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1

Analiza wpływu modyfikacji wylewu osłonowego na hydrodynamikę ciekłej stali w jednowylewowej kadzi pośredniej

Suchan Hanna

Hutnik, Wiadomości Hutnicze

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2022

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Vol. 89, nr 2

19--25

PL

Kadź pośrednia stanowi bardzo ważny element stanowiska COS (Ciągłego Odlewania Stali). Zabudowa jej przestrzeni roboczej, poprzez stosowanie m.in. urządzeń sterujących przepływem (USP), tj. przegrody czy inhibitory turbulencji, pozwala wpływać na hydrodynamikę przepływającej przez nią ciekłej stali. Urządzeniem kierującym przepływem może być również wylew osłonowy. Niniejsza praca ma na celu określenie wpływu nowego wylewu osłonowego wyposażonego w trzy otwory umieszczone w dnie kopuły znajdującej się na końcu wylewu, uwzględniając symetrię ułożenia otworów względem osi wzdłużnej kadzi oraz głębokość zanurzenia wylewu w kąpieli metalowej. W tym celu wykonano analizę zachowania ciekłej stali w kadzi pośredniej biorąc pod uwagę udział poszczególnych rodzajów przepływów oraz określono wpływ zmodyfikowanego wylewu osłonowego na masę wlewka ciągłego o przejściowym składzie chemicznym otrzymanego podczas sekwencyjnego odlewania dwóch różnych gatunków stali. W wyniku zastosowania jednego z zaproponowanych wylewów możliwe jest zmniejszenie udziału strefy stagnacyjnej o ponad 4,5% w stosunku do strefy uzyskanej w wyniku użycia prostego wylewu osłonowego w wariancie bazowym. Dodatkowo zastosowanie wylewów o zmodyfikowanej przestrzeni roboczej powoduje redukcję średnich prędkości ciekłej stali maksymalnie o 0,008 m/s (wyjątkiem jest wariant 3).

EN

Tundish is a very important device at the CSC (Continuous Steel Casting) process. Construction of its workspace, by using flow control devices (FCD), such as dams or turbulent inhibitors, has an impact on liquid steel hydrodynamics. One of the FCD is also a ladle shroud (LS). The purpose of the following article is to determine the impact of new construction of ladle shroud equipped with three outlets located at the bottom of special dome, including symmetry of the outlets arrangement and its immersion depth in the metal bath. For this purpose, analysis of liquid steel behaviour in tundish was carried out. Hydrodynamic conditions and slab masses with mixed chemical composition casted during sequential casting were determined. As a result of use of one of the proposed LS, it is possible to reduce the share of stagnant flow by more than 4,5% compared to this type of flow obtained as a result of using a straight LS in the base variant. Additionally, the use of LS with modified working space reduces the average liquid steel velocity by a maximum of 0,008 m/s (except variant 3).

2

Heat transfer study from square cylinder immersed in water-based nanofluid: Effect of orientation

Kaur Jaspinder, Ratar Jatinder Kumar, Tiwari Anurag Kumar

Chemical and Process Engineering

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2022

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Vol. 43, nr 2

243-–250

EN

Heat transfer study from the heated square cylinder at a different orientation angle to the stream of nanofluids has been investigated numerically. CuO-based nanofluids were used to elucidate the significant effect of parameters: Reynolds number (1–40), nanoparticle volume fraction (0.00–0.05), the diameter of the NPs (30–100 mn) and the orientation of square cylinder (0–90). The numerical results were expressed in terms of isotherm contours and average Nusselt number to explain the effect of relevant parameters. Over the range of conditions, the separation of the boundary layers of nanofluids increased with the size of the NPs as compared to pure water. NPs volume fraction and its size had a significant effect on heat transfer rate. The square cylinder of orientation angle (45) gained a more efficient heat transfer cylinder than other orientation angles. Finally, the correlations were developed for the average Nusselt number in terms of the relevant parameters for 45 orientation of the cylinder for new applications.

3

Flow structures in asymmetric compound channels with emergent vegetation on divergent floodplain

Rahim Ali Samadi, Yonesi Hojjat Allah, Shahinejad Babak, Podeh Hasan Torabi, Azamattulla Hazi Mohammad

Acta Geophysica

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2022

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Vol. 70, no 5

2403--2421

EN

Knowledge and management of hydraulic processes including flow pattern, sediment transport, and food level prediction in natural rivers require proper understanding of interactions between food flow and vegetation in floodplains. This study examined the flow structures and turbulence parameters in an asymmetric non-prismatic compound channel with different vegetation densities in divergent floodplain. Due to existence of vegetation, the bed shear stresses in the middle and end of the divergence floodplain decrease 78.5% and 86%, respectively. Also, the depth-averaged velocity in vegetated floodplain diminishing by about 60% and 69%. The results revealed that the production and dissipation of Reynolds shear stresses and the formed shear layer depend on the vortex shedding frequency formed behind each single rod and is very unstable. Finally, some equations were presented to estimate friction factor based on rod Reynolds number, calculate the frequency of the vortices generated behind the elements and the local drag coefficient.

4

Wpływ modyfikacji wylewu osłonowego na przepływ ciekłej stali w dwuwylewowej kadzi pośredniej

Suchan Hanna, Cwudziński Adam

Hutnik, Wiadomości Hutnicze

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2021

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Vol. 88, nr 3-4

2--9

PL

Kadź pośrednia jest jednym z urządzeń, przez które przepływa ciekła stal podczas procesu ciągłego odlewania i które pełni ważną rolę w kontroli zachowania się kąpieli metalowej. Przeprowadzone symulacje komputerowe miały na celu analizę wpływu modyfikacji wylewu osłonowego na hydrodynamikę ciekłej stali przepływającej przez dwuwylewową kadź pośrednią. Głównym parametrem, na który zwrócono uwagę w badaniach była prędkość przepływu ciekłej stali kształtująca się w przestrzeni roboczej wylewu osłonowego oraz w objętości kadzi pośredniej. Określono również wpływ turbulencji na procentowy objętościowy udział poszczególnych przepływów oraz na stopień mieszania kąpieli metalowej.

EN

Tundish is the one of the equipment of the continuous casting process, during the liquid steel flows through it, and it plays an important role of control metal bath behavior. Aim of the conducted computer simulations was to analyze influence of the modification of the ladle shroud on liquid steel hydrodynamics flowing through the two-strand tundish. The main parameter noted in the article was velocities in the working space of ladle shroud and in the volume of the tundish. The influence of the turbulence on the percentage volume of the individual flows and the mixing degree of the metal bath was also determined.

5

Numerical modeling of heat transfer in Al2O3/H2O nanofluid flowing through a Bessel-like converging pipe

Iweka Chukwuka S., Fadodun Olatomide G.

Archives of Thermodynamics

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2021

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Vol. 42, no 2

121--153

EN

This paper studies hydrodynamic and heat transfer performance of Al2O3/H2O nanofluid flowing through a Bessel-like converging pipe in laminar flow regime using the computational fluid dynamic approach. A parametric study was carried out on the effect of Reynolds number (300– 1200), convergence index (0-3) and nanoparticle concentration (0–3%) on the both hydrodynamic and thermal fields. The results showed the pressure drop profile along the axial length of the converging pipes is parabolic compared to the downward straight profile obtained in a straight pipe. Furthermore, an increase in convergence index, Reynolds number and nanoparticle concentration were found to enhance convective heat transfer performance. Also, a new empirical model was developed to estimates the average Nusselt number as a function of aforementioned variables. Finally, the result of the thermohydraulic performance evaluation criterion showed that the usage of Bessel-like converging pipes is advantageous at a low Reynolds number.

6

Numerical investigation for convective heat transfer of nanofluid laminar flow inside a circular pipe by applying various models

Saeed Farqad Rasheed, Al-Dulaimi Marwah Abdulkareem

Archives of Thermodynamics

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2021

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Vol. 42, no 1

71--95

EN

The work presents a numerical investigation for the convective heat transfer of nanofluids under a laminar flow inside a straight tube. Different models applied to investigate the improvement in convective heat transfer, and Nusselt number in comparison with the experimental data. The impact of temperature dependence, temperature independence, and Brownian motion, was studied through the used models. In addition, temperature distribution and velocity field discussed through the presented models. Various concentrations of nanoparticles are used to explore the results of each equation with more precision. It was shown that achieving the solution through specific models could provide better consistency between obtained results and experimental data than the others.

7

Analysis of selected aspects of a tank gassing-up process on board liquefied petroleum gas carrier. Part I

Wieczorek Agnieszka

Archives of Thermodynamics

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2021

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Vol. 42, no 2

43--58

EN

The paper is a thermodynamics analysis of the removal of any inert gas from the tank using the vapors of any liquefied petroleum gas cargo (called cargo tank gassing-up operation). For this purpose, a thermodynamic model was created which considers two boundary cases of this process. The first is a ‘piston pushing’ of inert gas using liquefied petroleum gas vapour. The second case is complete mixing of both gases and removal the mixture from the tank to the atmosphere until desired concentration or amount of liquefied petroleum gas cargo in the tank is reached. Calculations make it possible to determine the amount of a gas used to complete the operation and its loss incurred as a result of total mixing of both gases.

8

The effect of stenosis rate and Reynolds number on local flow characteristics and plaque formation around the atherosclerotic stenosis

Chen Xueping, Zhan Yiyi, Fu Yi, Lin Jiangguo, Ji Yanru, Zhao Chengbi, Fang Ying, Wu Jianhua

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 1

135--147

EN

Purpose: Atherosclerosis causes plaque to build-up in arteries. Effect of the specific local hemodynamic environment around an atherosclerotic plaque on the thrombosis formation does not remain quite clear but is believed to be crucial. The aim of this study is to uncover the flow effects on plaques formation. Methods: To study the mechanically regulated plaque formation, the flow fields in artery blood vessels with different stenosis rates at various Reynolds numbers were simulated numerically with the two-dimensional axisymmetric models, and the hemodynamic characteristics around the plaque were scaled with stenosis rate and Reynolds number. Results: The results showed that increases of both Reynolds number and stenosis rate facilitated the occurrence of flow separation phenomenon, extended recirculation zone, and upregulated the maximum normalized wall shear stress near the plaque throat section while downregulated the minimal normalized wall shear stress at the front shoulder of plaque, as it should be; in the atherosclerotic plaque leeside of the recirculation zone, an obvious catch bond region of wall shear stress might exist especially under low Reynolds number with stenosis rate smaller than 30%. This catch bond region in the plaque leeside might be responsible for the LBF (low blood flow)-enhanced formation of the atherosclerotic plaque. Conclusions: This work may provide a novel insight into understanding the biomechanical effects behind the formation and damage of atherosclerotic plaques and propose a new strategy for preventing atherosclerotic diseases.

9

Stanowisko pomiarowe do wyznaczania parametrów przepływu wody w rurociągach

Torbus Sławomir Andrzej, Grzembski Michał, Prałat Karol

Rynek Energii

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2020

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Nr 6

21--29

PL

W części teoretycznej pracy scharakteryzowano elementy stanowiska pomiarowego wraz z budową i zasadą ich działania. Przedstawiono również algorytm przeprowadzania pomiarów, których wyniki umożliwiają wyznaczenie wartości liczby Reynoldsa, liczby (współczynnika) przepływu i rodzaju przepływu. Praktyczna część pracy polegała na zbudowaniu stanowiska pomiarowego, umożliwiającego wyznaczenie parametrów przepływu wody w rurociągu zgodnie z aktualnie stosowanymi w przemyśle metodami i przyrządami pomiarowymi. Przeprowadzono szereg pomiarów i obliczeń, a następnie dokonano analizy uzyskanych wyników i sformułowano wnioski.

EN

The theoretical part of this paper presented elements of the measuring stand with the construction and principle of their operation. Also presented measurement algorithm, the results of which allow determining the value of Reynolds number, number (coefficient) of flow and type of flow. The aim of the practical part of thesis was to build a measuring position enabling the determination of water parameters in the pipeline in accordance with measurement methods and instruments currently used in industry. A number of measurements and calculations were carried out, and then the results obtained were analyzed and conclusions were formulated.

10

Thermal performance of corrugated plate heat exchanger using ethylene glycol as test fluid

Sreedhar Rao Battula, Keerthana Reddy Chittireddy, Meena Pullurwar, Kishore Kumar Sriramoju

Journal of Mechanical and Energy Engineering

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2020

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Vol. 4, No 2

167--171

EN

This paper reports an experimental comparative thermal analysis of a flat plate heat exchanger and corrugated plate heat exchanger (CPHE) of different corrugation angles using ethylene glycol as test fluid. The experiments were carried out in counter current mode using water as hot fluid at 75°C. Design of each plate provided with eleven thermocouple sensors to determine the temperatures, in which seven were used to measure the surface temperature of plate and four were used to measure the inlet and outlet bulk temperature of cold and hot fluids. The mass flow rate of test fluid, varied between 0.5 to 4 liters per minute and corresponding steady state temperatures is measured. Using experimental readings, temperature difference between the inlet and outlet streams (∆T), logarithmic mean temperature difference (LMTD) and overall heat transfer coefficient (U) are determined. The obtained ∆T and U values of corrugation angles (30°, 50°) of CPHE were compared with those of flat plate heat exchangers. For corrugation angle of 30° and 50°, the ∆T and U values increases with increase of mass flow rate of the fluid. The turbulence in the flow increases due to increase in the corrugation angle, which results in the enhancement of heat transfer. Moreover, thermal effectiveness (ε) is estimated using NTU method and compared for all the plates. As the NRe values gradually increases, ε decreases for flat plate and CPHE (θ = 30° and θ= 50°). At low NRe value of 114, observed a maximum ε (≅0.998) value for corrugated angle of 50°. There is adequate contact time between the cold and hot fluids at low Reynolds number, so maximum rate of heat transfer is possible, as a result ε values are high.

11

Performance analysis of three sides solar air heater having roughness elements as a combination of multiple-v and transverse wire on the absorber plate

Kumar Dhananjay, Prasad Laljee

Archives of Thermodynamics

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2020

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Vol. 41, no 3

125--146

EN

Artificial roughness has been found to enhance the thermal performance from the collector to air in the solar air heater duct. This paper presents the results of experimental investigation on thermal performance of three sides solar air heater roughened with combination of multiple-v and transverse wire. The range of variation of system and operating parameters is investigated within the limits of relative roughness pitch of 10−25, relative roughness height of 0.018 −0.042, angle of attack of 30°−75° at varying flow Reynolds number in the of range of 3000−12000 for fixed value of relative roughness width of 6. The augmentation in fluid temperature flowing under three side’s roughened duct is found to be 36.57% more than that of one side roughened duct. The maximum thermal efficiency is obtained at relative roughness pitch of 10 and relative roughness height of 0.042, and angle of attack of 60°. The augmentation in thermal efficiency of three sides over those of one side roughened duct is found to be 46−57% for varying values of relative roughness pitch, 38−50% for varying values of relative roughness height, and 40−46% for varying values of angle of attack.

12

Numerical investigation and sensitivity analysis of turbulent heat transfer and pressure drop of Al2O3/H2O nanofluid in straight pipe using response surface methodology

Fadodun Olatomide G., Amosun Adebimpe A., Salau Ayodeji O., Olaloye David O., Ogundeji Johnson A., Ibitoye Francis I., Balogun Fatai A.

Archives of Thermodynamics

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2020

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Vol. 41, no 1

3--30

EN

In this paper, investigation of the effect of Reynolds number, nanoparticle volume ratio, nanoparticle diameter and entrance temperature on the convective heat transfer and pressure drop of Al2O3/H2O nanofluid in turbulent flow through a straight pipe was carried out. The study employed a computational fluid dynamic approach using single-phase model and response surface methodology for the design of experiment. The Reynolds average Navier-Stokes equations and energy equation were solved using k-ε turbulent model. The central composite design method was used for the response-surface-methodology. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were performed. New models to evaluate the mean Nusselt number and pressure drop were obtained. Also, the result showed that all the four input variables are statistically significant to the pressure drop while three out of them are significant to the Nusslet number. Furthermore, sensitivity analysis carried out showed that the Reynolds number and volume fraction have a positive sensitivity to both the mean Nusselt number, and pressure drop, while the entrance temperature has negative sensitivities to both.

13

Numerical investigation and sensitivity analysis of entropy generation of Al2O3/H2O nanofluid in turbulent regime using response surface methodology

Fadodun Olatomide G., Olokuntoye Bolanle A., Salau Ayodeji O., Amosun Adebimpe A.

Archives of Thermodynamics

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2020

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Vol. 41, no 2

119--146

EN

This work investigates the effect of Reynolds number, nanoparticle volume ratio, nanoparticle size and entrance temperature on the rate of entropy generation in Al2O3 /H2O nanofluid flowing through a pipe in the turbulent regime. The Reynolds average Navier-Stokes and energy equations were solved using the standard k-ε turbulent model and the central composite method was used for the design of experiment. Based on the number of variables and levels, the condition of 30 runs was defined and 30 simulations were run. The result of the regression model obtained showed that all the input variables and some interaction between the variables are statistically significant to the entropy production. Furthermore, the sensitivity analysis result shows that the Reynolds number, the nanoparticle volume ratio and the entrance temperature have negative sensitivity while the nanoparticle size has positive sensitivity.

14

Analytical dynamic model of coefficient of friction of air pipeline under pressure

Dmytriv Vasyl, Dmytriv Ihor, Horodetskyy Ivan, Dmytriv Taras

Diagnostyka

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2019

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Vol. 20, No. 4

89--94

EN

To transport of the air in the pipeline, an analytical model is developed that takes into account the gas velocity, its kinematic and dynamic characteristics - density, viscosity depending on the pressure in a given space of the pipeline. The analytical model makes it possible to calculate the coefficient of friction of gas transportation in the pipeline at intervals of the absolute pressure from 220 to 2 kPa and M < 1 Mach numbers, depending on the diameter and length of the pipeline and physical and technological characteristics of the gas. The K1* aspect ratio is proposed, which characterizes in time the ratio of the dynamic force of movement of gas to the static pressure related to the diameter of the pipeline. The coefficient of air friction was modeled according to the vacuum pressure as a parameter of density and air flow. Air flow was taken from 1.917·10-3 m 3/s to 44.5·10-3 m 3/s respectively, diameters from 0.030 to 0.070 m and Mach number was M = 0.005-0.13. At the vacuum and excess pressures with increasing of Reynolds number and decreasing of Mach number the gas friction coefficient increased linearly. According to the simulation results as the pressure loss and the diameter of the pipeline are increased the friction coefficient increased as well. Analogically, at the vacuum metric pressure when the pressure loss and the diameter of the pipeline are increased the friction coefficient increased. At the pipeline internal diameters of 22, 30, 36 mm accordingly for pressure losses from 2 to 14 kPa the coefficient of air friction varies from 0.006 to 54.527 respectively.

15

Exergy based analysis of solar air heater duct with W-shaped rib roughness on the absorber plate

Patel Sumer Singh, Lanjewar Atul

Archives of Thermodynamics

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2019

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Vol. 40, no 4

21--48

EN

Exergy analysis is a powerful thermodynamic tool and it helps in computing the actual output of a system. It helps the researchers to optimize the roughened solar air heater design to compensate the present and also the future needs. In this study, investigation on exergetic performance evaluation of a solar air heater with W-shaped roughened absorber surface analytically by employing mathematical model and the results obtained are compared with smooth plate solar air heater under same operating conditions. The exergetic efficiency curves has been plotted as a function of different values of Reynolds number and temperature rise parameter for different roughness parameters. The maximum augmentation in the exergetic efficiency of the solar air heater with W-shaped roughened surface as compared to solar air heater with smooth surface has been obtained as 51% corresponding to the relative roughness height of 0.03375 and the rib angle of attack about 60°. Based on the exergetic efficiency the suitable design parameters of solar air heater with W-shaped roughened are determined.

16

Development of a source code to analyze the effect of Reynolds number on a square lid driven cavity

Rahi K. H., Mortuza G. M., Al-Faruk A.

Journal of Mechanical and Energy Engineering

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2018

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Vol. 2, No 2

147--154

EN

Numerical simulations of two-dimensional, steady, incompressible lid driven flow in a square cavity were investigated in this work. A commercial finite volume package of ANSYS-FLUENT was used to analyze and visualize the nature of the flow inside the cavity at different Reynolds Numbers. In addition, a MATLAB code was developed and validated by comparing the results with the reference values from literature. Staggered grid was employed in the discretization of the cavity to avoid checkerboard pressure while developing the code. The governing equations were discretized in terms of velocity and pressure fields. The artificial compressibility method was used to de-couple the pressure and velocity terms in the governing equations. A 129×129 grid system was used in both cases. The effects of Reynolds number (100≤ Re ≤ 1000) on the flow characteristics were illustrated through an analysis of stream function, velocity vector, pressure co-efficient and velocity contours. The thinning of the wall boundary layers with an increase in the Reynolds number is evident from the u and v velocity profiles along the vertical and horizontal lines at the geometric center, although the rate of this thinning is very slow for Re> 5000.

17

Studies of erosion resistance of protective coats on the surfaces of machine elements washed with fluids

Adamkiewicz A., Waliszyn A.

Advances in Materials Science

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2018

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Vol. 18, nr 2(56)

69--76

EN

This article indicated at erosion as one of the causes of degradation of surfaces washed by fluids and conditions of its occurrence. Corrosive – erosive theory of metal surface degradation has been discussed linking it with an instance of destructive processes taking place in cylinder liner blocks of combustion engines. Physics and conditions influencing processes on liquid – washed operational surface phase boundary have been justified. Out of the contemporary hypotheses explaining the physics of cavitation erosion, the bubble theory has been considered. A mathematical model of erosion has been presented in the context of cavitation implosion energy determining crash interactions of liquid cumulative fluxes on the washed surface. Occurring plastic deformations have been graphically explained linking them with the occurrence of fatigue micro-cracks and later with erosive pits. Influence of initial steel hardness on intensity of cavitation erosion has been checked. Discussion of ways to increase metal surface resistance to cavitation erosion has been carried out.

18

Numerical solutions of a steady 2-D incompressible flow in a rectangular domain with wall slip boundary conditions using the finite volume method

Ambethkar V., Srivastava M. K.

Journal of Applied Mathematics and Computational Mechanics

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2017

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Vol. 16, nr 2

5--16

EN

In this study, a finite volume method (FVM) is suitably used for solving the problem of a fully coupled fluid flow in a rectangular domain with slip boundary conditions. Numerical solutions for the flow variables, viz. velocity, and pressure have been computed. The FVM, with an upwind scheme, has been implemented to discretize the governing equations of the present problem. The well known SIMPLE algorithm is employed for pressure-velocity coupling. This was executed with the aid of a computer program developed and run in a C-compiler. Computations have been performed for unknown variables with Reynolds numbers (Re) = 50, 100, 250, 500, 750 and 1000. The behavior of steady-state solutions of velocity and pressure of the fluid along horizontal and vertical through geometric center of the rectangular domain have been illustrated. We observed that, with the increase of the Reynolds number, the absolute value of velocity components decreases whereas the pressure value increases.

19

Pomiar kryzą segmentową strumienia medium dla małych liczb Reynoldsa

Mrowiec A., Kasprzak D.

Zeszyty Naukowe Wydziału Elektrotechniki i Automatyki Politechniki Gdańskiej

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2016

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Nr 49

75--78

PL

Podstawowym surowcem energetycznym w Polsce jest węgiel. W ostatnich latach podejmowano próby spalania koloidalnych zawiesin pyłu węglowego w oleju napędowym lub opałowym. Przy pomiarach przepływu takich zawiesin, może dochodzić do wytrącania i zalegania w układach przesyłowych osadów, co w efekcie może prowadzić do zaburzeń strumienia przepływu. Wiarygodność pomiaru tego parametru, mogą zapewnić kryzy segmentowe. W artykule zaprezentowano wyniki badań przepływowych kryz segmentowych z przytarczowym punktowym odbiorem ciśnienia różnicowego, przy niewielkich liczbach Reynoldsa oraz symulacje numeryczne dla wybranej kryzy. W badaniach jako medium wykorzystano wodę.

EN

In Poland coal is the main energy resource. As part of the conducted research attempts were made at using suspensoids containing coal dust in gas oil and furnace oil. This leads to a reduction in NOx and SOx percentage without the need for an expensive desulphurization and dust extraction installation. However, there is a need for using cheap but reliable systems to measure the flow of the injected fuel. In real operating conditions various residues may often deposit in fuel transmission systems, which in turn can lead to flow fluctuations. Reliable flow factor measurement requirements can be met by segmental orifices. In the article, based on a research and measurement station, presented were the results of flow measurements with segmental orifices with point reception of differential pressure for small Reynolds numbers as well as numerical simulations. For the selected segmental orifice the flow factor characteristic in the function of the Reynolds number was calculated. In the research, water was used as the medium; the next stage of the research will involve the realization of the proposed solution with the use of hydraulic oil.

20

Sprawdzenie możliwości pomiaru kryzą mimośrodową strumienia medium dla małych liczb Reynoldsa

Kasprzak D., Mrowiec A.

Pomiary Automatyka Robotyka

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2016

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R. 20, nr 2

25--28

PL

Węgiel to podstawowy surowiec energetyczny w Polsce. Od połowy ubiegłego wieku podejmowano próby spalania koloidalnych zawiesin pyłu węglowego w oleju napędowym lub opałowym. Ze względów ekonomicznych podjęto badania nad wykorzystaniem koloidalnych zawiesin wodno-węglowych CWL (Coal-Water Liquid), jako paliwa w energetyce ciepłowniczej. Pozwala to na obniżenie zawartości NOx i SOx bez konieczności inwestowania w drogie układy odsiarczania i odpylania, co jest atutem ekologicznym i ekonomicznym. Wymagane, ze względów technologicznych, układy pomiaru strumienia dostarczanego paliwa, powinny być tanie w eksploatacji, niezawodne oraz odporne na zanieczyszczenia. Warunki te mogą spełnić kryzy mimośrodowe lub segmentowe. W artykule przedstawiono stanowisko doświadczalno-pomiarowe, pozwalające na przeprowadzenie przepływowych badań wstępnych, kryz mimośrodowych z punktowym odbiorem ciśnienia różnicowego, przy małych liczbach Reynoldsa. Wyniki wykonanych pomiarów charakterystyk przepływowych oraz symulacji numerycznych przedstawiono w tabelach i na wykresach. Dla wybranej kryzy mimośrodowej wyznaczono wartość współczynnika przepływu C w funkcji liczby Reynoldsa. Przedstawione w artykule analizy dotyczą przepływu wody. Planowane są dalsze badania dla oleju hydraulicznego.

EN

The energy industry in Poland is mostly based on coal as an energy resource. Until the half of the previous century studies and attempts were made at burning coal dust-based suspensoids in gas oil and furnace oil, with positive results. For economic reasons, studies and attempts were made at using coal and water-based CWL (Coal-Water Liquid) suspensoids as fuel in the heating industry. Using this fuel leads to a reduction in NOx and SOx percentage without the need for an expensive desulphurization and dust extraction installation, which is a huge economic and ecological advantage. For technological reasons required are systems for measuring the flow of the injected fuel that are cheap in use, reliable and residue-resistant. These requirements can be met by segmental and eccentric orifices. In the article, presented was a research and measurement station which enables its users to conduct introductory flow measurements for eccentric orifices with point reception of differential pressure for small Reynolds numbers. The results of the flow characteristic measurements as well as of numerical simulations were presented in the form of tables and charts. For the selected eccentric orifice the C flow parameter in the Reynolds number function was determined. The analysis of the study results presented in the article refers to the flow of water. The next planned stage of the research will involve flow studies and measurements with the use of hydraulic oil as the medium.