2005 Vol. 20, No. 4

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Display Method:
Integral Estimate Method for Censored Data
FU Hui-min, LIN Feng-chun
2005, 20(4): 529-533.
Abstract PDF(2979KB) icon1400 icon435
Abstract:
An integral estimate method for censored data or incomplete data of valuable products is presented. Combining the results of simulation or digital design and censored data or incomplete data,it can totally infer the censored data or the incomplete data in multi-state (for multi-population).And then,in each state,it can derive the estimators of the location and the scale parameter,and the confidence limits and intervals of population percentiles.Compared with traditional method,this presented method not only has higher precision but also solves the problem of reliability assessment with very small sample.Another method is also presented,which can test the results of simulation or digital design with censored data or incomplete data.
Pseudo-Time Method of Weighted ENO-Strongly Compact High Resolution Schemes and Its Application to Turbomachinery Unsteady Flow
WANG Bao-guo, LIN Shu-yan, ZHANG Ya, JI Xiu-ling, JIN Yan-mei
2005, 20(4): 534-539.
Abstract PDF(3599KB) icon1922 icon510
Abstract:
The Pseudo-time Method and high accuracy rapid iterative scheme were developed for unsteady 3D N-S equations with unstructured grids.This scheme has two-order accuracy in time,and combines weighted ENO scheme (r=3) and strongly compact scheme to treat convection term in N-S equation and the right terms of the discrete equation.Besides,four-order accurate strongly compact scheme is used to calculate viscosity term of N-S equation.Three typical cases were used to check the scheme in different ways.Numerical test shows that the scheme not only has the character of high efficiency and high resolution,but also can keep high-order accuracy.Further,the computed results obtained from the proposed scheme are in good agreement with experiment and show the scheme can simulate physical process of unsteady flow with unstructured grids.
The Effect of Unsteady Wake on Leading Edge Film Cooling
JIANG Xue-hui, ZHAO Xiao-lu
2005, 20(4): 540-544.
Abstract PDF(286KB) icon1891 icon438
Abstract:
Numerical simulations were performed to study the affect of unsteady wake on leading edge film cooling.The calculated film cooling effectiveness was compared with the experimental results.The unsteady numerical simulation shows that the stagnation point moving to the cooling flow slit causes the cooling flow to diverge when the unsteady wake swept through the film-cooling slit.The divergence of the cooling flow results in sharply decreasing of the film cooling effectiveness downstream the film-cooling slit.
Numerical Simulation of Turbofan Engine Afterburner Light-on Process
XUE Qian, XIAO Hong, LIAN Xiao-chun
2005, 20(4): 545-548.
Abstract PDF(230KB) icon1958 icon446
Abstract:
Numerical simulation of turbofan engine afterburner light-on process was presented.The volume effects of mixer,afterburner and outlet duct was taken into account.Performances of fan,compressor,turbine and time consumed for filling afterburner fuel ducts were incorporated into simulation.Based on the dynamic equations of three volumes,i.e.volumes of afterburner,main combustion chamber and fan duct,the simulation could be rapidly performed with high fidelity and without iteration.
Direct Numerical Flow Simulation in a Two-Dimensional Turbine Cascade
WEI Dong-hai, ZOU Zheng-ping, YE Jian, YAN Ming, LU Li-peng
2005, 20(4): 549-555.
Abstract PDF(2221KB) icon1875 icon478
Abstract:
Using high order finite difference scheme,a Direct Numerical Simulation (DNS) of vortex shedding in a two-dimensional VKI turbine cascade has been carried out.The Reynolds number is 10 000,and the angles of attack are 0 deg,8 deg and -8 deg.The mechanism of unsteady flow in turbine cascade was investigated.Numerical results indicate that,near cascade trailing edge region,clockwise and anticlockwise primary vortices generate alternately from the surface.Secondary vortices form at the interactions of primary vortices and main flow.When secondary vortices mix with the main flow,primary vortices are divided and shedded from trailing edge.The changes of incidence in a certain range have no prominent influences on the development of blade boundary layer.The statistical characteristics and velocity defect characteristics in the wake region are also analyzed.
Numerical Simulation of the Influence of Nozzle Area Control Accuracy on Turbofan Afterburning Performance
LI Wei, LI Jun, DONG Shun-yi
2005, 20(4): 556-560.
Abstract PDF(374KB) icon1947 icon507
Abstract:
Numerical simulation was used to simulate the turbofan engine performance under afterburning condition.The volume effect of the mixer,afterburner,main combustor and fan duct as well as the variation of the nozzle area was considered.Based on the developed simulation model,the influence of nozzle critical area change on engine performance under afterburning condition was calculated.The results are consistent with the experimental data.The simulation model can lay an academic foundation for evaluating the effect of nozzle area control.
Numerical Investigation of Boundary Layer Suction in Compressor Cascade with Large Turning Angles
SONG Yan-ping, CHEN Fu, ZHAO Gui-jie, CHEN Kai-Ying, WANG Zhong-qi
2005, 20(4): 561-566.
Abstract PDF(809KB) icon3184 icon531
Abstract:
Numerical study of the effects of suction location and suction flow rate on performance of low-speed compressor cascade with large turning angles shows that with the same inlet Mach number,the optimal suction location,corresponding to the least cascade total loss,exists at a lower suction flow rate,and the decrease of total loss is not sensitive to the suction location at a higher level of suction flow rate.As suction flow rate increases,the accumulation of low energy fluid in the suction corner is alleviated,and the flow turning as well as the cascade load increases,therefore,total loss is reduced by 28.2% at most.The diffusion recovery due to the boundary layer suction and the separation of passage vortex are two main factors for the selection of the optimal suction location and suction flow rate.
Application of Probability Density Function Analysis in the Monitoring of Engine Aerodynamic Instability Precursor
ZHANG Pu, LI Ying-hong, WU Yun, LIU Jian-xun, ZHANG Bai-ling
2005, 20(4): 567-571.
Abstract PDF(1006KB) icon1989 icon428
Abstract:
Experiments were performed to investigate surge problem of a single shaft axial flow turbojet engine during throttling.If the discharge bleed valve of the engine is closed manually,the working line of the engine will traverse the stalling region in a mass flow range,thus throttling from full speed may surely transit the engine into unstable operation.It is observed that the casing wall static pressure of the first compressor stage stator is most sensitive to throttling operation, and that probability density functions of the pulsating components of the static pressure vary accordingly.An eigenvalue,θ,is then introduced to quantify the variation of probability density functions.Further data analysis demonstrates that eigenvalue θ is capable of reflecting some aspects of flow separation in the tip region of the first compressor stage, and that θ may serve as an indicator of imminent aerodynamic instability of the engine, thus long stall warning time of the examined turbojet engine is achievable than that to directly detect modes or spikes.
Application of the Reynolds Stress Model to the Calculation of Three-Dimensional Turbulent Flow-Field
ZHANG Ya, LIU Shu-Yan, WANG Bao-guo
2005, 20(4): 572-576.
Abstract PDF(2210KB) icon1950 icon445
Abstract:
Based on the Reynolds Stress Model, the three-dimensional flow field was numerically simulated using the Reynolds averaged N-S system equations.The flow fields were calculated and compared with the results of several turbulent models.Two typical examples were presented.Comparing numerical results to experimental data,we can find that the numerical results with the Reynolds Stress Model (RSM) are closer to the experimental data than with the Standard k-ε model.Besides,detail flow field of a typical problem was simulated with RSM using three-dimensional unstructured grids.Numerical results show that the Reynolds Stress Model could simulate turbulence anisotropic behavior of the complex three-dimensional flow field.
Knowledge Sharing for Aircraft Engine Design Based on Knowledge Management
DU Bing-lao
2005, 20(4): 577-583.
Abstract PDF(857KB) icon1728 icon477
Abstract:
Knowledge sharing is the core of knowledge management.Sharing of design knowledge is a key to successful implement of knowledge management for aircraft engine design.It is helpful to improve the capability of learning,to increase the gross knowledge capital,to optimize the structure of knowledge capital,to enhance the capability of innovation of the design organization and to introduce the mechanism for knowledge sharing in the research institute of aircraft engine design.Consequently,this would enhance the design capability of aircraft engine design organization.The knowledge management flow for aircraft engine design were drawn out with an emphasis on correlation matter of knowledge sharing,which include knowledge transfer,obstacle to implement knowledge sharing,implement strategy and key technology of knowledge sharing.
Research on the Discrepancy of Composite Effective Properties Induced by the Stochastic Fiber Location
GAO Xi-guang, SONG Ying-dong, SUN Zhi-gang
2005, 20(4): 584-589.
Abstract PDF(1030KB) icon1763 icon464
Abstract:
Based on Monte-Carlo method,uniform simulation and Gaussian simulation were used to simulate the stochastic fiber location.The digital images of the material cross-section were generated by the simulation method.Grids were generated by meshing the digital image pixels.Based on these grids a GMC (General Method of Cell) method is used to calculate the composite elastic properties.Then,the properties were analyzed by statistic method.The results show that the simulation methods accurately represent the stochastic fiber location.The discrepancy of elastic properties increased with the vf (volume fraction of fiber) when the vf is low and decreased with vf when the vf is high. The three-parameter Weibull pdf and Gaussian pdf describe the distributions of every elastic coefficient accurately.
Numerical Simulation and Analysis of a Finger Seal Leakage Flow
WANG Xu, ZHANG Wen-ping, LAI Liang, LIANG Hai-dong
2005, 20(4): 590-594.
Abstract PDF(305KB) icon1879 icon492
Abstract:
The Basic structures of finger seal were introduced,and according to the features of finger seal structure,the mathematic model and calculating model of finger seal leakage flow were set up.In the light of the main affecting factors of finger seal leakage characteristics,the numerical simulations and analysis were done using the CFD software FLUENT.Some important conclusions were given in the paper.
Temperature Fields Calculation of Fiber Reinforced Composite at Micro-Level
SUN Zhi-gang, SONG Ying-dong, GAO De-ping
2005, 20(4): 595-599.
Abstract PDF(784KB) icon1630 icon476
Abstract:
The efficient reformulation of higher-order theory was deduced.In this approach,averaged quantities at the interface were the primary variables,and the averaged quantities were used to replace the coefficient of temperature.By using the heat exchange equations,the relationship between heat flux and average temperature was established,and temperature field was solved.This procedure reduces the number of equations involved and eliminates the concept of generic cells.The temperature fields of fiber reinforced composite at micro-level were calculated.Numerical results agree well with the available results from finite elements and theoretical analysis.
Rotor Balancing Taking Nonlinear Stiffness Characteristics into Account
TANG Yun-bing, LUO Gui-huo, ZHANG Jing-xuan, GAO De-ping
2005, 20(4): 600-605.
Abstract PDF(1012KB) icon2025 icon492
Abstract:
The linear relationship between the corrected value and measured value is used to balance the rotor in the influence coefficient method.When rotor are supported on the bearings having nonlinear stiffness characteristics,it would be difficult to balance the rotors since linear hypothesis would not be valid.The motion equation of a multiple-degree rotor system is formulated by using Lagrange equation and flexibility influence coefficients.The equivalent linearization model of the nonlinear multiple-degree system is used to balance the nonlinear system in this paper.The example shows that the vibration response caused by unbalance mass reduces greatly and the method developed in this paper is successful.
Adaptive Demodulated Resonance Technique for the Rolling Bearing Fault Diagnosis
WANG Ping, LIAO Ming-fu
2005, 20(4): 606-612.
Abstract PDF(359KB) icon1932 icon473
Abstract:
There are two drawbacks of the Demodulated Resonance Technique (DRT), which are: impact test is needed to determine the excitation frequency of a bearing system;the central frequency of the band-pass filter is unchangeable.Adaptive Demodulated Resonance Technique (ADRT) was used to overcome the drawbacks.ADRT can auto-identify the high-frequency resonance frequency by analyzing the vibration signal measured on the bearing housing,and can adaptively change the central frequency of the band-pass filter based on the high-frequency resonance frequency of the bearing system.Experimental results of the 6307 bearings show that the ADRT is more convenient and effective in extracting the symptoms of the rolling bearing faults than DRT.
Experimental Investigation of the Affect of Endwall Fence Location on Compressor Cascade Loss
TIAN Fu, ZHONG Jing-jun, MENG Li-yan
2005, 20(4): 613-618.
Abstract PDF(345KB) icon1889 icon475
Abstract:
The affect of endwall fences at different locations on compressor cascade loss and secondary flow were investigated through detailed experimental investigation in a low speed wind tunnel.The results show that the secondary flow in the compressor cascade can be controlled effectively and the total cascade loss can be reduced in case of the proper selection of the end wall fence location.Through the measurement of the cascade internal flow with the optimum fence location in terms of minimum loss,the vortices in the cascade with endwall fence were analyzed.The formation and development of the endwall fence vortices were also discussed.
Effect of Casing Treatment on the Response to Steady Circumferential Pressure Distortions of an Axial Flow Compressor with Inlet Guide Vanes
WU Hu, SIRI Guleng, GAO Shuang-lin
2005, 20(4): 619-624.
Abstract PDF(412KB) icon1959 icon487
Abstract:
An efficient calculation procedure was established which allowed the rapid computation of the total pressure distortion development through any combination of rotors,stators and clearances.The predictions of the response to steady circumferential pressure distortion of an axial flow compressor inlet guide vanes,rotor,stator and axial clearance were presented with four casing configurations:solid casing,circumferential groove casing,axial skewed slot casing,and blade angle slot casing.The affects of inlet guide vanes on response to steady circumferential pressure distortion of an axial flow compressor with four casing configurations were obtained.In comparison with solid casing,greatest attenuation of total pressure distortion and static pressure distortion through the rotor and stator of three casing treatment configurations were obtained.It is obvious that effective improvement in stall margin can be achieved with three casing treatment configurations under conditions of inlet circumferential pressure distortions.Appropriate design of casing treatment configurations for multistage axial flow compressors would be able to make axial compressors have high tolerant to inlet pressure distortions.
Investigation of 3D Axial Flow Compressor Blade Shape Optimization Based on NURBS
JIN Jun, LIU Bo, CAO Zhi-peng, NAN Xiang-yi
2005, 20(4): 625-629.
Abstract PDF(617KB) icon1794 icon469
Abstract:
The NURBS method was introduced for the 3D geometric optimization of axial-flow compressor blade design.A set of optimization rule was developed by relating some aerodynamic performance parameters with the weights factor of NURBS.In the design of an axial compressor stator blade,the flow structures comparison have been made between the optimized new blade and the original one.The results show that this method could flexibly and rapidly optimize the blade shape to meet the aerodynamic requirements.
Curve Fitting Method of Fan Performance Map with Constraint
FANG Qian, SHI Zhong-ke
2005, 20(4): 630-635.
Abstract PDF(791KB) icon1728 icon504
Abstract:
Experimental fan performance map is important for turbofan engine performance simulation,but the experimental data are always very limited.In order to get more information from the experimental data, the relationships between the increments of fan’s inlet and outlet total temperature and rotational speed under constant corrected spool speed were discussed.On the basis of the results,the relationship of the characteristic data was obtained and the constraint for fan performance map fitting was established.Via quadratic programming,a new method for fan performance map fitting was established.Numerical simulation was given which demonstrated the effectiveness of the method.
Research on the High-Temperature Rise Combustor Lean Blow-out and Smoke Emission Characteristics
XU Quan-hong, LIN Yu-zhen, LIU Gao-en, WANG Zhi-ping
2005, 20(4): 636-640.
Abstract PDF(782KB) icon2084 icon492
Abstract:
A new high temperature rise combustor design with a three-swirler and hybrid injector to improve the smoke emission and lean blow-out characteristics was presented.The uniformity of fuel air mixture distribution in the primary zone of the new design is fairly good,while the fuel air mixture in the recirculation zone is rich.Experimental research was conducted to compare the new design with base-line design in terms of smoke emission and lean blow-out characteristics under the same inlet condition.The experimental result shows that the new high temperature rise combustor design successfully broadens the operation range and improves the smoke emission characteristics.
Application of Characteristic Method to the Performance Calculation of the Pulse Detonation Engine
CHEN Yong-gang, HE Li-ming, LIU Jian-xun
2005, 20(4): 641-644.
Abstract PDF(623KB) icon1719 icon504
Abstract:
A physical model of the detonation wave propagation process in the detonation combustion chamber was developed on the x-t diagram,and one-dimensional numerical simulation of the unsteady flow in a pulse detonation engine was conducted by applying characteristic method.With that an engine performance calculation method was deduced.The PDE performance calculation result shows that characteristic method is feasible and accurate.
Numerical Simulation and Validation of Pulse Detonation Engine on Ejector Mode
LI Mu, YAN Chuan-jun
2005, 20(4): 645-650.
Abstract PDF(414KB) icon1575 icon486
Abstract:
Numerical investigation was conducted in which ejecting mode of a multi-cycle pulsed detonation rocket engine with a simple cylindrical ejector was simulated using unsteady axisymmetric N-S Eqs.Experiments were carried out to measure the ejection ratio,which was used as the comparative parameter.The result of simulation is in good agreement with that of experiment.Ejecting process was divided into three phases corresponding to three different working mechanisms:(1) air compression and acceleration by shockwave;(2) shearing and dragging of the plume;(3) action of inertia and pressure gradients.The simulation result can also be used as a reference for the design of fuel injection.
Preparation and Thermal Properties of Microencapsulated Phase Change Material for Enhancing Heat Transfer
RAO Yu, LIN Gui-ping, LUO Yan, CHEN Shui-lin, WANG Liang
2005, 20(4): 651-655.
Abstract PDF(367KB) icon1939 icon537
Abstract:
Microencapsulated Phase Change Material (MEPCM) suspension liquid is a coolant with high heat capacity,which can enhance considerably liquid cooling performance.MEPCM with a double-layered shell containing paraffin and melamine resin as wall material was prepared.Its surface condition and thermal characteristics were obtained through SEM and DSC respectively.The spherical shape particles were observed to be well-wrapped by using optical microscope and Scanning Electronic Microscope (SEM).The influence of different parameters in terms of radius distribution and encapsulation properties on the characteristics of the MEPCM has been investigated.Very high heat sink capacity of the MEPCM was found by DSC method.
Numerical Investigation on Heat Transfer in a Rotating Cavity with Axial Throughflow Cooling Air
TIAN Shu-qing, TAO Zhi, DING Shui-ting, XU Guo-qiang
2005, 20(4): 656-661.
Abstract PDF(414KB) icon1961 icon508
Abstract:
To investigate the heat transfer in heated rotating cavities with axial throughflow cooling air,numerical simulations have been carried out based on the time-independent incompressible equations in rotating system.The effects of unstable flow and various forces on heat transfer were studied,and the heat transfer coefficient variations with Reynolds number and Rayleigh number were calculated.The results show that the heat transfer in a rotating cavity with axial throughflow cooling air is enhanced with the increase of the inertia force and buoyancy force,and is weakened with the increase of the Coriolis force.The heat transfer coefficient rises with Reynolds number,and varies slightly with the increase of Rayleigh number.The sudden enhancement of heat transfer is caused by the penetration of cooling air through the disc cavity.
Prediction of Turbulent Flow and Heat Transfer within Rotating U-Shaped Passages
LIU Chuan-kai, DENG Hong-wu, TAO Zhi, DING Shui-ting, XU Guo-qiang
2005, 20(4): 662-667.
Abstract PDF(933KB) icon1359 icon473
Abstract:
Numerical predictions of three-dimensional flow and heat transfer in the rotating serpentine passages with and without rib turbulators were presented.The coolant air is pressurized and its operating conditions are selected to closely match with the real turbine operating parameters.Two different arrangements of rib turbulators were studied:(1) transverse ribs on the leading and trailing walls and (2) transverse ribs on all four walls.The rib height-to-hydraulic diameter ratio (h/Dh) is 0.143;the rib pitch-to-height ratio (s/e) is 7.Results for the roughened rib serpentine passages were compared with those of smooth ones found in the literature.It is disclosed that a significant enhancement is achieved by means of rib turbulators in a serpentine passage in steady state as well as in rotating state.In the radially-outward flow passages, effect of rotation on heat transfer is relatively prominent.The secondary flows induced by the Coriolis forces are most intensive in the channel with four ribbed surfaces.The heat transfer after 180° sharp turn in the smooth channel is influenced more by the sharp-turn induced flow than in the roughened rib ones.
Study of Heat Transfer Characteristics of Different Cooling Configurations inside a Typical Low Pressure Turbine Blade
ZHANG Li-min, WEN Jie, DING Shui-ting, TAO Zhi, XU Guo-qiang
2005, 20(4): 668-672.
Abstract PDF(756KB) icon1707 icon450
Abstract:
Numerical simulation and experiment were carried out to study the characteristic of different cooling configurations in a typical low pressure turbine blade.Numerical simulations were performed to investigate the heat transfer of original blade and the improved blades.The numerical results show a good agreement with the experimental ones.Compared to the original blade,the improved blade enhanced the heat transfer effectiveness about 7.8%.The research results indicate that the configuration improving of the inner passage not only reinforces the performance of heat transfer,but also improves temperature distribution and avoids superheated regions.
Investigation of Corrected-Parameter Adaptive Control for an Aeroengine Digital Control System
YAO Hua, JIANG Ping-guo, SUN Jian-guo
2005, 20(4): 673-678.
Abstract PDF(397KB) icon1769 icon483
Abstract:
According to the aeroengine nonlinear and time-varying features in the entire flight envelope,the design method of parameters-adaptive PID controller was put forward,and two kinds of parameter estimators including least-squares method and corrected-parameter method for on-line identification and tuning were investigated.The two control algorithms were compared through the simulation with aeroengine linear or component-level nonlinear models.The results show that the control system using corrected-parameter adaptive PID controller is stable and the control algorithm is simple and adaptable to the entire flight envelope.The corrected-parameter adaptive PID controller was implemented to an aeroengine FADEC system,and its advantages were validated by ground test and flight test.
Application of Robust Control to the Design of Jet Engine Digital Controller
WANG Xi, YANG Jie, TAN Dao-liang, TIAN Xin-feng, WANG Hai-long
2005, 20(4): 679-683.
Abstract PDF(791KB) icon1851 icon434
Abstract:
Based on the LMI (Linear Matrix Inequality) method,the PID (Proportional Integral Derivative) control law was combined with robust control technique,and the subsection switch skill of PI output feedback control design with constraint of control input for aero-engine was proposed.The technology was applied to the steady state control of the full function digital electronic control system of a jet engine.The constitution of the system,including hardware,software,step motor actuating mechanism and fuel metering device,was introduced.Electronic controller not only can control the rotating speed stable but also have enough logic,multiple control monitor and protective functions.It fulfills all requirements of multiple FADEC control.The designed electronic controller has been carried through robust validity check on the engine semi-hardware-in-loop simulation platform.
Research of Aeroengine Modeling Based on UML
DOU Jian-ping, HUANG Jin-quan, ZHOU Wen-xiang
2005, 20(4): 684-688.
Abstract PDF(292KB) icon2040 icon453
Abstract:
The object-oriented technology is an effective approach in establishing an extendable and reusable simulation platform for aeroengines.The method and process of developing simulation software for aeroengines with Unified Modeling Language (UML) was discussed.The simulation model software was described using case diagram,class diagram,sequence diagram and activity diagram.Aeroengine model classes,solver classes and user interface classes were programmed with C++ language.On the simulation platform,steady state and transient simulation of a twin-spool turbofan engine have been realized.It shows that UML is effective in establishing extendable and flexible simulation software for aeroengines.
Experimental Investigation and Analysis of Coaxial Injector Discharge Coefficient
SUN Ji-guo
2005, 20(4): 689-692.
Abstract PDF(635KB) icon1971 icon473
Abstract:
Effects of design parameters on hydrogen-oxygen coaxial injector discharge coefficient were investigated by hot tests and numerical analysis.Experimental and theoretical analysis results are in good agreement.The deeper recess length of liquid post leads to smaller injector discharge coefficients of oxygen and hydrogen.The larger annular gap leads to a greater oxygen discharge coefficient but a smaller hydrogen discharge coefficient.
Altitude Characteristics Analysis of Plug Nozzle
JU Chun-guang, LIU Yu, QIN Li-zi
2005, 20(4): 693-697.
Abstract PDF(291KB) icon1960 icon476
Abstract:
According to the altitude compensation capability of the plug nozzle and the actual flow characteristics on plug surface,the thrust of plug nozzle was divided into two parts.Two different models of the pressure distribution on plug surface were established to analyze the change of nozzle efficiency with altitude and the effect of pressure distribution on the plug surface.Results show that the thrust aroused from the altitude compensation capability is the cause of the non-monotone variation of nozzle efficiency with altitude at high ambient pressure; the maximum of the thrust efficiency occurs before the design point at low ambient pressure.
Numerical Simulation on the Starting Process of Satellite Propulsion System
SU Long-fei, ZHANG Li-hui, PAN Hai-lin
2005, 20(4): 698-701.
Abstract PDF(249KB) icon2016 icon486
Abstract:
The analytical model was developed using the water hammer and one-dimensional fluid transient theory.The combustion time delay was considered.All system parameter changes during the propulsion system engine starting process were considered.The characteristic method and the classical Runge-Kutta method were adopted for simulation.The simulation results are consistent with experiments.The results show that these models give reasonable descriptions for water hammer and flow oscillation during engine starting process.The simulation methods meet the accuracy requirements and could provide guidance for designs and experiments of propulsion system.
LOX/Kerosene Rocket Engine Starting Fault Detection
TAN Song-lin, ZHAO Wan-ming, MAO Gen-wang
2005, 20(4): 702-706.
Abstract PDF(761KB) icon1919 icon495
Abstract:
To meet the requirement of fault detection for LOX/Kerosene rocket engine starting,both detection methods of time sequence model and nonlinear regression model were applied.A general principle for parameter selection was proposed.With consideration of the LOX/Kerosene rocket engine features,the monitored parameters were determined.All the software and hardware for detection system were designed.This detection system was verified to be effective through debugging and engine hot testing.This system is important to engine reliability and safety improvement.
Numerical Simulation of Heat Transfer and Fluid Flow in Cooling Channel of the Liquid Rocket Engine Thrust Chamber
WU Feng, WANG Qiu-wang, LUO Lai-qin, SUN Ji-guo
2005, 20(4): 707-712.
Abstract PDF(1096KB) icon2121 icon695
Abstract:
The turbulent fluid flow and heat transfer in a regenerative-cooling channel of the liquid propellant rocket engine were numerically investigated by solving three-dimensional elliptical Navier-Stokes equations.The coolant is hydrogen,whose thermal properties such as thermal conductivity,density,dynamic viscidity etc.are varied with both temperature and pressure.The specific heat of hydrogen and thermal properties of solid metal are varied with temperature only.The standard κ-ε turbulent model and gas-solid coupled technique was adopted.The results show that both the highest temperature of hydrogen and the maximal wall heat fluxes at the hot-gas side occur at the throat region,and the maximal cross-sectional temperature gradients of the solid region occur close to the hot-gas side.In addition,the secondary flow is generated near the throat region perpendicular to the main flow,the highest heat flux and convective heat transfer coefficient of gas-solid coupled interface also occur at throat region.

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