Wyniki wyszukiwania - BazTech

1

Przegląd metod wyznaczania parcia mieszanki betonowej na deskowanie

Ambroziak Andrzej

Przegląd Budowlany

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2024

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R. 95, nr 3

19--25

PL

W pracy poruszono tematykę wyznaczania parcia mieszanki betonowej na deskowanie. Zebrano i opisano wybrane cztery modele stosowane do wyznaczania rozkładu ciśnienia poziomego świeżej mieszanki betonowej oddziaływującej na deskowanie. Dokonano krótkiego przeglądu literatury z zakresu omawianej tematyki parcia mieszanki betonowej na deskowanie.

EN

The paper addresses determining the pressure of the fresh concrete mix on the formwork. Selected four models used to determine the horizontal pressure distribution of fresh concrete mix acting on the formwork are collected and described. A short review of the literature on the subject of concrete mix pressure on the formwork is presented.

2

The effect of the stern wedge length and height on the drag and trim of a chine-planing hull

Ghassemi Mohammad A., Ghadimi Parviz, Sajedi Sayyed Mahdi

Zeszyty Naukowe Akademii Morskiej w Szczecinie

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2021

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nr 67 (139)

39--52

EN

This paper examines the effect of the stern wedge length and height on the drag and trim of a chine-planing hull in calm water. To this end, fluid flow was simulated by Star-CCM+ software by applying an overset mesh and k-ε turbulent model. The finite volume method was used to discretize the fluid domain, and the fluid volume was utilized to capture the generated free surface. The considered model is a prismatic planing hull with a deadrise angle of 24°, a mass of 86 kg, a length (L) of 2.64 m, and a beam (B) of 0.55 m. For validation, the numerical results of drag and trim were compared against experimental data, which displayed good compliance. Subsequently, the hydrodynamic performance of the planing hull was investigated, and the wedge effect was assessed. The stern wedge was located at the bottom and near the aft perpendicular to the hull to facilitate a moderate distribution. Various wedge lengths of 0.2B, 0.5B, and B at two different heights of 5 mm and 10 mm were examined to assess the hydrodynamic performance of the hull at various speeds. The trim angle, resistance, water surface elevation, porpoising, roster tail, and the stern and bow were computed and analyzed. Based on the numerical results, it was concluded that when the wedge length increased, the drag and trim were reduced. It was also concluded that the best wedge for a vessel with desirable wake generation is one with a length of 0.2B and a height of 5 mm.

3

The impact of selected parameters on pressure distribution in the face throttle of a centrifugal pump automatic balancing device

Tarasevych Yuliia, Sovenko Nataliia

Tribologia

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2021

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nr 3

35--44

EN

Face throttles are a necessary functional element of non-contact face seals and automatic balancing devices of centrifugal pumps of different constructions. To calculate the hydrodynamic forces and moments acting on the rotor and fluid flow through the automatic balancing device, it is necessary to know the pressure distribution in the cylindrical and face throttle when considering all important factors which predetermine fluid flow. The face throttle surfaces are moving, which leads to unsteady fluid flow. The movement of the walls of the face throttle causes an additional circumferential and radial flow, which subsequently leads to the additional hydrodynamic pressure components. The paper analyses viscous incompressible fluid flow in the face throttle of an automatic balancing device taking into account the axial and angular displacements of throttle’s surfaces and the inertia component of the fluid. The effect of local hydraulic losses as well as random changes in the coefficients of local hydraulic resistance at the inlet and outlet of the throttle is analysed.

PL

Szczeliny poprzeczne są niezbędnym elementem funkcjonalnym bezstykowych uszczelnień czołowych oraz tarcz odciążających pomp odśrodkowych o różnej konstrukcji. Konieczna jest znajomość rozkładu ciśnienia w szczelinie poprzecznej z uwzględnieniem wszystkich najważniejszych czynników determinujących przepływ cieczy w celu obliczenia sił hydrodynamicznych oraz natężenia przepływu. Powierzchnie szczeliny są ruchome, co powoduje niestacjonarny przepływ płynu. Ruch ścianek szczeliny powoduje dodatkowy przepływ obwodowy oraz promieniowy, a to w konsekwencji prowadzi do powstania dodatkowego ciśnienia hydrodynamicznego. W pracy wykonano analizę przepływu lepkiego nieściśliwego płynu przez szczelinę poprzeczną tarczy odciążającej pompy odśrodkowej z uwzględnieniem przemieszczeń osiowych i kątowych powierzchni szczeliny. Uwzględniono składowe bezwładności płynu. Przeanalizowano wpływ strat lokalnych oraz losowych zmian współczynników hydraulicznych strat miejscowych na wlocie i wylocie szczeliny poprzecznej na rozkład ciśnienia.

4

Gas flow simulation in the working gap of impulse gas-barrier face seal

Kuznetsov Eduard, Nahornyi Volodymyr, Krenický Tibor

Management Systems in Production Engineering

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2020

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nr 4 (28)

298--303

EN

Numerical simulation method of the working process of a centrifugal unit contactless face impulse seal is proposed. A seal functioning physical model was created. Its operation key aspects that are not taken into account in the traditional methods of calculating contactless impulse seals are identified. A numerical simulation of seal working process based on the Reynolds equation solution for the medium vortex-free motion in the gap between moving surfaces is proposed. Hypothesis that simplify the equation's numerical solution for the face impulse seal is formulated. The numerical solution is obtained using the boundary element method. Based on the obtained numerical solution, the distribution of the working medium pressure field in the seal gap is simulated.

5

A laboratory study of pressure distribution and residual settlements in wide grading double layer railway ballast under long-term cyclic loading

Sysyn M., Gerber U., Nabochenko O., Dehne S.

Archives of Civil Engineering

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2020

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Vol. 66, nr 4

561--578

EN

Ballast layer has weighty share in the lifecycle costs of railway track. The strict standards and maintenance rules of ballast grading significantly contribute to the ballast costs. One ways to the costs reduction is differential demands to ballast grading for the secondary and low loaded railway lines. Additional one is the different ballast grading over the ballast height. This study presents a full scale laboratory investigation of technical efficiency of such railway ballast under the long-term cyclic loading in comparison with the standard ballast layer. The double layer is presented with standard grading ballast upper layer and bottom sub ballast layer consists of ballast mixture. Pressure distribution under the ballast layer and permanent settlements of the layers are measured during the loading cycles. The reference measurements with standard grading ballast material are carried out. The study shows that initial settlement accumulation of the double layer railway ballast are lower to that of the standard ballast layer. However, the settlements accumulation intensity of the ballast is higher. The analysis of the pressure distribution measurements under the ballast layer and the settlements inside the ballast layer explain the causes of the different settlement accumulation.

6

Oddziaływanie wiatru na dachy budynków

Gaczek Mariusz

Materiały Budowlane

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2019

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nr 6

6--9

7

Simulations of the influence of the heat flux at the shaft surface of the conical slide bearing on its hydrodynamic lubrication and operating parameters

Czaban Adam, Miszczak Andrzej

Journal of KONES

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2019

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Vol. 26, No. 4

29--37

EN

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.

8

Numerical analysis of turbulent flow around twodimensional bodies using non-orthogonal body-fitted mesh

Tarafder M. Shahjada, Mursaline M. Al

International Journal of Applied Mechanics and Engineering

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2019

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Vol. 24, no. 2

387--410

EN

This paper deals with the numerical simulation of a turbulent flow around two-dimensional bodies by the finite volume method with non-orthogonal body-fitted grid. The governing equations are expressed in Cartesian velocity components and solution is carried out using the SIMPLE algorithm for collocated arrangement of scalar and vector variables. Turbulence is modeled by the turbulence model and wall functions are used to bridge the solution variables at the near wall cells and the corresponding quantities on the wall. A simplified pressure correction equation is derived and proper under-relaxation factors are used so that computational cost is reduced without adversely affecting the convergence rate. The numerical procedure is validated by comparing the computed pressure distribution on the surface of NACA 0012 and NACA 4412 hydrofoils for different angles of attack with experimental data. The grid dependency of the solution is studied by varying the number of cells of the C-type structured mesh. The computed lift coefficients of NACA 4412 hydrofoil at different angles of attack are also compared with experimental results to further substantiate the validity of the proposed methodology.

9

Numerical analysis of influence of bearing material thermal conductivity coefficient on hydrodynamic lubrication of a conical slide bearing

Czaban A.

Journal of KONES

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2018

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Vol. 25, No. 2

89--96

EN

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.

10

The effect of aging and gender on plantar pressure distribution during the gait in elderly

Gimunova M., Zvonař M., Mikeska O.

Acta of Bioengineering and Biomechanics

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2018

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Vol. 20, no. 3

139--144

EN

The effect of age on structural foot characteristics as well as on the plantar pressure distribution has been shown previously. However, the number of studies focused also on gender gait differences of elderly is lacking. The purpose of this study was to compare dynamic gait characteristic in younger and older elderly and to investigate the gender differences as the life-long load and footwear choice differ in males and females. Methods: 61 healthy elderly participants were divided by age and gender into four groups: males 60–69, males 70–79, females 60–69 and females 70–79 years old. Plantar pressures were recorded during barefoot walking at naturally chosen speed using Emed-at (Novel GmbH, Germany). Three steps of the left foot of each participant were used for further analysis, furthermore, hallux angle, foot progression angle, and arch index were calculated by the Emed software from obtained footprints. To compare the differences between the analyzed groups, effect size obtained by Cohen’s d was used. Results: Comparing the two age male groups, higher mean pressure was found in the 70–79 age group in region MH4, MH5 and mid-foot, suggesting a greater lateral load and decreased longitudinal arch of the foot. Comparing female groups, the higher mean pressure was found in the older age group in region MH1. In all other regions, the mean pressures were reduced in the older groups. Conclusions: The results suggest that the effect of aging on plantar pressure distribution during the gait is affected by gender and should be considered when evaluating the gait of elderly.

11

Analiza MES wpływu zużycia powierzchni przyłożenia narzędzia na jego obciążenie w skrawaniu ortogonalnym stali 42CrMo4

Madajewski M., Nowakowski Z., Znojkiewicz N.

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2017

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z. 89 [295], nr 4

497--507

PL

W artykule przedstawiono analizę wpływu zużycia powierzchni przyłożenia (wskaźnik VBB) na składowe siły całkowitej oraz rozkład nacisków na ostrzu podczas toczenia ortogonalnego. Dane eksperymentalne uzyskano, mierząc składowe siły całkowitej siłomierzem tensometrycznym oraz przez rejestrację wartości reakcji ostrza w modelu MES procesu formowania wióra. Badania eksperymentalne posłużyły do walidacji modeli numerycznych przygotowanych w programie ABAQUS. Określone pasmo zużycia zostało zamodelowane geometrycznie na powierzchni przyłożenia, a wpływ tego zużycia został oceniony w niezależnych symulacjach. Model numeryczny formowania wióra wykorzystuje równanie konstytutywne Johnsona-Cooka do opisu wartości i rozkładu naprężeń w przedmiocie obrabianym, a ostrze z zamodelowanym zużyciem zostało opisane jako ciało idealnie sztywne. Mechanikę procesu skrawania przedstawiono, odwołując się do modelu Merchanta skrawania ortogonalnego, nanosząc wykreślnie wektory przyrostu składowych siły całkowitej obliczone MES na tle zamodelowanego konturu strefy skrawania. Wyniki pomiarów i symulacji wskazują, że wzrost zużycia określony wskaźnikiem VBB wpływa bezpośrednio na wzrost składowych siły całkowitej.

EN

In this paper an analysis of influence of flank wear (VBB index) on total force components and pressure distribution in orthogonal cutting is presented. The experimental results were obtained based on the measurement of total force components using force gauge and values of reaction of the blade in the finite element model of the chip formation process. The experimental investigations were used in validation of the numerical models prepared in ABAQUS program. The determined range of wear has been modeled on the flank and their influence has been assessed by independent simulations. The numerical models of chip formation utilized Johnson-Cook equation to calculate the value and stress distribution in the workpiece. The blade with modeled wear was assumed as a rigid body. The mechanics of cutting process is presented based on the Merchant model of orthogonal cutting. The vectors of increments of total force components determined by FEM were geometrically drawn up to scale on cutting zone stress contour plot. The results indicated that increasing of wear described by VBB index has a direct effect on increasing of components of total force.

12

CFD analysis of effect of misalignment plane position on hydrodynamic lubrication of slide conical bearing

Czaban A.

Journal of KONES

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2017

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Vol. 24, No. 2

65--72

EN

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.

13

Influence of total inertia effects in a thrust curvilinear bearing lubricated with Newtonian lubricants

Walicka A., Jurczak P.

International Journal of Applied Mechanics and Engineering

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2017

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Vol. 22, no. 4

1045--1058

EN

In the paper, the flow of a Newtonian type of lubricant in the clearance of a curvilinear bearing is considered. It is assumed that the bearing walls are modelled as smooth and impermeable. In analytical considerations, full inertia of the longitudinal flow and partial inertia of the circumferential flow are taken into account. The equation of motion of the lubricant is solved by the modified method of averaged inertia. A thrust bearing and spherical bearing are considered, for which dimensionless pressure distributions and the bearing capacity are given.

14

Badania teoretyczno-eksperymentalne przepływu płynu nieściśliwego przez kryzę szczelinową

Tomaszewska B.

Informatyka, Automatyka, Pomiary w Gospodarce i Ochronie Środowiska

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2017

|

T. 7, nr 2

62--65

PL

W praktyce pomiarowej coraz częściej stosuje się prototypowe rozwiązania konstrukcyjne przepływomierzy zwężkowych. Na uwagę zasługują kryzy szczelinowe, gdzie jeden centralny otwór zastąpiony jest szczelinami. W pracy przedstawiono wyniki badań numerycznych i eksperymentalnych prototypowego rozwiązania konstrukcyjnego kryzy szczelinowej. Ruch płynu opisano równaniami Reynoldsa, domkniętymi k-ε modelem turbulencji. Obliczenia przeprowadzono przy użyciu pakietu ANSYS Fluent. Rozpatrywano przepływ płynu przez kryzę standardową i szczelinową o przewężeniu β = 0,5. Wyniki obliczeń porównano z wynikami pomiarów. Stwierdzono dobrą jakościową i ilościową zgodność wyników badań dla współczynnika przepływu C. Wykazano, że kryza szczelinowa generuje znacznie mniejszą trwałą stratę ciśnienia niż kryza standardowa przy porównywalnej niepewności pomiaru.

EN

Prototype designs of orifice flowmeters are commonly used in measurements. One area which has attracted considerable interest includes slotted orifices, where a single central opening is replaced by the use of several slots. This paper reports the results of numerical and experimental research of a prototype design of a slotted orifice plate. The movement of the fluid was described with use of Reynolds equations closed by the k-ε turbulence model. The calculations were performed using ANSYS Fluent software package by consideration of the fluid flow through an orifice plate and slotted orifice with the equal β ratio = 0.5. The results of calculations are compared with the measurements. Good qualitative and quantitative conformity was obtained during the study for the C flow coefficient. It was indicated that the slotted orifice generates a considerable lower pressure drop in comparison to an orifice plate while maintaining comparable level of measurement uncertainty.

15

Generalized Newtonian fluids as lubricants in the hydrodynamic conical bearings : a CFD analysis

Czaban A.

Journal of KONES

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2016

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Vol. 23, No. 2

89--95

EN

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.

16

CFD analysis of the impact of a cone opening angle parameter on the hydrodynamic lubrication of the conical slide bearing

Czaban A.

Journal of KONES

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2016

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Vol. 23, No. 3

71--77

EN

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.

17

Laboratory study about pressure distribution on car seats with people of different anthropometric features participation

Zuska A., Jurecki R., Jaśkiewicz M.

Archiwum Motoryzacji

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2016

|

Vol. 74, nr 4

115--127

EN

This article refers to actual problem of cars’ travelling comfort. In the first part of the article, an experiment was described in which particular attention was given to measuring system that is used in studying pressure distribution on the car seat bottom and backrest of the car seat. The structure of this system and usage possibilities, including basic parameters of its’ work were also discussed. In the second part, an analysis of the conducted study results was presented, with special consideration taken to dependence between particular values which characterize the pressure distribution on car seat bottom and basic anthropometric parameters of the human body

PL

Artykuł odnosi się do aktualnej problematyki komfortu podróżowania pojazdami samochodowymi. W pierwszej części opisano przeprowadzony eksperyment, zwracając szczególną uwagę na system pomiarowy wykorzystywany do badania rozkładu nacisków na siedzisko i oparcie fotela samochodowego. Omówiono budowę tego systemu oraz możliwości wykorzystania, podając podstawowe parametry jego pracy. W części drugiej przedstawiono analizę wyników przeprowadzonych badań eksperymentalnych ze szczególnym uwzględnieniem zależności między wybranymi wielkościami charakteryzującymi rozkład nacisków na siedzisko fotela a podstawowymi parametrami antropometrycznymi ciała człowieka.

18

Research of the spatial-temporal gait parameters and pressure characteristic in spastic diplegia children

Pauk J., Ihnatouski M., Daunoraviciene K., Laskhousky U., Griskevicius J.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 2

121--129

EN

Purpose: Spastic diplegia is the most common form of cerebral palsy. It presents with symmetric involvement of the lower limbs and upper limbs. Children with spastic diplegia frequently experience problems with motor control, spasticity, and balance which lead to gait abnormalities. The aim of this study is twofold. Firstly, to determine the differences in spatial-temporal gait parameters and magnitude of plantar pressure distribution between children with spastic diplegia (CP) and typical children. Secondly, to compare and evaluate main changes of plantar pressure and spatial-temporal gait parameters instead of data between spastic diplegia children with prescribed ankle – solid foot orthosis (AFOs) and without using AFOs. Methods: The evaluation was carried out on 20 spastic diplegia children and 10 agematched children as a control group aged 6–15 years. Twenty children with spastic diplegia CP were divided into two groups: ten subjects with prescribed AFOs and ten subjects without use of assistive device. Patients used the AFOs orthosis for one year. Measurements included in-shoe plantar pressure distribution and spatial-temporal gait parameters. Results: Spatial-temporal gait parameters showed meaningful difference between study groups in velocity, stride length, step length and cadence ( p < 0.05). However no significant differences between patients with and without AFOs were found ( p > 0.05). Significant differences between typical and spastic diplegia children with AFOs were observed in the magnitude of plantar pressure under the toes, the metatarsal heads, the medial arch, and the heel ( p < 0.05). For typical subjects, the highest pressure amplitudes were found under the heel and the metatarsal heads, while the lowest pressure distribution was under the medial arch. In CP patients the lateral arch was strongly unloaded. The peak pressure under heel was shifted inside. Conclusions: Collected data and calculated scores present a state of the gait in test groups, showed the difference and could be valuable for physicians in decision making by choosing qualitative therapy. Furthermore, it allows predicting probability of further possible changes in gait of spastic diplegia patients with AFOs and without it. In conclusion, our current results showed that the use of AFOs, prescribed on a clinical basis by doctors improves gait patterns and gait stability in children with spastic cerebral palsy.

19

Badania wybranych charakterystyk pracy przepływowej maszyny energetycznej

Komorowski A., Nozdrzykowski K.

Mechanik

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2015

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R. 88, nr 12

956--958

PL

Przedstawiono wyniki badań charakterystyk pracy nowego typu pompy rotacyjnej z tłokami wirującymi w przestrzeniach toroidalnych. Wykorzystano naukowe podstawy badań eksperymentalnych, aby wyznaczyć zależności funkcyjne pomiędzy parametrami pracy pompy oraz jej wymiarami charakterystycznymi a wartościami ciśnień mierzonych w wybranych miejscach badanego prototypu pompy. Wyniki badań pokazano w postaci trójwymiarowych wykresów umożliwiających jakościową i ilościową ocenę tych wyników.

EN

The paper presents the results of tests conducted on the prototype rotary pump with pistons rotating in toroidal cavity. Functional correlations between the pump operating parameters and its standard dimensions versus the values of pressure as measured in selected sections of the pump are presented against results of laboratory experiments. The test results are illustrated on 3D plots providing for their quantitative and qualitative assessment.

20

Analiza rozkładu ciśnień i prędkości w przewodzie o zmiennym przekroju

Pietkiewicz P., Miąskowski W., Nalepa K., Leszczyński P.

Mechanik

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2015

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R. 88, nr 7CD

663--670

PL

W artykule przedstawiono wyniki badań rozkładu prędkości i ciśnienia powietrza przepływającego przez przewód o zmiennej średnicy. Przewód stanowi model dydaktyczny do sprawdzenia słuszności równania Bernoulliego. Analizę przeprowadzono trzema metodami. Wykonano obliczenia numeryczne, przeprowadzono obliczenia analityczne. Otrzymane wyniki zweryfikowano doświadczalnie. Przedstawione w artykule wyniki są podstawą do wnioskowania na temat przydatności metod numerycznych w analizie przepływów.

EN

The article presents results of the investigations of the distribution of velocity and the pressure of the air flowing through. The line makes up the didactic model for checking the legitimacy of the Bernoulli equation. The analysis was conducted using three methods. Numeric calculations as well analytic calculations were carried out. Received results were verified experimentally. Results presented in the article are the basis to conclude about the usefulness of numeric methods in the flow analysis.