Wyszukiwarka
Filtry
wszystkich: 2871
-
Katalog
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: flow of a stokes liquid
-
New hybrid quadrature schemes for weakly singular kernels applied to isogeometric boundary elements for 3D Stokes flow
PublikacjaThis work proposes four novel hybrid quadrature schemes for the efficient and accurate evaluation of weakly singular boundary integrals (1/r kernel) on arbitrary smooth surfaces. Such integrals appear in boundary element analysis for several partial differential equations including the Stokes equation for viscous flow and the Helmholtz equation for acoustics. The proposed quadrature schemes apply a Duffy transform-based quadrature...
-
The vortex flow caused by sound in a bubbly liquid
PublikacjaGeneration of vorticity in the field of intense sound in a bubbly liquid in the free half-space is considered. The reasons for generation of vorticity are nonlinearity, diffraction, and dispersion. Acoustic streaming differs from that in a Newtonian fluid. Under some conditions, the vortex flow changes its direction. Conclusions concern streaming induced by a harmonic or an impulse Gaussian beam.
-
About nutrient liquid flow between potential flow and cartilage surface in bioreactor
PublikacjaW niniejszej pracy wyznaczony został przepływ cieczy odżywczej o właściwościach nienewtonowskich w cienkiej warstwie granicznej w pobliżu powierzchni komórek chrząstki (chondrocytu) podczas hodowli w bioreaktorze. Ruch cieczy w warstwie granicznej jest wywołany wydatkiem przepływu dostarczanej cieczy do bioreaktora. Ponadto prędkość przepływu cieczy w warstwie granicznej wokół hodowanych komórek chrząstki stawowej jest uzależniona...
-
Uncertainty of the liquid mass flow measurement using the orifice plate
PublikacjaThe article presents an estimation of measurement uncertainty of a liquid mass flow using the orifice plate. This subject is essential because of the widespread use of this type of flow meters. Not only the quantitative estimation but also the qualitative results of those measurements are important. To achieve these results the authors of the paper propose to use the theory of uncertainty. The article shows the analysis of the...
-
Flow of liquid in flat gaps of the satellite motor working mechanism
PublikacjaThe article describes the methodology and results of investigations of the flow of oil and HFA-E emulsion in flat gaps of the working mechanism of a satellite motor. The flow of liquid in those gaps is turbulent and not fully developed. The article presents two methods of modelling this flow. Method I makes use of the Darcy-Weisbach formula, while Method II bases on the assumption that in the variable-length gaps the flow is turbulent...
-
Estimating the uncertainty of the liquid mass flow using the orifice plate
PublikacjaThe article presents estimation of measurement uncertainty of a liquid mass flow using the orifice plate. This subject is essential because of the widespread use of this type of flow meters, which renders not only the quantitative estimation but also qualitative results of this type so those measurements are important. To achieve this goal, the authors of the paper propose to use the theory of uncertainty. The article shows the...
-
Analysis and interpretation of radiometric signals in a liquid-gas bubble flow
PublikacjaThe article presents the analysis of signals from a radiometric system consisting of two scintillation probes and two gamma radiation sealed sources. Calculations and interpretation were carried out for the bubble flow of the water-air mixture in the horizontal pipeline. The analysis of the obtained signals was done in time and frequency domain. In the frequency domain, a range of usable frequencies was identified, which were associated...
-
Evaluation of the structures size in the liquid-gas flow by gamma-ray absorption
PublikacjaThe rapid development of tomography methods particularly electrical, X and gamma rays allows for a wide range of the information about flow structure. However, all of such methods are quite complicated. At the same time much simpler systems as the measuring system of gamma rays absorption, allows to obtain a all key flow information which describe the two-phase flow. In the article the results of analyzes of radiometric signal...
-
Selected thermal and flow issues in a reversed thermosiphon with a steam liquid lifter
Publikacja -
Heat transfer and fluid flow visualization using liquid crystal thermography
PublikacjaW pracy przedstawiono możliwości wykrzystania termografii ciekłokrystalicznej do badań wymiany ciepła oraz wizualizacji pola przepływu w elementach urządzeń przemysłowych.
-
The use of liquid crystal thermography for heat, fluid flow and biomedical research.
PublikacjaW ostatniej dekadzie termografia ciekłokrystaliczna (TLC) i cyfrowa analiza kolorowych obrazów była z powodzeniem stosowana w różnych aplikacjach technicznych, przemysłowych i biomedycznych. Cienkie warstwy ciekłokrystaliczne zastosowano dla uzyskania lokalnych pól temperatury, współczynników przekazywania ciepła i określenia rodzaju procesu. Materiał ciekłokrystaliczny można również zastosować do wizualizacji pól temperatury i...
-
Turbulent flow and heat transfer of a liquid film formed by impinging jet.
PublikacjaZaproponowano prosty model wymiany ciepła w turbulentnym filmie cieczowym utworzonym przez uderzająca strugę. Rozpatrzono dwa przypadki: przepływ rozwijający się i w pełni rozwinięty filmu cieczowego. W obu przypadkach model wyprowadzono na podstawie zmiany grubości filmu w wyniku działania sił bezwładności i sił tarcia. Wyznaczono profile prędkości w obu zakresach co umożliwia wyznaczenie współczynników wymiany ciepła.
-
Radioisotope measurements of the liquid-gas flow in the horizontal pipeline using phase method
PublikacjaThe paper presents application of the gamma-absorption method to a two-phase liquid-gas flow investigation in a horizontal pipeline. The water-air mixture was examined by a set of two Am-241 radioactive sources and two NaI(Tl) scintillation probes. For analysis of the electrical signals obtained from detectors the cross-spectral density function (CSDF) was applied. Results of the gas phase average velocity measurements for CSDF...
-
The Use of Liquid Crystal Thermography an Image Processing in Heat and Fluid-Flow Research
PublikacjaLiquid crystal thermography (LCT) have been used in many technical, industrial and biomedical applications [1]. During over 20 years it has been successfully applied in Department of Energy and Industrial Apparatus at Gdansk University of Technology for visualization of steady-state and transient temperature fields. In order to demonstrate feasibility of LCT techniques in practical heat transfer contexts, the authors have performed...
-
Two-dimensional vertical Reynolds-averaged naviers-stokes equations versus one-dimensional Saint-Venant model for rapidly varied open channel water flow modelling
PublikacjaPrzedstawiono dwa modele przepływu wody ze swobodną powierzchnią -płaski pionowy model Reynoldsa i model de Saint-Venanta.Do rozwiązania równań pierwszego modelu zastosowano schemat SIMPLE oraz wykorzystano metodę cząstek znaczonych MAC do wyznaczania swobodnej powierzchni wody. Równania Saint-Venanta rozwiązano metodą objętości skończonych. Obydwa modele zastosowano do symulacj zjawiska typu katastrofa zapory. Porównano wyniki...
-
Signals Features Extraction in Radioisotope Liquid-Gas Flow Measurements using Autocorrelation Function
PublikacjaKnowledge of the two-phase flow structure is essential for the proper conduct of industrial processes. Description of liquid-gas flow regimes is possible by using of data analysis in time, frequency, or state-space domain. In this research studies, the autocorrelation function is applied for analysis of signals obtained for liquid-gas flow by use gamma-ray absorption. The experiments were carried out on the laboratory hydraulic...
-
Signal Processing in the Investigation of Two-phase Liquid-gas Flow by Gamma-ray Absorption
Publikacjan this paper, the use of the gamma-absorption method applied in the investigation of the two-phase liquid-gas flow in the pipeline is described. An example of its application to the air transported by water in a horizontal pipeline is evaluated. In the measurements, Am-241 radioactive sources and probes with Nal (Tl) scintillation crystals have been used. The signals from the radiometric set were used to determine the velocity...
-
Signals features extraction in radioisotope liquid-gas flow measurements using wavelet analysis
PublikacjaKnowledge of the structure of a flow is significant for the proper conduct of a number of industrial processes. In this case, a description of a two-phase flow regimes is possible by use of the time-series analysis in time, frequency and state-space domain. In this article the Discrete Wavelet Transform (DWT) is applied for analysis of signals obtained for water-air flow using gamma ray absorption. The presented method was illustrated...
-
Radioisotope measurement of selected parameters of liquid-gas flow using single detector system
PublikacjaTo determine the parameters of two-phase flows using radioisotopes, usually two detectors are used. Knowing the distance between them, the velocity of the dispersed phase is calculated based on time delay estimation. Such a measurement system requires the use of two gamma-ray sealed sources. But in some situations it is also possible to determine velocity of dispersed phase using only one scintillation probe and one gamma-ray source....
-
Computational Fluid Dynamics Simulation of Gas–Liquid Multiphase Flow in T-junction for CO2 Separation
PublikacjaThe article presents the results of a computational fluid dynamics (CFD) analysis of gas-liquid multiphase flow. The simulation was conducted using CFD code and the Euler–Euler approach. The presented study relates to the non–reactive, steady-state, turbulent flow of water and carbon dioxide mixture in a 3D pipe. Separation phenomenon between phases is observed. The solution was obtained using a mixture model. Different values...
-
Experimental and numerical simulations of flow and heat transfer in heatexchanger elements using liquid crystal thermography.
PublikacjaPrzedstawienie koncepcji badań eksperymentalnych i numerycznych oraz ich wyników podczas wymiany ciepła w modelach klasycznych i płytowych wymienników ciepła w warunków przepływów przejściowych i turbulentnych.
-
Measurement of mass flow of viscous liquid through a Cylindrical Orifice under laminar flow (CylOr)
Dane BadawczeThe data was obtained as part of the project "Measurement of mass flow of viscous liquid through a Cylindrical Orifice under laminar flow (CylOr)", in which flow tests of hydraulic oil through a cylindrical orifice with a thickness of l = 25 mm and a throat b = 0.5 (diameter pipes D = 50 mm, orifice diameter d = 25 mm) on the test stand at the Department...
-
EVALUATION OF LIQUID-GAS FLOW IN PIPELINE USING GAMMA-RAY ABSORPTION TECHNIQUE AND ADVANCED SIGNAL PROCESSING
PublikacjaLiquid-gas flows in pipelines appear in many industrial processes, e.g. in the nuclear, mining, and oil industry. The gamma-absorption technique is one of the methods that can be successfully applied to study such flows. This paper presents the use of thegamma-absorption method to determine the water-air flow parameters in a horizontal pipeline. Three flow types were studied in this work: plug, transitional plug-bubble,...
-
Investigation of Liquid–Gas Flow in a Horizontal Pipeline Using Gamma-Ray Technique and Modified Cross-Correlation
PublikacjaThis article presents the application of the radioisotope absorption method in the study of two-phase water–air flow in a horizontal pipe. The measurement principle and the test stand are briefly described. The main part of the article presents the signal analysis methods applied to data obtained from scintillation detectors. Because these signals are mostly stochastic waveforms, they were analyzed statistically using the cross-correlation...
-
Improved finite element method for flow, heat and solute transport of Prandtl liquid via heated plate
PublikacjaIn the current study, a vertical, 3D-heated plate is used to replicate the generation of heat energy and concentration into Prandtl liquid. We discuss how Dufour and Soret theories relate to the equations for concentration and energy. In order to see how efectively particles, interact with heat and a solvent, hybrid nanoparticles are used. It does away with the phenomena of viscous dissipation and changing magnetic felds. The motivation...
-
Experimental and numerical simulations of flow and heat transfer in heat exchanger elements using liquid crystal thermography.
PublikacjaW artykule przedstawiono założenia oraz sposób prowadzenia eksperymentu i obliczeń numerycznych wymiany ciepła w modelu wymiennika ciepła przy użyciu termografii ciekłokrystalicznej.
-
Direct Current Atmospheric Pressure Microdischarge Generated between a Miniature Flow Helium Microjet and a Flowing Liquid Cathode
Publikacja -
Decolorization of organic dyes solution by atmospheric pressure glow discharge system working in a liquid flow-through mode
Publikacja -
Comparison of the performance of direct current atmospheric pressure glow microdischarges operated between a small sized flowing liquid cathode and miniature argon or helium flow microjets
Publikacja -
The effect of a miniature argon flow rate on the spectral characteristics of a direct current atmospheric pressure glow micro-discharge between an argon microjet and a small sized flowing liquid cathode
Publikacja -
Coupling of cold vapor generation with an atmospheric pressure glow microdischarge sustained between a miniature flow helium jet and a flowing liquid cathode for the determination of mercury by optical emission spectrometry
Publikacja -
Application of gas flow headspace liquid phase micro extraction coupled with gas chromatography-mass spectrometry for determination of 4-methylimidazole in food samples employing experimental design optimization
Publikacja -
Equations of tribological parameters for liquid flow in boundary layer on the tissue surface in bioreactor = Wyznaczanie parametrów tribologicznych dla przepływu cieczy w warstwie granicznej na powierzchni tkanki w bioreaktorze
PublikacjaW niniejszej pracy przedstawiony został problem tribologiczny wynikający z przepływu nieustalonego odżywczej cieczy lepkiej w cienkiej warstwie przyściennej w bezpośrednim kontakcie z zewnętrzną powierzchnią warstwy wierzchniej wzrastających komórek (chondrocytów) w trakcie procesu ich hodowli w bioreaktorze. Efektem rozważań będą wartości sił tarcia powstające na powierzchni wzrastającej tkanki. Najnowsze badania wykazały lepszą...
-
Application of the Boundary Element Method for the Simulation of Two-dimensional Viscous Incompressible Flow
PublikacjaThe paper presents the application of an indirect variant of the boundary element method (BEM) to solve the two-dimensional steady flow of a Stokes liquid. In the BEM, a system of differential equations is transformed into integral equations. Thi smakes it possible to limit discretization to the border of the solution. Numerical discretization of the computational domain was performed with linear boundary elements, for which a...
-
Dariusz Mikielewicz prof. dr hab. inż.
OsobyDariusz Mikielewicz – urodził się 6 lutego 1967 roku w Gdańsku, w 1985r. zdał pomyślnie egzaminy wstępne na Wydział Budowy Maszyn Politechniki Gdańskiej, który ukończył z wynikiem bardzo dobrym w 1990 roku na specjalności Maszyny i Urządzenia Energetyczne. Zainteresowania pracą naukową skłoniły go do podjęcia badań na University of Manchester na wydziale mechanicznym i energetyki jądrowej (Mechanical and Nuclear Engineering Department)...
-
A conceptual design and numerical analysis of the mixerless urea-SCR system
PublikacjaIn the present study, an innovative design of the urea-selective catalytic reduction (SCR) system without conventional mixing elements was developed. The aim was to obtain a high degree of urea decomposition, and uniform ammonia distribution at the inlet to the catalyst, while minimising the liquid film deposition and keeping the compact design. The concept of the design was based on creating high turbulences and elongating...
-
A Comparison of Simplified Two-dimensional Flow Models Exemplified by Water Flow in a Cavern
PublikacjaThe paper shows the results of a comparison of simplified models describing a two-dimensional water flow in the example of a water flow through a straight channel sector with a cavern. The following models were tested: the two-dimensional potential flow model, the Stokes model and the Navier-Stokes model. In order to solve the first two, the boundary element method was employed, whereas to solve the Navier-Stokes equations, the...
-
Fluid Mechanics and Hydraulics EE Msc sem. I r.a. 22/23
Kursy OnlineBasic definitions. Physical properties of liquids. Forces acting on fluids. Hydrostatics - basic equations. Pressure on a flat and curved wall. Buoyancy. Archimedes' law. Balance of submerged bodies. The balance of floating bodies. Hydrodynamics. Hydrodynamic quantities. Continuity equation for the liquid stream. Bernoulli equation. Basic laws of hydrodynamics. Equation of mass behavior, preservation of the amount of motion, Bernoulli's...
-
Fluid Mechanics and Hydraulics EE Msc sem. I r.a. 23/24
Kursy OnlineBasic definitions. Physical properties of liquids. Forces acting on fluids. Hydrostatics - basic equations. Pressure on a flat and curved wall. Buoyancy. Archimedes' law. Balance of submerged bodies. The balance of floating bodies. Hydrodynamics. Hydrodynamic quantities. Continuity equation for the liquid stream. Bernoulli equation. Basic laws of hydrodynamics. Equation of mass behavior, preservation of the amount of motion, Bernoulli's...
-
FURTHER REMARKS ON THE NEO-CLASSICAL NAVIER-STOKES EQUATIONS
PublikacjaThe seminal Navier-Stokes equations have been stated yet before creation of principles of thermodynamics and the first and second laws. In the literature there is the common opinion that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of “working fluid” which is able to describe transformation of “ heat” into “work” and vice versa. Therefore, in the paper, a new exposition of thermodynamically...
-
The Discrete-Continuous, Global Optimisation of an Axial Flow Blood Pump
PublikacjaThis paper presents the results of the discrete-continuous optimisation of an axial flow blood pump. Differential evolution (DE) is used as a global optimisation method in order to localise the optimal solution in a relatively short time. The whole optimisation process is fully automated. This also applies to geometry modelling. Numerical simulations of the flow inside the pump are performed by means of the Reynolds-Average Navier-Stokes...
-
Neoclassical Navier–Stokes Equations Considering the Gyftopoulos–Beretta Exposition of Thermodynamics
PublikacjaThe seminal Navier-Stokes equations were stated even before the creation of the foundations of thermodynamics and its first and second laws. There is a widespread opinion in the literature on thermodynamic cycles that the Navier-Stokes equations cannot be taken as a thermodynamically correct model of a local "working fluid", which would be able to describe the conversion of "heating" into "working" (Carnot's type cycles) and vice...
-
Discrete-continuous optimisation of an axial flow blood pump
PublikacjaThis paper presents results of discrete-continuous optimisation of an axial flow blood pump. Evolution Strategies (ES) are used as a global optimisation method in order to localise the optimal solution in relatively short time. The whole optimisation process is fully automated. This also applies to geometry modelling. Numerical simulations of the flow inside the pump is performed by means of the Reynolds-Average Navier-Stokes...
-
Fluid Mechanics, L/L/E, DaPE, sem. 04, summer 21/22 (PG_00050282)
Kursy OnlineLECTURES Introduction and basic definitions. Properties of fluids. Models of fluids. Fluids in equilibrium. Determination of hydrostatic forces. Archimedes" law. Methods of fluid flow description. General motion of fluid. Deformation of fluid element. Vortex motion of fluid. Principles of conservation of mass, momentum and energy. Balance of entropy. Navier-Stokes equation. Bernoulli equation. Similarity of flow phenomena. Potential...
-
Experimental and Computational Analysis of the Ship Propeller in Open Water Conditions for Inclined Flow
PublikacjaThe paper presents the results of computational analyses simulating the open water tests of ship propeller in inclined flow. The results of computations are compared with the results of corresponding experimental analyses carried out in the towing tank of Ship Design and Research Centre (CTO S.A.). The object of the research was the model propeller identified as CP469. The aim of the study was to validate the results of numerical...
-
Porous structures in aspects of transpirating cooling of oxycombustion chamber walls
PublikacjaA wet oxycombustion chamber, which must be effectively cooled due to high temperature evolved during the oxy-combustion process, by using the phenomena of Reynolds thermal transpiration and Navier slip velocity. Closures needed to execute mass flow rate in a microchannel, which should be treated as a single porous structure in the walls of the combustion chamber, have been obtained by applying a local 3D approach. The Navier-Stokes...
-
Monitoring wizyjny w systemach zabezpieczenia transportu wodnego. Koncepcja implementacyjna
PublikacjaW artykule autorzy przedstawiają koncepcję zastosowania własnych badań nad pomiarem prędkości przepływu cieczy do zastosowań praktycznych w pomiarach przepływu wody w kanałach otwartych i rzekach. Jako narzędzie pomiarowe wykorzystują zestaw aparatów synchronicznych, które rejestrują indykatory przepływu znajdujące się na powierzchni analizowanej cieczy. Aparat matematyczny przedstawiony w rozwiązaniu sprowadza się do stosowania...
-
Novel Analytic-Numerical Model of Free Convection: with Leading Edge Considered
PublikacjaA novel solution of the free convection boundary problem is represented in analytical form for velocity and temperature for an isothermal vertical plate, as an example. These fields are built as a Taylor Series in the x coordinate with coefficients as functions of the vertical coordinate (y). We restrict ourselves by cubic approximation for both functions. The basic Navier-Stokes and Fourier-Kirchhoff equations and boundary conditions...
-
Heat transfer intensification by jet impingement – numerical analysis using RANS approach
PublikacjaJet impingement is a method of the heat transfer enhancement applied in the engineering systems. The idea is to generate fast-flow fluid jet which impinge on the heated (or cooled) surface, causing significantly higher heat transfer rate. Although some flat surface jet impingement cases are described in the literature, the validated data is still limited. The reason is coming from the fact, that these flows are hydrodynamically...
-
CHARAKTERYSTYKA WYMIANY CIEPŁA I OPORÓW PRZEPŁYWU OMYWANIA MIKROSTRUGAMI ROZWINIĘTEJ POWIERZCHNI
PublikacjaW artykule przedstawiono eksperymentalne badania kompaktowego wymiennika ciepła z intensyfikacją przejmowania ciepła przy użyciu mikrostrug. Niniejszy artykuł przedstawia projekt i testy prototypu, wymiennika ciepła typu mikrostrugowego. Modułowa konstrukcja wymiennika umożliwia zmianę wymiarów geometrycznych, a także zmianę materiału przegrody wymiennika ciepła. Metoda graficzna Wilsona została z zastosowana w celu określenia...