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Investigation of the Compressible Flow through the Tip-Section Turbine Blade Cascade with Supersonic Inlet

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Journal of Thermal Science 2016年第2期25卷 138-144页

作者： Martin Luxa Jaromír Príhoda david simurda Petr Straka Jaroslav Synác Institute of Thermomechanics AS CR v.v.i. Dolejskova 1402/5 18200 Prague Czech Republic Aerospace Research and Test Establishment Plc Beranovych 130 19905 Prague Czech Republic Doosan Skoda Power Co. Ltd. Tylova 1/57 30128 Pilsen Czech Republic

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.

关键词： long turbine rotor blade supersonic tip section optical methods transition modelling CFD

Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade

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Journal of Thermal Science 2018年第2期27卷 95-102页

作者： Jindrich Hala Martin Luxa david simurda marek Bobcik Ondrej Novak Bartolomej Rudas Jaroslav Synac Institute of Thermomechanics of The Czech Academy of Sciences Prague Czech Republic Doosan Skoda Power Ltd Pilsen Czech Republic Faculty of Mechanical Engineering University of West Bohemia Pilsen Czech Republic

This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Math number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements （optical and pneumatic）.

关键词： steam turbine blade cascade root section

Hybrid LES/RANS Simulations of Compressible Flow in a Linear Cascade of Flat Blade Profiles

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Journal of Thermal Science 2024年第5期33卷 1839-1850页

作者： Jaromír PRIHODA Petr STRAKA david simurda Petr SIDLOF Jan LEPICOVSKY Institute of Thermomechanics of the Czech Academy of Sciences Dolejskova 1402/518200 Prague 5Czech Republic Aerospace Research and Test Centre Beranovych 13019905 PragueCzech Republic Technical University of Liberec Faculty of MechatronicsStudentska 246117 Liberec 1Czech Republic

The paper reports on 3D numerical simulations of unsteady compressible airflow in a blade cascade consisting of flat profiles using a hybrid LES/RANS approach including a transition *** a first step towards simulation of blade flutter in turbomachinery,various incidence angle offsets of the middle blade were *** simulations were run for the flow regime characterized by outlet isentropic Mach number M_(is)=0.5and zero *** results of the LES/RANS simulations(pressure and Mach number distributions)were compared to a baseline RANS model,and to experimental data measured in a high-speed wind *** numerical results show that both methods overpredict flow separation taking place at the leading *** this regard,the hybrid LES/RANS method does not provide superior results compared to the traditional RANS ***,the LES/RANS results also capture vortex shedding from the blunt trailing *** frequency of the trailing edge vortex shedding in CFD simulations matches perfectly the spectral peak recorded during wind tunnel measurements.

关键词： numerical simulation blade cascade hybrid LES/RANS

Computational study of flow separation in truncated ideal contour nozzles under high-altitude conditions

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International Journal of Fluid Engineering

International Journal of Fluid Engineering 2024年第1期1卷 21-30页

作者： Ijas Muhammed V V Shamsia Banu N Abhilash Suryan Vincent Lijo david simurda Heuy Dong Kim College of Engineering Trivandrum Government Engineering College Thrissur Faculty of Mechanical Engineering Technical University of Liberec Andong National University

Flow separation in rocket nozzles has been studied mostly under sea-level conditions, which fail to take into account changes in ambient density and ambient pressure during the flight of a rocket. In the present study, numerical analysis is conducted of flow characteristics within a truncated ideal contour(TIC) nozzle to investigate the influence of ambient density and pressure on flow separation. Six different altitudes from a typical flight are considered, from a very low altitude to a high altitude. The flow is analyzed by varying the nozzle pressure ratios corresponding to these altitudes. Both cold flow and hot flow simulations are conducted. The locations of separation positions at various altitude conditions are accurately captured and are found to be in good agreement with experimental results. The results of the study establish that for a given nozzle pressure ratio, the flow separation point is shifted upstream with increasing altitude. This clearly points to a dependence of separation position on the altitude of operation for TIC rocket nozzles.

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