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Large Eddy Simulation of the By-pass Transition process under Different Inlet Turbulence Conditions

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Journal of Thermal Science 2021年第6期30卷 2112-2121页

作者： barsi Dario COSTA Carlo LENGANI Davide SIMONI Daniele UBALDI Marina DIME-University of Genova Via Montallegro 11-16145 GenovaItaly

The transition process of the boundary layer developing over a flat plate with elevated inlet Free Stream Turbulence Intensity(FSTI)has been studied by means of Large Eddy Simulation(LES).To this purpose,four cases with different inflow disturbances have been tested varying the magnitude and the length scale of *** has been performed by using the finite-volume ANSYS Fluent *** computational domain,which was constituted by a rectangular domain with a zero thickness plate,was based on an ERCOFTAC test case in order to provide a validation with a well-known set of data by comparing the boundary layer integral parameters and mean and fluctuating streamwise velocity *** four cases were discussed within the paper by looking at classical statistical properties as well as advanced post-processing *** was shown that the decrease in the free stream turbulence level postpones the transition location,whereas the variation of the integral length scale has a very low influence on the distribution of the time-mean flow *** Orthogonal Decomposition(pOD)has been applied to the instantaneous LES flow fields in order to provide a statistical representation of the structures responsible for transition and their response to free-stream turbulence intensity and length *** presence of vortical filaments parallel to the wall,typically referred as boundary layer streaks,is clearly identified;their characteristic dimensions and how they change as a function of FSTI properties were analyzed within the paper.

关键词： by-pass transition Large Eddy Simulation(LES) proper Orthogonal Decomposition(pOD) boundary layer streaks

Experimental and Numerical Analysis of Cavity/Mean-Flow Interaction in Low pressure Axial Flow Turbines

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Journal of Thermal Science 2021年第6期30卷 2178-2185页

作者： barsi Dario COSTA Carlo LENGANI Davide SIMONI Daniele VENTURINO Giulio ZUNINO pietro DIME-Universita di Genova Via Montallegro 11-16145 Genova

The increasing performance of modern aeroengines led the research towards the optimization of machine components not deeply analyzed in the *** this context,the mechanisms driving the interaction process between the secondary flows evolving at the hub of low-pressure turbines with the rotor-stator cavity systems have been poorly investigated in the *** this work,an experimental and numerical analysis of the interaction between the endwall near wall flow and the leakage flow of a real cavity system is *** experimental results were carried out in the annular low-pressure axial flow turbine of the University of *** blade loading and pressure distributions into the cavity,as well as the measured total pressure loss coefficient,have been used for a proper validation of CFD *** steady and unsteady calculations were carried out through the commercial solver ***,several numerical approaches have been tested into this work:RANS,Non Linear Harmonic(NLH),and *** most promising CFD techniques have been firstly identified by comparison with experimental results and then systematically employed to extend the analysis of secondary flow-cavity flow interaction to positions and quantities not available from the *** characterizing the mean flow-cavity flow interaction process will be shown to cover a great amount of the overall stage losses and should be properly accounted for the design of future optimized cavity configurations.

关键词： axial flow turbine cavity mean-flow interaction experimental analysis CFD

Compressor and Turbine Multidisciplinary Design for Highly Efficient Micro-gas Turbine

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Journal of Thermal Science 2018年第3期27卷 259-269页

作者： barsi Dario pERRONE ANDrea QU Yonglei RATTO Luca RICCI Gianluca SERGEEV Vitaliy ZUNINO pietro Department of Mechanical Energy Management and Transport Engineering Università degli Studi di Genova Faculty of power and Energy Engineering Harbin Engineering University Institute of Energy and Transport Systems "Peter the Great" St. Petersburg Polytechnic University

Multidisciplinary design optimization(MDO) is widely employed to enhance turbomachinery components efficiency. The aim of this work is to describe a complete tool for the aero-mechanical design of a radial inflow turbine and a centrifugal compressor. The high rotational speed of such machines and the high exhaust gas temperature(only for the turbine) expose blades to really high stresses and therefore the aerodynamics design has to be coupled with the mechanical one through an integrated procedure. The described approach employs a fully 3D Reynolds Averaged Navier-Stokes(RANS) solver for the aerodynamics and an open source Finite Element Analysis(FEA) solver for the mechanical integrity assessment. Due to the high computational cost of both these two solvers, a meta model, such as an artificial neural network(ANN), is used to speed up the optimization design process. The interaction between two codes, the mesh generation and the post processing of the results are achieved via in-house developed scripting modules. The obtained results are widely presented and discussed.

关键词：设计优化汽轮机压缩机多学科开放源代码气体动力学有限元素分析动力学设计

Design of a Centrifugal Compressor for Micro Gas Turbine: Investigation of Scaling and Tip Clearance Effects

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Open Journal of Fluid Dynamics 2019年第1期9卷 49-62页

作者： Dario barsi Alberto Bottino Andrea perrone Luca Ratto pietro Zunino Department of Mechanical Energy Management and Transportation Engineering University of Genova Genova Italy

The aim of this paper is to investigate the design in similarity of a centrifugal compressor for micro gas turbine and the related scaling effects on performance using CFD investigations. This work is part of a research project carried out by the Department DIME of the University of Genova, with the purpose of investigating the performance of a micro gas turbine in the change from 100 kW electrical output to 250 kW, while maintaining the compressor pressure ratio and geometry in similarity. The first part of the work focuses on the comparison between the original and the scaled machine, while the second part of the study deeply investigates the tip gap effect in the new configuration. The aim is to provide information about the performance of the compressor designed in geometrical similarity and to evaluate the tip gap height impact. From the efficiency point of view, the scaled-up machine has higher efficiency (up to 1.4% increment in design conditions) keeping the same technological limit for impeller manufacturing. However, the variation of tip gap height in the range 0 ÷ 1 mm strongly affects this parameter, leading to 10% alteration in design conditions between the ideal and worst case. The results, both in terms of overall performance and flow fields, are widely discussed in order to obtain simple yet reliable correlation for preliminary design.

关键词： Centrifugal Compressor Scaling Tip Gap CFD

In Vivo Recovery of Cell Type-specific Transcriptome from the Developing Embryo

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In Vivo Recovery of Cell Type-specific Transcriptome from th...

第二届全国发育生物学大会

作者： Qiang Tu Julius C barsi Eric H Davidson Institute of Genetics and Developmental Biology Chinese Academy of Sciences Division of Biology California Institute of TechnologyPasadenaCalifornia 91125USA

Cell type-specific gene sets are critical for multiple important problems in developmental *** cell types of interest have been recovered by various methods and ***,systematic recovery of multiple cell type-specific gene sets from whole developing organisms has remained *** we describe a method to recover such cell-type specific gene sets,which utilizes the knowledge of marker genes expressed by given cells of the embryo to define cell type and includes a fluorescence activated cell sorting(FACS)procedure that results in no perturbation of transcript *** have extensively validated the method by spatial and qualitative analyses of the transcriptome expressed in isolated sea urchin embryonic skeletogenic cells and as a consequence,generated a prototypical cell type-specific transcriptome *** cell types that cover the majority of the sea urchin embryo are under investigation.

关键词： cell-type specific transcriptome embryo

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大流域径流预报的混合模型

长江工程职业技术学院学报 1992年第4期9卷 71-75页

作者： J.E.Nash B.I.barsi 毛荣生武汉水利电力学院

格雷克和克沃科斯的研究表明:从最小二乘的意义上讲,在径流变化有明显的季节性特征的流域,把前几年(率定期)的同一时期的实测流量的平均值,作为简单的季节性预报值.要比用性能较好的降雨——流量模型得出的予报值好得多.本文试图把降雨... 详细信息

格雷克和克沃科斯的研究表明:从最小二乘的意义上讲,在径流变化有明显的季节性特征的流域,把前几年(率定期)的同一时期的实测流量的平均值,作为简单的季节性预报值.要比用性能较好的降雨——流量模型得出的予报值好得多.本文试图把降雨——流量模拟的概念与纯粹的季节性预报方法结合起来,以便得到更好的预报结果,这一结果要优于上述两种方法.假设用季节性平均值偏差表示的降雨和流量的时间函数,线性相关(该假设可用世界气象组织资料检验)对比检验结果表明,利用混合模型求得的结果要比单独用季节性予报模型或用较完善的降雨——流量模型求得的结果好得多.因此,这类模型对具有明查季节性特征的大流域可能是很有用的.

关键词：混合模型流量模型径流预报季节性特征比用二乘世界气象组织线性相关径流变化对比检验

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锰工人中疾病的发生情况

中华预防医学杂志 1956年第3期04卷 240-240页

作者： G.prosperi C.barsi 姚光弼

直到1930年代前期所报告的关於锰工人的特殊病情是有关於中枢神经系统的,并且是巴金森氏综合病征类型的。之后,学者们发现肺炎也有一些常见。如西班牙Huelva省的其一锰矿中对62名工人作了12年的观察,其中肺炎和中枢神经系病变的发病率...

直到1930年代前期所报告的关於锰工人的特殊病情是有关於中枢神经系统的,并且是巴金森氏综合病征类型的。之后,学者们发现肺炎也有一些常见。如西班牙Huelva省的其一锰矿中对62名工人作了12年的观察,其中肺炎和中枢神经系病变的发病率分别为9.2%及3%。

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