Temat: pressure distribution - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: CFD analysis of effect of misalignment plane position on hydrodynamic lubrication of slide conical bearing
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/246851.pdf
Data publikacji:: 2017
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: slide bearing
hydrodynamic lubrication
conical bearing
misalignment
CFD
pressure distribution
Opis:: The numerical calculations of the hydrodynamic lubrication of slide bearings can be carried out by modelling the oil flow for a given value of height of bearing lubrication gap. On the basis of the assumed height of the lubrication gap, the values of hydrodynamic pressures, load carrying capacities, friction forces, temperatures, can be determined. The bearing lubrication gap height can be influenced by many effects, e.g. misalignment between the shaft axis and the axis of the sleeve, vibrations, varying load, change in the viscosity value of lubricating oil caused by changes in temperature, pressure, shear rate or by oil ageing, wear of journal and sleeve surfaces. This article presents the results of numerical simulations concerning the influence of the misalignment between the axis of shaft and the axis of sleeve of the sliding conical bearing on its hydrodynamic lubrication, by taking into account the position of the plane in which the misalignment occurs. In this study, there was defined an angle between the plane in which the misalignment occurs and the plane in which lies the line of centres of corresponding bearing without misalignment. In this research, to investigate the impact of the position of the plane in which the misalignment occurs, the CFD software, designed to solve general flow phenomena, was used. It was assumed, that the bearings operate in a steady state conditions, the flow in the bearing lubrication gap is laminar and non-isothermal. A lubricating oil has shear properties as the Ostwald-de Waele fluid.
Źródło:: Journal of KONES; 2017, 24, 2; 65-72
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: CFD analysis of hydrodynamic lubrication of slide conical bearing with consideration of the bearing shaft and sleeve surface roughness
Autorzy:: Czaban, A
Powiązania:: https://bibliotekanauki.pl/articles/246600.pdf
Data publikacji:: 2014
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: conical bearing
surface roughness
hydrodynamic lubrication
CFD simulation
non-Newtonian oil
pressure distribution
sand-grain roughness
Opis:: In this work is shown the result of CFD simulation of hydrodynamic conical bearing lubrication with consideration of the effect of the bearing shaft and sleeve surface roughness. The oil flow in a bearing lubrication gap largely depend on the condition of the cooperating surfaces of a bearing. Surface irregularities are formed already at the manufacturing process and furthermore the quality of the surface may change during operation of a bearing. In this work, as a parameter describing surface condition, the Ks roughness height parameter was taken (i.e. sand-grain roughness height). The hydrodynamic pressure distribution in lubrication gaps of investigated bearings were calculated by using the commercial CFD software ANSYS Academic Research for fluid flow phenomenon (Fluent). Calculations were conducted for bearings without misalignment. The Ostwald-de Waele model for non-Newtonian fluids was adopted in this simulation. The coefficients of Ostwald-de Waele relationship were determined by application of the least squares approximation method and fitting curves described by this model to the experimental data, obtained for some motor oils, presented in previous work. The calculated hydrodynamic pressure distributions were compared with the data obtained for corresponding bearings, but assuming that bearings have smooth surfaces and there is no slip on surfaces. This paper presents results for bearings with different rotational speeds and of different bearing gap heights.
Źródło:: Journal of KONES; 2014, 21, 3; 35-40
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: CFD analysis of non-Newtonian and non-isothermal lubrication of hydrodynamic conical bearing
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/243876.pdf
Data publikacji:: 2014
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: conical bearing
hydrodynamic lubrication
CFD simulation
non-Newtonian oil
non-isothermal flow
pressure distribution
Opis:: In this work is shown the result of CFD simulation of hydrodynamic conical bearing lubrication with consideration of non-isothermal oil flow in a bearing lubrication gap and also with assumption, that oil has non- Newtonian properties. The determination of hydrodynamic pressure distribution in bearing gap was carried out by using the commercial CFD software ANSYS Academic Research for fluid flow phenomenon (Fluent). Calculations were performed for bearings without misalignment, i.e. where the cone generating line of bearing shaft is parallel to the cone generating line of bearing sleeve. The Ostwald-de Waele model for non-Newtonian fluids was adopted in this simulation. The coefficients of Ostwald-de Waele relationship were determined by application of the least squares approximation method and fitting curves described by this model to the experimental data, obtained for some motor oils, presented in previous work. The calculated hydrodynamic pressure distributions were compared with the data obtained for corresponding bearings, but assuming that the flow in the bearing lubrication gap is isothermal. Some other simplifying assumptions are: a steady-state operating conditions of a bearing, incompressible flow of lubricating oil, no slip on bearing surfaces, pressure on the side surfaces of bearing gap is equal to atmospheric pressure. This paper presents results for bearings with different rotational speeds and of different bearing gap heights.
Źródło:: Journal of KONES; 2014, 21, 4; 49-56
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: CFD analysis of pressure distribution in slide conical bearing lubricated with non-Newtonian oil
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/241851.pdf
Data publikacji:: 2013
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: slide conical bearing
CFD
non-Newtonian oil
pressure distribution
Źródło:: Journal of KONES; 2013, 20, 3; 117-124
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: CFD analysis of the impact of a cone opening angle parameter on the hydrodynamic lubrication of the conical slide bearing
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/242697.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: hydrodynamic lubrication
slide bearing
conical bearing
cone opening angle
CFD
pressure distribution
Opis:: The height of the oil lubrication gap is the primary quantity that determines in simulations the operating parameters of a hydrodynamic slide bearing. It is influenced by multiple effects, such as vibrations during operation, varying load, misalignment between the shaft axis and the axis of the bearing sleeve, the roughness of the journal and sleeve surfaces, change in the viscosity value of lubricating oil caused by changes in temperature, pressure, shear rate or by oil ageing, wear of journal and sleeve surfaces etc. It is important to take into account such effects considering hydrodynamic lubrication simulations and design of the slide bearings. The one of the factors influencing the height of the oil lubrication gap of the conical slide bearing is the difference between the opening angle of the cone of bearing shaft and opening angle of the cone of bearing sleeve. The aim of this work is to investigate the impact of the difference between the values of these angles on the hydrodynamic lubrication of the conical slide bearing. The commercial CFD software Ansys Fluent, from the Ansys Workbench 2 platform, was used to determine the hydrodynamic pressure distributions, load carrying capacities and friction torques of the simulated bearings. It was assumed, that the bearings operate in a steady state conditions, the flow in the bearing lubrication gap is laminar and non-isothermal, there is no misalignment between the axis of bearing journal and axis of bearing sleeve, the surfaces of the journal and sleeve are smooth and lubricating oil acts as a liquid described by the Ostwald-de Waele power law model.
Źródło:: Journal of KONES; 2016, 23, 3; 71-77
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Generalized Newtonian fluids as lubricants in the hydrodynamic conical bearings : a CFD analysis
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/242462.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: hydrodynamic conical bearing
generalized Newtonian fluid
CFD
non-Newtonian oil
pressure distribution
dynamic viscosity
ferro-oil
Opis:: Additives, ageing or wear and impurities can cause, that relationship between shear stress and shear rate in a lubricating oil is or becomes non-linear, and due to this, a significant change in the values of operating parameters of slide hydrodynamic bearings may occur. It is important to take into account such dependence during design and simulations of slide bearings. The calculations, which consider the non-linear properties of the lubricating oil, can be carried out by adopting the generalized Newtonian fluid models. This paper shows the result of CFD simulation of slide conical bearings hydrodynamic lubrication, assuming that the lubricating oil behaves as a generalized Newtonian fluid. The hydrodynamic pressure distributions, load carrying capacities and friction torques were calculated for bearings lubricated with different types of generalized Newtonian fluids and the obtained data were compared. In the study, the following models of fluids were adopted: the Power-law fluid (Ostwald-de Waele), the Cross fluid and the Carreau fluid. The coefficients of mentioned relationships were determined by fitting the curves described by each model to the experimental data using the least squares approximation method. The calculations of hydrodynamic pressure distributions, load carrying capacities and friction torques were carried out using the commercial CFD software Ansys Fluent from the Ansys Workbench 2 platform.
Źródło:: Journal of KONES; 2016, 23, 2; 89-95
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Numerical analysis of influence of bearing material thermal conductivity coefficient on hydrodynamic lubrication of a conical slide bearing
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/246592.pdf
Data publikacji:: 2018
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: slide bearing
hydrodynamic lubrication
conical bearing
heat conduction
pressure distribution
Opis:: One of the main parameters affecting the hydrodynamic lubrication of slide bearings is the viscosity of lubricating oil. Many studies show, that significant changes in the viscosity of oil occur along with changes in its temperature. The influence on the temperature distribution in the lubrication gap of the slide bearing have a variety of factors, and one of them is the amount of heat exchanged between the lubricant and the environment. The temperature of the lubricating oil of operating bearing is usually higher than the ambient temperature. In addition to the convection, which occurs during the flow (heat exchange related to the oil supply and discharge system) some amount of heat is transferred to the bearing sleeve material (and also to the bearing shaft), and then it is conducted to sleeve outer surface. The amount of heat transferred through the bearing sleeve is mainly dependent on the difference of temperatures between inner and outer sleeve surfaces and also depend on the heat conduction coefficient of sleeve material. This article presents the results of modelling of the influence of amount of heat conducted through the bearing material, on the hydrodynamic lubrication of a conical slide bearing. The study concerned various values of the heat conduction coefficient of the bearing material to investigate its influence on the temperature values of lubricating oil, and thus, on its viscosity, on the distribution of hydrodynamic pressure and on the calculated values of bearing load carrying capacities and friction forces.
Źródło:: Journal of KONES; 2018, 25, 2; 89-96
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The influence of the microgrooves on the hydrodynamic pressure distribution and load carrying capacity of the conical slide bearing
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/246488.pdf
Data publikacji:: 2012
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: conical slide bearing
pressure distribution
microgrooves
Reynolds equation
load carrying capacity
Opis:: The aim of this work is to determine the hydrodynamic pressure distribution in oil film and the load carrying capacities of conical slide micro bearings with grooved sleeves. The results for some bearings examples are presented. For the bearings taken into account, the Reynolds equation was solved by the method of Finite Differences. In the calculations, the Reynolds boundary condition was applied. The simulation was performed for the conical slide micro bearings with the groves parallel to the cone generating line. The function of lubrication gap height for the conical slide bearings with sleeves covered with microgrooves was assumed on the basis of existing papers. The results obtained for the analogous bearings without the microgrooves are also shown, therefore the influence of microgrooves on the conical slide micro bearings can be observed. On the basis of the results, one can conclude, that applying microgrooves on the bearing sleeve surface causes the increase of the value of hydrodynamic pressure and longitudinal and transverse components of the load carrying capacity of the bearing. Furthermore, the effect of the microgrooves and their impact is noticeable in graphs of hydrodynamic pressure distribution. The applied method of investigation of the impact of microgrooves on a bearing operation is simpler and less expensive than the experimental studies, however it is necessary to verify that the results obtained with this method are correct and whether in fact applying microgrooves, besides form facilitate lubrication, causes the improvement in bearing operating parameters.
Źródło:: Journal of KONES; 2012, 19, 3; 85-91
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Simulations of the influence of the heat flux at the shaft surface of the conical slide bearing on its hydrodynamic lubrication and operating parameters
Autorzy:: Czaban, Adam
Miszczak, Andrzej
Powiązania:: https://bibliotekanauki.pl/articles/243495.pdf
Data publikacji:: 2019
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: hydrodynamic lubrication
slide bearing
conical bearing
heat conduction
pressure distribution
viscosity
Opis:: The aim of this work is to investigate, how in the adopted model of hydrodynamic lubrication of a conical slide bearing, the change of the heat flux value at the bearing shaft, affects bearing operating parameters. In this research, the authors use, the known from the literature, Reynolds type equation, describing the stationary hydrodynamic lubrication process of a conical slide bearing. The analytical, solutions, that determine the components of the lubricating oil velocity vector and the equation (analytical solution of energy equation) determining the threedimensional temperature distribution in the lubrication gap, was also adopted from previous works. In order to obtain numerical solutions, the Newton’s method was used, and the derivatives in the Reynolds type equation were approximated by the finite differences. An application of the method of subsequent approximations allowed considering the influence of temperature, pressure and shearing rate on the viscosity of lubricating oil. The considerations were performed by adopting the Reynolds condition of the hydrodynamic oil film. It was tested, how the assumed value of the heat flux on the bearing shaft surface affects the values of the obtained operating parameters, i.e. the transverse and longitudinal component of the load carrying capacity, friction force and coefficient of friction.
Źródło:: Journal of KONES; 2019, 26, 4; 29-37
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Simulating particle packing for soil porosity investigations
Autorzy:: Czachor, H.
Konstankiewicz, K.
Powiązania:: https://bibliotekanauki.pl/articles/2056984.pdf
Data publikacji:: 1995
Wydawca:: Polska Akademia Nauk. Instytut Agrofizyki PAN
Tematy:: moisture
packing
grain size
soil
pore
particle packing
capillary pressure
porosity
distribution
Źródło:: International Agrophysics; 1995, 09, 4
0236-8722
Pojawia się w:: International Agrophysics
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 11.

Tytuł:: Application of Multilayer Perceptron for the Calculation of Pressure Losses in Water Supply Lines
Zastosowanie perceptronu wielowarstwowego do obliczeń strat ciśnienia w przewodach wodociągowych
Autorzy:: Czapczuk, A.
Dawidowicz, J.
Piekarski, J.
Powiązania:: https://bibliotekanauki.pl/articles/1813822.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: water distribution systems
artificial intelligence
expert systems
artificial neuronal networks
heuristic methods
calculation of pressure losses
systemy dystrybucji wody
sztuczna inteligencja
systemy ekspertowe
sztuczne sieci neuronowe
metody heurystyczne
obliczenia strat ciśnienia
Opis:: Numerical methods have been widely used for many years in the design and operation of water supply systems. Specialised computer programmes offer more and more facilities, especially for data entry and viewing, but they still function on the basis of predetermined algorithms. At present, however, we strive to create computational programmes with a certain degree of creativity, which should make it easier for users to make decisions at various stages of the task and improve the quality of their solutions. The increasing power of computers will not solve complex problems alone. Only by introducing appropriate calculation methods can we obtain the right results. It seems that classical algorithms with a formalised course can be supplemented, nowadays, with far more advanced computational techniques. This paper presents an literature review on the use of artificial neural networks in the design and operation of water distribution systems. Presented in the second part of the paper, is an overview of the artificial neural network, developed for the calculation of pressure losses in water supply lines. The calculation of hydraulic piping with the EPANET programme for various input parameters resulted in a collection of 16,260 training examples. Input parameters of the neural network include pipe length, measurable flow, absolute roughness coefficient and the nominal diameter. Very high compatibility was obtained between the calculation results for those pressure losses obtained from the EPANET programme and those obtained from the multi-layered perceptron with one hidden layer.
Metody numeryczne stosuje się powszechnie od wielu lat w projektowaniu i eksploatacji systemów zaopatrzenia w wodę. Specjalistyczne programy komputerowe oferują coraz więcej udogodnień, szczególnie w zakresie wprowadzania danych oraz przeglądania wyników, lecz nadal funkcjonują na podstawie z góry określonych algorytmów. Obecnie dąży się jednak do stworzenia programów obliczeniowych, które będzie charakteryzować pewien stopień kreatywności, co powinno ułatwić użytkownikom podejmowanie decyzji na różnych etapach realizacji zadania i poprawić jakość rozwiązań. Zwiększająca się moc obliczeniowa komputerów samoistnie nie rozwiąże złożonych problemów. Dopiero wprowadzanie odpowiednich metod obliczeniowych, pozwala uzyskać właściwe efekty. Wydaje się, że klasyczne algorytmy o sformalizowanym przebiegu, można obecnie uzupełnić znacznie bardziej zaawansowanymi technikami obliczeniowymi. W niniejszej pracy dokonano przeglądu literatury w zakresie zastosowania sztucznych sieci neuronowych w projektowaniu systemów dystrybucji wody. W drugiej części artykułu zamieszczono omówienie sztucznej sieci neuronowej do obliczeń strat ciśnienia w przewodach wodociągowych. W wyniku obliczeń hydraulicznych przewodów wodociągowych za pomocą programu EPANET dla różnych wartości parametrów wejściowych uzyskano zbiór 16260 przykładów uczących. Parametry wejściowe sieci neuronowej to długość przewodu, przepływ miarodajny, współczynnik chropowatości bezwzględnej oraz średnica nominalna. Uzyskano bardzo wysoką zgodność pomiędzy wynikami obliczeń strat ciśnienia z programu EPANET i perceptronu wielowarstwowego z jedną warstwą ukrytą.
Źródło:: Rocznik Ochrona Środowiska; 2017, Tom 19; 200-210
1506-218X
Pojawia się w:: Rocznik Ochrona Środowiska
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 12.

Tytuł:: Insights into hydrodynamics of spinning fluids reactor
Autorzy:: Dargacz, A.
Aranowski, R.
Powiązania:: https://bibliotekanauki.pl/articles/109782.pdf
Data publikacji:: 2017
Wydawca:: Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:: hydrodynamics
spinning fluids reactor
pressure field distribution
separation
flotation
Opis:: Spinning fluids reactor (SFR) is one of the most efficient gas-liquid contacting system with high potential of application in many fields. The unique solution of SFR is the contacting of two spinning fluids which generated centrifugal force. The aim of this study was to investigate the pressure field distribution on the inner surface of reactors dispersing element. Obtained results confirm the high heterogeneity of the field pressure in the reactor system with a cylindrical wall. This is due to the low tangential force generated by rotating liquid on a cylindrical wall, and pressure drop in the locations of surface irregularities. The change of the sparger element to conical shape element increases the pressure exerted by fluid on the wall. In this case the effects of solid particles and inequality in the fluid flow are negligibly small compared to the measured pressure exerted on the sparger element.
Źródło:: Physicochemical Problems of Mineral Processing; 2017, 53, 1; 173-183
1643-1049
2084-4735
Pojawia się w:: Physicochemical Problems of Mineral Processing
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 13.

Tytuł:: Badania struktur sieci neuronowych typu mlp do oceny układu stref ciśnienia systemu dystrybucji wody
Research of structures of mlp artificial neural networks to evaluate the pressure zones of water distribution system
Autorzy:: Dawidowicz, J.
Powiązania:: https://bibliotekanauki.pl/articles/403185.pdf
Data publikacji:: 2015
Wydawca:: Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:: system dystrybucji wody
sieci neuronowe
strefa ciśnienia
klasyfikacja
water distribution system
neural networks
zone pressure
classification
Opis:: W artykule opisano badania nad różnymi strukturami sztucznych sieci neuronowych typu perceptron wielowarstwowy MLP przeznaczonych do oceny układu systemu dystrybucji wody. Problem oceny układu systemu został potraktowany jako zadanie klasyfikacji. Zdefiniowano klasy opisujące problemy występujące w procesie obliczeń związane z wysokością ciśnienia i podziałem systemu na strefy. Sieć neuronowa na podstawie zmiennych wejściowych, opisujących warunki hydrauliczne i terenowe, dokonuje klasyfikacji wskazując występujący problem w danym węźle systemu dystrybucji wody. Zamieszczono zestawienia tabelaryczne struktur przebadanych sieci neuronowych, wartości błędu uczenia, trafność klasyfikowania oraz analizę wrażliwości zmiennych wejściowych. Uzyskana sieć neuronowa ma za zadanie uzupełnić podstawową metodykę obliczeń systemów dystrybucji wody o elementy oceny uzyskanych wyników obliczeń.
Designing of water distribution systems is inherently associated with hydraulic simulations the purpose of which is to determine the flow rate in individual system sections, selection of pipe diameters, calculation of pressure losses and of the pressure head at nodes. In the water distribution system design and hydraulic calculations one should, inter alia, check a pressure head in different parts of the system. It is also important to establish whether the system should consist of one or more pressure zones. It is connected with the appropriate location of network pumping stations and pressure reducing stations. There are many methods of calculation of water distribution systems that allow you to solve tasks for various structures of pipeline. Computer programmes based on the above methods calculate the value required variables describing the individual elements of the system, but do not have procedures for assessing their accuracy. Currently, there are no, and probably there will be no programmes which would replace a designer in the aforementioned tasks. However, nowadays one tries to develop computer programmes featuring certain degree of creativity in order to facilitate user decision making. The article describes research on the various structures of multilayer perceptrons designed to evaluate the pressure zones the water distribution system. The task of evaluation system was defined as a classification. Problems in the calculation of water distribution systems related to the amount of pressure and the division of the system into zones described using classes. A neural network based on input variables that describe the hydraulic conditions and terrain, classifies the problem occurring in a given node water distribution system. The article contains a table with tested multilayer perceptrons, learning error values, classification results and a table with sensitivity analysis network input variables. The resulting neural network should complement the basic methodology for calculating the water distribution systems with elements of evaluate the results calculations.
Źródło:: Budownictwo i Inżynieria Środowiska; 2015, 6, 2; 53-60
2081-3279
Pojawia się w:: Budownictwo i Inżynieria Środowiska
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 14.

Tytuł:: The Application of Artificial Neural Networks in the Assessment of Pressure Losses in Water Pipes in the Design of Water Distribution Systems
Zastosowanie sztucznych sieci neuronowych do oceny strat ciśnienia w przewodach wodociągowych
Autorzy:: Dawidowicz, J.
Czapczuk, A.
Piekarski, J.
Powiązania:: https://bibliotekanauki.pl/articles/1813711.pdf
Data publikacji:: 2018
Wydawca:: Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:: water distribution system
hydraulic calculations
pressure losses
artificial neural networks
system dystrybucji wody
obliczenia hydrauliczne
liniowe straty ciśnienia
sztuczne sieci neuronowe
Opis:: The water distribution system is one of the most important elements of the water supply system, the construction of which accounts for the largest part of the costs involved, while at the same time, being the determining factor in the supply of water. Pipelines should be equipped to continue fulfilling their role for many years. In connection with the above, a very important task is the correct design and execution of hydraulic calculations. During the implementation of calculations, it is often necessary to correct data frequently, in order to obtain the correct solution. Numerous parameters are evaluated in the calculation process, including flow velocity through water supply pipelines, flow rate, pressure loss and pressure in individual, network nodes. An important parameter, often underestimated, is the level of pressure loss in the calculation sections of water pipes. This paper proposes a method for the assessment of pressure loss and for the use of artificial neural networks. For this purpose, one DH1 class, describing the correct conditions and four DH2-DH5 classes, characterising problems related to the amount of pressure losses in the water pipes, have been determined. Based on the parameters characterising the operation of the water pipe, the artificial neural network, selects one of the classes and thus indicates the occurrence of a specific problem, or gives the ‘all clear’.
System dystrybucji wody stanowi jeden z najważniejszych elementów wodociągu, którego budowa pochłania największą część kosztów, a jednocześnie w głównej mierze decyduje o możliwościach dostawy wody. Rurociągi wodociągowe powinny spełniać swoją rolę przez wiele lat. W związku z powyższym bardzo ważnym zadaniem jest poprawne zaprojektowanie i wykonanie obliczeń hydraulicznych. Podczas realizacji obliczeń najczęściej konieczne jest wielokrotne korygowanie danych w celu uzyskania poprawnego rozwiązania. W procesie obliczeń ocenie podlega wiele parametrów, w tym prędkość przepływu przez rurociągi wodociągowe, natężenie przepływu, wysokość strat ciśnienia oraz ciśnienie w poszczególnych węzłach sieci. Istotnym parametrem, często niedocenianym, jest wysokość strat ciśnienia na odcinkach obliczeniowych przewodów wodociągowych. W niniejszej pracy zaproponowano metodę oceny strat ciśnienia a pomocą sztucznych sieci neuronowych. W tym celu zdefiniowano jedną klasę DH1 opisującą poprawne warunki oraz cztery DH2-DH5, charakteryzujące problemy związane z wysokością strat ciśnienia w przewodach wodociągowych. Sztuczna sieć neuronowa na podstawie parametrów charakteryzujących pracę przewodu wodociągowego dokonuje wyboru jednej z klas, wskazując w ten sposób na występowanie określonego problemu lub jego brak.
Źródło:: Rocznik Ochrona Środowiska; 2018, Tom 20, cz. 1; 292-308
1506-218X
Pojawia się w:: Rocznik Ochrona Środowiska
Dostawca treści:: Biblioteka Nauki

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Tytuł:: Baro-paedometric biofeedback for foot unloading procedures investigation
Autorzy:: Descatoire, A.
Moretto, P.
Powiązania:: https://bibliotekanauki.pl/articles/333748.pdf
Data publikacji:: 2007
Wydawca:: Uniwersytet Śląski. Wydział Informatyki i Nauki o Materiałach. Instytut Informatyki. Zakład Systemów Komputerowych
Tematy:: urządzenia biologicznego sprzężenia zwrotnego
rozkład ciśnienia podeszwowego
obciążenia stopy
biofeedback devices
plantar pressure distribution
foot unloading
Opis:: Numerous studies on new biofeedback devices conception development were undertaken. They are used for some compensation methods of the data lost on sensors set. The aim of the study was carried out for introducing several approaches of investigations and testing of the biofeedback devices that support a plantar pressure analysis, for foot unloading processes implementation. The healthy man is walking in normal conditions first; on a walkway. The recorded load on 6 sensors has to be reduced next in a specified area. The pressure was considered at the beginning on metatarsal head, in time of 100 steps. The visual and auditory signals were then adjusted to a specific plantar pressure threshold setting. The peak pressure was evaluated for various walking condition. The introduced device enables us reducing the peak plantar pressure within the appointed risk-regions.
Źródło:: Journal of Medical Informatics & Technologies; 2007, 11; 41-45
1642-6037
Pojawia się w:: Journal of Medical Informatics & Technologies
Dostawca treści:: Biblioteka Nauki

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