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推进技术 2002年第2期23卷 150-153页

作者：刘友宏李立国清华大学工程力学系北京100084 南京航空航天大学能源与动力学院江苏南京210016

为了了解有中心锥圆排波瓣喷管引射器内流场和温度场的特性 ,从圆柱坐标系出发 ,推导了非正交曲线坐标系下引射器内流场的基本方程 ,采用SIMPLEC算法和一种完全压力修正方法 ,在同位网格上求解了流场控制方程 ,并与实验测量结果进行了... 详细信息

为了了解有中心锥圆排波瓣喷管引射器内流场和温度场的特性 ,从圆柱坐标系出发 ,推导了非正交曲线坐标系下引射器内流场的基本方程 ,采用SIMPLEC算法和一种完全压力修正方法 ,在同位网格上求解了流场控制方程 ,并与实验测量结果进行了比较。结果表明 ,在中心锥壁面的作用下 ,圆柱混合管中流向涡很快形成 ,次流的低温等值线可以延伸至混合管中心轴线处。计算结果与测量值符合较好。

关键词：波瓣喷管引射喷管排气引射系统气动性能数值仿真流场模拟飞机

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喷管加装小突片强化射流混合的PIV测量

推进技术 2004年第1期25卷 15-18页

作者：左秀娟黄勇李永袁辉靖北京航空航天大学能源与动力工程学院北京100083 清华大学热能工程系北京100084 北京大学力学系北京100084

在常温、超声速流动状态下,采用PIV技术定量测量了收敛喷管和收扩喷管加装小突片时射流纵截面的速度场和涡量场,并对其速度场和涡量场进行了比较。结果表明,对于收扩喷管,虽然其速度边界层厚度明显大于收敛喷管,但加装小突片结构也能够... 详细信息

在常温、超声速流动状态下,采用PIV技术定量测量了收敛喷管和收扩喷管加装小突片时射流纵截面的速度场和涡量场,并对其速度场和涡量场进行了比较。结果表明,对于收扩喷管,虽然其速度边界层厚度明显大于收敛喷管,但加装小突片结构也能够明显的强化射流的混合。并且发现,小突片结构不仅能产生流向涡,而且对周向涡有明显的强化作用。

关键词：小突片射流喷管喷射流混合流涡流

CREEP BEHAVIOR OF γ-TiAl POLYSYNTHETICALLY TWINNED CRYSTALS

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Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 577-583页

作者： Y.G. Zhang J.G. Lin Y.J. Zhou and C.Q. Chen(Department of Materials Science and engineering, Beijing University of aeronautics and {2.,Beijing 100083, china Beijing Univ of aeronautics and Astronautics Beijing China

Creep behavior of γ-TiAl polysynthetically twinned (PST) crystals has been investigated at temperature between 700 and 800℃. The results show that the creep behavior of the crystals is strongly dependent on the angle between the lamellar boundaries and loading axis. The samples with the angle φ=45 deg. have the lowest creep resistance, while the samples with φ=0 deg., rather than φ=90 deg.,show the strongest creep resistance. The stress exponent and creep activation energy for the power law creep vary with the orientations of samples, which indicates that the creep mechanisms of the samples with different angle φ are quite *** deformation substructure has been examined by transmission electron microscopy (TEM),which shows that both gliding, perhaps also climbing, of dislocations and twinning contribute to the creep deformation with some particular observation in the samples with φ=90 deg. in which rotation of the γ plates across a true twin boundary was observed, which indicates the deformation mechanism of the samples is different from the samples in other orientations.

关键词： TiAl alloy PST crystal creep behavior lamellar microstructure

Numerical Simulation and PIV Measurement of Flow Field in Centrifugal Pump

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Numerical Simulation and PIV Measurement of Flow Field in Ce...

Automatic Generation Control Strategy Based on Balance of Daily Electric energy

第五届流体传动与控制国际会议

作者： Shao Chunlei Gu Boqin~* Chen Ye college of Mechanical and power {2. nanjing University of Technology 5 Xinmofan Road nanjing Jiangsu 2.0009 china

＜正＞Centrifugal pump is a kind of important industrial installation for fluid *** research on the flow field in centrifugal pump is very meaningful to optimizing the structure of pump,improving the efficiency,and reducing *** centrifugal pump was designed for PIV measurement with six backward curved *** flow field of a model centrifugal pump was numerically investigated by solving Navier-Stokes equations coupled with the standard κ-ε turbulence *** three-dimensional geometric model of the centrifugal pump was built using preliminary treatment software GAMBIT *** numerical analysis was performed by means of FLUENT 6.1 program on the assumption of steady, incompressible flow with decreasing flow rate.A multiple reference frame technique was applied to take into account the impeller-volute *** distribution of the velocity and the pressure in the blade-to-blade passages under the design and off-design operating conditions was *** all operating conditions,the distribution of velocity,pressure,and turbulent kinetic energy in every passing-way of the pump is highly *** H-Q performance curve was obtained at design *** to the velocity distribution,the H-Q performance curve was divided into four sections,namely design section,above design section,critical flow section,and back flow *** numerical simulation results are in agreement with the experimental data obtained by PIV.

关键词： centrifugal pump numerical simulation internal flow PIV

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Electricity 2005年第A4期16卷 32-36页

作者： By Yang Wei,Sun Qi and Wu Junji college of power {2., nanjing University of Science & Technology college of power {2. Nanjing University of Science & Technology

An automatic generation control strategy based on balance of daily total electric energy is put forward. It makes the balance between actual total generated energy controlled by automatic generation system and planned total energy on base of area control error, and makes the actual 2.-hour active power load curve to approach the planned load curve. The generated energy is corrected by velocity weighting factor so that it conducts dynamic regulation and reaches the speed of response. Homologous strategy is used according to the real-time data in the operation of automatic generation control. Results of simulation are perfect and power energy compensation control with ideal effect can be achieved in the particular duration.

关键词： AGC ACE velocity weighting factor balance of daily electric energy

The frequency estimation of harmonic signals embedded in multiplicative and additive noise

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Chinese Journal of Acoustics 2002年第3期21卷 271-277页

作者： FAN Yangyu1,2.TAO Baoqi1 XIONG Ke1 SHANG Jiuhao2.SUN Jincai3 LI Yaan3(1 The key Laboratory for Smart Materials and Structures, nanjing University of aeronautics and{2. nanjing 2.0016)(2.Mechanical & Electrical engineering college, Northwest Unive

A method to separate a harmonic signal from multiplicative and additive noises is proposed. The method is to square the signal x(t), which consists of a harmonic signal embedded in multiplicative and additive noises, to form another signal y(t) = x2.t)-E[x2.t)]. After y(t) having been gotten, the Fourier transform is imposed on it. Because the information of x(t) (especially about frequency) is included in y(t), the frequency of x(t) can be estimated from the power spectrum of y(t). According to the simulation, under the condition where frequencies divided by resolution dω are integer, the maximum relative error of estimated frequencies is less than 0.4% when the signal-to-noise ratio (SNR) is greater than -2. dB. If frequencies divided by resolution dω are not integer, the maximum relative error will be less than 2.9%. But it is still small in terms of engineering.

关键词： The frequency estimation of harmonic signals embedded in multiplicative and additive noise

Flow Characteristics in Labyrinth Glands with Straight Teeth

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Flow Characteristics in Labyrinth Glands with Straight Teeth

Study on Laser Transformation Hardening of HT2.0 by High Speed Axis Flow CO_2.Laser

2.11 IEEE International Conference on Computer Science and Automation engineering(CSAE 2.11)

作者： SUN Tao college of power and {2. engineering Harbin engineering University Harbin china ZHANG Yi college of power and {2. engineering Harbin engineering University Harbin china SUN Haiou college of power and {2. engineering Harbin engineering University Harbin china WANG Zhongyi college of power and {2. engineering Harbin engineering University Harbin china

The flow Characteristics in vapor seal has a significant effect on the performance of vapor seal. Considering the flow field characteristics and engineering applications, the following work has been done: First, based on the theoretical analysis, the factors which have effect on sealing is found out. Second, models of the labyrinth glands with straight teeth have been established using CFD method. The full-flow simulation results are acquired. At last, the characteristics of the flow field in labyrinth glands with straight tooth have been analyzed according discharge coefficient.

关键词： labyrinth glands straight tooth numerical simulation leakage

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Journal of Materials Science & Technology 2003年第2期19卷 170-173页

作者： Yunxia YE, Yonghong FU and Yongkang ZHANGMechanical engineering college, Jiangsu University, Zhenjiang 2.2.13, {2. Mechanical engineering college Jiangsu University Zhenjiang 212013 China

In this article, laser transformation hardening of HT2.0 material by high speed axis flow CO2.laser was investigated for first time in china. Appropriate laser hardening parameters, such as laser energy {2. P(W), laser scanning rate V(m/min), were optimized through a number of experiments. The effect of the mentioned parameters on the hardened zone, including its case depth, microhardness distributions etc., were analyzed. Through the factual experiments, it is proved that axial flow CO2.aser, which commonly outputs low mode laser beam, can also treat materials as long as the treating parameters used are rational. During the experiments, the surface qualities of some specimens treated by some parameters were found to be enhanced, which does not coincide with the former results. Furthermore in the article, the abnormal phenomenon observed in the experiments is discussed. According to the experimental results, the relationship between laser {2. density q and scanning rate V is shown in a curve and the corresponding formulation, which have been proved to be valuable for choosing the parameters of laser transformation hardening by axial flow CO2.lasers, was also given.

关键词： Laser transformation hardening Hardened case Laser parameters Cast iron

Design,fabrication and experimental research for an electrohydrodynamic micropump

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Science china(Technological Sciences) 2010年第10期53卷 2839-2845页

作者： YU He, YU Jian & MA ChongFang Key Lab of Enhanced Heat Transfer & energy Conservation, Ministry of Education and Key Lab of Heat Transfer & energy Conversion, Beijing Municipality, {2. of Enviromental and energy engineering, Beijing University of Technology, Beijing 10012., china 1. Key Lab of Enhanced Heat Transfer & energy Conservation Ministry of Education and Key Lab of Heat Transfer & Energy Conversion Beijing Municipality College of Enviromental and Energy Engineering Beijing University of Technology Beijing 100124 China

This paper presented a novel electrohydrodynamic (EHD) micropump based on MEMS technology. The working mechanisms and classification of EHD micropump were introduced. The fabrication process of EHD micropump was presented with the material selection,optimal design of microelectrode and assembly process. Static pressure experiments and flow experiments were carried out using different fluid and the channel depth. The results indicated that the micropump could achieve a maximum static pressure head of 2.8 Pa at an applied voltage of 90 V. The maximum flow rate of the micropump-driven fluid could reach 106 μL/min. This paper analyzed the future of combining micropump with heat pipe to deal with heat dissipation of high power electronic chips. The maximum heat dissipation capacity of 87 W/cm2.can be realized by vaporizing the micropump-driven liquid on vaporizing section of the heat pipe.

关键词： electrohydrodynamic (EHD) MEMS micropump electronic cooling