Wyniki wyszukiwania - Biblioteka Nauki

1

Computational and experimental analysis of gas-particle flow in furnance power boiler instalations with respect to erosion phenomena

100%

Dobrowolski B. , Wydrych J.

Journal of Theoretical and Applied Mechanics

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2007

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tom Vol. 45 nr 3

513-537

EN

The paper presents a method for finding such instalation elements which are especially subjected to erosion wear and a method for quantitative assessment of the erosion loss at a given operational time of a pneumatic conveying system. Motion of the gas is described by the Reynolds equation with the turbulence model. Motion of solid particles is described by the Lagrange equation. Then, the erosive loss of the wall material is calculated according to the Bitter model. The calculations are performed for a part of the dust system in BP-1150 boiler. It is found that a "cord" of particles is formed as a result of some changes of the flow direction inside the stream. High local intensity of particle collisions with the walls is the main reason for accelerated erosion of some parts of the system. The numerical calculation results are compared wit h the results of measurements on material losses of the elbow.

PL

W pracy przedstawiono metodę pozwalającą na ocenę prędkości zużycia erozyjnego instalacji jako funkcji jej budowy oraz warunków eksploatacji. Idea metody polega na opisie ruchu fazy gazowej równaniami Reynoldsa, uzupełnionymi modelem turbulencji. Ruch cząstek opisano metodą Lagrange'a. Następnie szacowano lokalny ubytek materiału ścianki w wyniku erozji z zastosowaniem modelu Bittera. Porównanie szczegółowych obliczeń numerycznych z wynikami pomiarów wykonano dla fragmentu instalacji pyłowej kotła BP-1l50. Stwierdzono, że przy zmianie kierunku przepływu formuje się tzw. "sznur" cząstek, powodujący intensywne zużycie niektórych sekcji instalacji. Wystąpienie sekcji szczególnie narażonych na zużycie erozyjne jest uwarunkowane aerodynamiką przepływu. Stwierdzono zgodność w prognozowaniu zarówno obszarów przyśpieszonej erozji, jak i intensywności zużycia.

2

Mechanisms Of Erosion Wear In Pipes Caused By A Stream Of Solid Particles

100%

Krupicz B.

Journal of Polish CIMAC

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2007

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tom Vol. 2, no 2

291-296

EN

In the paper an analysis of pipe bend erosion was conducted. This erosion was compared to the erosion of flat samples. The function of particle velocity change: v/vo=e-af was assessed and contact stress caused by the centrifugal force of inertia of solid particles (diameter d < 0,1 mm) in the bend material was calculated.

3

Analysis of Dune Erosion on the Coast of South Baltic Sea Taking into Account Dune Landslide Processes

100%

Szmytkiewicz P. , Zabuski L.

Archives of Hydro-Engineering and Environmental Mechanics

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2017

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tom Vol. 64, nr 1

3--15

EN

An analysis was carried out to determine the influence of landslide process at a few meters depth under the dune surface on the rebuilding of the dune. In the first step, calculations were done using the XBEACH model to determine seabed rebuilding as well as shore and dune undercutting for the assumed hydrologic and hydrodynamic conditions. Next, the obtained tachymetric profile of the dune and beach was fed into the FLAC2D program, and calculations of stress distribution, displacements and stability conditions were made. In this way, landslide movement was identified. The theoretical investigations clearly prove that waves attacking the dune not only cause surface erosion, but also trigger a landslide within the dune mass to a maximum depth of about 5 m. It results in a lowering of the dune crown by about 0:6 0:7 m. Numerical models such as XBEACH, SBEACH or CSHORE do not take into account landslide occurrence, and thus underestimate dune erosion.

4

The Impact of Crushed Rock Spoil on Pitting Corrosion of Selected Stainless Steels

100%

Krakowiak S. , Kierepa S.

Archives of Metallurgy and Materials

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2019

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tom Vol. 64, iss. 4

1627--1632

EN

The paper presents the results of the pitting resistance investigations of selected stainless steels in the chloride environment and the simultaneous impact of erosive factors using the cyclic polarization technique. Additionally, using electrochemical techniques, ie: electrochemical impedance spectroscopy (EIS) and measurement of corrosion potential, the behavior of the passive layer of selected stainless steels in the environment of chlorides and erosion was examined. On the basis of the obtained results, the resistance of stainless steels 1.4301 and 1.4404 was found, both on the effect of chloride ions and erosive factors in the studied systems. Both tested steels are susceptible to pitting corrosion. It was found that a good measure of erosive impact on stainless steel is both impedance spectrum analysis and continuous monitoring of the corrosion potential of steel.

5

Polish coastal zone erosion in the aspect of need for coastal defence

100%

Zawadzka E.

Biuletyn Instytutu Morskiego w Gdańsku

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1999

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tom Vol. 26, No. 2

49--55

EN

The balance of changes of the position of the coastline and of land area changes, made for the period 1875-1979, and of changes of the waterline and dune/cliff foot line for the period 1960-1983, has shown that in the last decades erosional processes are steadily increasing. At present 22% ( 110 km) of the Polish coastline is protected by structures. The growing rates of erosion, and the widening reach of damages, indicate that coastal protection works should be intensified and/or the hitherto used method should be verified.

6

Cavitation erosion of X5CrNi18-10 austenitic stainless steel alloyed with TiC

100%

Szkodo M.

Advances in Materials Science

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2008

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tom Vol. 8, nr 1(15)

159-164

EN

This work presents investigations of cavitation resistance of X5CrNi 18- 10 austenitic stainless steel after alloying its surface by CO2 laser beam. Laser beam machining was performed in two variants. In the first case, surface layer was enriched with TiC in amount of 1.55 % wt. and in the second one in amount of 3.97 % wt. The obtained results revealed that content of 3.97 % wt. TiC caused an increase of plastic deformations resistance of surface under the cavitation loading and simultaneous increase in embrittlement of alloyed layer.

7

Modelling of coal particle combustion in fluidized bed

100%

Pelka P.

Archivum Combustionis

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2015

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tom Vol. 35 nr 2

65--74

EN

In the article the analysis of issues of modelling of coal particle combustion in a fluidized bed was carried out. Moreover, the results of the validation of a new proposition of a mathematical model of single char particle combustion in a fluidized bed were presented in the paper. This model takes account of the mass loss resulting from the contact of the bed particle with the surface of a burning char particle. In the opinion of many authors, the contact of inert material with a char particle causes their fragmentation which in some conditions of combustion and hydrodynamics of bed leads to the elutriation of unburnt fine particles from the combustion chamber increasing the incomplete loss of combustion. During the model validation the mechanical coal properties i.e. Vickers hardness and fracture toughness were taken into account as presented in [2]. The wide range of experimental tests, on which basis of which the model validation allowed the determination of the possibility of the model application to predict a combustion rate in fluidized bed conditions, as well as the contribution of the erosion process to the total mass loss. It also indicated that the main reason for combustion intensification in the fluidized bed is the clearance (elimination) of ash from the surface of the burning char and the increase of mass transfer coefficient in the particle region.

8

The Impact of Crushed Rock Spoil on Pitting Corrosion of Selected Stainless Steels

100%

Krakowiak S. , Kierepa S.

Archives of Metallurgy and Materials

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2020

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tom Vol. 65, iss. 1

163--168

EN

The paper presents the results of the pitting resistance investigations of selected stainless steels in the chloride environment and the simultaneous impact of erosive factors using the cyclic polarization technique. Additionally, using electrochemical techniques, ie: electrochemical impedance spectroscopy (EIS) and measurement of corrosion potential, the behavior of the passive layer of selected stainless steels in the environment of chlorides and erosion was examined. On the basis of the obtained results, the resist-ance of stainless steels 1.4301 and 1.4404 was found, both on the effect of chloride ions and erosive factors in the studied systems. Both tested steels are susceptible to pitting corrosion. It was found that a good measure of erosive impact on stainless steel is both impedance spectrum analysis and continuous monitoring of the corrosion potential of steel.

9

Calculation of Dune Profile Changes Generated by Hurricane: Preliminary Results

100%

Szmytkiewicz P. , Szmytkiewicz M. , Schönhofer J. , Morawski J. , Malicki J.

Archives of Hydro-Engineering and Environmental Mechanics

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2018

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tom Vol. 65, nr 3

221--239

EN

The paper presents the main theoretical concepts related to methods of calculating the erosion rate for sandy dunes on natural coasts, namely, the beach equilibrium profile and incident waves. To illustrate calculations of dune erosion in the vicinity of the Coastal Research Station (CRS) in Lubiatowo, the Xbeach model (an incident wave model) was used. The calculations were carried out for hydrological and hydrodynamic conditions that accompanied Hurricane Ksawery (December 6–8, 2013). The results of the calculations were compared with the measured data. A satisfactory agreement was obtained between the predicted and measured results.

10

Erosional Damages on Concave Banks of Directional Arcs in Natural Torrent Bed

100%

Jakubis M. , Jakubisová M.

Journal of Ecological Engineering

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2022

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tom Vol. 23, nr 9

44--52

EN

The article deals with the research of erosive damages of concave (outer) sides in directional circular arcs in the natural torrent bed. The research was carried out on 22 reference circular arcs on the Hučava torrent in the geomorphological unit of Poľana (Central Slovakia). The relation between R/Wbkf ratio (radius of curvature R/torrent bed width inside the banks Wbkf) and the bank slope angle BA of the concave arc BA = f(R/Wbkf) was analyzed. The relationship between R/Wbkf ratio and the percentage of vegetation cover VEG on the concave bank of the directional arc VEG = f(R/Wbkf) was analyzed as well. At the same time, the relation between ratio R/Wbkf and the VEG/BA coefficient was studied, which simultaneously the influence of vegetation cover and bank slope in connection with its erosive damage VEG/BA = f(R/Wbkf). It was found that the determination index for the relation BA=f(R/Wbkf) has the value of R2 = 0.924, for the relation VEG = f(R/Wbkf) the value of R2 = 0.953 and for the relation VEG/BA = f(R/Wbkf) the value of R2 = 0.967.

11

Modeling by finite element methods of impact of erosion on frequency of normal modes of l-0 blade

100%

Gołuński Ł. , Augustyniak B.

Advances in Materials Science

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2011

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tom Vol. 11, nr 4(30)

5-10

EN

After some time of exploitation steam turbine rotors blades in energetic industry they are being eroded and also their frequency of normal modes is changed. Those changes can cause to unwanted shift of blades normal mode frequencies. It is necessary to find quick method of rating changes of frequency in connection of mass loss due erosion. The evaluation of this dependence was made by finite element modeling method using HyperWorks 8.0 software. Geometrical model of blade L-0 with mass of 22 kg and length of 74 cm was used. There were calculated frequencies of the first five modes in function of mass loss along the leading blade edge (up to mass loss of 1,2%). Small losses of weight (around 0,2%) cause similar changes in values (around 0,2%) for all modes but with different types of frequency change (decrease or increase). The frequency decreases for all modes except mode the 3rd. For bigger mass loss an monotonic decrease of frequency was observed in 1st, 2nd, 5th mode and maximum (around +1,5 %) for 3rd mode and minimum (- 0,5%) for 4th mode. For maximum mass loss (1,2%) maximal decrease of frequency was observed in 2nd mode around -2%. Results of this modeling can be used to estimate changes of frequencies caused by erosion in exploited blades when their mass loss is known.

12

Chronology of phases of various fluvial activity, of erosion and deposition in the Vistula catchment during late quaternary

100%

Starkel L.

Geochronometria

|

2000

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tom Vol. 19

53-58

EN

The former extensive studies in the Vistula catchment with dozens of profiles well dated by 14C, helped to recognise great diversity of phases with dominance of erosion or aggradation changing in the longitudinal profile. Among them are very distinct synchronous phases with clusterings of extreme events during the Interpleni-glacial and during the Holocene.

13

Wpływ przejścia fali wezbrania na zmiany kształtu koryta rzeki górskiej

100%

Łapuszek M.

Czasopismo Techniczne. Budownictwo

|

1998

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tom R. 95, z. 5-B

71-80

EN

The flood wave influence on the changes in gauging cross-sections in the paper is presented. On the base of flood waves' hydrodynamic parameters and amound of sediment transport during the flood analysis studies were carried out. Computation were made for three cross-section of Dunajec River: Nowy Sącz, Zg?obice, Żabno. basing on the changes in gauging cross-section in Żabno the mean river bed depression were calculated. The cross-sections have been geodesic measured before and after the flood wave.

14

Variability of Soil Properties in Eroded Agricultural Landscape

100%

Wysocka-Czubaszek A. , Roj-Rojewski S.

Journal of Ecological Engineering

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2020

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tom Vol. 21, nr 1

72--80

EN

Erosion strongly influences the soil properties and affects the intra-field variation of nutrients not only in steep young morainic landscapes but also on gentle slopes of old-glacial landscapes. The aim of the study was the evaluation of changes in the plant-available nutrient contents in the complex old-glacial eroded landscape of the Bielska Plain in the north-eastern part of Poland. The soil samples were collected from the soil profiles located along the transect beginning on the flat summit of the kame hummock extending through south-facing convex slope, the toeslope and footslope and further through the north-facing uniform slope. The content of plant-available forms of phosphorus (Pdl) and potassium (Kdl) and mineral forms of nitrogen (NH4-N and NO3-N) were determined in every soil profile. The soils located in various landscape positions were characterized with different fertility. In the soil located on the toeslope the content of NO3-N, Pdl and Kdl was high, while the soil located on the summit was rich in NH4-N and poor in the plant-available forms of K and P. The erosional distribution of plant-available N, P and K enhances the variation of nutrient content within one field and contributes to high variability of crops.

15

Quantitative analysis of post-orogenic erosion of the Polish Outer Carpathian Foredeep Basin-fill – preliminary results

100%

Poprawa P. , Krzywiec P. , Pelczarski A.

Biuletyn Państwowego Instytutu Geologicznego

|

1999

|

tom nr 387

167--168

16

Contribution of water and tillage erosion to bright patches formation on the base of erosion modelling (Case study Trnavská pahorkatina Hill Land, Slovakia) : preliminary results

100%

Smetanová A.

Landform Analysis

|

2008

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tom Vol. 9

45--48

17

A New Optimization Algorithm for Dilation and Erosion

88%

Yin K.

Journal of Applied Computer Science Methods

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2011

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tom Vol. 3 No. 1

5--16

EN

Effectively optimizing dilation and erosion is an extensively studied but not completely resolved problem. In this paper, a new optimization algorithm is proposed to improve the efficiency of dilation and erosion. Four notions are given to define the edges for any simply connected structuring element (SE). An assistant algorithm is proposed to detect these edges. Based on these notions, three iteration equations can be derived, which redefine dilation and erosion as iteration calculation. Time complexity of the new algorithm is reduced to O(n³). In addition, the new algorithm is suitable for online applications without the decomposition of SE. Simulation shows that with the same parameters, the performance of the new algorithm is better than that of Yang's algorithm.

18

Numerical modelling of rivers on Earth and Titan

88%

Misiura K. , Czechowski L.

Geological Quarterly

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2015

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tom Vol. 59, No. 3

565--580

EN

The differences in the evolution of rivers on Earth and on Titan are investigated. Dynamical analysis of the rivers was performed using a numerical package CCHE2D developed by the National Center for Computational Hydroscience and Engineering, University of Mississippi. The model is based on the Navier-Stokes equations for depth-integrated two-dimensional turbulent flow and the three-dimensional convection-diffusion equation of sediment transport. The model enables investigation of the evolution of rivers as a function of total discharge and other parameters of the river. Series of short (from one to several hours) and long (up to 67 days) simulations were performed. We have found that three different liquid hydrocarbons considered for Titan’s rivers give similar velocity fields. It was also found that the suspended load is the main means of transport in Titan’s rivers, while in terrestrial ones, for the same discharge, the bedload could be of the same order as suspended load. Moreover, we suppose that for specific boundary conditions, the evolution of rivers on the Earth promotes the development of braided rivers, while for the same conditions evolution on Titan favours regular meandering rivers

19

Investigation of surface after erosion using optical profilometry technique

88%

Tarasiuk W. , Szymczak T. , Borawski A.

Metrology and Measurement Systems

|

2020

|

tom Vol. 27, nr 2

265--273

EN

The paper reports experimental results of the analysis of the 145Cr6 steel surface after erosion using the profilometrical technique by means of interferometry streaks. Erosive tests were carried out using abrasive containing quartz sand used in water jet cutting. Differences in the intensity of erosive wear were dependent on the angle of the abrasive stream (10°; 15°; 20°; 30°; 60°; 90°). In order to determine the characteristic features of the surface layer after the impact of the erosive stream, its characteristic parameters, such as roughness Ra and Sa for linear and field measurements, were analysed. Geometrical features of the regions investigated, such as shape, depth, angle of the abrasive stream, are presented. The analysis was carried out in two-dimensional (2D) and three-dimensional (3D) coordinate systems.

20

Wybrane problemy erozji na składowiskach odpadów komunalnych

88%

Węgorek T. , Patro M.

Prace Instytutu Nafty i Gazu

|

2007

|

tom nr 145

95-99

PL

Składowisko odpadów (szczególnie jego skarpy wewnętrzne i zewnętrzne) narażone jest na erozję wodną i ruchy masowe w fazie budowy, eksploatacji i rekultywacji. Omówiono główne przyczyny i sposoby zapobiegania tym zjawiskom. Zwrócono uwagę na problem erozji warstw izolujących uszczelnienia skarp wewnętrznych w okresie eksploatacji oraz czaszy składowiska na etapie zamykania obiektu.

EN

Landfill site (particularly its internal and external scarpes) are at risk of water erosion and mass-movements during construction, exploitation and land reclamation. The main reasons and ways of prevention these phenomena were discussed. They paid attention to problem of erosion of isolation layers of external scarpes during exploitation and of landfill plateau in stage of its shutdown.