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Search results for: FLOW PATTERN LATTICE-GAS AUTOMATON
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Application of gamma densitometry and statistical signal analysis to gas phase velocity measurements in pipeline hydrotransport
PublicationThe work presents selected methods of signal analysis used in the processing of data obtained from radiometric probes. The used data came from an exemplary study of a two-phase liquid-gas flow at the laboratory installation. In such rigs many possible transport types may be observed, i.e. slug, plug and bubble flow, and each of them gives different signal-to-noise ratio of recorded data. Therefore, available radiometric methods...
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Application of gamma densitometry and statistical signal analysis to gas phase velocity measurements in pipeline hydrotransport
PublicationThe work presents selected methods of signal analysis used in the processing of data obtained from radiometric probes. The used data came from an exemplary study of a two-phase liquid-gas flow at the laboratory installation. In such rigs many possible transport types may be observed, i.e. slug, plug and bubble flow, and each of them gives different signal-to-noise ratio of recorded data. Therefore, available radiometric methods...
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Electrohydrodynamic Secondary Flow and Particle Collection Efficiency in Spike-Plate Multi-Electrode Electrostatic Precipitator
PublicationIn this work the results of electrohydrodynamic (EHD) secondary flowmeasurements in a spike-plate type electrostatic precipitator (ESP) are presented. In the investigated ESP two-sided and one-sided spike electrodes were used as a discharge electrodes. The results of 2D PIVmeasurements showed that flow pattern obtained for a different spike tips positions in respect to the primary flow direction significantly changing the flow...
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Gas sampling system for matrix of semiconductor gas sensors
PublicationSemiconductor gas sensors are popular commercial sensors applied in numerous gas detection systems. They are reliable, small, rugged and inexpensive. However, there are a few problem limiting the wider use of such sensors. Semiconductor gas sensor usually exhibits a low selectivity, low repeatability, drift of response, strong temperature and moisture influence on sensor properties. Sample flow rate is one of the parameters that...
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On Accuracy Modeling of Gas Turbine Cycles by the In-house COM-GAS Code
PublicationIn this paper, a comparison of accuracy modeling of gas turbine cycles between the basic (classical) model and the in-house COM-GAS code has been presented. The basic model uses a semi-perfect gas and well known projecting assumption. On the other hand, the computational flow mechanics (CFM) basis on a real gas by using thermodynamic tables. The thermodynamic analysis of thermal cycles, simply gas cycle GT8C and gas turbine cycle...
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Wpływ wybranych parametrów środowiska na przebieg degradacji rur okładzinowych ze stali P110
PublicationMateriały używane na orurowanie odwiertów w poszukiwaniu i wydobyciu ropy i gazu poddawane są niekorzystnym warunkom eksploatacji takich jak: podwyższona temperatura, wysokie ciśnienie, turbulentny przepływ korozyjnych cieczy z zawieszonymi cząstkami stałymi. Jednym z gatunków stali używanych do produkcji rur okładzinowych jest stal P110 (za normą API 5CT) będąca stalą średnio-węglową, niskostopową o wysokiej wytrzymałości. Celem...
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Operational causes of fatigue failures within the passages of gas turbine engines
PublicationThe short profile of a fatigue wear process of gas turbine engine's constructional elements has been introduced in the article. The primary causes of a fatigue cracks formation within the mechanical system as well as within the passages of the engine have been showed. Especial attention was devoted to the low-cycle fatigue, what is associated with unsteady thermal-flow processes being worked out in the passages.The selected damages...
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Analysis of the possibility of increasing thermal-electric energy conversion ratio in CHP units based on micro gas turbine
PublicationThe aim of this paper is to analyze the possibility of increasing thermal energy to electricity conversion efficiency in combined heat and power (CHP) units based on micro gas turbine during low heat demand periods. At the beginning sustainable development postulates under power engineering are explained. Next micro CHP as part of distributed generation idea is presented. The main part of the article is based on results of thermodynamic...
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Design and computational fluid dynamics analysis of the last stage of innovative gas-steam turbine
PublicationResearch regarding blade design and analysis of flow has been attracting interest for over a century. Meanwhile new concepts and design approaches were created and improved. Advancements in information technologies allowed to introduce computational fluid dynamics and computational flow mechanics. Currently a combination of mentioned methods is used for the design of turbine blades. These methods enabled us to improve flow efficiency...
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Determination of toxic gases based on the responses of a single electrocatalytic sensor and pattern recognition techniques
PublicationA response from an electrocatalytic gas sensor contains fingerprint information about the type of gas and its concentration. As a result, a single gas sensor can be used for the determination of different gases. However, information about the type of gas and its concentration is hidden in the unique shape of the current–voltage response and it is quite difficult to explore. One of the ways to get precise information about the measured...
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Effect of nitrogen doping on TiOxNy thin film formation at reactive high-power pulsed magnetron sputtering
PublicationThe paper is focused on a study of formation of TiOxNy thin films prepared by pulsed magnetron sputtering of metallic Ti target. Oxygen and nitrogen were delivered into the discharge in the form of reactive gases O2 and N2. The films were deposited by high-power impulse magnetron sputtering working with discharge repetition frequency f = 250 Hz at low (p = 0.75 Pa) and high (p = 10 Pa) pressure. The substrates were on floating...
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Wybrane zagadnienia przepływowe turbiny gazowej pracującej w tłoczni gazu ziemnego.
PublicationW niniejszym artykule przedstawiono cieplno-przepływowe obliczenia turbiny gazowej, stanowiącej napęd sprężarki w tłoczni gazu ziemnego. Wartości parametrów wejściowych niezbędnych do przeprowadzenia obliczeń przyjęto na podstawie danych technicznych tłoczni zasilających polski odcinek gazociągu tranzytowego Jamał-Europa, w których pracują turbiny gazowe SGT-600 firmy Siemens, o mocy 25,3 MW.
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Measurements of Two-phase Flows in Pipelines Using Radioisotopes and Statistical Signal Processing
PublicationThis paper presents an application of radiotracers and gamma absorption method in two-phase flow measurements in pipelines. Two different methods were implemented to analysis of acquired signals. Investigated methods are based on the cross-correlation function and the phase of the cross-spectral density distribution. The examples presented in the article illustrate the application of the radioisotopes to evaluation of liquid-gas...
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Application of fuzzy logic to determine the odour intensity of model gas mixtures using electronic nose
PublicationThe paper presents the possibility of application of fuzzy logic to determine the odour intensity of model, ternary gas mixtures (α-pinene, toluene and triethylamine) using electronic nose prototype. The results obtained using fuzzy logic algorithms were compared with the values obtained using multiple linear regression (MLR) model and sensory analysis. As the results of the studies, it was found the electronic nose prototype along...
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A calibration model for gas sensor array in varying environmental conditions
PublicationAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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A calibration model for gas sensor array in varying environmental conditions
PublicationAbstract: Gas-analyzing systems based on gas sensors, commonly referred to as electronic noses, are the systems which enable the recognition of volatile compounds in their working environment and provide the on-line results of analysis. The most commonly used type of sensors in such systems is semiconductor gas sensors. They are considered to be the most reliable in the long-term applications (more than 1 year), however,...
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OPTIMIZATION OF THE LAST STAGE OF GAS-STEAM TURBINE USING A HYBRID METHOD
PublicationThis paper relates to the CFD calculation of a new turbine type which is in the phase of theoretical analysis, because the working fluid is a mixture of steam and gas generated in wet combustion chamber. At first, this article concentrates on a possibility of streamlining the flow efficiency of a last stage of axial turbine working on gas-steam mixture using a hybrid of the particle swarm optimization algorithm with the Nelder-Mead...
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Exhaust gas temperature measurements in diagnostics of turbocharged marine internal combustion engines. Part I. Standard measurements.
PublicationThe article discusses the problem of diagnostic informativeness of exhaust gas temperature measurements in turbocharged marine internal combustion engines. Theoretical principles of the process of exhaust gas flow in turbocharger inlet channels are analysed in its dynamic and energetic aspects. Diagnostic parameters are defined which enable to formulate general evaluation of technical condition of the engine based on standard...
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Comparison of EHD devices with parallel and in series spiked electrodes
PublicationIn this paper two electrohydrodynamic (EHD) devices for gas pumping and cleaning are presented. In both cases to induce an airflow in these EHD devices corona discharge was used. The discharge was generated between the spiked electrodes set parallel (the first case) or in series (the second case) and the plate electrodes. An asymmetric electric field and generated discharge result in unidirectional gas flow through the EHD device....
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Particle Image Velocimetry Measurements of Airflow in Electrohydrodynamic Device for Dust Particle Collection
PublicationIn this paper the electrohydrodynamic (EHD)device for gas pumping and cleaning is presented. To induce an airflow in this EHD device corona discharge was used. The discharge was generated between the one-sided spike electrodes and the plate electrodes. An asymmetric electric field and generated discharge result in unidirectional gas flow through the EHD device. The current-voltage characteristics were measured and the corona discharge...
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Numerical Modeling of Water and Ice Dynamics for Analysis of Flow Around the Kiezmark Bridge Piers
PublicationThis paper presents the results of a numerical model study on the effect of ice on the proposed bridge piers in the Vistula River outlet and its effect on flow conditions in the river. The model DynaRICE is used in this study, which is a two-dimensional hydro-ice dynamic numerical model developed for dynamic ice transport and jamming in rivers. To simulate river hydrodynamics in the vicinity of the bridge piers, 2-dimensional numerical...
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Decomposition of Acoustic and Entropy Modes in a Non-Isothermal Gas Affected by a Mass Force
PublicationDiagnostics and decomposition of atmospheric disturbances in a planar flow are considered in this work. The study examines a situation in which the stationary equilibrium temperature of a gas may depend on the vertical coordinate due to external forces. The relations connecting perturbations are analytically established. These perturbations specify acoustic and entropy modes in an arbitrary stratified gas affected by a constant...
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Exhaust gas temperature measurements in diagnostic examination of naval gas turbine engines. Part II. Unsteady processes
PublicationThe second part of the article presents the results of operating diagnostic tests of a two- and three-shaft engine with a separate power turbine during the start-up and acceleration of the rotor units. Attention was paid to key importance of the correctness of operation of the automatic engine load control system, the input for which, among other signals, is the rate of increase of the exhaust gas flow temperature. The article...
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Features extraction from the electrocatalytic gas sensor responses
PublicationOne of the types of gas sensors used for detection and identification of toxic-air pollutant is an electrocatalytic gas sensor. The electrocatalytic sensors are working in cyclic voltammetry mode, enable detection of various gases. Their response are in the form of I-V curves which contain information about the type and the concentration of measured volatile compound. However,...
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Power enhancement of the Brayton cycle by steam utilization
PublicationThe paper presents thermodynamic analysis of the gas-steam unit of the 65 MWe combined heat and power station. Numerical analyses of the station was performed for the nominal operation conditions determining the Brayton and combined cycle. Furthermore, steam utilization for the gas turbine propulsion in the Cheng cycle was analysed. In the considered modernization, steam generated in the heat recovery steam generator unit is directed...
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Application of ANN and PCA to two-phase flow evaluation using radioisotopes
PublicationIn the two-phase flow measurements a method involving the absorption of gamma radiation can be applied among others. Analysis of the signals from the scintillation probes can be used to determine the number of flow parameters and to recognize flow structure. Three types of flow regimes as plug, bubble, and transitional plug – bubble flows were considered in this work. The article shows how features of the signals in the time and...
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Al(III) and Cu(II) simultaneous foam separation: Physicochemical problems
PublicationSimultaneous removal of Al(III) and Cu(II) from dilute aqueous solutions by ion and precipitate flotation methods is investigated. Influence of the pH of the initial solution, the surface active collector concentration and the gas flow rate on the final removal ratio and the course of ion and precipitate flotations is presented. Results show that simultaneous flotations of Al(OH)3 and Cu(OH)2 insoluble species occur allowing to...
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Spectroscopic study of atmospheric pressure 915 MHz microwave plasma at high argon flow rate
PublicationIn this paper results of optical emission spectroscopic (OES) study of atmospheric pressure microwave 915 MHz argon plasma are presented. The plasma was generated in microwave plasma source (MPS) cavity- resonant type. The aim of research was determination of electron excitation temperature Texc gas temperature Tg and electron number density ne. All experimental tests were performed with a gas flow rate of 100 and 200 l/min and...
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Permeation and sorption properties of poly(ether-block-amide) membranesfilled by two types of zeolites
PublicationThe experimental study of transport properties of mixed matrix membranes (MMMs) based on PEBA-4033 with two types of zeolites is reported. Gas (CO2, O2, N2) and vapor (benzene, toluene, methanol, water) permeation measurements were performed using the differential flow permeameter at temperature of 298.15 K and at atmospheric pressure. Gas/vapor permeation was monitored by measuring the changes of the thermal conductivity of carrier...
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Power augmentation of PGE Gorzow's gas turbine by steam injection - thermodynamic overview
PublicationThe impact of steam injection upon a gas turbine and a combined power plant performance has been investigated. This article describes and summarizes possibilities of modification for current gas turbine in PGE Gorzow power plant into the Cheng cycle. Our modification deals with a thermal cycle, in which steam produced in a heat recovery steam generator is injected into the gas turbine's combustion chamber. It has been proved that...
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The Application of Fluidic Sealing in Shrouded Gas Turbine Blades
PublicationThis paper presents a study conducted on a new gas turbine designed to limit leakage in the labyrinth seal. The slots in the fin are used to generate a bypass flow, which obstructs the flow in the gap above the fin. The method was tested numerically and experimentally beforehand using a simplified model without rotation or blade passages. In this paper, the validation of the method using a model of a turbine stage is shown. Reynolds-averaged...
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Zastosowanie addytywów w separacji pianowej białek serwatkowych i białek mlecznych
PublicationZaproponowano proces separacji pianowej do wydzielania białek ze strumieni poprodukcyjnych przemysłu mleczarskiego Ponadto zaproponowano zastosowanie w separacji pianowej białek serwatkowych i mlecznych addytywów dopuszczonych ustawą do stosowania w żywności. Jako cel pracy przyjęto uzyskanie wyników uzasadniających wybór takich addytywów, które intensyfikują przebieg i polepszają wynik procesu separacji pianowej białek. W części...
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Three phase transient model of wet coal pyrolysis
PublicationA one-dimensional transient mathematical model was developed to describe the thermal and flow phenomena during coal pyrolysis in a coke oven. The model was solved numerically using partly implicit methods for gas flow and heat transfer problems. It was successfully validated with industrial-scale measurements of temperature change in the middle-plane of the coke oven chamber. The evolution of temperature and pressure, distributions...
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Time window based features extraction from temperature modulated gas sensors for prediction of ammonia concentration
PublicationElectronic gas recognition systems, in literature commonly referred as electronic noses, enable the recognition of a type and a concentration of various volatile compounds. Typical electronic gas-analyzing device consists of four main elements, namely, gas delivery subsystem, an array of gas sensors, data acquisition and power supply circuits and data analysis software. The commercially available metal-oxide TGS sensors are widely...
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Low energy elastic electron scattering from benzonitrile (C6H5CN)
PublicationWe present experimental differential elastic scattering cross sections (DCSs) for low energy electron scattering from benzonitrile along with integral and momentum-transfer cross sections that are determined from these DCSs. The measurements of DCSs are obtained using the relative flow method with helium as the standard gas, in a crossed electron-molecular gas beam arrangement. Our measurements are made at incident electron energies...
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Limited selectivity of amperometric gas sensors operating in multicomponent gas mixtures and methods of selectivity improvement
PublicationIn recent years, smog and poor air quality have became a growing environmental problem. There is a need to continuously monitor the quality of the air. The lack of selectivity is one of the most important problems limiting the use of gas sensors for this purpose. In this study, the selectivity of six amperometric gas sensors is investigated. First, the sensors were calibrated in order to find a correlation between the concentration...
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A novel concept of enhanced direct-contact condensation of vapour- inert gas mixture in a spray ejector condenser
PublicationAn analytical model of direct steam condensation (DCC) in the novel idea of spray ejector condenser (SEC) in the presence of inert gas has been developed. It is based on continuity, momentum and energy equations for the steam-carbon dioxide mixture and direct contact condensation mechanisms due to heat transfer and concentration. Crucial in the process of DCC is atomisation of the motive fluid in the ejector. The effect of atomised...
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Selectivity of amperometric gas sensors in multicomponent gas mixtures
PublicationIn recent years smog and poor air quality became a growing environmental problem. There is a need to continuously monitor the quality of air. The lack of selectivity is one of the most important problems limiting the use of gas sensors for this purpose. In this study, a selectivity of the six amperometric gas sensors is being investigated. Calibration of sensors has been performed in order to find a correlation between concentration...
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Nitrogen-doped diamond thin films: potential application in Fabry-Pérot interferometer
PublicationIn this paper we present results of preliminary research of using nitrogen-doped diamond (NDD) films as reflective layer in Fabry-Pérot interferometer. NDD films were deposited on Si substrates by Microwave Plasma Enhanced Chemical Vapor Deposition (MPECVD) with the use of CH4, H2 and N2 gas mixtures. During deposition process methane flow rate varied while nitrogen flow was constant. We performed series of measurements which showed...
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Nitrogen dioxide sensing properties of PEDOT polymer films
PublicationThis work presents a simple and fully electrochemical route for the polymerization of poly(3,4-ethylenedioxytiophene) (PEDOT) films for fabricating a NO2 gas sensor prepared by electropolymerization of 3,4-Ethylenedioxythiophene (EDOT) monomer in lithium perchlorate/acetonitrile solution. The main aim of this study is to determine the sensing properties of conductive polymer at elevated temperatures. The effects of the humidity,...
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Efficiency of linear and non-linear classifiers for gas identification from electrocatalytic gas sensor
PublicationElectrocatalytic gas sensors belong to the family of electrochemical solid state sensors. Their responses are acquired in the form of I-V plots as a result of application of cyclic voltammetry technique. In order to obtain information about the type of measured gas the multivariate data analysis and pattern classification techniques can be employed. However, there is a lack of information in literature about application of such...
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Instantaneous Heating and Cooling Caused by Periodic or Aperiodic Sound of Any Characteristic Duration in a Gas with Vibrational Relaxation
PublicationThermodynamic relaxation of internal degrees of a molecule's freedom in a gas occurs with some characteristic time. This makes wave processes in a gas behave differently depending on the ratio of characteristic duration of perturbations and the relaxation time. In particular, generation of the secondary non-wave modes by intense sound in a nonlinear flow dependens on frequency. These kinds of interaction are considered in this...
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Air flow phenomena in the model of the blind drift
PublicationIn the presented paper, Particle Image Velocimetry (PIV) has been used to investigate flow pattern and turbulent structure in the model of blind drift. The presented model exist in mining, and has been analyzed to resolve ventilation issues. Blind region is particularly susceptible to unsafe methane accumulation. The measurement system allows us to evaluate all components of the velocity vector in channel cross-section simultaneously....
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Nonlinear Influence of Sound on the Vibrational Energy of Molecules in a Relaxing Gas
PublicationDynamics of a weakly nonlinear and weakly dispersive flow of a gas where molecular vibrational relaxation takes place is studied. Variations in the vibrational energy in the field of intense sound is considered. These variations are caused by a nonlinear transfer of the acoustic energy into energy of vibrational degrees of freedom in a relaxing gas. The final dynamic equation which describes this is instantaneous, it includes a...
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Methods of measurement signal acquisition from the rotational flow meter for frequency analysis
PublicationOne of the simplest and commonly used instruments for measuring the flow of homogeneous substances is the rotational flow meter. The main part of such a device is a rotor (vane or screw) rotating at a speed which is the function of the fluid or gas flow rate. A pulse signal with a frequency proportional to the speed of the rotor is obtained at the sensor output. For measurements in dynamic conditions, a variable interval between...
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Wykorzystanie tomografii komputerowej przy analizie jakości zacementowania - migracja gazu
PublicationArtykuł przedstawia opis zjawiska znanego w wiertnictwie otworowym jako migracja gazu. Opisano główne przyczyny powstawania tego negatywnego zjawiska polegającego na przepływie gazów a także płynów w zaczynie cementacyjnym lub kamieniu cementowym. Przygotowano próbki imitujące zacementowany odcinek rur okładzinowych. Skupiono się na wykorzystaniu tomografii komputerowej, oraz analizie zrekonstruowanego trójwymiarowego obrazu, w...
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Numerical analysis of the flow rig for UWS spray examination in exhaust system-relevant conditions
PublicationIn the present study, a flow rig with optical access intended for spray investigations in exhaust system-relevant conditions was analysed in terms of flow and temperature in the spray area using numerical simulations. The operation of the rig was examined for a wide range of exhaust mass flow rates, temperatures and various forms of UWS (urea-water solution) spray plumes. The locations of the injector and thermocouple were verified....
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Influence of Holes Manufacture Technology on Perforated Plate Aerodynamics
PublicationTranspiration flow is a very important and still open subject in many technical applications. Perforated walls are useful for the purpose of “flow control”, as well as for the cooling of walls and blades (effusive cooling) in gas turbines. We are still not able to include large numbers of holes in the numerical calculations and therefore we need physical models. Problems are related also to the quality of the holes in perforated...
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Techniques of acquiring additional features of the responses of individual gas sensors
PublicationGas sensors usually exhibit lack of selectivity, require fre quent calibration, exhibit drift of the response and a lot of factors, such as humidity or ambient temperature, influen ce their performance. Different approaches can be used to overcome this shortcomings. Building arrays of different sensors and usage of pattern recognition methods to analyze responses of elements...
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An asymmetrical λ-foot of condensing steam flow in the IMP PAN nozzle
PublicationIn the present paper we have focused on the precise prediction of the spontaneous condensation phenomena in wet steam flow. Novelty of our approach lies on modelling both the moment of initiation of a phase transition, as well as the moment of its reverse progress - called here re-vaporization of the condensate phase. The practical issue is to elaborate of a model of spontaneous condensation/vaporization of water steam flow...