of the engine is improved to a great extent and the optimal thrust characteristics of the engine are provided in a broad range of the flight Mach numbers.

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