Wyniki wyszukiwania - BazTech

1

Investigation of mechanical motion amplification for vibration energy harvesting

Satpute Nitin, Iwaniec Marek, Narina Ramesh, Satpute Sarika

Vibrations in Physical Systems

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2022

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Vol. 33, nr 1

art. no. 2022113

EN

Vibration Energy Harvesting is being investigated for autonomous sensors and actuators that mainly utilize ambient and machine induced vibrations. Recently mechanical motion amplification is incorporated for improving power to weight ratio of vibration harvesters. The present study is motivated to investigate mechanical motion amplification characteristics with different configurations. The parameters investigated are motion amplification ratio, force transmissibility characteristics, weight of the electrical generator, effective damping coefficient achieved and linear nature of damping. Numerical analysis has been performed to compare important characteristics of device operating without amplification to that of with amplification with different configuration. The study has been concluded with comments on application of suitable type of amplification mechanism depending on weight/space constraints and desired effective damping coefficient.

2

Akustyka przeszkleń architektonicznych - podstawy zasad przenoszenia dźwięku i właściwości folii akustycznych

Ju Hengyi

Świat Szkła

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2022

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R. 27, nr 4

45--48

3

Improving the operation characteristics of non-insulated overhead power lines

Kozlovskyi Oleksandr, Trushakov Dmitro, Savchenko Oleksandr, Rendzinyak Serhiy, Korud Vasyl

Przegląd Elektrotechniczny

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2022

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R. 98, nr 2

28--32

EN

Methods of protection of wires of overhead power lines of group "anti-icing" are analyzed. The expediency of applying the winding method of protection of wires of overhead lines in operation for a long time is shown. Based on numerical simulations of the hydrodynamic problem, the degree of influence of the protective coating on the wind load of the wire is analyzed. The research results showed a decrease in the modified wire's drag coefficient with increasing wind speed.

PL

Przeanalizowano metody ochrony przewodów linii napowietrznych z grupy „przeciwoblodzeniowa”. Pokazano celowość zastosowania metody uzwojenia do ochrony przewodów linii napowietrznych eksploatowanych od dłuższego czasu. Wykorzystując symulacje numeryczne zagadnienia hydrodynamicznego analizowany jest stopień wpływu powłoki ochronnej na obciążenie żyły kabla wiatrem. Wyniki badań wykazały spadek współczynnika rezystancji zmodyfikowanej żyły wraz ze wzrostem prędkości wiatru.

4

Air Pollution Regulations in China: A Policy Simulation Approach with Evolutionary Game

Chu Zhaopeng, Bian Chen, Yang Jun

Problemy Ekorozwoju

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2022

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Vol. 17, nr 1

222--233

EN

In the institutional context of China’s political centralization and fiscal decentralization, this study explores the environmental regulations that make the central and local governments join efforts in air pollution control. Policy simulations in an evolutionary game show that the best approach is to internalize environmental costs and benefits in local governments’ objective function. The effectiveness of several policy instruments is examined individually and jointly, including administrative inspection, transfer payment, and environmental taxes. It is shown that in case environmental consequences are not internalized, appropriate application of policy instruments can incentivize goal-oriented local governments to choose the socially optimal strategy.

PL

W kontekście instytucjonalnym chińskiej centralizacji politycznej i decentralizacji fiskalnej, niniejsze badanie analizuje regulacje środowiskowe, które zmuszają rządy centralne i lokalne do wspólnych wysiłków na rzecz kontroli zanieczyszczenia powietrza. Symulacje polityki w grze ewolucyjnej pokazują, że najlepszym podejściem jest internalizacja kosztów i korzyści środowiskowych w funkcji celu samorządu. Skuteczność kilku instrumentów polityki jest badana indywidualnie i wspólnie, w tym kontroli administracyjnej, płatności transferowych i podatków ekologicznych. Wykazano, że w przypadku braku internalizacji konsekwencji środowiskowych, odpowiednie zastosowanie instrumentów polityki może zmotywować zorientowane na cel samorządy lokalne do wyboru społecznie optymalnej strategii.

5

Badania eksperymentalne i symulacje komputerowe ściany osłonowej MB-SR50N HI obciążonej wiatrem

Juraszek Janusz, Woźniczka Piotr, Rusin Dawid

Materiały Budowlane

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2022

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nr 9

53--55

PL

W artykule przedstawiono wyniki badań i symulacji numerycznych MES ściany osłonowej MB-SR50N HI wykonanej z profili aluminiowych. Przeprowadzono badania polegające na obciążeniu wiatrem ściany osłonowej, zarówno ciśnieniem, jak i podciśnieniem o wartości 2400 Pa w specjalnej komorze badawczej. Wyznaczono wartości ugięć w wybranych punktach pomiarowych. Zbudowano model numeryczny ściany osłonowej za pomocą systemu MES Abaqus. Uwzględniono nieliniowość geometryczną oraz rzeczywiste obciążenie o wartościach analogicznych, jak w przypadku badań eksperymentalnych. Otrzymane wyniki symulacji numerycznych są porównywalne z rezultatami badań doświadczalnych. Badanie przemieszczeń i ugięć aluminiowo-szklanych ścian osłonowych ma istotne znaczenie z punktu widzenia ich bezpieczeństwa eksploatacyjnego.

EN

This paper presents results of testing and numerical FEM simulations of the MB-SR50N HI curtain wall of aluminium profiles. Wind-load tests were carried out in a special testing chamber making it possible to load the curtain wall with pressure and partial vacuum of 2400 Pa. Values of deflection were determined in selected measuring points. A numerical model of the curtain wall was built using the Abaqus FEM system. Geometrical nonlinearity and the real load with values analogous to those obtained from experiments have been taken into account. The obtained results of numerical simulations are comparable with results of experimental research. The testing of displacements and deflections of aluminium-glass curtain wallsis important from the point of view of their operational safety.

6

Wyniki symulacji numerycznej cyklu roboczego silnika o ZS w programie DIESEL-RK oraz ocena ich użyteczności w procesie planowania badań diagnostycznych okrętowego silnika tłokowego

Puzdrowska Patrycja

Journal of Polish CIMEEAC

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2022

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Vol. 17, no 1

74--82

PL

W artykule przedstawiono wyniki symulacji numerycznej procesu roboczego realizowanego w silniku tłokowym o zapłonie samoczynnym. W zastosowanym programie użytkowym DIESEL-RK zaimplementowano silnik laboratoryjny Farymann Diesel typ D10. Wprowadzono wybraną niesprawność jego układu funkcjonalnego zasilania paliwem - obniżone ciśnienie otwarcia wtryskiwacza pwtr. Wyznaczono wartości adekwatnych parametrów diagnostycznych: temperaturę i ciśnienie gazu roboczego w cylindrze Tcyl i pcyl, temperaturę i ciśnienie spalin wylotowych Tsp i psp, temperaturę spalania (płomienia) Tspal, prędkość spalin wylotowych vsp oraz stężenie cząsteczek NOx. Oceniono użyteczność wyników przeprowadzonej symulacji do wyboru analizowanych parametrów struktury konstrukcyjnej silnika oraz do selekcji parametrów, które mogą być wykorzystane w badaniach diagnostycznych silnika laboratoryjnego.

7

Physical and numerical model of electrocoagulation process with aluminum electrodes for phosphate removal

Halkijevic Ivan, Loncar Goran, Posavcic Hana, Vouk Drazen

Environment Protection Engineering

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2022

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Vol. 48, nr 3

53--68

EN

The efficiency of the electrocoagulation process for the removal of phosphate ions (PO43--P) has been analyzed using a batch full-scale reactor with aluminum electrodes. The effects of the flow rate through the reactor applied current density, and reactor volume were the focus of the study. The initial (PO43--P) concentration was reduced by 90% after 90 min of reactor operation time. Additionally, a three-dimensional numerical model for PO43--P removal via the electrocoagulation process is developed that includes the processes of phosphate adsorption and desorption on coagulated/flocculated particles, along with particles settling. Numerical model parametrization relies on the results from the experiments.

8

Numeryczna weryfikacja skuteczności wzmocnienia żelbetowego zbiornika na węgiel brunatny

Lytvyn Oleksandr, Miodoński Beniamin, Marcinowski Jakub, Sakharov Volodymyr, Szerszeń-Zamorska Agata

Builder

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2022

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R.26, nr 4

16--19

PL

Przedmiotem analiz numerycznych zamieszczonych w pracy jest żelbetowy zbiornik na węgiel brunatny. Pojemność całkowita zbiornika wynosi około 26 tys. ton. W początkowym okresie eksploatacji zasobnika w latach 60. pojawiły się liczne spękania oraz nadmierne deformacje wymuszające podjęcie pilnych działań naprawczych. Wprowadzono wtedy stalowe ściągi podłużne, poprzeczne i ukośne. Skuteczność tych wzmocnień nie była weryfikowana w przeszłości. Inwentaryzacja oraz wykonane w ostatnim czasie badania materiałowe dostarczyły danych użytych w analizach numerycznych, których celem była ocena aktualnego stanu technicznego analizowanego obiektu. Model numeryczny samej konstrukcji został uzupełniony o grunt, na którym zasobnik został posadowiony. Analizy numeryczne zostały wykonane autorskim programem weryfikowanym wcześniej za pomocą innych programów komercyjnych.

EN

The subject of numerical analyzes included in the paper is a reinforced concrete lignite bunker. The total capacity is about 26 thousand tone. In the initial period of the bunker's operation, disturbing symptoms (cracks, excessive deformations) appeared, necessitating taking urgent corrective actions. Then, longitudinal, transverse and diagonal steel ties were introduced. The effectiveness of these reinforcements has not been verified in the past. Their careful inventory and material tests performed recently provided the necessary data to perform numerical analyzes, the purpose of which was to assess the current technical condition of the analyzed object. The numerical model of the structure itself was supplemented with the ground on which the bunker was placed. Numerical analyzes were performed with author’s program that was previously verified with other commercial programs.

9

Numerical Simulation and Analysis of Airflow in the Condensing Zone of Compact Spinning with Lattice Apron

Saty Malik Y. H., Akankwasa Nicholus T., Wang Jun

Autex Research Journal

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2022

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Vol. 22, no. 3

258--263

EN

The airflow field pattern in the condensing zone plays a vital role in the pneumatic compact spinning, which significantly affects the yarn's qualities. This study aimed to analyze the effects of the different negative air pressures on fiber condensing in compact spinning with lattice apron using ANSYS. The results of airflow simulations reveal that by increasing the negative pressure, the flow velocity increases, leading to a more tremendous increase in the transverse condensing effects. Additionally, a better convergence led to reduced fiber width and eliminated the spinning triangle. Experimental results showed that the three yarns spun with the highest negative pressure had better strength, hairiness, and evenness than those spun with lower negative pressure.

10

Numerical Investigation of Heat Transfer in Garment Air Gap

Zhang Yijie, Jia Juhong

Autex Research Journal

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2022

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Vol. 22, no. 1

89--95

EN

This article aimed to study the characteristics and mechanisms of 3D heat transfer through clothing involving the air gap. A three-dimensional finite volume method is used to obtain the coupled conductive, convective, and radiative heat transfer in a body-air-cloth microclimate system. The flow contours and characteristics of temperature, heat flux, and velocity have been obtained. The reason for the high flux and temperature regions was analyzed. Computational results show that the coupled effect of the air gap and the airflow between the skin and garment strongly influences the temperature and heat flux distribution. There are several high-temperature regions on the clothing and high heat flux regions on the body skin because the conductive heat flux can cross through the narrow air gap and reach the cloth surface easily. The high-speed cooling airflow brings about high forced convective heat flux, which will result in the temperature increase on the upper cloth surface. The radiative heat flux has a strong correlation with the temperature gradient between the body and clothing. But its proportion in the total heat flux is relatively small.

11

Study on the three-phase flow of the water transfer export elbow of natural gas hydrate

Chen Wei, Xu Hai-Liang, Wu Bo, Yang Fang-Qiong

Archives of Mining Sciences

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2022

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Vol. 67, no. 2

239--258

EN

The Euler multiphase flow and population equilibrium model were used to simulate the three-phase flow field in the bubble expansion stage of the outlet curved pipe section. The influence of the ratio of the bending diameter and the volume fraction of the gas phase on the pressure loss is revealed, and the safety range of the optimum bending diameter ratio and the volume fraction of the outlet gas phase is determined. The results show that the three-phase flow in the tube is more uniformly distributed in the vertical stage, and when the pipe is curved, the liquid-phase close to the pipe wall gathers along the pipe flank to the outside of the pipe, the solid phase is transferred along the pipe flank to the inside of the pipe, and the gas phase shrinks along the pipe flank to the inner centre. The maximum speed of each phase of the three-phase flow in the elbow is at the wall of the tube from 45° to 60° inside the elbow, and the distribution law along the axial direction of the pipe is about the same as the distribution law of volume fraction. The pressure loss of the elbow decreases with the increase of the bend diameter ratio, when the bend diameter ratio increases to 6, the pressure loss of the pipe decreases sharply, and the pressure loss decreases slowly with the increase of the bend diameter ratio. When the gas phase volume score in the elbow reaches 70%, there will be an obvious wall separation phenomenon, to keep the system in a stable working state and prevent blowout, the gas phase volume score should be controlled within 60%.

12

Study on the subgrade service depth of moving vehicles under multi-wheeled superposition effect

Zhou Yanmin, Wang Haiyang, Kong Lingyun, Liu Jialiang, Wang Jie, Wang Zhimei

Archives of Civil Engineering

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2022

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Vol. 68, nr 2

483--499

EN

The stress superposition effect in the midline area of the multi-wheeled vehicles produced by moving vehicles load is generally ignored, which leads to smaller results in research of subgrade service depth. Based on the elastic mechanics theory, the analytical solution of subgrade dynamic response under moving vehicles load is derived with compound elastic layers. The characteristics of subgrade dynamic stress distribution under the action of moving vehicles are analyzed by using Midas Gts Nx numerical simulation software, and the influence of static and dynamic axle load on the subgrade service depth is compared. The results demonstrate that the subgrade dynamic stress in the under-wheel area attenuates rapidly along the depth direction, while the subgrade dynamic stress in the midline area increases at first and subsequently decreases along the same direction. With the increase of subgrade dynamic stress, the shape of dynamic stress isosurface changes from bimodal to unimodal. Whether in the form of static or dynamic axle load, the subgrade service depth in the middle line area is larger than that in under-wheel area, and the influence of dynamic axle load on the subgrade service depth is greater than that of static axle load. The wheel distance and vehicle velocity have a significant influence on the subgrade service depth. With the increase of vehicle velocity, the subgrade service depth decreases. With the increase of wheel distance, the subgrade service depth decreases.

13

Study on stress characteristics of deep roadway bolt based on nonlinear dilatancy angle model

Lin Zenghua

Archives of Civil Engineering

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2022

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Vol. 68, nr 1

635--651

EN

Full-length bonded bolts are widely used in deep mining engineering and an in-depth understanding of their mechanical characteristics under complex and high ground stress conditions is of great significance for deep roadway support systems. Based on a quantitative GSI rating system of surrounding rocks and rock nonlinear dilatancy angle model, a nonlinear dilatancy angle model suitable for jointed rocks was developed. The Hoek-Brown strain-softening model parameters were transformed into equivalent Mohr-Coulomb strength parameters, and a numerical model of the deep roadway was constructed using FLAC3D numerical simulation software as a tool. The force characteristics of full-length bonded anchors under different constitutive model and dilatancy angle model conditions were analyzed, and the effects of different lengths of anchors on the stability of the surrounding rock were studied. The obtained results revealed a big difference between the axial forces of bolts calculated by strain-softening and ideal elastic-plastic models. It was also found that bolt shear force was less influenced by the strain-softening behaviors of surrounding rocks. Dilatancy angle greatly affected bolt axial force. Therefore, if the dilatancy angle was neglected, great errors would be created in the calculation results of supporting structure designs. The nonlinear dilatancy angle model of jointed rock masses more accurately captured the stress properties of bolts after field monitoring and analysis. The findings of the study can serve as a guide for calculating the stability of surrounding rocks in deep mining engineering.

14

Mechanical characteristics of ultra-shallow buried high-speed railway tunnel in broken surrounding rock during construction

Hao Shaoju, Fei Ruizhen, Yu Jia

Archives of Civil Engineering

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2022

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Vol. 68, nr 3

645--659

EN

The mechanical state of broken surrounding rock during the construction of ultra-shallow buried high-speed railway tunnel is very complicated, seriously affecting the construction safety. Taking Huying Xishan tunnel on Beijing-Shenyang Line as engineering background, MADIS/GTS NX numerical simulation and field test methods are used to analyze the characteristics of stress field, overall displacement, horizontal convergence of tunnel sidewalls and vault settlement during construction. The main mechanical characteristics of ultra-shallow buried high-speed railway tunnel with broken surrounding rock include: (1) After the stress redistribution, the stress concentration occurs at the boundary of the tunnel sidewall and surrounding rock, and the vertical displacement of tunnel vault and bottom appears obviously. (2) The horizontal displacement on both sides of the initial lining is obvious, while the horizontal displacement on the upper and lower support is small. The maximum lateral displacement of the initial lining is 1.71 cm, while the maximum vault settlement of the lower invert is 9.3 cm. (3) Both the horizontal convergence and the vault settlement increase with time. The growth rate is large in the early stage and tends to be stable in the later stage. (4) Compared with exponential and hyperbolic functions, the logarithmic function is most suitable for regression analysis of horizontal convergence and measured vault settlement data, and its fitting accuracy is higher than 90%.

15

Analysis of uniaxial compression of rock mass with parallel cracks based on experimental study and PFC2D numerical simulation

Yang Jie, Chen Haijun, Liangxiao Xiong, Xu Zhongyuan, Zhou Tao, Yang Changheng

Archives of Civil Engineering

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2022

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Vol. 68, nr 1

111--128

EN

In this study, the uniaxial compression test and the numerical simulation of the two-dimensional particle flow code (PFC2D) were used to study the mechanical properties and failure laws of rock masses with parallel cracks. The experiment considers the influences of crack length (l), crack angle (β1L β2), and numerical changes in the rock bridge length (ℎ) and bridge angle (α) on failures of rock-like specimens. The results indicate that the uniaxial compressive strength (UCS) of the rock-like specimens with parallel cracks decreases with increasing l under different α values. The smaller angle between the preset crack and the loadinging direction (β) resulting in higher UCS. In addition, a larger ℎ results in higher UCS in the specimen. When β1 or β2 is fixed, the UCS and elastic modulus of the specimen show an ‘M’ shape with an increase in α. Moreover, the crack growth or failure mode of samples with different l values is similar. When β1 or β2 is small, the failure of the specimen is affected by the development and expansion of wing cracks. If one of β1 and β2 is large, the failure of the specimen is dominated by the expansion and development of the secondary cracks which is generated at the tip of the prefabricated crack. Furthermore, when the angle between the prefabricated crack and the loading direction is β1 = 0º, the rock bridge is less likely to reach penetration failure as ℎ increases. Secondary crack connections between the prefabricated cracks occur only when α is small.

16

Second-order approximate refection coefficients of vertical transversely isotropic thin beds

Huang Peidong, Lu Jun, Wang Yun

Acta Geophysica

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2022

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Vol. 70, no 3

1155--1169

EN

Due to the periodicity and rhythmicity of sedimentation, short-term cycles are commonly developed in sedimentary strata. Under the assumption of a long seismic wavelength, such strata can be regarded as a seismic single thin bed with vertical transversely isotropic (VTI) characteristics. A thin interbed can be formed by the stacking of a series of isotropic and VTI single thin beds. In seismic inversion, the interference of multiples and mode-converted waves generated within and between thin beds and transmission losses are ignored. These interferences are hardly addressed in seismic data processing due to being submerged in first arrivals. In this work, to thin interbeds of isotropic and VTI single thin beds, we propose second order approximations of Kennett refection coefficients for PP-, SP-, PS-, and SS-waves, which consider the internal and interlayer wave propagation effects. The numerical analyses show that the proposed approximations are of high accuracy when the P-wave impedance difference in the VTI single thin bed is from−40 to 100% and of strong anisotropy. The proposed approximations can be used for the efficient and accurate simulation of the wavefields of media with thin interbedding, bringing great potential for the studies of the inversion methods for the internal property parameters of thin interbeds.

17

Deep-neural-networks-based approaches for Biot-squirt model in rock physics

Xiong Fansheng, Liu Jiawei, Guo Zhenwei, Liu Jianxin

Acta Geophysica

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2022

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Vol. 70, no 2

593--607

EN

A new cost-effective surrogate model using deep neural network (DNN) for seismic wave propagation in rocks saturated with fluid is presented. In this field, the dispersion/attenuation analysis and wave-field simulation are two key measurements which can be carried out by solving wave equations. The Biot–squirt (BISQ) equation is a classical wave propagation model in geophysical forward modeling and has been widely used. The solution of such equation, especially by numerical method, is often complex and time-consuming. In this work, a DNN model is trained with the dataset of velocity and inverse quality factor generated from BISQ model. The results show that the relative mean square error between the predictions of DNN model and that of BISQ model on the test sets are all less than 3%. It indicates that the DNN model has learned the high-dimensional space well and then can realize the dispersion/attenuation analysis for any given rock physical parameters. Besides, the other well-trained DNN model is used to obtain the simulation results with second-order accuracy according to results by finite difference scheme with first-order accuracy. It reveals that the fast wave-field simulation can be implemented once the results with lower accuracy are obtained.

18

Numerical simulation of the exit temperature pattern of an engine using a temperature-dependent turbulent Schmidt number

Kravchenko Igor F., Kozel Dmytro V., Yevsieiev Serhii A.

Transactions on Aerospace Research

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2021

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Nr 3 (264)

34--46

EN

This paper presents a numerical simulation for predicting the combustor exit temperature pattern of an aircraft engine, developed using the commercial fluid simulation software Ansys Fluent, which assumes a shape probability density function for the instantaneous chemistry in the conserved scalar combustion model and the standard k-ε model for turbulence. We found the compliance of the radial and circumferential non-uniformities of the exit temperature with the experimental data to be insufficient. To achieve much more accurate result, the mixing intensity was enhanced with respect to the initial calculation due to using the reduced value of the turbulent Schmidt number Sc. Numerical simulation was performed for values of the turbulent Schmidt number from Sc = 0.85 (default) up to Sc = 0.2, with results confirming the reduction of radial and circumferential non-uniformities of exit temperature. However, correlation between radial and circumferential non-uniformities is not admissible for these cases. Therefore, we propose to use a temperature-dependent formulation of the turbulent Schmidt number Sc, accounting for the increase in Sc number with increasing gas temperature. A user defined function (UDF) was used to implement the Sc number temperature dependence in Ansys Fluent. The numerical results for the proposed Schmidt number Sc temperature dependence were found to be in acceptable agreement with the experimental data both for radial and circumferential non-uniformities of the exit temperature pattern.

PL

W niniejszym artykule przedstawiono symulację numeryczną do przewidywania rozkładu temperatury przy wylocie z komory spalania silnika lotniczego, opracowaną przy użyciu komercyjnego oprogramowania Ansys Fluent. Przyjęto funkcję gęstości prawdopodobieństwa kształtu dla natychmiastowych reakcji chemicznych w zachowanym skalarnym modelu spalania oraz standardowy model k-ε dla turbulencji. Stwierdzono niewystarczającą zgodność niejednorodności promieniowych i obwodowych temperatury wylotowej z danymi eksperymentalnymi. W celu uzyskania bardziej dokładnego wyniku, intensywność mieszania została wzmocniona w stosunku do początkowych obliczeń w związku z zastosowaniem zredukowanej wartości turbulentnej liczby Schmidta Sc. Symulacje numeryczne zostały przeprowadzone dla wartości turbulentnej liczby Schmidta od Sc = 0,85 (domyślnej) do Sc=0,2, z wynikami potwierdzającymi redukcję niejednorodności promieniowej i obwodowej temperatury wylotowej. Jednakże korelacja pomiędzy niejednorodnością promieniową i obwodową nie jest dopuszczalna dla tych przypadków. Zaproponowano więc, żeby liczb turbulencji Schmidta Sc była ujęta w sposób uzależniony od temperatury, z rosnącym liczby Sc wraz ze wzrostem temperatury gazu. Posłużono się funkcją zdefiniowaną przez użytkownika (UDF) w oprogramowaniu Ansys Fluent w celu implementacji zależności liczby Sc od temperatury. Wyniki numeryczne otrzymane dla zaproponowanej zależności liczby Schmidta od temperatury były w akceptowalnej zgodzie z danymi eksperymentalnymi zarówno dla niejednorodności promieniowej, jak i obwodowej temperatury wylotowej.

19

Numerical analysis of laser-welded flange pipe joints in lap and fillet configurations

Danielewski Hubert, Skrzypczyk Andrzej, Zowczak Włodzimierz, Gontarski Dariusz, Płonecki Leszek, Wiśniewski Hubert, Soboń Dominika, Kalinowski Artur, Bracha Gabriel, Borkowski Krzysztof

Technical Transactions

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2021

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Vol. 118, iss. 1

art. no. e2021030

EN

This article presents a numerical analysis of laser-welded flange pipe joints. The presented results concern the welding of low carbon S235JR and stainless 316L steels using a CO2 laser in lap and fillet joint configurations. The estimation of welding parameters was achieved using Simufact Welding software and numerical simulation, where output power, feed rate, efficiency and intensity distribution (Gaussian parameter) were analysed. In accordance with the established model, a thermo-mechanical simulation was performed. The calculated joint geometries show good agreement with experiments; therefore, the obtained results were used to study selected joint properties of both joint types. Stress-strain distribution was estimated on the basis of thermomechanical analysis. Weld bead geometry obtained from numerical simulation was compared with the results from trial joints. The numerical model established for both joint configurations shows good agreement with experimental results and were assumed to be accurate. The results of the performed analysis shown some advantages of the use of this configuration of lap joints in flange pipe joints.

20

Influence of technical condition of control and measurement equipment on calibration results

Kawalec Małgorzata, Czerwińska Karolina, Pacana Andrzej

System Safety : Human - Technical Facility - Environment

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2021

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Vol. 3, nr 1

79--88

EN

In the paper there are analyzed the procedures used in the process of calibrating concerning control and measurement equipment. There was assumed the mathematical model of the measuring instrument which was then analyzed. The factors that result from the imperfect technical condition of the control and measurement equipment and may have an impact on the measurement results were also analyzed. Models of errors' models were assumed that may affect the calibration results. The static calibration of control and measurement equipment was analyzed. The results of numerical simulations concerning the static calibration of control and measurement equipment were presented, taking into account the linear and non-linear processing functions of the measurement equipment. The results of computations obtained for various models of processing functions were compared with each other and conclusions were drawn regarding the accuracy of the mapping of the measured quantity.