Wyszukiwarka
Filtry
wszystkich: 2212
-
Katalog
wyświetlamy 1000 najlepszych wyników Pomoc
Wyniki wyszukiwania dla: LS-FLOWS
-
Pawlak's flow graph extensions for video surveillance systems
PublikacjaThe idea of the Pawlak's flow graphs is applicable to many problems in various fields related to decision algorithms or data mining. The flow graphs can be used also in the video surveillance systems. Especially in distributed multi-camera systems which are problematic to be handled by human operators because of their limited perception. In such systems automated video analysis needs to be implemented. Important part of this analysis...
-
Modeling of entrained flow steam gasification of sewage sludge
PublikacjaProper management of sewage sludge becomes increasingly problematic due to legal requirements aiming at diminishing environmental impact, as well as rationalizing the utilization from the point of view of logistics. Steam gasification of sewage sludge can result in very good quality of the producer gas. So far, the works have been focused on the gasification in fixed bed gasifiers. However, this does not allow to take full advantage...
-
Rational determination of dynamic characteristics of fluid-flow Reactors
PublikacjaPodstawowa charakterystykę reaktorów stanowi krzywa rozkładu czasu zatrzymania. Jej dokładne wyznaczenie jest trudne i kosztowne. W pracy zaproponowano wykorzystanie metody aproksymacyjnej, polegającej na zastąpieniu rzeczywistej funkcji przez jej przebieg uproszczony. Zaproponowano aproksymację rozkładem trójkątnym. Na konkretnym przykładzie pokazano, że metoda ta daje lepsze wyniki niż powszechnie stosowany model przepływu tłokowego.
-
Application of a cellular automaton to simulations of granular flow in silos
PublikacjaA cellular automaton based on a gas model of hydrodynamics was used to calculate the kinematics of non-cohesive granular materials during confined flow in a mass flow and funnel flow model silo. In the model, collisions of particles were taken into account during granular flow. In addition, a simplified automaton was used wherein granular flow was assumed as an upward propagation of holes through a lattice composed of cells representing...
-
Silo music - mechanism of dynamic flow and structure interaction
PublikacjaArtykuł omawia zjawisko muzyki silosowe. Wykonano pomiary dynamiczne przyspieszeń, częstotliwości i postaci drgań własnych. Zaproponowano nowa hipotezę powstawania efektów dynamicznych podczas przepływu silosowego.
-
Dynamic and tomography analysis of granular flow in cylindrical shell
PublikacjaW pracy przedstawiono wyniki badań ekperymentalnych dotyczących efektów dynamicznych występujących podczas przepływu materiałów sypkich w silosie cylindrycznym.
-
Reduction of dynamic effects during granular flow in silos
PublikacjaOmówiono kilka efektywnych sposobów redukcji nadmiernych dynamicznych efektów występujących w przepływie silosowym w silosach modelowych. Sposoby te mogą być wykorzystane w praktyce silosowej.
-
Silo music - mechanism of dynamic flow and structure interaction
PublikacjaArtykuł omawia zjawisko muzyki silosowej. Wykonano pomiary dynamiczne przyspieszeń, częstotliwości i postaci drgań własnych. Zaproponowano nowa hipotezę powstawania efektów dynamicznych podczas przepływu silosowego.
-
Confined granular flow in silos : experiments and numerical investigation
PublikacjaW monografii opisano niektóre charakterystyczne zjawiska mające miejsce podczas przepływów silosowych materiałów sypkich. Wykonano badania doświadczalne oraz obliczenia numeryczne celem wyjaśnienia zjawisk. Doświadczenia wykonano w dużych i małych silosach. Obliczenia wykonano przy zastosowaniu metody elementów skończonych opartej na hipoplastycznym modelu konstytutywnym dla materiałów sypkich.
-
Large eddy simulations of wall-bounded flows using a simplified immersed boundary method and high-order compact schemes
Publikacja -
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...
-
Simplified Numerical Model for Transient Flow of Slurries at Low Concentration
PublikacjaRapid transients are particularly dangerous in industrial hydro-transport systems, where solid-liquid mixtures are transported via long pressure pipelines. A mathematical description of such flow is difficult due to the complexity of phenomena and difficulties in determining parameters. The main aim of the study was to examine the influence of the simplified mixture density and wave celerity description on satisfactory reproduction...
-
Elektrochemiczne magazyny energii - baterie przepływowe typu "redox flow"
PublikacjaRozwój i wzrost udziału energii odnawialnej, ze względu na kurczące się zasoby konwencjonalnych źródeł energii i ochronę środowiska, jest możliwy tylko dzięki współpracującym z nimi odpowiednim stacjonarnym magazynom energii. Technologia baterii przepływowych (ang. redox flow batteries, RFB) pozwala świetnie zaspokoić tego typu potrzeby ze względu na: (i) wyjątkowo dużą skalowalność układów; (ii) niezależny dobór mocy i pojemności...
-
OBTAINING FLUID FLOW PATTERN FOR TURBINE STAGE WITH NEURAL MODEL.
PublikacjaIn the paper possibility of applying neural model to obtaining patterns of proper operation for fluid flow in turbine stage for fluid-flow diagnostics is discussed. Main differences between Computational Fluid Dynamics (CFD) solvers and neural model is given, also limitations and advantages of both are considered. Time of calculations of both methods was given, also possibilities of shortening that time with preserving the accuracy...
-
Hysteresis curves for some periodic and aperiodic perturbations in magnetosonic flow
PublikacjaA thermodynamic relation between perturbations of pressure and mass density in the magnetohydrodynamic flow is theoretically studied. Planar magnetohydrodynamic perturbations with the wave vector, which forms a constant angle with the equilibrium magnetic field, are under study. The theory considers thermal conduction of a plasma and the deviation from adiabaticity of a flow due to some kind of heating–cooling function. It also...
-
The equivariant spectral flow and bifurcation of periodic solutions of Hamiltonian systems
PublikacjaWe define a spectral flow for paths of selfadjoint Fredholm operators that are equivariant under the orthogonal action of a compact Lie group as an element of the representation ring of the latter. This G-equivariant spectral flow shares all common properties of the integer valued classical spectral flow, and it can be non-trivial even if the classical spectral flow vanishes. Our main theorem uses the G-equivariant spectral flow...
-
A numerical and experimental analysis of multi-hole orifice in turbulent flow
PublikacjaIn this research study, the comprehensive metrological analysis is investigated for a 4-hole orifice with module m = 0.25 installed in the pipeline with an internal diameter of 50 mm. A detailed numerical simulation was performed for the turbulence models: k-ε-realizable and k-ω-BSL. The novelties of the research include model validation by comparing the results of numerical studies with the experiment conducted in the area of...
-
NP-hardness of compact scheduling in simplified open and flow shops
Publikacja -
Power flow in typical series-parallel hybrid filters topologies
Publikacja -
Numerical Analysis of Flow in Building Arrangement: Computational Domain Discretization
Publikacja -
Design and evaluation of a flow-to-frequency converter circuit with thermal feedback
Publikacja -
Laboratorial studies on the seepage impact in open-channel flow turbulence
Publikacja -
Analysis of Turbulent Flow Measurements in a Flume with Induced Upward Seepage
Publikacja -
Flow cytometry as an estimation tool for honey bee sperm viability
Publikacja -
Acoustic and Flow Aspects of Synthetic Jet Actuators with Chevron Orifices
Publikacja -
Determination of free surface and gravitational flow of liquid in triangular groove
Publikacja -
Efficiency of acoustic heating produced in the thermoviscous flow of a fluid with relaxation
PublikacjaInstantaneous acoustic heating of a fluid with thermodynamic relaxation is the subject of investigation. Among others, viscoelastic biological media described by the Maxwell model of the viscous stress tensor, belong to this type of fluid. The governing equation of acoustic heating is derived by means of the special linear combination of conservation equations in differential form, allowing the reduction of all acoustic terms in...
-
Modelling of energy flow in electrical machines. A bond graph approach
PublikacjaPrzedstawiono w ujęcia grafów wiązań model przepływu energii/mocy w maszynach elektrycznych pracujących w hybrydowych systemach przetwarzania energii. Jako przykład do rozważań przyjęto system napędu trakcyjnego pojazdów hybrydowych.
-
Application of vertical flow cw for highly contaminated wastewater treatment
PublikacjaBasing on quantitative and qualitative characteristics of reject waters generated during digested sewage sludge dewatering on centrifuges in conventional WWTP (RWC) and municipal landfill leachate (LL), the pilot constructed wetlands for treatment of both types of highly contaminated wastewater were designed. In the paper the characteristics of the pilot plants and assumed treatment efficiencies are presented. According to the...
-
Monitoring of solid behaviour during gravitational flow in rectangular silo
PublikacjaW pracy przedstawiono wyniki pomiarów zmian koncentracji w protokątnym modelu silosu. Omówiono przyczyny błędów pomiarowych w modelu protkątnym, zarówno dla danych surowych, jak rózniez danych zrekonstruowanych.
-
Modelling of energy flow in mechatronic systems. A bond graph approach
PublikacjaW referacie przedstawiono w sposób jednoliy modelowanie systemów mechatroniki metodą grafów wiązań (GW) w aspekcie symulacji przepływu energii. Omówiono ogólne założenia modelowania w ujęciu GW. Modelowanie przepływu energii rozważano na przykładzie napędu pojazdu hybrydowego PH-MAK.
-
Determination of selected parameters in a 1D open channel flow model
PublikacjaOkreślenie parametrów jest ważnym etapem tworzenia modelu matematycznego. W przypadku jednowymiarowego modelu przepływu ze swobodną powierzchnią opisanego układem równań de Saint-Venanta, jedną z grup parametrów wymagających identyfikacji są parametry związane z tarciem. Mogą one być określone w różny sposób, ale w większości przypadków problem ten stanowi zagadnienie żle postawione. W takich przypadkach najczęściej stosowaną...
-
Cross-Flow Microfiltration of Glycerol Fermentation Broths with Citrobacter freundii
Publikacja -
Effect of flow-rate on ethanol separation in membrane distillation process
Publikacja -
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...
-
Analysis of radiometric signal in sedimentating suspension flow in open channel
PublikacjaThe article discusses issues related to the estimation of the sedimentating solid particles average flow velocity in an open channel using radiometric methods. Due to the composition of the compound, which formed water and diatomite, received data have a very weak signal to noise ratio. In the process analysis the known determining of the solid phase transportation time delay the classical cross-correlation function is the most...
-
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...
-
Selected studies of flow maldistribution in a minichannel plate heat exchanger
PublikacjaAnalysis of the state of-the-art in research of minichannel heat exchangers, especially on the topic of flow maldistribution in multiple channels, has been accomplished. Studies on minichannel plate heat exchanger with 51 parallel minichannels with four hydraulic diameters, i.e., 461 μm, 574 μm, 667 μm, and 750 μm have been presented. Flow at the instance of filling the microchannel with water at low flow rates has been visualized. The...
-
Comparative study of flow condensation in conventional and small diameter tubes
PublikacjaFlow boiling and flow condensation are often regarded as two opposite or symmetrical phenomena, however their description with a single correlation has yet to be suggested. In the case of flow boiling in minichannels there is mostly encountered the annular flow structure, where the bubble generation is not present. Similar picture holds for the case of inside tube condensation, where annular flow structure predominates. In such...
-
Comparative study of flow condensation in conventional and small diameter tubes
PublikacjaIn the paper a method developed earlier by the first author is applied to calculations of heat transfer coefficient for inside tube condensation. The method has been verified using experimental data from literature on several fluids in different microchannels and compared to three well established correlations.
-
Flow Boiling in Minigap in the Reversed Two-Phase Thermosiphon Loop
PublikacjaThe paper presents the results of experimental investigations of a model of a heat exchanger featuring a minigap, which is perceived as an evaporator for an inverted thermosiphon. The system works with a single component test fluid. The tested evaporator generates pumping power in the test loop in a way similar to the mammoth pump. The tests regarded a module of the heat exchanger, consisting of a hot leg and a cold leg with the...
-
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...
-
Pressure drop of HFE7000 and HFE7100 during flow condensation in minichannels
PublikacjaAttention is focused on the issues of flow resistance and pressure drop of perspective refrigeration fluids during condensation in the two-phase flow in minichannels. The case of the flow through a cylindrical single channel of 2.3 mm inner diameter was carefully analyzed. Pressure drop tests have been performed in diabatic flow conditions. The effect of heat flux, mass flux, vapour quality and saturation temperature on the two-phase...
-
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...
-
Numerical Study of Turbulent Flow and Heat Transfer of Nanofluids in Pipes
PublikacjaIn this work, Nusselt number and friction factor are calculated numerically for turbulent pipe flow (Reynolds number between 6000 and 12000) with constant heat flux boundary condition using nanofluids. The nanofluid is modelled with the single-phase approach and the simulation results are compared with experimental data. Ethylene glycol and water, 60:40 EG/W mass ratio, as base fluid and SiO2 nanoparticles are used as nanofluid...
-
Reduction of Computational Complexity in Simulations of the Flow Process in Transmission Pipelines
PublikacjaThe paper addresses the problem of computational efficiency of the pipe-flow model used in leak detection and identification systems. Analysis of the model brings attention to its specific structure, where all matrices are sparse. With certain rearrangements, the model can be reduced to a set of equations with tridiagonal matrices. Such equations can be solved using the Thomas algorithm. This method provides almost the same values...
-
Acoustic Heating Produced in the Thermoviscous Flow of a Shear-Thinning Fluid
PublikacjaThis study is devoted to the instantaneous acoustic heating of a shear-thinningfluid. Apparent viscosity of a shear-thinning fluid depends on the shear rate. Thatfeature distinguishes it from a viscous Newtonian fluid. The special linear combi-nation of conservation equations in the differential form makes it possible to derivedynamic equations governing both the sound and non-wave entropy mode inducedin the field of sound. These...
-
Numerical Simulation of Open Channel Flow between Bridge Piers
PublikacjaPrzedstawiono dwuwymiarowy model przepływu wody płytkiej, który wykorzystano do symulacji przepływu wody w kanale otwartym w rejonie przekroju mostowego. Równania przepływu rozwiązano metodą objętości skończonych. Wyniki symulacji ruchu wody pomiędzy filarami mostowymi porównano z pomiarami laboratoryjnymi przeprowadzonymi w Laboratorium Hydrauliki i Inżynierii Środowiska politechniki Gdańskiej. Zgodność uzyskanych wyników obliczeń...
-
Examination of the effect of altering model complexity on representing groundwater flow
PublikacjaW artykule przedstawiono wyniki badań na dokładnością modeli numerycznych przepływu wód podziemnych. Analizowano wpływ upraszczania struktury przestrzennej modelu na wyniki obliczeń.
-
Electrical capacitance tomography for studying the flow of friable materials in silos.
PublikacjaArtykuł opisuje możliwość aplikacji tomografii do pomiarów przepływu materiałów sypkich w silosach