Praca przedstawia numeryczną analizę pracy konwekcyjnego ogrzewacza pomieszczeń opalanego paliwem gazowym w warunkach równowagi cieplnej dla układu z naturalną grawitacją. Uzyskano informacje na temat sprawności cieplnej urządzenia oraz jego bilans masowy. Pokazano rozkład temperatury na powierzchni urządzenia i w jego wnętrzu. Podano również zalety stosowania metod numerycznych do optymalizacji geometrii urządzenia. Obliczenia numeryczne CFD przeprowadzono z wykorzystaniem komercyjnego kodu ANSYS Workbench 17.0 - program FLUENT.
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This paper presents a numerical investigation of the independent gas-fired convection heater work in thermal equilibrium for natural gravity system. Tested convection gas heater was connected to air/flue duct. In this paper information about thermal efficiency, mass and fluid flow and contours of temperature on the surface of the device and in his interior are given. The advantages of using numerical methods to optimize the geometry of the device were also presented. Numerical calculation were performed using commercial code ANSYS Workbench 17.0 - Fluent program.
The aim of the present paper is to develop a computational fluid dynamics (CFD) analysis to study the combustion process in a four-stroke marine diesel engine, the Wärtsilä 6L 46. The motivation comes from the importance of emissions from marine engines in the global emissions, particularly for nitrogen oxides (NOx) and sulfur oxides (SOx). The pressure and temperature fields were obtained, as well as the exhaust gas composition. In order to validate this work, the numerical results were satisfactory compared with experimental ones, which indicates that this model is accurate enough to reproduce the fluid pattern inside the cylinder during the combustion process. Accordingly, the aim of future works is to use this numerical procedure to optimize the performance and reduce the emissions of the new marine engine designs.
W artykule przedstawiono analizę aerodynamiczną modeli lokomotyw trzech różnych typów oraz ich wpływ na konstrukcje przytorowe. Otrzymane rezultaty porównane zostały z danymi normatywnymi. Uwagę poświęcono głównie ciśnieniom generowanym przez pociągi poruszające się z prędkością 250 km/h oraz parametrom procesu obliczeniowego. Analizę wykonano przy pomocy programów Dolfyn (Cyclone Fluid Dynamics BV) oraz Autodesk Algor Simulation Multiphysics, w których do rozwiązania równań Naviera-Stokesa używana jest metoda objętości skończonych.
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This article presents aerodynamic analysis of three types of locomotives and their impact on a track side constructions. Obtained results have been compared with normative data. Attention was paid mainly to pressures generated by train moving with speed of 150 mph and parameters of numerical analysis process. Simulation has been prepared with use of Dolfyn (Cyclone Fluid Dynamics BV) and Autodesk Algor Simulation Multiphysics software. Navier-Stokes equations are being solved using the finite volume method.
Investigations on integration of optoelectronic components with LTCC (low temperature co-fired ceramics) microfluidic module are presented. Design, fabrication and characterization of the ceramic structure for optical absorbance is described as well. The geometry of the microfluidic channels has been designed according to results of the CFD (computational fluid dynamics) analysis. A fabricated LTCC-based microfluidic module consists of an U-shaped microchannel, two optical fibers and integrated light source (light emitting diode) and photodetector (light-to-voltage converter). Properties of the fabricated microfluidic system have been investigated experimentally. Several concentrations of potassium permanganate (KMnO4) in water were used for absorbance/transmittance measurements. The test has shown a linear detection range for various concentrations of heavy metal ions in distilled water. The fabricated microfluidic structure is found to be a very useful system in chemical analysis.
An experimental facility and methodology of pulverized coal thermokinetic properties determination with the use of mathematical modeling is described in this paper. Thermokinetic properties as a mean for better understanding the nature of combustion process can be determined by an experiment using a Drop Tube Test Facility (DTTF). The test provides conditions occurring in a pulverized coal fired boiler by emulated oxygen concentration, temperature and reaction gas speed. The test presented in the paper was built recently at the Energy Research Center. Experimental data acquired from the tests are used in mathematical modeling using the code Fluent. The ANSYS Fluent 12.1 code can define different mathematical models of volatile evolution (devolatilization model) and char combustion (kinetic/diffusion surface reaction rate model) to simulate coal combustion. In this paper, a char combustion model is defined with specification of a basic equation for char combustion reaction rate. Resulting values are evaluated by decrease of pulverized coal char in the drop tube in dependence of time. The process of burnout is evaluated for comparison with experimental tests. Results acquired from the adjusted mathematical model should provide more detailed information about the combustion process in a real operation.
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