实验流体力学

Research progress on model flight test of powered aircraft with autonomous control system

He Kaifeng, Liu Gang, Zhang Lihui, Mao Zhongjun

2016, 30(2): 1-7. doi: 10.11729/syltlx20150078

Abstract(196) PDF(11)

Abstract:
Model flight test is one of the important methods in aerodynamic research.In recent years,model flight test of powered aircraft with autonomous control has become a low-cost,low-risk and effective technical approach for aerodynamic research and for demonstration and validation of aerodynamic configuration.In this paper we introduce the development tendency and typical application of foreign model flight tests.The newly-built model flight test platform of CARDC (China Aerodynamics Research and Development Center )is presented with its basic components and key technologies.In the end,we propose the development directions in the future.

Determination and verification of critical ice shape for the certification of civil aircraft

Zhou Feng, Feng Lijuan, Xu Chaojun, Zhao Keliang, Han Zhirong

2016, 30(2): 8-13. doi: 10.11729/syltlx20160019

Abstract(140) PDF(16)

Abstract:
Ice accretion of civil aircraft has been a major concern to flight safety.The civil air-craft must show compliance with the airworthness icing regulation to make sure that the aircraft can fly safely under the icing condition.The critical ice shape is the most important input for the evaluation of performance/stability and control under the icing condition,and therefore it must be determined at the very begining of ice certification.Firstly,the standard of the critical ice shape is set up,and the procedure of the critical ice shape determination is proposed.Then,the sensi-tivity of the icing conditions has been analysed by SADRICE code,and the critical icing condition is obtained.Icing wind tunnel tests have been conducted in Italian Aerospace Research Center to verify the critical icing condition.The test results show great agreement with numerical simula-tion results.It is found that MVD= 20μm,RAT= 0℃ is the most critical icing condition for the aircraft under research.Test and numerical resuts of the angle and height of the ice shape upper horn are the same,testifying the correctness of the sensitive analysis and the relevant critical ic-ing condition.The critical ice shape can be used in aircraft icing certification.This is of value to other aircrafts icing certifications.

An icing scaling parameter with the effects of phase change time

Yi Xian, Zhou Zhihong, Du Yanxia, Zhu Guolin

2016, 30(2): 14-19. doi: 10.11729/syltlx20160016

Abstract(203) PDF(11)

Abstract:
The icing wind tunnel test is the main method for the aircraft icing research.The icing scaling law is the theoretical foundation of an icing wind tunnel test.To overcome the disad-vantage of current icing scaling method in glaze and mixing ice simulation,a new scaling parame-ter,CT,is proposed in this paper based on the analysis of heat transfer in icing process.This pa-rameter differs significantly from the scaling parameters originated from Messinger’s thermody-namic model for it take the effects of the phase change time into account.Introducing CT into the traditional scaling law can effectively avoid the randomness in selecting the test pressure and speed.The new parameter has been evaluated with numerical method based on the NACA0012 airfoil and a supercritical airfoil.The results show that on the two airfoils,both the ice shapes and the droplet collection efficiency under the reference icing conditions agree with those under the selected test conditions,which indicates that the parameter is feasible.The research work has good reference value for improving the accuracy of experimental simulation of glaze or mixing ice.

Icing scaling law with the dynamic effects of water droplets

Zhou Zhihong, Yi Xian, Gui Yewei, Qu Jianmin

2016, 30(2): 20-25. doi: 10.11729/syltlx20160013

Abstract(233) PDF(8)

Abstract:
Constraints of the size and simulation ability are often encountered in the icing wind tunnel test.We established an icing scaling law with the dynamic effects of water droplets to solve the problem.It is based on the icing scaling laws with small size droplets.Similar parame-ters of ice accretion on aircraft surface were refined in this paper based on the similarity of a num-ber of conditions such as the flow field,droplet motion,impact properties and thermodynamic properties of ice accretion.Two constraint conditions are proposed to ensure the similarity of dy-namics effect of droplets.The first condition is the equal of Weber number,which ensures the similarity of droplet deformation.The second constraint is the equal of impact parameter,which ensures the similarity of droplet broken.The numerical method is used for the evaluation of the icing scaling law with the dynamic effects of water droplets.The results show that ice shapes on a full scale model and its sub-scaled model are similar,which illustrates that the law is effective and can be used in icing wind tunnel test.

Dynamic characteristics analysis after aircraft icing based on Monte Carlo method

Xue Yuan, Xu Haojun, Pei Binbin, Wang Xiaolong

2016, 30(2): 26-31,37. doi: 10.11729/syltlx20160007

Abstract(173) PDF(7)

Abstract:
The Monte Carlo simulation system constructed with random and uncertain factors taken into account.Specific experiment steps are discussed.The flight kinematics equations with six degrees of freedom are set up under the condition of aircraft icing,and the dynamic response of pilot-aircraft-environment system after icing is also studied.The flight parameters that can re-flect aircraft motion states intuitively after icing are analyzed,and the flight risk judgements are given under the condition that the relative velocity and angle of attack exceed the limits.The dis-tribution characteristics of one dimensional extreme flight parameters are calculated.The results show that the kurtosis of the two kinds of extreme samples are both larger than 3 ,that means the two kinds of extreme samples have longer tails than the normal distribution.The fact that both the extreme relative velocity and the extreme angle of attack have heavy tail distribution charac-teristics is verified.

Study on aerodynamic characteristics of ice accretion in different wing span sections

Kong Manzhao, Duan Zhuoyi, Ma Yumin

2016, 30(2): 32-37. doi: 10.11729/syltlx20160025

Abstract(235) PDF(7)

Abstract:
Aerodynamic characteristics of icing on different wing sections are one of the most important factors to be considered for designing anti/de-icing system.Wind tunnel routine force measure tests were carried out to obtain aerodynamic characteristics using simulation ice model on different wing sections of an airplane.Wing leading icing on different wing span sections would lead to different aerodynamic performance losses.Cruise and landing configurations were involved to study the lift,drag and pitch characteristics of the airplane.The results of the research showed that icing in the middle part of the wing lead to the greatest aerodynamic performance losses,and icing at the root and the tip of the wing leads to less aerodynamic performance losses which could be propitious to establish effective and efficient anti/de-icing system.

Study on Electro-Impulse De-Icing technology

He Zhoudong, Zhu Yongfeng, Zhou Jingfeng

2016, 30(2): 38-45. doi: 10.11729/syltlx20160022

Abstract(219) PDF(14)

Abstract:
Based on the introduction of anti de-icing system and the analysis of aircraft devel-opment,it is proposed in this paper that the Electro-Impulse De-Icing (EIDI)is a promising tech-nology for aircraft de-ice.The phylogeny,application and development status of EIDI is dis-cussed.EIDI has been developed abroad for years,and preliminary engineering application has been realized.However,the domestic research on EIDI has been constrained mainly in the scope of theory,and thus it is urgent to conduct relevant application-oriented research to master the key techniques.In the end,the problems and challenges of domestic research on EIDI are discussed and the research directions in the future are proposed.

Vibration de-icing method with piezoelectric actuators on airfoil surface

Miao Bo, Zhu Chunling, Zhu Chengxiang, Zhang Huijun, Fu Bin

2016, 30(2): 46-53. doi: 10.11729/syltlx20160010

Abstract(185) PDF(13)

Abstract:
This paper presents the theoretical and experimental research on a de-icing method with the piezoelectric transducer as the actuator.The work is conducted on an airfoil surface.Based on the planar point data of the airfoil finite element model,a method for calculating the suitable area on which the piezoelectric actuators can paste is presented,and an algorithm for calculating the normal vec-tors and tangent vectors of a point on the airfoil surface using a combination of five-point formula and four-point formula is designed.The placement of piezoelectric actuators is studied.The re-sults show that on the airfoil surface,the excitation of the piezoelectric actuators decreases with the increase of the distance between two actuators,and the maximum excitation takes place when the actuators are placed near the position of the vibration wave crest.Under the premise of the constant paste contact area,the excitation of the actuators is weakened with the increase of the relative actuator number.Meanwhile,the higher the concentration of the piezoelectric actuator is,the better the excitation is.The de-icing experiments got good results,and the power con-sumption was about 69.77W·m-2 ,which is lower than that of electro-thermal de-icing method.

Design of wind tunnel experiment system for wind turbine icing by using natural low temperature

Li Yan, Wang Shaolong, Zheng Yufang, Liu Qindong, Feng Fang, Tagawa Kotaro

2016, 30(2): 54-58,66. doi: 10.11729/syltlx20160001

Abstract(294) PDF(23)

Abstract:
A simple and low cost icing wind tunnel experiment system has been designed in or-der to study the characteristics of wind turbine blade icing and de-icing methods.The convention-al open j et wind tunnel has been transformed by using the natural low temperature condition of the northern winter,and a water spray system and the icing test section were installed to provide the icing conditions.The verification experiments were carried out in winter,and the three main parameters:the temperature stability,the liquid water content and the medium volume droplet diameter were tested and calibrated.The results show that the main indexes can meet the re-quirements of the wind turbine icing test to a certain degree at the relatively stable environment temperature.

Study of spanwise vortices in turbulent boundary layer flow based on tomographic PIV

Wang Hongping, Gao Qi, Wei Runjie, Wang Jinjun

2016, 30(2): 59-66. doi: 10.11729/syltlx20150086

Abstract(246) PDF(31)

Abstract:
Tomographic particle image velocimetry (Tomo-PIV )is a novel laser technique that can be applied to measure a three-dimensional three-component (3D3C)velocity field.In the current work,Tomo-PIV was utilized to measure a plate turbulent boundary layer (TBL)at Reτ= 1768,and 150 velocity fields with each size of 80mm×16mm×45mm were obtained.The swirl strengthλci was used to identify the local vortex,while its proj ection on the spanwise directionλzci was used to identify the spanwise vortex.The spatial coherent structures of spanwise vortices and their population trends along the wall-normal direction were studied through swirling strengthλzci .The statistic results suggest that the strength of the spanwise vortices reduces with the in-crease of the wall-normal distance y+ .The streamwise velocity of retrograde spanwise vortices is higher than that of the prograde vortices and there is a strong dependence between the streamwise velocity and the wall-normal velocity.High or low momentum regions of small scale in the stre-amwise and wall-normal plane are highly correlated with the spatial arrangement of spanwise vor-tices.Some 3D plots of instantaneous flow structures in TBL are presented and discussed at the end of the paper.

PIV measurement and numerical simulation of Taylor-Couette flow

Feng Junjie, Mao Yuhong, Ye Qiang, Liu Renhong, Chang Qing

2016, 30(2): 67-74. doi: 10.11729/syltlx20150091

Abstract(644) PDF(39)

Abstract:
Particle image velocimetry (PIV)and numerical simulation (CFD)were applied to measure the Taylor-Couette flow and the information of the vortex flow at different rotation speeds was obtained.The measurement results by PIV were compared carefully with numerical results by CFD under the same condition,and the variation characteristics of all phase velocities along the central axis and different radial lines of the vortex flow with different Reynolds num-bers were contrastively analyzed.The results indicate that there existed several speed ranges with various characteristics:when the rotation speed was within 2~7r/min(Re= 100~350)laminar vortex flow was found according to the characteristics of phase velocity vectors;when the rota-tion speed was within 7~40r/min(Re= 350~2000)wavy vortex flow was found;it was modula-ted wavy vortex flow when the rotation speed was within 40~60r/min(Re= 2000~3000);and it was turbulent vortex flow when the rotation speed was higher than 60r/min(Re≥3000).Then,in order to deeply explore the characteristics of Taylor vortex flow and the features of the vortex motion by quantitative analysis,this research explicitly analyzed the Reynolds number ranges where the form of the vortices was found to change under a certain geometric condition according to the relationship among the characteristics of the form of vortices,their corresponding rotation speeds,and the Reynolds number.

A new method of artificial boundary layer transition for hypersonic inlet

Zhang Hongjun, Shen Qing

2016, 30(2): 75-78,102. doi: 10.11729/syltlx20150088

Abstract(137) PDF(15)

Abstract:
In order to ensure the robustness of the scramjet propulsion system,the boundary layer approaching the hypersonic inlet should be turbulent.To develop boundary layer strips for the hypersonic vehicle,a new promising strip configuration with low drag and high efficiency was designed based on the theory of two dimensional hypersonic boundary layer transition and was tested in FD-07 wind tunnel.Whether the inlet is started or not can reflect the boundary layer/shock interaction.The pressure distribution of inlet symmetry planes and shock schlieren will be distinctively deferent for laminar and turbulent on the effect of incident shock,so pressure distri-bution of inlet symmetrical and shock schlieren were used to identify the inlet starting or not and the situation of boundary layer transition can be judged by inlet starting.The tests were conduc-ted including natural transition and artificial transition.The test results show that the boundary layer can be transited successfully using the same strip under the condition of Ma= 5 and 6 ,α=0°,and thus verifies the applicability of the strip which is designed based on the Linear Steady Theory in a wide range of Mach numbers.

CFD analysis and experimental validation on the scheme of calibration for MEMS wall shear stress sensors array for underwater applications

Huang Huan, Sun Hailang, Tian Yukui, Zhang Nan, Xie Hua, Shen Xue

2016, 30(2): 79-83,102. doi: 10.11729/syltlx20150094

Abstract(149) PDF(6)

Abstract:
The measurement of wall shear stress on hydrodynamic surface is important for the design of advanced naval technology.Accurate calibration,first of all the essential static calibra-tion,of the shear stress sensor is indispensable to any practical measurement.To aid the accurate calibration for MEMS wall shear stress sensors array for underwater applications,the flow field in the test section of a sophisticated calibrator which is a water flume based on the method of channel flow is numerically simulated in detail and verified by measurement with a Laser Doppler Anemometer (LDA).The distance needed for the flow to fully develop from the inlet inside the flume is estimated,as well as the pressure distribution along the wall and the range of wall shear stress available for calibration operation.The scheme of calibration for MEMS wall shear stress sensors array for underwater applications is then designed and further validated with the good agreement among the results of shear stress obtained by theoretical analysis,CFD simulation and experiments respectively,which would be of use to the next calibration experiments for MEMS wall shear stress sensors array for underwater applications.

A method to estimate the balance calibration uncertainty

Liu Chunfeng, Xiong Lin, Liu Jiahua, Li Haiyan

2016, 30(2): 84-90. doi: 10.11729/syltlx20150109

Abstract(131) PDF(7)

Abstract:
A complete uncertainty estimation process for balance calibration is established:as-sessing the calibration system uncertainty,assessing the bias limit and precision limit based on checking load residuals to estimate the uncertainty from other errors,and combining them to ob-tain the total uncertainty result.For the BCS-100 calibration system,balance TG624C is calibra-ted seven times repeatedly to implement the method.The result shows that:(1 )The uncertainty caused by the roll angle of balance installation and the angular displacement of balance in the cali-bration are the main components,which shows the direction to upgrade the calibration system;(2)Due to the interference ofY and Mz,the uncertainties of Q、Z and My are larger;(3)The pre-cision limit is much smaller compared to the bias limit.The method is also applicable to other calibration systems.

Research on evaluation method for uncertainty of a load adapter

Hu Guofeng, Zhao Liangliang, Li Fuhua

2016, 30(2): 91-96. doi: 10.11729/syltlx20150067

Abstract(157) PDF(5)

Abstract:
In the wind tunnel balance calibration system,the main function of the load adapter is to ensure that the application point’s location coordinates are accurate.However,because of the manufacture error and dimension measurement error,the application points’real locations are drifted off from the relevant right locations in the theory,which brings errors to the applica-tion point’s location coordinates.These errors would be transferred to a balance calibration for-mula by a load adapter,which affects the accuracy of the loads measured by the balance.There-fore,it is necessary to research on the evaluation and expression of the uncertainty for a load a-dapter.Firstly,according to GUM (guide to the expression of uncertainty in the measurement, ISO/IEC GUIDE 98-3:2008),a method and steps for uncertainty assessment of a load adapter are founded.Then an expression and technical indices of the uncertainty for a load adapter are given.Finally,taking the type A load adapter belonging to the balance calibrated rig (code:TJZ-1 )for example,detailed evaluation processes and results about the uncertainty are given.The e-valuation results of the uncertainty indicate that the mean value of the standard uncertainty of all application points is 0.044mm;the mean value of the relative expanded uncertainty of all mo-ment’s arms is 0.0072%.

Calibration for the FADS system applied to the vehicle with blunt fore-bodies

Wang Peng, Jin Xin, Zhang Weimin, Yue Caiqian

2016, 30(2): 97-102. doi: 10.11729/syltlx20150092

Abstract(147) PDF(4)

Abstract:
Based on the wind tunnel pressure data of a l/7-scale model of the F-14 airplane, three parameters of the FADS (Flush Air Data Sensing System,FADS)system,the angle-of-at-tack flow correction angle,the angle-of-sideslip flow correction angle,and the shape and com-pressibility parameter,were calibrated for applying to the vehicle with blunt fore-bodies.The wind-tunnel test Mach numbers were 0.73,0.90,1.05,1.20,and 1.39.Angles of attack were varied in 2°increments from -4°to 20°.Sideslip angles were varied in 2°increments from -8 ° to 8°.The calibration results show that different pressure points have great influence on the cali-bration of the angle-of-attack flow correction angle and the angle-of-sideslip flow correction angle based on the triple algorithm.And the best calibration results can be determined by the pressure points in a symmetrical configuration about the stagnation pressure point.And the calibration for the angle-of-attack flow correction angle is independent of the calibration for the angle-of-sideslip flow correction angle.As to the shape and compressibility parameter,it is related to the effective angle of attack,the effective angle of sideslip,the Mach number,the vehicle shape and other sys-tem factors.With the Mach number increases,the value of the shape and compressibility param-eter tends to zero .

Application of quantitative background oriented schlieren in laminar axisymmetric flame temperature measurement

Wang Genjuan, Yang Zangjian, Meng Sheng, Wang Mingxiao, Zhong Yingjie

2016, 30(2): 103-110. doi: 10.11729/syltlx20150083

Abstract(270) PDF(20)

Abstract:
Background Oriented Schlieren (BOS)is a new type of schlieren with the advanta-ges of being simple,flexible and cheap.The application of BOS in the measurement of the lami-nar axisymmetric flame temperature field is studied with the methane/air laminar premixed flame.Random or regular noise is usually used as the background of BOS,but this would limit the interrogation area size and camera parameters.Therefore the multi-scale wavelet noise back-ground is adopted in this paper.The cross-correlation method and the variational optical flow method under the constraint condition of Horn-Schunck and Lucas-Kanade are compared.A BOS experiment platform which can generate a methane/air laminar premixed flame is built,and BOS images are obtained.The pixel shift distribution is calculated from the BOS image and the result shows that the noise of the variational optical flow method is much smaller than that of the cross-correlation method under the same condition when the multi-scale wavelet noise background is used.Finally,under the axisymmetric assumption,the temperature distribution of the flame is obtained from deflection angle using the Gladstone-Dale relationship and the ideal gas state equa-tion.In the experiment,the flame temperature fields are measured at the equivalent ratios ofφ=1.06 andφ= 0.83,respectively.It is basically consistent with the result acquired by Raman-LIF.

2016, 30(2): 111-111.

Abstract(39) PDF(1)

Abstract:

2016, 30(2): 112-112.

Abstract(32) PDF(1)

Abstract:

2016 Vol. 30, No. 2