bluuebunny/crossref_metadata_2025 huggingface dataset:
The Research and Application of Microbial Degradation Technology on Heavy Oil Reservoir in Huabei Oilfield
Authors: Wang Guan , Wang Rui , Fu Yaxiu , Duan Lisha , Yuan Xizhi , Zheng Ya , Wang Ai , Huo Ran , Su Na
Published: June 2018

Mengulin sandstone reservoir in Huabei oilfield is low- temperature heavy oil reservoir. Recently, it is at later stage of waterflooding development. The producing degree of water flooding is poor, and it is difficult to keep yield stable. To improve oilfield development effect, according to the characteristics of reservoir geology, microbial enhanced oil recovery to improve oil displacement efficiency is researched. 2 microbial strains suitable for the reservoir conditions were screened indoor. The growth characteristics of strains, compatibility and function mechanism with crude oil were studied. Results show that the screened strains have very strong ability to utilize petroleum hydrocarbon to grow and metabolize, can achieve the purpose of reducing oil viscosity, and can also produce biological molecules with high surface activity to reduce the oil-water interfacial tension. 9 oil wells had been chosen to carry on the pilot test of microbial stimulation, of which 7 wells became effective with better experiment results. The measures effective rate is 77.8%, the increased oil is 1,093.5 tons and the valid is up to 190 days.
Modelling for Arsenic’s transferring process in Jiaozhou Bay
Authors: Yang Dongfang , Zhang Xiaolong , Wang Qi , Zhang Yuan , Li Haixia
Published: June 2018

This paper quantified the horizontal and vertical transferring processes of As in Jiaozhou Bay using investigation data in April and August 1988. Results showed that the horizontal absolute loss amounts of As contents in surface waters were 0.10-1.42 μg L-1, and the horizontal relative loss amounts in surface waters were 7.04%-25.00%, respectively. The horizontal absolute loss amounts of As contents in bottom waters were 0.04-1.00 μg L-1, and the horizontal relative loss amounts in bottom waters were 2.85%-41.66%, respectively. The vertical absolute dilution amounts of As contents were 0.02-0.28 μg L-1, and the vertical relative dilution amounts were 1.78%-16.66%. The vertical absolute accumulation amounts of Pb contents were 0.10-0.86 μg L-1, and the vertical relative accumulation amounts were 7.35%-35.83%. During the transferring processes through the bay mouth, no matter from the internal waters to the open water, or from the open waters to the internal waters, As contents in both surface and bottom layers were decreasing in a certain degree. The changes of As contents in surface and bottom waters were determined by the transferring distance of As in surface waters.
Regeneration of paint sludge and reuse in cement concrete
Authors: Feng Enqi , Sun Jitao , Feng Liming
Published: June 2018

Paint Sludge (PS) is a hazardous waste. Inappropriate disposal of PS might be harmful to public health and the environment. Various size of Paint Sludge Solid Powder (PSSP) particles have been produced by automatic processing equipment via dewatering, crushing, screening removing Volatile Organic Compounds (VOCs), and etc. Meanwhile, the test results show that PSSP is not a hazardous waste. Both flexural and compressive strength are increased by adding PSSP of polyurethane to cement concrete at a level of below 10% of cement weight. However, the strength has a significant reduction at a level of above 15% of cement weight. The reason for the increase of strength is probably due to a slow coagulation and copolymerization of PSSP and cement. The reduction is likely due to the self-reunion of PSSP.
Withdrawn article: The Removal of Perfluorinated Carboxylic Acids (PFCAs) on Zinc Anode by Electrocoagulation and the Effects of Chemical Flocculants
Authors: Xu Lei , Wu Jinhua
Published: June 2018

This article has been withdrawn by the authors. Request approved by the editors and the publisher on July 2, 2018.
Superhydrophobic Surface Fabricated on Carbon Steel Substrate by Zinc Electrodeposition for Prevention of Corrosion
Authors: Wang Liping , Zhuang Lei , Chen Gang , Leng Dong , wang Jian , Cheng Li , Liu Wei , Wang Jianbo , Hou Baorong
Published: June 2018

A facile, low cost, and relatively environmental friendly method was presented for the fabrication of superhydrophobic surface on carbon steel substrate. The superhydrophobic surface was obtained by zinc electrodeposition and chemical modification with ethanolic stearic acid. The wettability of the superhydrophobic surface was measured by a water contact angle (WCA) with a highest value of 155.7°. The morphology of the fabricated film was characterized by scanning electron microscopy (SEM). The chemical composition of the fabricated surface was analysed by energy dispersive spectrometer (EDS) and fourier transform infrared spectroscopy (FTIR), respectively. The corrosion resistance of the carbon steel substrate was measured by potentiodynamic polarization test in 3.5 wt% NaCl solution. The electrochemical measurements show excellent corrosion resistance, which may have promising applications in anticorrosion of carbon steel.
Comparison of Standards for Accessible Design between
America and China
Authors: Han Ying , Tao Xu Feng
Published: June 2018

Aiming at the accessibility design and environmental constructions of China, comparing the differences of codes for accessibility design between domestic and abroad. It’s including four aspects: the difference in audience of accessible design, content of the facilities, quantitative indexes and vision and hearing accessible design. It analyzed that the early stage of our country is backward in terms of accessibility and construction, mainly based on differences in values and professional education. In the end it put forward three suggestions to improve the construction of barrier-free environment in China.
CF60 Concrete Composition Design and Application on Fudiankou Xijiang Super Large Bridge
Authors: Qiu Yi Mei , Wen Sen Yuan , Chen Jun Xiang
Published: June 2018

Guangxi Wuzhou City Ring Road Fudiankou Xijiang super large bridge CF60 concrete is a new multi-phase composite high-performance concrete, this paper for the Fudiankou Xijiang bridge structure and characteristics of the project, in accordance with the principle of local materials and technical specification requirements, combined with the site conditions of CF60 engineering high performance concrete component materials, proportion and the technical performance, quantify the main physical and mechanical performance index. Analysis main influencing factors of the technical indicators, reasonable adjustment of concrete mix design parameters, and the use of technical means of admixture and multi-function composite admixture of concrete, obtain the optimal proportion of good work, process, mechanical properties stability and durability of engineering properties, recommend and verification of concrete mix; to explore the CF60 high performance concrete Soil in the Fudiankou Xijiang bridge application technology, detection and tracking the quality of concrete construction, concrete structure during the construction of the key technology and control points is proposed, evaluation of CF60 high performance concrete in the actual engineering application effect and benefit to ensure engineering quality of bridge structure and service life, and super long span bridge engineering construction to provide basis and reference.
Mechanical Performance Test of Rubber-Powder Modified Concrete
Authors: Zhang Yan Cong , Gao Ling Ling
Published: June 2018

A number of rubber cement concrete specimens that rubber powder dosage different were obtained using same cement, water and fine aggregates, by adjusting the dosage of rubber powder. Then it was used to research the influence of rubber powder dosage on performance of cement concrete by measuring its liquidity, strength and toughness. The results show that: when water-cement ratio was equal and rubber powder replacing the same volume sand, the fluidity of cement concrete almost linear increased with rubber powder dosage increasing. With dosage of rubber powder increasing, compressive strength and flexural strength reduced, but toughness linear growth trend when dosage of rubber powder less 30%.
Effect of Processing Parameters on 3D Printing of Cement - based Materials
Authors: Lin Jia Chao , Wang Jun , Wu Xiong , Yang Wen , Zhao Ri Xu , Bao Ming
Published: June 2018

3D printing is a new study direction of building method in recent years. The applicability of 3D printing equipment and cement based materials is analyzed, and the influence of 3D printing operation parameters on the printing effect is explored in this paper. Results showed that the appropriate range of 3D printing operation parameters: print height/nozzle diameter is between 0.4 to 0.6, the printing speed 4-8 cm/s with pumpage 9 * 10-2 m 3/ h.
Parametric Study on Dynamic Tension Behaviour of Offshore Pipeline for Deepwater S-lay Operation
Authors: Xu Pu , Gong Shun Feng , Zhang Ting , Chen Cheng
Published: June 2018

In recent years, higher demands for offshore pipeline design of deepwater installation are put forward. This paper mainly aims to investigate the influence of pipelay parameters on dynamic tension behaviour of deepwater S-lay pipeline to optimize the design of pipe structure and tensioner. A full finite element model for deepwater S-lay systems is developed to simulate the dynamic response of offshore pipeline from the pipelay vessel via stinger to the seabed. The influences of water depth, outer diameter and submerged self-weight of the pipe, and stinger length on the dynamic tension behaviour of the pipeline have been quantitatively studied. A strong relevance between the axial tension of offshore pipeline and pipelay parameters is observed, which offers very intuitive evidences for the design of pipe structure and tensioners.
Application of Tessellation in Architectural Geometry Design
Authors: Chang Wei
Published: June 2018

Tessellation plays a significant role in architectural geometry design, which is widely used both through history of architecture and in modern architectural design with the help of computer technology. Tessellation has been found since the birth of civilization. In terms of dimensions, there are two- dimensional tessellations and three-dimensional tessellations; in terms of symmetry, there are periodic tessellations and aperiodic tessellations. Besides, some special types of tessellations such as Voronoi Tessellation and Delaunay Triangles are also included. Both Geometry and Crystallography, the latter of which is the basic theory of three-dimensional tessellations, need to be studied. In history, tessellation was applied into skins or decorations in architecture. The development of Computer technology enables tessellation to be more powerful, as seen in surface control, surface display and structure design, etc. Therefore, research on the application of tessellation in architectural geometry design is of great necessity in architecture studies.
Research on Green Construction Technology Applied at
Guangzhou Hongding Building Project
Authors: Lou Yong Zhong
Published: June 2018

The green construction technology is the embodiment of sustainable development strategy in the construction industry, and it is a new construction mode which requires a higher environmental protection. Based on the Hongding building project, this paper describes the application and innovation of technical in the process of implementing green construction in the project, as well as the difficulties and characteristics in the specific practice; .The economic and social benefits of green construction are compared to the traditional construction model; .The achievements and experience of the green construction technology are summarized in the project; The ideas and methods in the process of implementing green construction are abstracted; some suggestions are put forward for the development of green construction.
Experimental Study on Impermeability of Recycled Concrete
Authors: Wang Shao Zhen , Yang Jian Gong , Wei Lu
Published: June 2018

Recycled concrete is a kind of concrete which is constructed by crushing and removing the building waste and concrete blocks and mixing them according to a certain proportion after grading. In this study, the applicability of recycled concrete is studied only in terms of impermeability.
Using BIM Technology to Optimize the Traditional Interior Design Work Mode
Authors: Zhu Ning Ke
Published: June 2018

the development of BIM technology and application in the field of architecture design has produced results, but BIM technology and application in the field of interior design is still immaturity because of construction and decoration engineering separation. The article analyzes the problems that BIM technology lead to the interior design work mode optimization, from the 3D visualization work environment, real-time collaborative design mode, physical analysis design mode, information integration design mode state the application in interior design.
An Antenna with Good Electrical Properties and Artistic Shape for Lampshade
Authors: Zhou Chang , Yu Yang , Ji Chen
Published: June 2018

An improved transparent antenna based on transparent ceramic MgAl2O4 with artistic shape which can be used as lampshade is presented in this paper. A great peak gain and good pattern can be achieved by choosing the property shape and optimizing location of the feed of the antenna. Simulation results indicate that this antenna can achieve return loss >-15dB, peak gain >8 dBi at 2 GHz and 40% relative impedance bandwidth. Both the electrical properties and artistic shape of the antenna are realized and the lampshade which made by MgAl2O4 meets the requirement for communication, decoration and high light transmission.
3D numerical simulation of flow field with incompletely flaring gate pier in large unit discharge and deep tail water project
Authors: Zhao Zhou , Junxing Wang
Published: June 2018

Limited by large unit discharge above the overflow weir and deep tail water inside the stilling basin, the incoming flow inside stilling basin is seriously short of enough energy dissipation and outgoing flow still carries much energy with large velocity, bound to result in secondary hydraulic jump outside stilling basin and scour downstream river bed. Based on the RNG k-ε turbulence model and the VOF method, this paper comparatively studies flow field between the conventional flat gate pier program and the incompletely flaring gate pier program to reveal energy dissipation mechanism of incomplete flaring gate pier. Results show that incompletely flaring gate pier can greatly promote the longitudinally stretched water jet to laterally diffuse and collide in the upstream region of stilling basin due to velocity gradients between adjacent inflow from each chamber through shrinking partial overflow flow chamber weir chamber, which would lead to large scale vertical axis vortex from the bottom to the surface and enhance mutual shear turbulence dissipation. This would significantly increase energy dissipation inside stilling basin to reduce outgoing velocity and totally solve the common hydraulic problems in large unit discharge and deep tail water projects.
Study on the Evaluation Scheme of Emergency Response Capacity of The Three Gorges - Gezhouba Dam
Authors: Li Renbo
Published: June 2018

according to different navigation condition and environment of traffic emergency strategy, using fuzzy algorithm to the actual situation of ship parameters of the actual situation assessment, the result will be according to the instruction from the data graph for the actual operation, effectively avoid risk. Ships that should be properly arranged in a non-emergency session should avoid the concentration of traffic in heavy traffic and cause unnecessary security risks. The general function of ship safety is established by mathematical modeling, and the application function is used to control the ship. Ensure safe navigation.
Analysis and Research on the Optimal Allocation of Regional Water Resources
Authors: rui-chao Xi , yu-jie Gu
Published: June 2018

Starting from the basic concept of optimal allocation of water resources, taking the allocation of water resources in Tianjin as an example, the present situation of water resources in Tianjin is analyzed, and the multi-objective optimal allocation model of water resources is used to optimize the allocation of water resources. We use LINGO to solve the model, get the optimal allocation plan that meets the economic and social benefits, and put forward relevant policies and regulations, so as to provide theoretical which is basis for alleviating and solving the problem of water shortage.
Electricity market liberalization under the power of customer value evaluation and service model
Authors: Bai Hong Kun , Wang Jiang Bo , Song Da Wei
Published: June 2018

After the power reform No. 9 was released in March 2015, the state officially released the Opinions on the Implementation of the Reform on the Power Sales Side. From this document, we can see that the openness of sales of social capital to the electricity business, the sales side of the market competition through multiple ways to train the main competitors, the result is more users have the right to choose, sales service quality and user energy levels will significantly improve. With the gradual promotion of the electricity sales market, the national electricity sales companies have been established one after another. In addition to power grid outside the power generation companies, energy-saving service companies and distributed power companies may become the main selling power, while industrial parks, commercial complex, large residential area, industrial and commercial users, large industrial users in the new electricity demand appearing The new changes, some power customers have also self-built distributed power supply, installation of energy storage devices or equipment to participate in the transformation of the electricity market. The main body of the electricity sales market has gradually evolved from the traditional electricity generation main body to the multi-unit main body and emerged new value points. Therefore, the electricity sales companies need to establish a power customer value evaluation method and service mode to adapt to the new electricity reform, Provide supportive decision support.
Analysis and Assessment of Operation Risk for Hybrid AC/DC Power System based on the Monte Carlo Method
Authors: Hu Xiaojing , Li Qiang , Zhang Hao , Guo Ziming , Zhao Kun , Li Xinpeng
Published: June 2018

Based on the Monte Carlo method, an improved risk assessment method for hybrid AC/DC power system with VSC station considering the operation status of generators, converter stations, AC lines and DC lines is proposed. According to the sequential AC/DC power flow algorithm, node voltage and line active power are solved, and then the operation risk indices of node voltage over-limit and line active power over-limit are calculated. Finally, an improved two-area IEEE RTS-96 system is taken as a case to analyze and assessment its operation risk. The results show that the proposed model and method can intuitively and directly reflect the weak nodes and weak lines of the system, which can provide some reference for the dispatching department.
The Analysis for Energy Consumption of Marine Air Conditioning System Based on VAV and VWV
Authors: Xu Sai Feng , Yang Xing Lin , Le Zou Ying
Published: June 2018

For ocean-going vessels sailing in different areas on the sea, the change of external environment factors will cause frequent changes in load, traditional ship air-conditioning system is usually designed with a fixed cooling capacity, this design method causes serious waste of resources. A new type of sea-based air conditioning system is proposed in this paper, which uses the sea-based source heat pump system, combined with variable air volume, variable water technology. The multifunctional cabins’ dynamic loads for a ship navigating in a typical Eurasian route were calculated based on Simulink. The model can predict changes in full voyage load. Based on the simulation model, the effects of variable air volume and variable water volume on the energy consumption of the air-conditioning system are analyzed. The results show that: When the VAV is coupled with the VWV, the energy saving rate is 23.2%. Therefore, the application of variable air volume and variable water technology to marine air conditioning systems can achieve economical and energy saving advantages.
Reforming the Exhaust Passage of Low-pressure Cylinder for 330MW Steam Turbine
Authors: Yan Tao , Cai Wen , Chen Wen , Lu Jin , Hong-yan Yang
Published: June 2018

In concern of the velocity distribution of the exhaust passage of 330MW turbine is not uniform, which results in higher the upper temperature difference of the condenser and higher exhaust pressure. It is introduced in this article that based on mathematical simulation, steam-equalizing equipment is augmented at the exhaust area of the condenser which makes the decrease in the steam resistance, much more uniform velocity distribution, and the increase of the heat transfer coefficient. By comparison of the condenser performance test before the amending and after, the result shows that after the amending, the upper temperature difference of the condenser and the exhaust pressure decreases dramatically.
Modeling and Simulation of Hydropower Station Diversion System's characteristic line method by introducing water head to flow feedback
Authors: Guangwen Xu , Xi Li , Ze Yao
Published: June 2018

To solve the damping problem of water hammer wave in the modeling method of water diversion system of hydropower station, this paper introduces the feedback regulation technology from head to flow, that is: A fixed water head is taken out for flow feedback, and the following conclusions are obtained through modeling and simulation. Adjusting the feedback coefficient F of the water head to the flow rate can change the damping characteristic of the system, which can simulate the attenuation process of the water shock wave in the true water diversion pipeline. Even if a small feedback coefficient is introduced, the damping effect of the system is very obvious, but it has little effect on the amplitude of the first water shock wave after the transition process. Therefore, it is feasible and reasonable to introduce water head to flow rate feedback coefficient F in hydraulic turbine diversion system.
Study on the construction of Intelligent Courier Station Model
Authors: zhao Ce , lu Jia xin , li Zhuang zhuang , shao Zi rong , pi Kun yi
Published: June 2018

Campus Express is an important window to observe the city consumption logistics service "last kilometer".The research on Campus Express service is not only conducive to campus environment improvement and service quality promotion, but also provides all types of community, agglomeration areas such as urban terminal "last kilometer" logistics with reference.This article first proposed the main problems of campus express service,analyzed the mode of smart express station and finally built a smart express station.
Study on the optimization allocation of wind-solar in power system based on multi-region production simulation
Authors: Xu Zhicheng , Yuan Bo , Zhang Fuqiang
Published: June 2018

In this paper, a power supply optimization model is proposed. The model takes the minimum fossil energy consumption as the target, considering the output characteristics of the conventional power supply and the renewable power supply. The optimal capacity ratio of wind-solar in the power supply under various constraints is calculated, and the interrelation between conventional power supply and renewable energy is analyzed in the system of high proportion renewable energy integration. Using the model, we can provide scientific guidance for the coordinated and orderly development of renewable energy and conventional power sources.
The Study on the Optimization of Container Multimodal Transport Business Process in Shandong
Authors: Wang Fengmei , Gong Xiaoyi , Ni Yingying , Zhan Jun , Che Huiping
Published: June 2018

Shandong is a coastal city with good location advantages. As a hub port for international trade goods and a port of transhipment, shandong's demand for multimodal transport is more urgent. By selecting the suitable non-water port and the multimodal transport carrier to improve the efficiency of multimodal transport, the purpose of saving the time of logistics is achieved, thus reducing the logistics cost.It branch out through Shandongt, and it can reach the central region of China, can reach the Western remote area ,too. This paper puts forward the optimization scheme of the business process of container multimodal transport. The optimization of freight forwarding business process is analyzed. The multimodal transport model in Shandong was designed. Finally, the optimal approach of multimodal transport in Shandong is put forward.
Prospects for the application of radiometric methods in the measurement of two-phase flows
Authors: Zych Marcin
Published: June 2018

The article constitutes an overview of the application of radiometric methods in the research of two-phase flows: liquid-solid particles and liquid-gas flows. The methods which were used were described on the basis of the experiments which were conducted in the Water Laboratory of the Wrocław University of Environmental and Life Sciences and in the Sedimentological Laboratory of the Faculty of Geology, Geophysics and Environmental Protection, AGH-UST in Kraków. The advanced mathematical methods for the analysis of signals from scintillation probes that were applied enable the acquisition of a number of parameters associated with the flowing two-phase mixture, such as: average velocities of the particular phases, concentration of the solid phase, and void fraction for a liquid-gas mixture. Despite the fact that the application of radioactive sources requires considerable carefulness and a number of state permits, in many cases these sources become useful in the experiments which are presented.
Experimental study on the formation of subaqueous barchan dunes in closed conduits
Authors: Alvarez Carlos A. , Franklin Erick
Published: June 2018

The present paper reports the formation of subaqueous barchan dunes by analyzing the temporal evolution of their main geometrical characteristics (width W, length L and horn lengths Lh). After certain time, the dunes reach an equilibrium state and it is possible to study the relation between W versus L, and the dependence of the dune velocity on L. The barchan dunes were formed from spherical glass and zirconium beads. An initial conical heap of beads was placed on the bottom wall of a rectangular channel and it was entrained by a water turbulent flow. The evolution of the dunes was filmed with a CCD camera placed above the channel and mounted on a traveling system. Our results show that after a characteristic time the dune shape does not change and it travels with a roughly constant velocity. Once the equilibrium state is reach, W and L are measured, showing linear dependence. Furthermore, we show that the dune velocity Vd scales with the inverse of the dune length.
Wet stack – Analysis of condensation
Authors: Bartoš Ondřej , Havlík Jan , Hrdlička František
Published: June 2018

The aim of the paper is to introduce the study of condensation processes in the wet stack. Because of the high cost of reheating (due to the loss of useful heat of flue gases), wet stacks are being considered for new or retrofit applications of wet flue gas desulfurization (FGD) systems around the word. Wet stacks, in contrast to classical chimneys where flue gases are heated up to avoid any condensation, works with wet flue gases and condensation is welcome. The study provides a quantitative analysis of the condensation.
Time-Fractional Fourier Law in a finite hollow cylinder under Gaussian-distributed heat flux
Authors: Blasiak Slawomir
Published: June 2018

This paper presents the solution of the theoretical model of heat conduction based on timefractional Fourier equation for a finite hollow cylinder treated with heat flux on one of the front surfaces. A derivative of fractional order in the Caputo sense was applied to record the temperature derivative in time. The distributions of temperature fields in the hollow cylinder were determined with the use of Fourier-Bessel series, as surface functions of two variables (r,θ) . The distributions of temperature fields were determined using analytical methods and applying integral transformation methods. The Laplace transform with reference to time, the Fourier finite cosine transform with reference to axial coordinatezand Marchi-Zgrablich transform for radial coordinater. The fractional heat conduction equation was analysed for 0 < α ≤ 2
The influence of flow modification on air and PCM temperatures in an accumulative heat exchanger
Authors: Borcuch Marcin , Musiał Michał , Sztekler Karol , Kalawa Wojciech , Gumuła Stanisław , Stefański Sebastian
Published: June 2018

The paper presents the influence of flow modification on the operation of an accumulative heat exchanger. This device can be used as a regenerator in ventilation and air supply systems. A heat exchanger uses ceresine (a mixture of paraffins) as a phase change material (PCM). The aim of this research was to determine the effect of flow modification on temperature distribution and pressure drops in the device. The introduction contains a short description of the test stand used, including the accumulative heat exchanger, the guide vanes, and the locations of measurement and control equipment. We found that additional objects limited vortex structures, increased the inside temperature, and dropped the pressure along the heat exchanger. Guidelines for further research are proposed and briefly discussed.
Mathematical model of compact type evaporator
Authors: Borovička Martin , Hyhlík Tomáš
Published: June 2018

In this paper, development of the mathematical model for evaporator used in heat pump circuits is covered, with focus on air dehumidification application. Main target of this ad-hoc numerical model is to simulate heat and mass transfer in evaporator for prescribed inlet conditions and different geometrical parameters. Simplified 2D mathematical model is developed in MATLAB SW. Solvers for multiple heat and mass transfer problems - plate surface temperature, condensate film temperature, local heat and mass transfer coefficients, refrigerant temperature distribution, humid air enthalpy change are included as subprocedures of this model. An automatic procedure of data transfer is developed in order to use results of MATLAB model in more complex simulation within commercial CFD code. In the end, Proper Orthogonal Decomposition (POD) method is introduced and implemented into MATLAB model.
Comparison of turbulence models and CFD solution options for
a plain pipe
Authors: Canli Eyub , Ates Ali , Bilir Sefik
Published: June 2018

Present paper is partly a declaration of state of a currently ongoing PhD work about turbulent flow in a thick walled pipe in order to analyze conjugate heat transfer. An ongoing effort on CFD investigation of this problem using cylindrical coordinates and dimensionless governing equations is identified alongside a literature review. The mentioned PhD work will be conducted using an in-house developed code. However it needs preliminary evaluation by means of commercial codes available in the field. Accordingly ANSYS CFD was utilized in order to evaluate mesh structure needs and asses the turbulence models and solution options in terms of computational power versus difference signification. Present work contains a literature survey, an arrangement of governing equations of the PhD work, CFD essentials of the preliminary analysis and findings about the mesh structure and solution options. Mesh element number was changed between 5,000 and 320,000. k-ϵ, k-ω, Spalart-Allmaras and Viscous-Laminar models were compared. Reynolds number was changed between 1,000 and 50,000. As it may be expected due to the literature, k-ϵ yields more favorable results near the pipe axis and k-ωyields more convenient results near the wall. However k-ϵ is found sufficient to give turbulent structures for a conjugate heat transfer problem in a thick walled plain pipe.
The effect of mixed convection on the thermal field of horizontal channel flow
Authors: Devera Jakub , Hyhlík Tomáš
Published: June 2018

An experimental study was conducted to investigate the thermal field of low-speed flow of moistair in a horizontal rectangular duct, uniformly heated from below (Poiseuille–Benard flow). Averaged temperature fields were measured in vertical mid-plane using thermocouples. The buoyancy-induced secondary flow is interacting with forced Poiseuille flow which leads to complex flow behaviour with flow reversal along the top surface. Two types of bottom boundary conditions were examined: aluminium plate (only heat transfer) and water film (simultaneous heat and mass transfer) heated to the same temperature. Presence of mass transfer causes stronger transient behaviour above the bottom surface and enhancing of heat transfer, but the overall character of the thermal field remains the same as in case of heat transfer only.
Complete Description of Forces Acting on a Flying Beach Volleyball
Authors: Dumek Jan , Šafařík Pavel
Published: June 2018

Complete description of all forces acting on a flying Beach Volleyball was made based on measurements in the wind tunnel. Forces (drag, lift and side force) were measured for different angle of attack β which varies from 0° to 47°. Velocity region was from 10 to 25 m/s and revolution region was from 0 to 12.5 rps. Moments (Roll, Yaw, Pitch) were detected. Results are described by means of non-dimensional numbers, such as Reynolds number Re, spin s, drag CD, lift CL and side force CS coefficients. Differences in results of CD, CL and CS were detected for various angle β and are further described in the article. Conclusions of the investigation can be utilized 1st by ball producers for practical use in development, 2nd for sport Methodist to build more exact methodology for Beach Volleyball, 3rd in basic and applied aerodynamic research.
An Investigation on the Effects of Different Stratifications on Negatively Buoyant Jets
Authors: Ferrari Simone , Badas Maria Grazia , Querzoli Giorgio
Published: June 2018

Negatively buoyant jets develop when fluids are released upwards into a lighter fluid or, vice versa, downwards into a heavier fluid. There are many engineering applications, such as the discharge, via submerged outfalls, of brine from desalination plants into the sea. Some concerns are raised about the potential negative environmental impacts of this discharge. The increase in salinity is the major cause for environmental impact, as it is very harmful to many marine species. The diffusers for brine discharge are typically inclined upwards, to increase the path before the brine reaches the sea bottom, as it tends to fall downwards driven by negative buoyancy. The negatively buoyant jet that develops conserves axisymmetry only when released vertically, so that it is not possible to use the well-known equations for axisymmetric jets. The main target of this paper is to investigate on a laboratory model the effects of different stratifications on the features of negatively buoyant jets. This has been done via a LIF (Light Induced Fluorescence) technique, testing various release angles on the horizontal and densimetric Froude numbers. Except for the initial stage, a different widening rate for the upper boundary and the lower boundary has been highlighted.
Experimental verification of the properties of pneumatic elements
Authors: Fojtášek K. , Dvořák L. , Chmura Š.
Published: June 2018

The subject of this article is experimental verification of properties of pneumatic elements. These elements have been a part of equipment for measuring of rotary air motors parameters. When comparing the measured data with the mathematical model, there were slight variations. The main objective is to verify the correct functioning of these pneumatic elements, comparing the measured results with theoretical data from the catalogs of manufacturers and determine their potential impact on the entire measuring system.
Cable vibration caused by wind
Authors: Golebiowska Irena , Peszynski Kazimierz
Published: June 2018

The paper briefly presents selected basic kinds of excitation of cable vibration caused by dynamic effect of wind. It describes the aerodynamic phenomena such as vortex excitation, wind-rain excitation, galloping and buffeting. Cables are structures which are characterised by low internal damping, low rigidity and low weight, so they are not capable of total excitation energy dissipation, hence they can reach large amplitudes of vibration. Large amplitude of vibration causes excessive stress, thereby lowering the safety of the structure.
Effect of flow velocity on the process of air-steam condensation in a vertical tube condenser
Authors: Havlík Jan , Dlouhý Tomáš
Published: June 2018

This article describes the influence of flow velocity on the condensation process in a vertical tube. For the case of condensation in a vertical tube condenser, both the pure steam condensation process and the air-steam mixture condensation process were theoretically and experimentally analyzed. The influence of steam flow velocity on the value of the heat transfer coefficient during the condensation process was evaluated. For the condensation of pure steam, the influence of flow velocity on the value of the heat transfer coefficient begins to be seen at higher speeds, conversely, this effect is negligible at low values of steam velocity. On the other hand, for the air-steam mixture condensation, the influence of flow velocity must always be taken into account. The flow velocity affects the water vapor diffusion process through non-condensing air. The presence of air significantly reduces the value of the heat transfer coefficient. This drop in the heat transfer coefficient is significant at low velocities; on the contrary, the decrease is relatively small at high values of the velocity.
Volumetric flow rate in simulations of microfluidic devices
Authors: Kovalčíková KristÍna , Slavík Martin , Bachratá Katarína , Bachratý Hynek , Bohiniková Alžbeta
Published: June 2018

In this work, we examine the volumetric flow rate of microfluidic devices. The volumetric flow rate is a parameter which is necessary to correctly set up a simulation of a real device and to check the conformity of a simulation and a laboratory experiments [1]. Instead of defining the volumetric rate at the beginning as a simulation parameter, a parameter of external force is set. The proposed hypothesis is that for a fixed set of other parameters (topology, viscosity of the liquid, …) the volumetric flow rate is linearly dependent on external force in typical ranges of fluid velocity used in our simulations. To confirm this linearity hypothesis and to find numerical limits of this approach, we test several values of the external force parameter. The tests are designed for three different topologies of simulation box and for various haematocrits. The topologies of the microfluidic devices are inspired by existing laboratory experiments [3 - 6]. The linear relationship between the external force and the volumetric flow rate is verified in orders of magnitudes similar to the values obtained from laboratory experiments.
Droplets size evolution of dispersion in a stirred tank
Authors: Kysela Bohus , Konfrst Jiri , Chara Zdenek , Sulc Radek , Jasikova Darina
Published: June 2018

Dispersion of two immiscible liquids is commonly used in chemical industry as wall as in metallurgical industry e. g. extraction process. The governing property is droplet size distribution. The droplet sizes are given by the physical properties of both liquids and flow properties inside a stirred tank. The first investigation stage is focused on in-situ droplet size measurement using image analysis and optimizing of the evaluation method to achieve maximal result reproducibility. The obtained experimental results are compared with multiphase flow simulation based on Euler-Euler approach combined with PBM (Population Balance Modelling). The population balance model was, in that specific case, simplified with assumption of pure breakage of droplets.
Simulation of transonic flows through a turbine blade cascade with various prescription of outlet boundary conditions
Authors: Louda Petr , Straka Petr , Příhoda Jaromír
Published: June 2018

The contribution deals with the numerical simulation of transonic flows through a linear turbine blade cascade. Numerical simulations were carried partly for the standard computational domain with various outlet boundary conditions by the algebraic transition model of Straka and Příhoda [1] connected with the EARSM turbulence model of Hellsten [2] and partly for the computational domain corresponding to the geometrical arrangement in the wind tunnel by the γ-ζ transition model of Dick et al. [3] with the SST turbulence model. Numerical results were compared with experimental data. The agreement of numerical results with experimental results is acceptable through a complicated experimental configuration.
Rainbow schlieren measurements in underexpanded jets from square supersonic micro nozzles
Authors: Maeda Hiroaki , Fukuda Hikaru , Nakao Shinichiro , Miyazato Yoshiaki , Ishino Yojiro
Published: June 2018

The slightly underexpanded free jet issued from a supersonic micro nozzle with a design Mach number of 1.5 and a square shape of 1 mm × 1 mm at the nozzle exit has been experimentally investigated using the rainbow schlieren deflectometry combined with the computed tomography where the nozzle operating pressure ratio is held constant at 4.0. Density fields in the free jet obtained from the rainbow schlieren deflectometry are the vortex sheet theory proposed by Tam. It is shown that there is good quantitative agreement between experiment and theory. It is shown that the rainbow schlieren deflectometry is a useful tool for studying the three-dimensional structure of shock containing free jets from micro-scale supersonic nozzles.
Internal flow characteristics in scaled pressure-swirl atomizer
Authors: Malý Milan , Sapík Marcel , Jedelský Jan , Janáčková Lada , Jícha Miroslav , Sláma Jaroslav , Wigley Graham
Published: June 2018

Pressure-swirl atomizers are used in a wide range of industrial applications, e.g.: combustion, cooling, painting, food processing etc. Their spray characteristics are closely linked to the internal flow which predetermines the parameters of the liquid sheet formed at the discharge orifice. To achieve a better understanding of the spray formation process, the internal flow was characterised using Laser Doppler Anemometry (LDA) and high-speed imaging in a transparent model made of cast PMMA (Poly(methyl methacrylate)). The design of the transparent atomizer was derived from a pressure-swirl atomizer as used in a small gas turbine. Due to the small dimensions, it was manufactured in a scale of 10:1. It has modular concept and consists of three parts which were ground, polished and bolted together. The original kerosene-type jet A-1 fuel had to be replaced due to the necessity of a refractive index match. The new working liquid should also be colourless, non-aggressive to the PMMA and have the appropriate viscosity to achieve the same Reynolds number as in the original atomizer. Several liquids were chosen and tested to satisfy these requirements. P-Cymene was chosen as the suitable working liquid. The internal flow characteristics were consequently examined by LDA and high-speed camera using p-Cymene and Kerosene-type jet A-1 in comparative manner.
Two-dimensional quantitative visualization of isolator shock trains by rainbow schlieren deflectometry
Authors: Matsuyama Atsushi , Nakao Shinichiro , Ono Daisuke , Miyazato Yoshiaki , Kashitani Masashi
Published: June 2018

The rainbow schlieren deflectometry is effective in studying quantitatively the density fields in shock-containing free jets at high precision and high spatial resolution. However, there has been no practical application of rainbow schlieren deflectometry for shock trains in a confined duct. Therefore, in the present study, the rainbow schlieren deflectometry is applied to the flow field including a shock train in a constant-area duct where just upstream of the shock train the freestream Mach number is 1.34, the unit Reynolds number is 5.39 × 107 m-1, and the boundary layer displacement thickness is 0.149 mm. As a result, a two- dimensional density field of the shock train is for the first time quantitatively displayed and the fine structure of the shock train is illustrated as a color gradation representation.
Fluidic Vectoring of a Planar Incompressible Jet Flow
Authors: Mendez Miguel Alfonso , Scelzo Maria Teresa , Enache Adriana , Buchlin Jean-Marie
Published: June 2018

This paper presents an experimental, a numerical and a theoretical analysis of the performances of a fluidic vectoring device for controlling the direction of a turbulent, bi-dimensional and low Mach number (incompressible) jet flow. The investigated design is the co-flow secondary injection with Coanda surface, which allows for vectoring angles up to 25° with no need of moving mechanical parts. A simple empirical model of the vectoring process is presented and validated via experimental and numerical data. The experiments consist of flow visualization and image processing for the automatic detection of the jet centerline; the numerical simulations are carried out solving the Unsteady Reynolds Average Navier- Stokes (URANS) closed with the k - ω SST turbulence model, using the PisoFoam solver from OpenFOAM. The experimental validation on three different geometrical configurations has shown that the model is capable of providing a fast and reliable evaluation of the device performance as a function of the operating conditions.
Influence of boundary conditions on the hydrodynamic forces of an oscillating sphere
Authors: Mirauda Domenica , Negri Marco , Martinelli Luca , Malavasi Stefano
Published: June 2018

The design of submerged structures in sea currents presents certain problems that are not only connected to the shape of the obstacle but also to the number of acting forces as well as the correct modelling of the structures dynamic response. Currently, the common approach is that of integrated numerical modelling, which considers the contribution of both current and structure. The reliability of such an approach is better verified with experimental tests performed on models of simple geometry. On the basis of these considerations, the present work analyses the hydrodynamic forces acting on a sphere, which is characterised by a low mass ratio and damping. The sphere is immersed in a free surface flow and can oscillate along the streamwise and transverse flow direction. It is located at three different positions inside the current: close to the channel bottom, near the free surface and in the middle, and equally distant from both the bottom and free surface. The obtained results for different boundaries and flow kinematic conditions show a relevant influence of the free surface on the hydrodynamic forces along both the streamwise and transverse flow directions.
Influence of the ambient temperature on the cooling efficiency of the high performance cooling device with thermosiphon effect
Authors: Nemec Patrik , Malcho Milan
Published: June 2018

This work deal with experimental measurement and calculation cooling efficiency of the cooling device working with a heat pipe technology. The referred device in the article is cooling device capable transfer high heat fluxes from electric elements to the surrounding. The work contain description, working principle and construction of cooling device. The main factor affected the dissipation of high heat flux from electronic elements through the cooling device to the surrounding is condenser construction, its capacity and option of heat removal. Experimental part describe the measuring method cooling efficiency of the cooling device depending on ambient temperature in range -20 to 40°C and at heat load of electronic components 750 W. Measured results are compared with results calculation based on physical phenomena of boiling, condensation and natural convection heat transfer.