5篇
您的检索式：作者名="Martin LUXA"
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| 1 | Pneumatic Measurements Downstream of a Radial Turbine Nozzle Cascade显示文摘This paper deals mainly with pneumatic measurements on a radial turbine nozzle cascade.The full radial cascade guarantees the exit flow field periodicity downstream of it.A special traversing mechanism with a five -hole conical probe moving along a circular path behind the cascade was used for flow field investigation in this type of cascade with very low aspect ratio.The analyses of results of 2D and 3D pneumatic measurements including loss coefficient values are presented. | Martin LUXA Rudolf DVORAK David SIMURDA Jan VIMMR | 2010 | Journal of Thermal Science2010，19，1： | 3 |
| 2 | Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade显示文摘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 Mach 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). | Jindrich Hala Martin Luxa David Simurda marek Bobcik Ondrej Novak Bartolomej Rudas Jaroslav Synac | 2018 | Journal of Thermal Science2018，27，2： | 1 |
| 3 | Investigation of the Compressible Flow through the Tip-Section Turbine Blade Cascade with Supersonic Inlet显示文摘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. | Martin Luxa Jaromír Príhoda David Simurda Petr Straka Jaroslav Synác | 2016 | Journal of Thermal Science2016，25，2： | 1 |
| 4 | Mathematical Modelling and Experimental Investigation of Gas Flow in Minichannels and Microchannels显示文摘The first part of this study is focused on the numerical modelling and experimental investigation of transonic flow through a 2D model of the male rotor-housing gap in a dry screw compressor.Numerical simulations of the clearance flow are performed with the help of the in-house compressible Navier-Stokes solver.Experimental measurements based on the Schlieren method in Toepler configuration are carried out.The objective of the second part of the study is to derive the analytical solution of gas microflow development in a gap between two parallel plates.The microflow is assumed to be laminar,incompressible and the velocity slip boundary conditions are considered at the walls.The constant velocity profile is prescribed at the inlet.For the mathematical description of the problem,the Oseen equation is used.The analytical results are compared with the numerical ones obtained using the developed incompressible Navier-Stokes solver including the slip flow boundary conditions. | Jan Vimmr Hynek Klterka Marek Hajzman Martin Luxa Rudolf Dvork | 2010 | Journal of Thermal Science2010，19，4： | 0 |
| 5 | Near-Wall Flow in the Blade Cascades Representing Last Rotor Root Sections of Large Output Steam Turbines显示文摘This paper investigates the flow past two variants of root section profile cascades for a last stage rotor considering three-dimensional flow structures in the near-wall region.Analyses were drawn based on RANS numerical simulations of both variants and on the experimental data obtained by the 3 D traversing in the exit flow field of one of the variants.Extent of 3 D structures at two different regimes and its influence on aerodynamic characteristics of the blade cascades was assessed.The distributions of Mach number along the profiles were compared with 2 D optical measurements and its distortion due to the presence of the sidewall was explored.The interaction between main vortical structures was described and its influence on the loading of the blades,mechanical energy losses and exit flow angle was discussed.The results showed that for a front loaded blade the vortical structures appeared earlier and at a larger extent than for an aft loaded variant.However,due to different Mach number distribution,contribution of end wall flow to the energy losses was lower in the case of the aft loaded variant.The influence of the near wall flow on the loading was found to be rather weak while the deviation of the exit flow angle appeared to be comparable for both of the variants. | ŠIMURDA David FÜRST Jiří HÁLA Jindřich LUXA Martin BOBČÍK Marek NOVÁK Ondřej SYNÁČJaroslav | 2021 | Journal of Thermal Science2021，30，1： | 0 |
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