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Synthesis of Calix[4]resorcinarene Core Dendrimers with Peripheral Salicylideneimine Functional Groups

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Chemical Research in Chinese Universities 2006年第4期22卷 537-542页

作者： han Jun ge Yun YAN Chao-guo College of Chemistry ＆ Chemical Engineering Yangzhou University Yangzhou 225002 P. R. China

First to third-generation calix[4] resorcinarene core dendrimers, compounds 4a, 4b, 7a, 7b, 10a and 10b, were prepared via the divergent method in seven steps with the corresponding tetraphenyl- and tetra （hydroxyphenyl） calix[4] resorcinarenes （compounds 1a, 1b） as the starting material. The repeat units of the polyamidoamines of these dendrimers were obtained by the ammonolysis of ethyl calixarylacetates 2a and 2b with 1,3-diaminopropane, that is, amide derivatives with terminal amino groups, which in turn reacted with ethyl acrylate to give a higher generation of ester derivatives. The structures of these dendrimers were characterized by IR, ^1H and ^13C NMR spoctrometries. The crystal structure of compound 2b with 12 ethoxycarbonylmethoxy groups was determined by X-ray analysis.

关键词： Calixresorcinarene Dendrimer Schiffbase Amide Calixarene

Simulation of bluff body stabilized flows with hybrid RANS and PDF method

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Acta Mechanica Sinica 2007年第3期23卷 263-273页

作者： Minming Zhu Xingsi han Haiwen ge Yiliang Chen Department of Thermal Science and Energy Engineering University of Science and Technology of China Hefei 230027 China

The motivation of this study is to investigate the turbulence-chemistry interactions by using probability density function （PDF） method. A consistent hybrid Reynolds Averaged Navier-Stokes （RANS）/PDF method is used to simulate the turbulent non-reacting and reacting flows. The joint fluctuating velocity-frequency-composition PDF equation coupled with the Reynolds averaged density, momentum and energy equations are solved on unstructured meshes by the Lagrangian Monte Carlo （MC） method combined with the finite volume （FV） method. The simulation of the axisymmetric bluff body stabilized non-reacting flow fields is presented in this paper. The calculated length of the recirculation zone is in good agreement with the experimental data. Moreover, the significant change of the flow pattern with the increase of the jet-to-coflow momentum flux ratio is well predicted. In addition, comparisons are made between the joint PDF model and two different Reynolds stress models.

关键词： Hybrid algorithm Unstructured mesh Finite volume method PDF method Bluff body stabilized flow

The Influence of Wedge Diffuser Blade Number and Divergence Angle on the Performance of a High Pressure Ratio Centrifugal Compressor

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Journal of Thermal Science 2018年第1期27卷 17-24页

作者： WANG Yi han ge LU Xingen ZHU Junqiang School of Aeronautics and Astronautics Central South UniversityChangsha 410083China Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China

Wedge diffuser is widely used in centrifugal compressors due to its high performance and compact size. This paper is aimed to research the influence of wedge diffuser blade number and divergence angle on centrifugal compressor performance. The impact of wedge diffuser blade number on compressor stage performance is investigated, and then the wedge diffusers with different divergence angle are studied by varying diffuser wedge angle and blade number simultaneously. It is found that wedge diffuser with 27 blades could have about 0.8% higher adiabatic efficiency and 0.14 higher total pressure ratio than the wedge diffuser with 19 blades and the best compressor performance is achieved when diffuser divergence angle is 8.3°.These results could give some advices on centrifugal compressor design.

关键词： Wedge diffuser Blade number Diffuser angle High pressure ratio Centrifugal compressor

Numerical simulation of underwater explosion bubble with a refined interface treatment

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Science China(Physics,Mechanics & Astronomy) 2015年第4期58卷 91-100页

作者： JIANG Liang ge han FENG ChengLiang CHEN DaRong State Key Laboratory of Tribology Tsinghua University Ocean College Zhejiang University School of Mathematics and Systems Science Beijing University of Aeronautics and Astronautics

With the intermediate flow states predicted by local two phase Riemann problem,the modified ghost fluid method(MGFM)and its variant(r GFM)have been widely employed to resolve the interface condition in the simulation of compressible multi-medium *** this work,the drawback of the construction procedure of local two phase Riemann problem in r GFM was investigated in detail,and a refined version of the construction procedure was specially developed to make the simulation of underwater explosion bubbles more accurate and *** the refined r GFM,the fast and accurate particle level set method was also adopted to achieve a more effective and computationally efficient capture of the evolving multi-medium interfaces during the *** demonstrate the improvement brought by current refinement,several typical numerical examples of underwater explosion bubbles were performed with original r GFM and refined r GFM,*** results indicate that,when compared with original r GFM,numerical oscillations were effectively removed with the proposed ***,with present refined treatment of interface condition,a more accurate and robust simulation of underwater explosion bubbles was accomplished in this work.

关键词： underwater explosion MGFM rGFM multi-medium flow particle level set method

Investigation on Multiple Cylindrical Holes Casing Treatment for Transonic Axial Compressor Stability Enhancement

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Journal of Thermal Science 2014年第4期23卷 346-353页

作者： YANG Chengwu ZHAO Shengfeng LU Xingen han ge ZHU Junqiang Key Laboratory of Light-duty Gas-turbine/Institute of Engineering Thermophysics Chinese Academy of Sciences University of Chinese Academy of Sciences

Casing treatment is one possible way of regaining axial compressor operating range. However, most of casing treatments extend the operating range with the cost of efficiency penalty. A new form of multiple cylindrical holes casing treatment(MHCT) with pre-swirl blowing for the NASA Rotor-37 has been designed based on profound understanding of the stall inception. Unsteady numerical simulations have been performed for Rotor-37 with and without MHCT. Parametric studies of the total extraction holes area and their axial locations show that the compressor performance deteriorates as the area ratio increases but the stall margin is extended and there is an optimum extraction holes axial location for stall margin extending. The better configuration of MHCT could extend the stall margin by 6.2% with only 0.23% peak efficiency reduction. Detailed analysis of the physical mechanism behind the stall margin improvement shows that the casing treatment could eliminate the passage blockage by suppressing breakup of tip leakage vortex and decrease the blade load in tip region, which both contribute to improve stall margin of transonic axial compressors.

关键词： Casing treatment Transonic axial compressor Stall margin extending Numerical simulation

Effect of Non-Axisymmetric End Wall on a Highly Loaded Compressor Cascade in Multi-Conditions

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Journal of Thermal Science 2021年第4期30卷 1363-1375页

作者： HUANG Song YANG Chengwu LI Ziliang han ge ZHAO Shengfeng LU Xin’gen Key Laboratory of Light-duty Gas-turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

As an effective method to influence end wall flow field,non-axisymmetric profiled end wall can improve the aerodynamic performance of compressor *** a highly loaded low pressure compressor cascade,called V103,the study found the optimal non-axisymmetric profiled end wall decreases total pressure loss coefficient by 4.57%,5.48%and 3.04%under incidences of–3°,0°,and 3°,respectively,compared with those of the planar end *** optimal non-axisymmetric profiled end wall changes the structure of secondary flow in hub region,generating a corner vortex near suction surface,inhibiting the development of the passage vortex towards suction surface and reducing flow *** the inlet Mach numbers are 0.62 and 0.72,the total pressure loss coefficient decreases by 3.19%and 4.58%for optimal non-axisymmetric profiled end wall compared with those of the planar end *** optimal non-axisymmetric profiled end wall increases total pressure loss near hub region in blade passage under different inlet Mach numbers,the peak value and region of high loss coefficient above 10%span in blade passage significantly *** addition,different incidences affect the secondary flow streamlines and vortex structure near the cascade hub region,however,different inlet Mach numbers hardly change the secondary flow streamlines and vortex *** short,the optimal non-axisymmetric profiled end wall shows better aerodynamic performance than the planar end wall for the highly loaded compressor cascade in multi-conditions.

关键词： non-axisymmetric profiled end wall total pressure loss highly loaded compressor cascade passage vortex

Inducer/Exducer Matching Characteristics inside Tandem Impellers of a Highly Loaded Centrifugal Compressor

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Journal of Thermal Science 2020年第4期29卷 928-944页

作者： LI Ziliang ZHAO Shengfeng LU Xin’gen han ge YANG Chengwu ZHU Junqiang Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

A centrifugal compressor usually operates with low isentropic efficiency and a terrible stable operating range, resulting from the complex impeller flow structure companied with the intense interaction among the impeller and the diffuser downstream. In many studies, the potential of centrifugal compressor tandem-impeller configurations for improving the compressor has been demonstrated. Whereas, compared with the convincing results on the tandem-designed axial compressors, the results on tandem impellers are limited and contradictory. Very little insight has been provided into the flow mechanisms inside tandem impellers, which is considered to be the primary reason for the confusion in tandem impeller design and application. Tandem impellers are expected to exhibit a totally different behavior due to the intense aerodynamic interaction between the inducer and the exducer, which substantially contributes to the flow structure and the compressor performance change. In the present study, a numerical study of a highly-loaded centrifugal compressor with various tandem designs was conducted to explore the inducer/exducer matching characteristics and the underlying flow mechanism inside tandem impellers. Two tandem impeller design parameters, namely, the inducer/exducer clocking fraction and the axial gap(overlap), were considered in the tandem impeller design process. The tandem impeller was also compared to the existing conventional impeller which the tandem impeller was redesigned for. The results demonstrated that the tandem-designed impeller can improve the centrifugal compressor stage performance and intense inducer/exducer interaction can be observed with changes in the clocking fraction and the axial gap(overlap). The tandem impeller performance is sensitive to changes in axial gap(overlap) when the suction side of the exducer blade is circumferentially close to the inducer blade. The fundamental reason for the performance variation in the inducer and the exducer l

关键词： highly loaded centrifugal compressor tandem impeller inducer/exducer matching flow mechanism Kutta condition

Numerical investigation of flow mechanisms of tandem impeller inside a centrifugal compressor

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Chinese Journal of Aeronautics 2019年第12期32卷 2627-2640页

作者： Ziliang LI Xin’gen LU Shengfeng ZHAO ge han Chengwu YANG Yanfeng ZhanG Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

This study numerically investigated a single stage centrifugal compressor "Radiver" with a wedge diffuser and several tandem-designed impellers to explore the flow phenomena within the tandem impeller and the potential to enhance compressor *** results demonstrate that tandem design and clocking fraction(ks)significantly affects the compressor *** compressor stage with tandem impellers of Series A of boundary layer growth interruption alone are observed to have a widely operating range but efficiency and total pressure ratio penalty compared with that of conventional *** tandem impeller with at least the same impeller efficiency as the conventional design is considered as a critical design criteria so that further modification process based on the flow characteristic of tandem impeller is *** order to restrain the inducer wake and exducer shock losses,parameters modification of blade angle and thickness distributions are necessary and the modified tandem impeller of Series B is *** modified tandem impeller with 25%clocking arrangement shows an 8.45%stall margin increase and maintains the total pressure ratio and efficiency as the conventional design,which proves the potential of tandem impeller to improve compressor stage *** is noteworthy that the tandem impellers of Radiver have not shown obviously balanced exit flow field and the fundamental mechanism of stall margin extending of tandem impeller lies on the improved impeller/diffuser matching performance resulting from the incidence angle variation at diffuser inlet.

关键词： Centrifugal compressor stage Flow mechanism Impeller/diffuser matching Stall margin Tandem impeller

Vortex dynamics and entropy generation in separated transitional flow over a compressor blade at various incidence angles

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Chinese Journal of Aeronautics 2022年第3期35卷 42-52页

作者： Mingyang WANG Ziliang LI ge han Chengwu YANG Shengfeng ZHAO Yanfeng ZhanG Xin’gen LU Key Laboratory of Light-Duty Gas-Turbine Institute of Engineering ThermophysicsChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

The transition process within a Laminar Separation Bubble(LSB)that formed on a compressor blade surface was investigated using Large Eddy Simulations(LESs)at a Reynolds number of 1.5×10;and incidence angles of 0°,+3°,and+5°.The vortex dynamics in the separated shear layers were compared at various incidence angles and its effects on the loss generation were clarified through entropy *** showed that transition onset,which was accurately identified by the Linear Stability Theory(LST),was significantly promoted at the increased incidence *** such,the development of LSB was suppressed and the relative role of viscous instability played in the transition process was *** the incidence angle of 0°,two-dimensional spanwise vortices detached from the blade surface and roiled up periodically,which were further stretched and eventually evolved into large-scale hairpin *** time passed,the fully developed hairpin vortices broke down into small-scale ***,the flow near the wall reversely ejected into the outer separated shear layers and a sweeping process happened subsequently,forcing the separated shear layers to reattach and accelerating the generation of turbulent *** comparison,the strength of vortex rolling-up was weakened at higher incidence angles,and the vortex pairing and breakdown of large-scale vortices were less ***,the level of turbulent fluctuations that generated in the separated shear layers was *** entropy analysis showed that the turbulent dissipation effect related to the Reynolds shear stresses determined the largest amount of positive entropy generation,which declined to a lower level as the incidence angle increased from 0°to+5°.Correspondingly,the profile loss was reduced by 50.4%.

关键词： Aerodynamic performance Compressor airfoil Entropy Incidence angle Separation bubble Vortex dynamics