检索结果-南通市图书馆

Real prospects for the development of power technologies based on renewable energy sources in Poland

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2017年第2期11卷 168-174页

作者： slawomir dykas Artur SZYMANSKI Xiaoshu CAI Silesian University of Technology Institute of Power Engineering andTurbomachinery Konarskiego 20 44-100 Gliwice Poland Institute of Particle and Two-Phase Flow Measurement University ofShanghai for Science and Technology Shanghai 200093 China

In Poland more than 40% of the power units have been operating for over 40 years now and more than 10% are over 50 years old, which indicates a high degree of decrease in the value of the energy sector. An analysis of the energy market shows that every year a new power plant should be built with a capacity of 1000 MW to ensure the national energy security. An energy market research indicates that in Poland the structure of energy production is changing in recent years-the share of fossil (solid) fuels in electricity and heat production was approximately 88% in 2009, while in 2004 it reached 93%. According to the analysis of the market, it can be seen that conventional energy, mainly based on coal and lignite, has been the most important segment of the sector for a long time. In this paper the prospects for the development of power technologies based on renewable energy sources (RES) in Poland are presented.

关键词： renewable energy sources energy sector energy mix Poland

Influence of Air Humidity on Transonic Flows with Weak Shock Waves

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Thermal Science 2020年第6期29卷 1551-1557页

作者： dykas slawomir MAJKUT Miroslaw SMOLKA Krystian Institute of Power Engineering and Turbomachinery Silesian University of TechnologyKonarskiego 18Gliwice 44-100Poland

The paper presents CFD results for the transonic flow of dry and moist air through a diffuser and a compressor *** both test geometries,*** Sajben transonic diffuser and the NASA Rotor 37,the air humidity impact on the structure of flows with weak shock waves was *** CFD simulations were performed by means of an in-house CFD code,which was the RANS-based modelling approach to compressible flow *** is shown that at high values of relative humidity,above 70%,the modelling of the transonic flow field with weak shock waves by means of the dry air model may produce wrong results.

关键词： dry air moist air transonic flow weak shock wave steam condensation

Liquid Phase Evaporation on the Normal Shock Wave in Moist Air Transonic Flows in Nozzles

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2017年第3期26卷 214-222页

作者： slawomir dykas Artur Szymański Miroslaw Majkut Institute of Power Engineering and Turbomachinery Silesian University of Technologyul.

This paper presents a numerical analysis of the atmospheric air transonic flow through de Laval nozzles. By nature, atmospheric air always contains a certain amount of water vapor. The calculations were made using a Laval nozzle with a high expansion rate and a convergent-divergent(CD) "half-nozzle", referred to as a transonic diffuser, with a much slower expansion rate. The calculations were performed using an in-house CFD code. The computational model made it possible to simulate the formation of the liquid phase due to spontaneous condensation of water vapor contained in moist air. The transonic flow calculations also take account of the presence of a normal shock wave in the nozzle supersonic part to analyze the effect of the liquid phase evaporation.

关键词： moist air condensation transonic flow shock wave CFD simulation in-house code

The Analysis of the Noise Generation in Gas Turbine Stage

在线全文

学校读者我要写书评

暂无评论

Open Journal of Acoustics 2014年第4期4卷 155-162页

作者： slawomir dykas Dawid Machalica Institute of Power Engineering and Turbomachinery Silesian University of TechnologyGliwicePoland

The aim of this paper is to assess the impact of the mutual positioning of the turbine stage stator and rotor blades on noise generation. The Ansys CFX commercial software package and the Scale-Adaptive Simulation (SAS) hybrid turbulence model are used for numerical analyses. The paper is focused on an analysis that the pressure wave generation resulting from unsteady flow phenomena. In order to present the problem, the Fast Fourier Transformation (FFT) analysis of pressure fluctuation is carried out at selected points of the turbine stage computational domain. A comparison of values of individual components for subsequent control points allows an approximate determination of the place of generation of pressure waves, the direction of their propagation and the damping rate. Moreover, the numerical analyses make it possible to evaluate the justification for the use of the SAS model, which is rather demanding in terms of equipment, in simulations of unsteady flow fields where generation and propagation of noise waves occur.

关键词： Turbine Stage Noise FFT Analysis

Numerical Analysis of the Losses in Unsteady Flow through Turbine Stage

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Fluid Dynamics 2013年第4期3卷 252-260页

作者： slawomir dykas Wlodzimierz Wroblewski Dawid Machalica Institute of Power Engineering and Turbomachinery Silesian University of TechnologyGliwicePoland

This paper presents an analysis of the operation of a stage of an aircraft engine gas turbine in terms of generation of flow losses. The energy loss coefficient, the entropy loss coefficient and an additional pressure loss coefficient were adopted to describe the losses quantitatively. Distributions of loss coefficients were presented along the height of the blade channel. All coefficients were determined based on the data from the unsteady flow field and analyzed for different mutual positioning of the stator and rotor blades. The flow calculations were performed using the Ansys CFX commercial software package. The analyses presented in this paper were carried out using the URANS (Unsteady Reynolds-Averaged Navier-Stokes) method and two different turbulence models: the common Shear Stress Transport (SST) model and the Adaptive-Scale Simulation (SAS) turbulence model, which belongs to the group of hybrid models.

关键词： Turbine Stage Stator Rotor Loss Coefficients

Numerical Modelling of Aerodynamic Noise in Compressible Flows

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Fluid Dynamics 2012年第3期2卷 65-69页

作者： slawomir dykas Sebastian Rulik Wlodzimierz Wroblewski Institute of Power Engineering and Technology Silesian University of TechnologyGliwicePoland

The solution of the AeroAcoustics (CAA) problems by means of the Direct Numerical Simulation (DNS) or even the Large Eddy Simulation (LES) for a large computational domain is very time consuming and cannot be applied widely for engineering applications. In this paper the in-house CFD and CAA codes are presented. The in-house CFD code is based on the LES approach whereas the CAA code is an acoustic postprocessor solving the non-linearized Euler equations for fluctuating (acoustic) variables. These codes are used to solve the aerodynamically generated sound field by a flow over a rectangular cavity with inlet Mach number 0.53.

关键词： Computational Aeroacoustics Noise Pressure Waves Cavity Noise

An Attempt to Evaluate the Cycloidal Rotor Fan Performance

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Fluid Dynamics 2019年第4期9卷 292-302页

作者： Tomasz Stasko slawomir dykas Miroslaw Majkut Krystian Smolka Silesian University of Technology Institute of Power Engineering and Turbomachinery Gliwice Poland

In this work, the cycloidal rotor fan (CRF) performance was estimated by means of a numerical method based on Unsteady Reynolds Averaged Navier-Stokes equations (URANS). The fan with a cycloidal rotor belongs to the positive displacement machines of the rotary type. The numerical algorithm for simulation of the flow in the cycloidal rotor as well as postprocessing of the CFD results was prepared using Ansys CFX CEL. The methodology for the assessment of the CRF performance was proposed and verified. It was found out that the CRF performance strongly depends on the shape of the profile of the applied rotor blade. The NACA 0012 and CLARK Y profiles were tested for the same CRF structure and flow conditions. Also, the crucial importance for the CRF performance has the range of the blade pitch angle change.

关键词： Cycloidal Rotor Computational Fluid Dynamics Fan Performance

Sensitivity Analysis of a 50+ Coal-Fired Power Unit Efficiency

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Power and Energy Engineering 2015年第12期3卷 19-31页

作者： Katarzyna Stepczyńska-Drygas slawomir dykas Krystian Smolka Institute of Power Engineering and Turbomachinery Silesian University of TechnologyGliwicePoland

The coal-fired power unit integration with a CO2 capture and compression installation involves a considerable rise in the costs of electricity generation. Therefore, there is a need for a continuous search for methods of improving the electricity generation efficiency in steam power plants. One technology which is especially promising is the advanced ultra-supercritical (A-USC) power unit. Apart from steam parameters upstream the turbine, the overall efficiency also depends on the efficiency values of individual elements of the plant and the size of energy consumption of the process of CO2 sequestration from the boiler flue gases. These problems are considered herein to emphasize that without specifying the efficiency values of the power plant main elements the information concerning its electricity generation efficiency is incomplete. This paper presents the influence of the efficiency of individual elements of the power plant on its electricity generation efficiency. The lack of information of the efficiencies of the power plant individual elements, by presenting its overall efficiency, may lead to the false conclusions.

关键词： Sensitivity Analysis A-USC Power Unit Efficiency CO_(2) Capture

Surface Texture Analysis after Hydrostatic Burnishing on X38CrMoV5-1 Steel

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Mechanical Engineering 2019年第6期32卷 164-173页

作者： slawomir Swirad Faculty of Mechanical Engineering and Aeronautics Rzeszow University of Technology

Ball burnishing is a plastic deformation process used as a surface smoothing and surface improvement finishing treatment after turning or milling processes. This process changes the surface stereometrics of the previously machining surface. Burnishing with hydrostatic tools can be easily and effectively used on both conventional and Computer Numeric Control(CNC) machines. The existing research of the burnishing process mainly focuses on the functional surface characterization, for example, surface roughness, wear resistance, surface layer hardness, etc. There is a lack of references reporting a detailed analysis of 3D parameters calculation with a mathematical model to evaluate the results of the ball burnishing. This paper presents the effect of ball burnishing process parameters with hydrostatic tools on the resulting surface structure geometry. The surface topography parameters were calculated using the Taly Map software. Studies were conducted based on Hartley’s static, determined plan. Such a plan can be built on a hypersphere or hypercube. In this work, a hypercube was used. In the case of Hartley’s plan makes it possible to define the regression equation in the form of a polynomial of the second degree. The input process parameters considered in this study include the burnishing rate, applied pressure, and line-to-line pitch. The significant influence of these parameters was confirmed and described as a mathematical power model. The results also showed a positive effect of hydrostatic burnishing on the roughness and geometric structure of the surface.

关键词： Ball burnishing Hydrostatic burnishing Surface structure