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1

A pre-protection method for a pipe-jacking channel over shield tunnels

Cui Yunliang, Yang Xukun, Wang Xinquan, Diao Hongguo, Li Xiao, Gao Yuanyuan

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2024

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Vol. 72, nr 2

art. no. e148443

EN

With the improvement of the planning level of underground space, the location of the planned under-crossing tunnel can be known in advance when constructing the upper-span tunnel. Therefore, pre-protection measures can be taken in advance during the construction of the upper-span tunnel. A new pre-protection method of a pipe-jacking channel was proposed to reduce the adverse effects of under-crossing shield tunnels. Numerical simulations of different pre-protection schemes were carried out using the finite element method to analyze its deformation control effect. The simulation results show that the deformation control effect of the gantry reinforcement scheme is the most significant. It is shown that the displacement of the pipe-jacking channel is more significantly suppressed with pre-protection measures than without preventive protection measures. The vertical displacement curve of the pipe-jacking channel exhibits a “W” shape after the construction of the double-lane shield underpass. By comparing the three different working conditions, it is found that the maximum vertical displacement and surface settlement of the pipe-jacking channel greatly reduced the gantry reinforcement pre-protection. Compared with Case 3, the effect of the pre-protection measures adopted in Case 2 was less obvious, which indicated that the form of the pre-protection had an important influence on controlling the deformation of the pipe-jacking channel.

2

Effect of surface energy on the contamination characteristics of porcelain double umbrella insulators

Lv Yukun, Wang Qian, Chen Zeze

Archives of Electrical Engineering

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2024

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Vol. 73, nr 1

235--250

EN

To explore the influence of surface energy on the contamination characteristics of insulators, COMSOL Multiphysics software was used to simulate the contamination characteristics of XWP 2 -160 insulators under wind tunnel conditions, and the rationality of the modified expression of the dynamic deposition model of the contaminated particles was verified. The change of contamination characteristics before and after changing the surface energy of insulators under natural conditions was simulated and analyzed. The results show that under the original surface energy (72 mJ/m2 ) and low surface energy (6.7 mJ/m2) with the increase in particle size, the contamination amount of an insulator surface area decreases first and then increases. When the wind speed is 2 m/s, the change in the particle size has the most pronounced effect on the amount of contamination. The amounts of contamination for the low surface energy are 64–75%, 60–95%, 55–91% and 54–78% lower than those for the original surface energy for particle sizes of 10, 15, 20 and 25 µm, respectively. For the same wind speed, when the size of contamination particles increases, the difference between the ratio of DC and AC contamination accumulation is gradually increasing because of the influence of the electric field force. From the perspective of the insulator preparation process, the development of low surface energy insulators can improve their anti-fouling performance.

3

Analiza nośności na ścinanie betonowych próbek zespolonych z wrębami w płaszczyźnie zespolenia

Sadowski Grzegorz, Wiliński Piotr, Halicka Anna

Przegląd Budowlany

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2023

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R. 94, nr 5-6

87--92

PL

W pracy przedstawiono badania próbek zespolonych z powierzchnią prefabrykatu z wrębami oraz referencyjnych elementów monolitycznych. Na podstawie wyników badań laboratoryjnych wykonano modele numeryczne, które posłużyły do analizy sposobu zniszczenia złącza. Przeprowadzono analizę porównawczą efektywności złącza badanych elementów z modelami numerycznymi oraz wynikami badań dostępnymi w literaturze. Badania i analizy wykazały, że zniszczenie złącza nastąpiło przez ścięcie wrębów, poprzedzone zerwaniem adhezji w styku. Nośność złącza uzależniona jest od geometrii próbek oraz sposobu ich obciążenia.

EN

The paper presents tests of composite specimens with the indented surface element and reference monolithic elements. Based on the results of laboratory tests, numerical models were made, which were used for further analysis of the interface cracking. A comparative analysis of the effectiveness of the notches of the tested elements with numerical models and the results of research available in the literature was carried out. Testing and analysis showed that the failure of the joint occurred by notch shear, preceded by adhesion rupture at the interface. The bearing capacity of interface between the concrete depends on the specimens’ geometry and the way they are loaded.

4

Wymiana ciepła w lufie armaty przeciwlotniczej w czasie strzelań amunicją ćwiczebną oraz bojową - porównanie wyników obliczeń

Koniorczyk Piotr, Zieliński Mateusz, Surma Zbigniew

Problemy Techniki Uzbrojenia

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2023

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R. 52, z. 165

23--39

PL

W pracy przedstawiono wyniki symulacji numerycznych wymiany ciepła w ściance lufy wykonanej ze stali 30HN2MFA ar-maty przeciwlotniczej kalibru 35 mm podczas strzelań amunicją bojową oraz ćwiczebną. Obliczenia wykonano dla pojedynczego strzału oraz sekwencji siedmiu strzałów dla dwóch rodzajów amunicji 35x228 mm: z pociskiem podkalibrowym FAPDS-T oraz z pociskiem ćwiczebnym TP-T. Lufę o długości 3150 mm podzielono na 6 stref i w każdej z nich obliczono temperaturę w funkcji czasu wzdłuż grubości ścianki lufy podczas strzelań. Wyniki porównano dla obu rodzajów amunicji.

EN

The paper presents results of numerical simulations of heat transfer in the 35 mm anti-aircraft gun barrel wall made of 30HN2MFA steel during firing with combat and practice ammunition. Calculations were made for a single shot and a sequence of seven shots for two types of ammunition 35x228 mm: with FAPDS-T projectile and TP-T practice projectile. The 3150 mm long barrel was divided into 6 zones and in each zone the temperature versus time was calculated along the barrel thickness during firing. The results were compared for both types of ammunition.

5

Selected Aspects of Heat Transfer Study in a Gun Barrel of an Anti-Aircraft Cannon

Zieliński Mateusz, Koniorczyk Piotr, Surma Zbigniew, Preiskorn Marek, Sienkiewicz Judyta

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2023

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Vol. 14, Nr 2 (52)

73--86

EN

The paper presents the results of computer simulations of the transient heat flow in the barrel wall of a 35 mm caliber cannon for a single shot and a sequence of seven shots for a selected 30HN2MFA barrel steel. It was assumed that the inner surface of the barrel does not have a protective layer of chromium or nitride. When calculating heat transfer in a barrel, constant and temperature variable values of thermal conductivity, specific heat and density (in the range from RT (Room Temperature) up to 1000℃) in the 30HN2MFA steel were assumed. The test results were compared for both cases. A barrel with a total length of 3150 mm was divided into 6 zones (i = 1,…, 6) and in each of them, the heat flux density was calculated as a function of the time 𝑞̇𝑖(𝑡) on the inner surface of the barrel. In each zone, the heat transfer coefficient, as a function of the time hi(t) and bore gas temperature as a function of the time Tg(t) to the cannon barrel for given ammunition parameters, was developed. A calculating time equaling 100 ms per single shot was assumed. The results of the calculations were obtained using FEM implemented in COMSOL Multiphysics ver. 5.6 software.

PL

W pracy przedstawiono wyniki symulacji komputerowych nieustalonego przepływu ciepła w ścianie lufy armaty kalibru 35 mm dla pojedynczego strzału i sekwencji siedmiu strzałów dla wybranej stali lufowej 30HN2MFA. Założono, że wewnętrzna powierzchnia lufy nie posiada ochronnej warstwy chromu lub azotku. Przy obliczaniu wymiany ciepła w lufie przyjęto stałe oraz temperaturowo zmienne wartości przewodności cieplnej, ciepła właściwego i gęstości (w zakresie od temperatury pokojowej (Room Temperature) do 1000℃) dla stali 30HN2MFA. Wyniki badań porównano dla obu przypadków. Lufa o łącznej długości 3150 mm została podzielona na 6 stref (i=1,…,6) i w każdej z nich obliczono gęstość strumienia ciepła w funkcji czasu 𝑞̇𝑖(𝑡) na wewnętrznej powierzchni lufy. W każdej strefie obliczono współczynnik przejmowania ciepła w funkcji czasu ℎ𝑖 (𝑡) oraz temperatury gazów prochowych w funkcji czasu 𝑇𝑔(𝑡) w lufie armaty dla zadanych parametrów amunicji. Dla pojedynczego strzału do obliczeń przyjęto czas równy 100 ms. Wyniki obliczeń uzyskano za pomocą MES zaimplementowanego w oprogramowaniu COMSOL Multiphysics ver. 5.6.

6

Study on the influence of chamfer perforation on heave and pitch of a single floating platform

Wang Wei, Fan Sheming, You Yunxiang, Zhao Cheng, Xu Liqun, Wang Guibiao, Lu Zhiqiang

Polish Maritime Research

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2023

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nr 1

43--53

EN

The aim of this work is to study the influence of chamfered perforation and chamfering on the heave and pitch motion of a single floating wind power platform with an anti-heave device. Firstly, the hydrodynamic performance of a single floating body with different chamfers, or without perforation, is calculated and analysed. Secondly, the motion of a model without perforation and with 35° chamfered perforation is captured and studied in a towing tank. The results show that when the wave height is large and the period is small, the perforated device has a certain effect. When the wave height and period are small, the pitch suppression effect of chamfered perforation is more obvious than that of non-chamfered perforation. When the period and wave height are large, the heave suppression effect of non-chamfered perforation is better than that of chamfered perforation. In experimental research, the perforated floating body has a certain effect on restraining the heave and pitch of a floating body under most working conditions, and the effect of restraining the pitch is obviously better than that of restraining the heave.

7

CFD-DEM simulation of raceway size and mechanical characteristics of industrial scale blast furnace

Gao Yuzhen, Chan Choon Kit

Polish Journal of Chemical Technology

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2023

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Vol. 25, nr 3

71--78

EN

The raceway plays a crucial role in ensuring the stable functioning of the ironmaking blast furnace. It is the key site where the chemical reaction of coke combustion takes place, providing the necessary heat and reducing gas for the upper iron ore reduction process. Consequently, the size of the raceway serves as an essential indicator of the blast furnace’s operational condition. In this study, a mathematical model for the raceway of an industrial-scale blast furnace was established. Extensive innovation investigations were conducted to explore the characteristics pertaining to the raceway’s size. The simulation outcomes demonstrate that both the particle size and the inlet velocity exert significant influences on the raceway dimensions. Specifically, the height of the raceway is predominantly affected by the particle size, whereas the inlet velocity predominantly influences the depth of the raceway.

8

The influence of air inlet layout on the inner flow field for a vertical turbo air classifier

Yu Yuan, Li Xingshuai, Zhang Yu, Jiao Zhiwei, Liu Jiaxiang

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 175859

EN

In this study, the influence of air inlet layout on the flow field distribution and particle movement trajectory for the vertical turbo air classifier are analyzed comparatively using the numerical simulation method. The air inlet layout adjustment can increase the axial velocity and turbulent dissipation rate at the feeding inlet and do not generate the axial negative velocity, which improves powder material pneumatic transportation and dispersion capacity; the air inlet layout adjustment can match the airflow rotation direction with the rotation direction of the rotor cage, which can eliminate the vortices in the rotor cage channel effectively. Moreover, the particle movement time is shortened and fast classification is completed, which can decrease the particle agglomeration probability and weaken the ‘fish-hook’ effect. The optimization scheme of the air inlet layout is Type-BC. In accordance with the numerical simulation results, the calcium carbonate classification experimental results indicate that the classification performance of the classifier is improved using Type-BC.

9

Effect of spiral vanes width on the separation performance of a hydrocyclone

Liu Peikun, Wang Xiaoguo, Jiang Lanyue, Zhang Yuekan, Yang Xinghua, Li Xiaoyu, Wang Hui

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 173563

EN

Aiming at the problem of “entrainment fine particles in underflow” of hydrocyclone in grinding and classification process, a hydrocyclone with spiral vanes (the SV hydrocyclone) was proposed. The CFD techniques were used to study the pressure field, velocity field, turbulence field, particle field and classification efficiency of hydrocyclones with spiral vanes of different widths. The results show that the pressure drop, axial velocity, tangential velocity, turbulence intensity of SV hydrocyclone are reduced in different degrees compared with conventional hydrocyclone, and the reduction becomes more obvious with the increase of vane width. In the case of a vane width of 0.04D, the underflow recovery rate of 5μm and 10μm fine particles was reduced by 16.2% and 15.7%. The selection of spiral vanes with small widths is beneficial to improve the separation accuracy of fine particles and reduce the cut particle size.

10

Towards an Optimal Motor Mounting Bracket Using Topology Optimization Combined with Sustainability and Manufacturing Cost Analysis

Fassi Hicham Fihri, Aniyou Hadji

Management and Production Engineering Review

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2023

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Vol. 14, No. 4

109--116

EN

The engine is the most important component of a vehicle. It attaches to the main frame via the engine mounting bracket which supports weight and operating loads. The engine mount therefore plays a crucial role in the durability and comfort of the vehicle. This article contributes to the search for the most optimal model from the point of view of resistance, environmental impact, and manufacturing cost. This involves, on the one hand, optimizing the support by reducing its initial mass by 30%, and on the other hand, seeking suitable material and manufacturing process with the least environmental impact. To this end, topology optimization will be combined with an environmental assessment and a manufacturing cost analysis. Four materials will be tested and evaluated. Finally, a cost analysis will present a comparison between a conventional process and 3D printing.

11

Research on stability of rock mass and þ30 level surface construction works when re-exploiting the seam H10 at Mong Duong Coal Mine, Vietnam

Vu Tien T., Dao Doan V.

Journal of Sustainable Mining

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2023

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Vol. 22. iss. 2

100--109

EN

The re-exploitation of coal seams located near the ground is one of the solutions to increase output, reduce mining investment costs, and avoid wasting coal resources. The re-exploitation of coal seams will also cause instability of the surrounding rock mass and may affect surface construction works. Through the process of re-exploiting the longwall in seam H10 at Mong Duong Coal Mine, the authors have studied and evaluated the stability of the rock mass and þ30 level surface works (including fan station and gateroad). To achieve the results in this study, the numerical simulation model method and the analytical method were applied. The model analysis results have determined that the displacement and deformation areas of the rock mass around the mining area correspond to the length of the cut in the strike direction of the longwall H10. The analysis and calculation results from the model show that the longwall in seam H10 can be re-exploited when leaving a protective coal pillar about 50 m from the center of the þ30 fan station at the east side; this distance ensures the stability of the rock mass that located near the ground and the surface works at þ30.

12

Supporting a Mine Working with a Shelter in Various Mining and Geological Conditions

Krukovskyi Oleksandr, Krukovska Viktoriia

Inżynieria Mineralna

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2023

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no. 1

45--52

EN

Shelters are used to protect miners from exposure to harmful gases and for the work of rescuers. Such shelters are built in a niche adjacent to the mine working. The purpose of this work is a numerical study of the stress state of a coal-rock massif with a mine working and a shelter, their stability in various mining and geological conditions and with various supporting schemes. Numerical simulation of the stress state of a coal-rock massif with a mine working and a shelter was performed; their stability was studied in various mining and geological conditions and with various supporting schemes. It is shown that, over time, near-contour rocks are unloaded from rock pressure, and an area of increased difference of the stress tensor compo-nents expands around the mine working and the shelter. This leads to cracks formation of varying degrees of intensity. When the mine working with the shelter is driven at a shallow depth in hard rocks, the basic scheme, which consists mainly of metal frames and a reinforced concrete barrier, is sufficient for their supporting. If the host rocks are weaker, the stability of the mine working and the shelter is broken and it is necessary to strengthen their supporting with rock bolts. In the bolted area, the rocks are in triaxial compression conditions, a rock-bolts arch is formed above the mine working and the shelter, which pre-vents the displacement of the roof rocks into the mine working and increases its stability. With an increase in the depth of min-ing operations, the stability of the mine working decreases; the inelastic deformation zone in the mine walls grows; the load on the support increases. For the rock-bolts arch formed in the mine roof, supports are required in the walls of the mine working and the shelter. For this purpose, side rock bolts are installed. The use of an appropriate supporting scheme leads to a de-crease of the area of inelastic deformation zone by 2.5 times and the area of the zone unloaded from rock pressure by 2.6 times. Thus, such schemes for supporting the mine working and the shelter are selected, which ensure their stability in the considered mining and geological conditions.

PL

Schrony służą do ochrony górników przed narażeniem na szkodliwe gazy oraz do pracy ratowników. Schrony takie budowane są w niszy przylegającej do wyrobiska kopalnianego. Celem pracy jest numeryczne badanie stanu naprężeń masywu węglowo-skalnego z wyrobiskiem i osłoną, jego stateczności w rożnych warunkach górniczo-geologicznych i przy rożnych układach obudowy. Wykonano symulację numeryczną stanu naprężeń masywu węglowo-skalnego z wyrobiskiem i schronem. Badano ich stabilność w rożnych warunkach górniczych i geologicznych oraz przy rożnych schematach podparcia. Pokazano, że w miarę upływu czasu skały przykonturowe odciążają się od naporu skał, a wokół wyrobiska i schronu rozszerza się obszar zwiększonej różnicy składowych tensora naprężeń. Prowadzi to do powstawania pęknięć o rożnym stopniu intensywności. Gdy kopalnia współpracująca ze schronem jest prowadzona na płytkiej głębokości w twardych skałach, do ich podparcia wystarcza podstawowy schemat, składający się głownie z metalowych ram i bariery żelbetowej. Jeżeli skały macierzyste są słabsze, stabilność wyrobiska kopalnianego i osłony jest zerwana i konieczne jest wzmocnienie ich podparcia kotwami skalnymi. W rejonie kotwionym skały znajdują się w stanie trójosiowego ściskania, nad wyrobiskiem i schronem tworzy się łuk kotwowy, co zapobiega przemieszczaniu się skał stropowych do wyrobiska i zwiększa jego stateczność. Wraz ze wzrostem głębokości eksploatacji zmniejsza się stabilność wyrobiska górniczego, powiększa się strefa odkształceń niesprężystych w ścianach kopalni, obciążenie podpory wzrasta. Dla łuku kotwiowego formowanego w stropie kopalni wymagane są podpory w ścianach wyrobiska i schronu. W tym celu montowane są boczne kotwy skalne. Zastosowanie odpowiedniego schematu podparcia prowadzi do 2,5-krotnego zmniejszenia powierzchni strefy odkształceń niesprężystych oraz 2,6-krotnej powierzchni strefy odciążonej od parcia skał. W związku z tym dobierane są takie schematy obudowy wyrobiska i osłony, które zapewniają ich stabilność w rozważanych warunkach górniczo-geologicznych.

13

Numerical simulation of hydrogen storage in the Konary deep saline aquifer trap

Luboń Katarzyna, Tarkowski Radosław

Gospodarka Surowcami Mineralnymi

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2023

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T. 39, z. 3

103--124

EN

Nowadays, hydrogen is considered a potential successor to the current fossil-fuel-based energy. Within a few years, it will be an essential energy carrier, and an economy based on hydrogen will require appropriate hydrogen storage systems. Due to their large capacity, underground geological structures (deep aquifers, depleted hydrocarbon fields, salt caverns) are being considered for hydrogen storage. Their use for this purpose requires an understanding of geological and reservoir conditions, including an analysis of the preparation and operation of underground hydrogen storage. The results of hydrogen injection and withdrawal modeling in relation to the deep Lower Jurassic, saline aquifer of the Konary geological structure (trap) are presented in this paper. A geological model of the considered structure was built, allowable pressures were estimated, the time period of the initial hydrogen filling of the underground storage was determined and thirty cycles of underground storage operations (gas injection and withdrawal) were simulated. The simulations made it possible to determine the essential parameters affecting underground hydrogen storage operation: maximum flow rate of injected hydrogen, total capacity, working gas and cushion gas capacity. The best option for hydrogen storage is a two-year period of initial filling, using the least amount of cushion gas. Extracted water will pose a problem in relation to its disposal. The obtained results are essential for the analysis of underground hydrogen storage operations and affect the economic aspects of UHS in deep aquifers.

PL

Ze względu na bardzo dużą pojemność podziemne struktury geologiczne (głębokie poziomy wodonośne, sczerpane złoża węglowodorów, kawerny solne) są rozważane do magazynowania wodoru. Ich wykorzystanie w tym celu wymaga rozpoznania uwarunkowań geologiczno-złożowych, w tym analizy przygotowania oraz pracy podziemnego magazynu wodoru. Przedstawiono wyniki modelowania zatłaczania i odbioru wodoru do głębokiego dolnojurajskiego poziomu solankowego struktury geologicznej Konary. Zbudowano model geologiczny rozważanej struktury, oszacowano dopuszczalne ciśnienia szczelinowania oraz ciśnienie kapilarne nadkładu, wyznaczono długości wstępnego okresu zatłaczania wodoru do podziemnego magazynu, przeprowadzono modelowanie przebiegu 30-letniej pracy podziemnego magazynu (zatłaczania i odbioru gazu). Przeprowadzone symulacje umożliwiły określenie istotnych parametrów wpływających na prace podziemnego magazynu wodoru: maksymalną wielkość przepływu zatłaczanego wodoru, pojemność całkowitą, pojemność roboczą i wielkość poduszki gazowej. Pozwoliły stwierdzić, że im dłuższy wstępny okres zatłaczania wodoru, tym większą musimy zastosować poduszkę gazową. Za najlepszą opcję dla magazynowania wodoru zaproponowano dwuletni okres wstępnego zatłaczania gazu do struktury; opcja z najmniejszą wielkością poduszki gazowej. Stwierdzono, że ilość wody, jaka jest eksploatowana w trakcie odzyskiwania wodoru, podczas cyklicznej eksploatacji magazynu, spada wraz ze zwiększeniem długości wstępnego okresu zatłaczania wodoru. Eksploatowana woda będzie stanowiła znaczący problem związany z jej unieszkodliwieniem. Otrzymane wyniki są istotne w analizie pracy podziemnego magazynu wodoru i wpływają na aspekty ekonomiczne UHS w głębokich solankowych poziomach wodonośnych.

14

A comparative study of one-dimensional models for stratified thermal energy storage

Osiadacz Andrzej J., Kotyński Łukasz, Kwestarz Małgorzata

Gaz, Woda i Technika Sanitarna

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2023

|

Nr 9

8--14

EN

In the article, a comparative analysis of one-dimensional dynamic models describing Thermal Energy Storages is carried out. A model based on energy balance was compared with a model of conductivity and convection and with a convection model. For each of them, the effect of time on the temperature distribution in the tank was examined and temperature distributions in the tank obtained for the analysed models were compared. Also, the effect of the number of nodes (discretization intervals) on the shape of the stratification curve was studied and the impact of the flow rate of the supplied hot water on the stratification curve was examined.

PL

W artykule dokonano analizy porównawczej jednowymiarowych dynamicznych modeli opisujących Thermal Energy Storages. Porównywano model oparty na bilansie energii z modelem przewodzenia i konwekcji oraz modelem konwekcyjnym. Dla każdego modelu badano wpływ czasu na rozkład temperatury w zasobniku, porównywano rozkłady temperatury w zasobniku otrzymane dla analizowanych modeli a także badano wpływ liczby węzłów (przedziałów dyskretyzacji) na kształt krzywej stratyfikacji. Badano także wpływ natężenia przepływu dostarczanej wody gorącej na krzywą stratyfikacji.

15

Numerical simulation study on NO oxidation by OH radical clusters in flue gas

Wen Zhengcheng, Zhang Xiaofeng, Huang Ju, Yang Zhengyin

Environment Protection Engineering

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2023

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Vol. 49, nr 3

69--82

EN

Fenton reaction is an important method to remove NO from flue gas. • OH radicals generated in the Fenton reaction can effectively oxidize NO to NO2, which is absorbed and removed by alkali sorbent. To supply guidance for engineering research, numerical simulation of NO oxidation by • OH radical clusters in flue gas has been carried out using Fluent software. The average concentration of NO on the cross sections at various positions of a cylindrical pipe with a circular surface was calculated by simulation. Under various working conditions (temperature, • OH/NO molar ratio, NO concentration in flue gas, and jet velocity), NO oxidation efficiency by • OH radical was simulated and the key factors affecting NO oxidation were analyzed. The results show that temperature and • OH/NO molar ratio are the key factors affecting the oxidation of NO by • OH radicals. The injection velocity has also a significant effect on the oxidation efficiency while the moisture and oxygen content are minor factors influencing the process. The optimum oxidation efficiency of NO is obtained at 473–523 K, the molar ratio of • OH/NO ca. 1.4, the jet velocity 10 m/s, and the flue gas velocity of 3 m/s.

16

Methodology for the Composite Tire Numerical Simulation Based on the Frequency Response Analysis

Karpenko Mykola, Skačkauskas Paulius, Prentkovskis Olegas

Eksploatacja i Niezawodność

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2023

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Vol. 25, no. 2

art. no. 163289

EN

Reliability and maintenance analysis in transport focus on the main objective of accident and incident investigations that benefit to better understanding of the causes of accidents and prevention of them in the future. The conducted research presents theoretical and experimental research on composite pneumatic tire used in transport engineering. The approach of the numerical simulation sequence which is offered in this research facilitates engineers in efficient determination of the dynamic properties and behaviour of vehicle tire at design stage. The tire materials have been tested by employing piezoelectric micro-vibration tests and frequency analyses. The Finite Element Method used for numerical simulation in combination with experimental measurements based on optimization by material frequency response, was applied in modelling tire material behaviour avoiding problems of composite structure modelling. The obtained results indicate that the offered methodology can be used in numerical simulation of composite tire investigation and considering material viscos-elastic properties.

17

Simulation analysis for the efficiency enhancement of Sb2S3 solar cell using SCAPS-1D

Oglah Mubarak Hamad, Mahmood Watban Ibrahim, Adday Nawras Basheer

Computer Methods in Materials Science

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2023

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Vol. 23, No. 4

19--29

EN

The simulation analysis was performed to enhance the efficiency of Sb2 S3 solar cells using the SCAPS-1D software. The Sb2 S3 compound was used as the absorber layer in the solar cell. The simulation was conducted to verify the efficiency and accuracy of the results obtained from the program. The results were found to be in agreement with the practical results. The original cell’s efficiency was 11.47% with a fill factor of 61.18%, and after the simulation, the efficiency was found to be 11.43% with a fill factor of 61.2%. To enhance the efficiency of the solar cell, a reflective background layer (BSL) was added. Different BSL layers were examined, including SnS, Si, CIGS, CZTSSe, and CUS bS3 , and the best reflective layer was found to be CUSbS3 . The solar cell structure was designed as follows: glass/Mo/CUSbS3 /Sb2 S3 /CdS/i:ZnO/AL:ZnO. After adding the reflective layer, the efficiency of the solar cell was found to be 20.59% with a fill factor of 87.53%. The results suggest that adding reflective layers to solar cells can enhance their performance and increase their efficiency.

18

Evaluation of the influence of the opening pressure of a marine diesel engine injector on the results of numerical simulation of the working cycle and their comparison with the results of the laboratory experiment

Puzdrowska Patrycja

Combustion Engines

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2023

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R. 62, nr 2

9--14

EN

The article presents the results of a numerical simulation of the working process carried out in a diesel engine. In the applied utility program DIESEL-RK, the laboratory engine Farymann Diesel type D10 was implemented. A selected inoperability of its functional fuel supply system - reduced opening pressure of the injector pinj - was introduced. The values of adequate diagnostic parameters were determined: working gas temperature in the cylinder Tcyl, exhaust gas temperature Texh, combustion (flame) temperature Tcomb and concentration of nitrogen oxides in the exhaust gas NOx. Experimental tests were carried out on the experimental engine with the inoperative condition actually introduced, analogous to the numerical simulation, and the diagnostic parameters Texh and NOx were recorded. The results obtained by numerical simulation of the processes and during the active experiment on the experimental engine were compared.

19

Experimental and numerical analysis of vortex generators designed for utility vehicles

Chidambaram Ramesh Kumar, Kanna Rajesh, Gopal Poomanandan, Arumugam Senthil Kumar

Archives of Thermodynamics

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2023

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Vol. 44, no 3

217--240

EN

The main goal of today’s car designers is to minimize fuel consumption in all possible ways at the same time maintaining the vehicle’s performance as usual. The goal of this work is to study the effect of adding a vortex generator (VG) on the aerodynamics of the vehicle and fuel economy. Both theoretical and experimental works were carried out and the outcomes of the numerical simulations are contrasted with those of the experimental results. A utility vehicle model with a scale ratio of 1:15 was used as a test model. Experimental research has been done on the fluctuation of the coefficient of pressure, dynamic pressure, and coefficients of lift and drag with and without VG on the roof of a utility vehicle. The delta-shaped VG was put to the test both numerically and experimentally. At a velocity of 2.42 m/s, it is observed that the addition of VG can raise the pressure coefficient by about 17%. When compared to the vehicle model without vortex generators, the velocity profile of the ccomputational fluid dynamics analysis shows that at the back end of the vehicle, the wake has been minimized with VG.

20

Damage and stability analysis of sandstone-type uranium ore body under physical and chemical action of leaching solution

Liu Yulong, Huang Lei, He Guicheng, Hu Nan, Zhou Shuhui, Yu Qing, Ding Dexin

Archives of Mining Sciences

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2023

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Vol. 68, no. 3

409--423

EN

In this paper, the typical sand-conglomerate uranium ore in north China was taken as the research object. The uniaxial compression and tensile tests of sand-conglomerate specimens under natural status and acidic solution status were used to research the compressive strength, tensile strength, Young’s modulus, cohesion and internal friction angle. Focusing on this type of uranium deposit, during the underground design of the in-situ leaching mining method, the three-dimensional finite element method was used to conduct a numerical simulation of the liquid collecting tunnel with different structural parameters of 10 m×2 m, 3 m×2 m, 2 m×2 m, and comprehensively analyse the vertical displacement, principal stress and plastic deformation zone changes of the tunnelbefore and after leaching. Based on the results, influenced by an acidic aqueous solution, the grain of the conglomerate became soft and secondary pores appeared, resulting in the superimposed effect of physical damage and chemical damage. Macroscopically, an obvious decrease was witnessed in mechanical property. Based on the stability and economy factor of three scenarios before and after leaching, the scenario was recommended as the experimental testing scenario, specifically, two longitudinal collecting tunnel were arranged along the strike of the orebody, with the size of 3 m×2 m and the width of the middle pillar of 4 m. The results of the numerical simulation are significant in guiding the design of underground in-situ leaching technology and determining the structural parameters of the deposit.