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Numerical Investigation of Circumferential Groove Casing Treatment in a Highly-Loaded Low-Reaction Transonic Compressor Rotor

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Journal of Thermal Science 2020年第4期29卷 916-927页

作者： ZHU Wei cai le WANG Songtao WANG Zhongqi School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China

In this paper, a computational investigation of circumferential groove casing treatment in a highly-loaded low-reaction transonic compressor rotor is conducted, in which the stage reaction is significantly reduced due to a larger meridional contraction with respect to conventional transonic compressors. Steady computation at near-stall point is performed first to capture the stall inception of the rotor with smooth casing. Detailed observations, which mainly focus on the tip leakage flow behavior, obstruction and vortical structures in the tip region, determine the reason for the compressor stall. There is tip leakage vortex breakdown in the tip region. Moreover, it yields passage obstruction, and finally leads to the compressor stall. Then, attempts are made to investigate how the circumferential grooves can be applied for the compressor’s stall margin enhancement without compromising efficiency. Three configurations are obtained and analyzed by changing axial position and the number of the circumferential grooves. The results of computational parametric study indicate the optimal location of the groove is near the leading edge and the downstream grooves combine their influence on the compressor’s stabilization and performance in a cumulative manner. The optimal circumferential groove configuration produces an increase of 1% in total pressure ratio at the near-stall point and a gain of 3.7% in stall margin, without any penalty in efficiency. Furthermore, the impact the grooves will exert on the flow mechanisms between the grooves and the main flow is also considered.

关键词： low-reaction transonic compressor circumferential casing groove vortex breakdown stall margin

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Heat Transfer and Flow Structure of a Turbine Blade's Air-cooled leading Edge Considering Different Hole Shapes and Additional Flow Angles

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Journal of Thermal Science 2024年第4期33卷 1421-1442页

作者： QIN Runxuan ZHOU Xun WANG Songtao cai le School of Energy Science and Engineering Harbin Institute of TechnologyHarbin150001China

A numerical study is conducted to elucidate the impact of hole shapes and additional flow angles on the flow structure of the coolant and temperature field in the leading edge area of the gas turbine *** typical hole shapes are considered for the GE-E3 *** impact of the additional flow angle(E)within each hole shape on the temperature field is *** results indicate that for the leading edge area and suction surface,the fan-shaped hole case performs best in decreasing temperatures,with a decrease of about 43 *** is mainly due to the fact that the fan-shaped hole has the maximum expansion in hole spanwise *** the pressure surface,the console hole case performs best in decreasing temperatures,with a maximum reduction of about 47.2 *** influence of E on the surface temperature at leading edge area varied between the different hole *** the cylinder hole and console hole,the E=-20°case has the lowest area-averaged *** both the fan-shaped hole and the 7-7-7 shaped hole are expansion holes,the pattern of variation of the leading edge area temperature with increasing E is similar for the fan-shaped hole case and 7-7-7 shaped hole *** E=20°case shows the lowest spanwise-averaged temperature near the hole outlet,and the E=-20°case shows the lowest spanwise-averaged temperature further downstream.

关键词： film cooling GE-E3 turbine rotor blade conjugate heat transfer leading edge

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Numerical Investigation on Effectiveness of Flow Separation Control in Two-dimensional High-load Compressor Cascade by Synthetic Jet

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Journal of Thermal Science 2012年第5期21卷 441-446页

作者： Songtao Wang le cai Xun Zhou Shaopeng Lu Engine Aerodynamics Research Centre Harbin Institute of Technology Harbin 150001 China

The effectiveness of flow separation control in two-dimensional high load cascade by synthetic jet is investigated through numerical simulation of the effect of excitation frequency and amplitude together with the adaptability of synthetic jet to off-design conditions. Test results indicate that synthetic jet can be used to effectively control the large-scale two-dimensional flow separation in compressor cascade. Preferable results can be obtained when excitation frequency is close to or times of the characteristic frequency of original flow field. Excitation amplitude has a more important effect on the effectiveness of flow separation control, and the increase in excitation amplitude can bring about a dramatic decrease in the loss of total pressure. Synthetic jet has also a very good adaptability to off-design conditions. It can therefore be concluded that the incidence sensitivity of compressor cascade can be effectively reduced by synthetic jet.

关键词： synthetic jet excitation frequency excitation amplitude off-design conditions numerical simulation

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Numerical Investigations of the Influence of Unsteady Vane Trailing Edge Shock Wave on Film Cooling Effectiveness of Rotor Blade leading Edge

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Journal of Thermal Science 2018年第2期27卷 135-145页

作者： WANG Yufeng cai le WANG Songtao ZHOU Xun Engine Aerodynamics Research Centre Harbin Institute of Technology Harbin 150001 China

Unsteady numerical simulations of a high-load transonic turbine stage have been carried out to study the influences of vane trailing edge outer-extending shockwave on rotor blade leading edge film cooling performance. The turbine stage used in this paper is composed of a vane section and a rotor one which are both near the root section of a transonic high-load turbine stage. The Mach number is 0.94 at vane outlet, and the relative Mach number is above 1.10 at rotor outlet. Various positions and oblique angles of film cooling holes were investigated in this research. Results show that the cooling efficiency on the blade surface of rotor near leading edge is significantly affected by vane trailing edge outer-extending shockwave in some cases. In the cases that film holes are close to leading edge, cooling performance suffers more from the sweeping vane trailing edge outer-extending *** addition, coolant flow ejected from oblique film holes is harder to separate from the blade surface of rotor, and can cover more blade area even under the effects of sweeping vane trailing edge shockwave. As a result, oblique film holes can provide better film cooling performance than vertical film holes do near the leading edge on turbine blade which is swept by shockwaves.

关键词： transonic turbine trailing edge shock wave ftlm cooling unsteady simulation

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Conformal Invariance of Higher-Order Lagrange Systems by Lie Point Transformation

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Chinese Physics letters 2011年第11期28卷 8-11页

作者： HUANG Wei-Li cai Jian-le Department of Physics and Telecom Engineering Hunan City UniversityYiyang 413000 College of Science Hangzhou Normal UniversityHangzhou 310018

Conformal invariance and conserved quantities for a higher-order Lagrange system by Lie point transformation of groups are *** differential equation of motion for the higher-order Lagrange system is *** definition of conformal invariance for the system together with its determining equations and conformal factor are *** necessary and sufficient condition that the system’s conformal invariance would be Lie symmetry by the infinitesimal one-parameter point transformation group is *** conserved quantity of the system is derived using the structural equation satisfied by the gauge *** example of a higher-order mechanical system is offered to illustrate the application of the result.

关键词： function conformal system

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Phenomenological Studies on Internal Friction of Noncrystalline Materials in Structural Relaxation Processes

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Chinese Physics letters 1998年第4期15卷 281-283页

作者： cai Jian-le QIAO Chu-liang Department of Applied Physics Hunan UniversityChangsha 410082 Department of Physics Yiyang Teachers’CollegeYiyangHunan 413049

Based on not only the ideas of phenomenological investigations about the internal friction of crystalline materials but also the studies on the internal friction laws of noncrystalline materials during structural relaxation processes in recent years,the method of making relaxation cell is put *** the method,traditional mechanics parameter model and two-level model are unified,so phenomenological studies on the internal friction of noncrystalline materials during structural relaxation processes are made and a new relaxation law is formed.

关键词： friction relaxation Internal

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In situ growth of large-area and self-aligned graphene nanoribbon arrays on liquid metal

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National Science Review 2021年第12期8卷 37-45页

作者： le cai Wanzhen He Xudong Xue Jianyao Huang Ke Zhou Xiahong Zhou Zhiping Xu Gui Yu Beijing National Laboratory for Molecular Sciences CAS Research/Education Centre for Excellence in Molecular SciencesInstitute of ChemistryChinese Academy of Sciences School of Chemical Sciences University of Chinese Academy of Sciences Applied Mechanics Laboratory Department of Engineering Mechanics and Centre for Nano and Micro MechanicsTsinghua University

Intrinsic graphene features semi-metallic characteristics that limit its applications in electronic devices,whereas graphene nanoribbons(GNRs) are promising semiconductors because of their bandgap-opening feature. However, the controllable mass-fabrication of high-quality GNR arrays remains a major *** particular, the in situ growth of GNR arrays through template-free chemical vapor deposition(CVD) has not been realized. Herein, we report a template-free CVD strategy to grow large-area, high-quality and self-aligned GNR arrays on liquid copper surface. The width of as-grown GNR could be optimized to sub-10 nm with aspect ratio up to 387, which is higher than those of reported CVD-GNRs. The study of the growth mechanism indicates that a unique comb-like etching-regulated growth process caused by a trace hydrogen flow guides the formation of the mass-produced self-aligned GNR arrays. Our approach is operationally simple and efficient, offering an assurance for the use of GNR arrays in integrated circuits.

关键词： graphene nanoribbons template-free chemical vapor deposition comb-like etching self-alignment in situ growth

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Brainin A,a novel flavanol from Brainea insignis

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Chinese Chemical letters 2011年第4期22卷 455-457页

作者： Ming Hui Yang le cai Zhi Gang Tai Xue Qiong Yang Zhong Tao Ding Key Laboratory of Medicinal Chemistry for Nature Resource Ministry of Education School of Chemical Science and Technology Yunnan University Kunming 650091 China School of Pharmaceutical Sciences and Chemistry Dali University Dali 671000 China

A novel flavanol bearing phenylpropionic acid moiety at C-4 through a C-C bonding,named brainin A（1）,was isolated from the rhizomes of Brainea *** structure was elucidated on the basis of spectral data including 2D ... 详细信息

关键词： Fern Flavanol Brainea insignis Brainin A

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Increasing Trends and Species Diversity of Nontuberculous Mycobacteria in A Coastal Migrant City−Shenzhen, China

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Biomedical and Environmental Sciences 2022年第2期35卷 146-150页

作者： JI le cai CHEN Shuai PIAO Wei HONG Chuang Yue LI Jin Li JIANG Qi Department of Tuberculosis Control Institute of Laboratory ResearchShenzhen Center for Chronic Disease ControlShenzhen 518020GuangdongChina School of Public Health Wuhan UniversityWuhan 430071HubeiChina National Institute for Nutrition and Health Chinese Center for Disease Control and PreventionKey Laboratory of Trace Element Nutrition of National Health CommissionBeijing 100050China

Nontuberculous mycobacteria(NTM)are opportunistic pathogens of environmental origin that can cause human infections in a wide variety of tissues[1].Lung involvement is the most common manifestation of NTM infection[1].The symptoms and radiographic signs are similar to those of patients with pulmonary tuberculosis(TB)who are infected with Mycobacterium tuberculosis complex(MTBC)[1].Most NTM species are naturally resistant to first-line anti-TB drugs and have different resistance profiles,thus misdiagnosis leads to inappropriate treatment and increases the risk of poor prognosis for patients with an NTM infection,and even wider spread through person-to-person contact[2].

关键词： involvement tuberculosis drugs

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Three new phenanthrenes from Monomeria barbata Lindl.

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Chinese Chemical letters 2010年第3期21卷 325-328页

作者： Yang, Ming Hui cai, le Li, Mei Hong Zeng, Xiang Hui Yang, Ya Bin Ding, Zhong Tao Yunnan Univ Sch Chem Sci & Technol Minist Educ Key Lab Med Chem Nat Resource Kunming 650091 Peoples R China Dali Coll Dept Biochem Dali 671000 Peoples R China

Three new monophenanthrene compounds were isolated from an acetone extract of the tubers of Monomeria barbata Lindl. (Orchidaceae).Using spectroscopic methods,the structures of compounds 1-3 were determined as 1,4,7-trihydroxy-2-methoxy- 9,10-dihydrophenanthrene(1),1-(p-hydroxybenzoyl)-2-methoxy-4,7-dihydroxy-9,10-dihydrophenanthrene(2),1,3,8-tri(p-hydroxybenzyl) -4-methoxy-phenanthrene-4,7-diol(3).These compounds showed cytotoxicities on four tumor cell lines(HepG2, HL-60,Skov-3,A431).

关键词： Monomeria barbata Orchidaceae Monophenanthrene Cytotoxicity

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