Study on Filtration Performance of Rotary Disc Filter with Different Filter Discs

2012 ◽  
Vol 610-613 ◽  
pp. 1265-1269
Author(s):  
Jun Xia Hou ◽  
You Chen Zhang
Keyword(s):  
Pressure Drop ◽  
Filtration Efficiency ◽  
Field Configuration ◽  
Operation Condition ◽  
Know How ◽  
Velocity Magnitude ◽  
Filter Disc ◽  
Distribution Uniformity ◽  
The One ◽  
Triangular Type

Rotary disc filter is widely used in industrial water treatment. There are two methods to improving the filtration efficiency, which are the higher filtration velocity and lower filtration pressure drop; while the type of the filter disc plays an important role on the performance of filtration, In order to know how the filter disc affect performance of filtration, simplified model was used. On this basis, rectangular and triangular type was numerically simulated with the CFD software Fluent, DPM model, then the flow field configuration, velocity magnitude, pressure drop through the filter medium and the distribution of the particles were obtained. Then, the simulation results were analyzed and the conclusion was achieved that was under the same operation condition and porous parameters. Filter disc with a triangular type has greater advantages than the one with a rectangular type in the aspects of lower pressure drop, velocity distribution uniformity and particle distribution, which can highly improve the filtration efficiency.

scholarly journals Study on the Leakage and Inter-Stage Pressure Drop Characteristics of Two-Stage Finger Seal

2021 ◽  
Vol 11 (5) ◽  
pp. 2239
Author(s):  
Hailin Zhao ◽  
Hua Su ◽  
Guoding Chen ◽  
Yanchao Zhang
Keyword(s):  
Pressure Drop ◽  
Pressure Difference ◽  
Radial Displacement ◽  
Mean Square ◽  
The Finite Element Method ◽  
Axial Pressure ◽  
Two Stage ◽  
One Stage ◽  
The One ◽  
Lower Contact

To solve the high leakage and high wear problems faced by sealing devices in aeroengines under the condition of high axial pressure difference, the two-stage finger seal is proposed in this paper. The finite element method and computational fluid dynamics (FEM/CFD) coupling iterative algorithm of the two-stage finger seal is developed and validated. Then the performance advantages of two-stage finger seal compared to the one-stage finger seal are studied, as well as the leakage and the inter-stage pressure drop characteristics of two-stage finger seal are investigated. Finally, the measure to improve the inter-stage imbalance of pressure drop of two-stage finger seal is proposed. The results show that the two-stage finger seal has lower leakage and lower contact pressure than the one-stage finger seal at high axial pressure difference, but there exists an inter-stage imbalance of pressure drop. Increasing the axial pressure difference and the root mean square (RMS) roughness of finger element can aggravate the imbalance of pressure drop, while the radial displacement excitation of rotor has little influence on it. The results also indicate that the inter-stage imbalance of pressure drop of the two-stage finger seal can be improved by increasing the number of finger elements of the 1st finger seal and decreasing the number of finger elements of the 2nd finger seal.

scholarly journals Electret Filters—From the Influence of Discharging Methods to Optimization Potential

Atmosphere ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 65
Author(s):  
Maximilian Kerner ◽  
Kilian Schmidt ◽  
Stefan Schumacher ◽  
Christof Asbach ◽  
Sergiy Antonyuk
Keyword(s):  
Fine Particles ◽  
Operating Time ◽  
Filtration Efficiency ◽  
Long Term Stability ◽  
Aerosol Filtration ◽  
Charge Decay ◽  
The One ◽  
Testing Standards ◽  
Discharge Efficiency

Electret filters are electrostatically charged nonwovens which are commonly used in aerosol filtration to remove fine particles from gases. It is known that the charge and thus also the filtration efficiency can degrade over time. Thus, many testing standards require to remove the charge by treatment with liquid isopropanol (IPA) or IPA-saturated air. However, the parameters influencing this discharge have not been completely clarified yet. The aim of this work was, on the one hand, to experimentally investigate the influence of the IPA treatment on different electret filters and, on the other hand, to show the optimization potential of electret filters with respect to efficiency and long-term stability by numerical simulations. The experiments revealed that the air permeability is a central influencing parameter. Small pores lead to a reduced discharge efficiency using liquid IPA, while both treatment methods are suitable for larger pores. The simulations showed that a homogeneous charge distribution within the filter depth is advantageous for the initial performance. In contrast, charge penetrating deeper in the filter medium delays the charge decay and thus increases the operating time, with the trade-off of a lower initial performance.

Numerical and Experimental Analysis of Turbulent Flow in Corrugated Pipes

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
Henrique Stel ◽  
Rigoberto E. M. Morales ◽  
Admilson T. Franco ◽  
Silvio L. M. Junqueira ◽  
Raul H. Erthal ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Pressure Drop ◽  
Turbulent Flow ◽  
Friction Factor ◽  
Turbulence Models ◽  
Reynolds Numbers ◽  
Velocity Magnitude ◽  
Geometric Configurations ◽  
Corrugated Surfaces ◽  
Friction Factors

This article describes a numerical and experimental investigation of turbulent flow in pipes with periodic “d-type” corrugations. Four geometric configurations of d-type corrugated surfaces with different groove heights and lengths are evaluated, and calculations for Reynolds numbers ranging from 5000 to 100,000 are performed. The numerical analysis is carried out using computational fluid dynamics, and two turbulence models are considered: the two-equation, low-Reynolds-number Chen–Kim k-ε turbulence model, for which several flow properties such as friction factor, Reynolds stress, and turbulence kinetic energy are computed, and the algebraic LVEL model, used only to compute the friction factors and a velocity magnitude profile for comparison. An experimental loop is designed to perform pressure-drop measurements of turbulent water flow in corrugated pipes for the different geometric configurations. Pressure-drop values are correlated with the friction factor to validate the numerical results. These show that, in general, the magnitudes of all the flow quantities analyzed increase near the corrugated wall and that this increase tends to be more significant for higher Reynolds numbers as well as for larger grooves. According to previous studies, these results may be related to enhanced momentum transfer between the groove and core flow as the Reynolds number and groove length increase. Numerical friction factors for both the Chen–Kim k-ε and LVEL turbulence models show good agreement with the experimental measurements.

Pressure drop axial distribution uniformity of the particle bed in the radial bed

2021 ◽  
Author(s):  
Tianhang Wu ◽  
Dewu Wang ◽  
Ruojin Wang ◽  
Bin Zhao ◽  
Meng Tang ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Axial Distribution ◽  
Distribution Uniformity ◽  
Particle Bed

Observations of the Earth’s resources

1969 ◽  
Vol 308 (1493) ◽  
pp. 173-182 ◽  
Keyword(s):  
Mineral Exploration ◽  
Geological Mapping ◽  
The Other ◽  
Ground Control ◽  
Great Contribution ◽  
Know How ◽  
Control Information ◽  
The World ◽  
The One ◽  
Effective Development

In attempting to present some observations on the kind of information on the Earth’s resources which may be obtained from spacecraft and space satellites, I think I should explain that I speak as a geographer with research interests in the field of biogeography/geobotany where I have been concerned with the use of vegetation in mineral exploration work and in the assessment of land potential for agricultural and other uses. In the course of this work I have come to appreciate major problems of regional or even continental dimensions and have become aware of the great potential offered by suitably equipped Earth resources satellites for providing information which would assist their solution. At the same time I have come to recognize the great contribution which Earth resources satellites can make in the fields of agriculture, forestry and conservation, topographical and geological mapping, hydrology, oceanography, land use and urban planning, to mention but a few. As a setting for my subsequent remarks I would like to state what I believe to be the relative positions of the U. S. A. and the U. S. S. R. on the one hand and this country and certain West European countries on the other with regard to the acquisition of information from Earth resources satellites. America and Russia have led the world in space research. They have the resources, the facilities and the technical know-how for placing spacecraft and satellites in orbit. For the effective development of Earth resources satellites, however, ground control information is essential. Here this country, together with member and former member countries of the Commonwealth possesses a body of people scattered through universities, government departments and organizations, commerce and industry whose firsthand knowledge of remote terrain in many parts of the world is unrivalled. This knowledge harnessed into an Earth resources satellites programme could enable this country to make a leading contribution to the development of the less developed parts of the world and at the same time materially assist the economy of this country.

scholarly journals Teaching and Learning Physics with Smartphones

2015 ◽  
Vol 17 (1) ◽  
pp. 31-50 ◽  
Author(s):  
M. Á. González ◽  
Manuel Á. González ◽  
M. Esther Martín ◽  
César Llamas ◽  
Óscar Martínez ◽  
...  
Keyword(s):  
Mobile Applications ◽  
Teaching And Learning ◽  
Low Cost ◽  
Positive Influence ◽  
Mobile Technologies ◽  
Traditional Learning ◽  
Know How ◽  
Measurement Devices ◽  
The One ◽  
Physics Experiments

The use of mobile technologies is reshaping how to teach and learn. In this paper the authors describe their research on the use of these technologies to teach physics. On the one hand they develop mobile applications to complement the traditional learning and to help students learn anytime and anywhere. The use of this applications has proved to have very positive influence on the students' engagement. On the other hand, they use smartphones as measurement devices in physics experiments. This opens the possibility of designing and developing low cost laboratories where expensive material can be substituted by smartphones. The smartphones' sensors are reliable and accurate enough to permit good measurements. However, as it is shown with some examples, special care must be taken here if one does not know how these apps used to access the sensors' data are programmed.

scholarly journals An Exploratory Study on Digital Transformation and Communication within the Moroccan Firms

2021 ◽  
pp. 92-101
Author(s):  
Houda Bassim
Keyword(s):  
Focus Group ◽  
Research Question ◽  
Empirical Studies ◽  
Digital Transformation ◽  
Policy Implications ◽  
Economic Sectors ◽  
Main Research ◽  
Know How ◽  
The One ◽  
Use Of Internet

Starting from the beginning of the third millennium, firms around the world in various economic sectors have been powerfully affected by the evolution process of digital technology and associated internet developments. The use of Internet and new digital technologies has been considered as a great revolution that will allow companies to benefit from new opportunities, in order to extend their activities and profitability, specifically through decreases in costs. While some companies have been investing rapidly in this new filed with the aim to take advantages of new opportunities, others seem to fail in following such developmental pattern. The main research question in the present paper is to understand perceptions of a sample of Moroccan firms operating in Casablanca, regarding the currently observed process of communication-based digital transformation worldwide. In this sense, our study turns to be exploratory, that is based on open interviews, within a focus group of professionals in the digital sector, rather than on collected data and effective orientations. Such exploratory analysis will be followed by upcoming empirical studies for a more comprehensive understanding of the profession. Our research paper aspires thereby to better grasping the process of digitalization of communication channels among the firms’ professionals, as selected. The ultimate target is to know how well firms are evolving in utilizing newly integrated digital tools, with respect to innovation and trademarks. To address this issue in an exploratory perspective, we have resorted to a focus group-based enquiry with six professionals of firms operating in Casablanca. The methodological framework relies upon qualitative data, as collected through the conducted interviews.      The major research finding of the present paper is that the pattern of digital transformation and communication seems to follow the one observed worldwide. Nevertheless, in spite of strong customers’ expectations, some hesitations and inadequate fundraising allocations partially explain the relative slowness of the process. In terms of policy implications, a suitable public-private partnership is still needed so as Morocco can foster digital transformation for economic and social development as well as improvements in the population’s standards of life, especially through investment in human capital for better attractivity-generating progress.

scholarly journals On the Possibilities of Researching the Marriage Policies of the Rurikids: The Case of Mstislav Fyodor Vladimirovich Monomakhovich

2018 ◽  
Vol 8 ◽  
pp. 91-110
Author(s):  
Dariusz Dąbrowski
Keyword(s):  
Middle Ages ◽  
Source Material ◽  
The Other ◽  
Primary Sources ◽  
Basic Question ◽  
The Political ◽  
Know How ◽  
Cultural Sphere ◽  
The Subject ◽  
The One

The main goal of the article is to present the possibilities and methods of research on the Rurikid’s matrimonial policy in the Middle Ages on the example of a selected group of princes. As the subject of studies were chosen Mstislav Vladimirovich and his children. In total, 12 matrimonial relationships were included. The analysis of the source material revealed very unfavorable phenomena from the perspective of the topic under study. The Rus’ primary sources gave information on the conclusion of just four marriages out of twelve. The next four matrimonial arrangement inform foreign sources (Scandinavian and Norman). It should be emphasized particularly strongly that – save for two exceptions of Scandinavian provenance – the sources convey no information whatsoever as regards the political aims behind this or that marriage agreement. It appears, then, that the chroniclers of the period and cultural sphere in question did not regard details concerning marriages (such as their circumstances or the reasons behind them) as “information notable enough to be worth preserving”. Truth be told, even the very fact of the marriage did not always belong to this category. Due to the state of preservation of primary sources the basic question arises as to whether it is possible to study the Rurikids’ matrimonial policy? In spite of the mercilessly sparse source material, it is by all means possible to conduct feasible research on the Rurikids’ marriage policy. One must know how to do it right, however. Thus, such studies must on the one hand be rooted in a deep knowledge of the relevant sources (not only of Rus’ provenance) as well as the ability to subject them to astute analysis; on the other hand, they must adhere to the specially developed methodology, presented in the first part of the article.

scholarly journals Competențele – expresie a rezultatelor școlare

2020 ◽  
Vol 46 (3) ◽  
pp. 93-99
Author(s):  
Elena Ramona Cenușe
Keyword(s):  
Educational System ◽  
Social Expectations ◽  
Educational Organization ◽  
Know How ◽  
Modern Education ◽  
The World ◽  
Education School ◽  
The One ◽  
Teaching Learning

In the Romanian educational system, the concept of competence is relatively new, its appearance and use being related to the curricular perspective of educational organization. Synthetically, competence can be defined as ”an ensamble of `savoir faire` (know how) and `savoir-e’tre’ (manners) allowing a good accomplishment of a role, of a function or of an activity” (D`Hainaut). The model of curricular projection centered on competences is meant to improve the efficiency of the internal structure of the curriculum, and of the teaching, learning and evaluation processes. This ”new educational target” aims to: -focus on the final learnig acquisitions; accenuate the action-related dimension of the pupil’s personality; clearly define the school offer according to the pupil’s interests and skills, and to social expectations. Thus it is possible for the modern education to assume an increasing autonomy for the one who learns, so that the differences between the world of education/school/ the didactic process and the real (social, professional) world may palpably decrease.

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