scholarly journals Application of Polyhedral Spherical Packing Precipitation Technology in Water Plant Reform

2019 ◽  
pp. 10-17
Author(s):  
LI Ya wen ◽  
Cheng Sheng gao ◽  
Li Ru yi
Keyword(s):  
Rural Areas ◽  
Engineering Application ◽  
Sphere Packing ◽  
Solid Particles ◽  
Inertia Force ◽  
Spherical Packing ◽  
Sedimentation Tank ◽  
Inclined Tube ◽  
New City ◽  
Pass Through

On the basis of micro flocculation interception sedimentation technology, polyhedral spherical packing is used as intercepting material in sedimentation tank. The process utilizes the characteristics of polyhedral sphere to make flocs and water move relatively, and continuously change the direction of water flow to produce turbulent vortices. When water moves in a vorticity, solid particles move relative to the flow along the radial direction under the action of centrifugal inertia force, which provides for the radial collision of particles with different scales along the vortices. Under these conditions, the micro flocs collide and aggregate continuously as they pass through the blades, and the concentration of alum in the water is increased. Finally, the precipitation is removed under the action of gravity. The process is applied to the reconstruction of Miluo New City Waterworks, and the original inclined pipe sedimentation tank is retained and put into operation. The results show that the turbidity of effluent from polyhedral spherical sedimentation tank can reach below 2NTU, while that from inclined tube sedimentation tank is above 2NTU. The treatment effect of polyhedral sphere on low turbidity water is better than that of inclined tube, which provides a reference for the transformation of small and medium-sized water plants in rural areas. Keywords: Polyhedral sphere packing; Interception sedimentation; Technological transformation; Engineering application

Turbine Nozzle Insert Clogging With Seeded Medium Size Particles

2020 ◽  
Author(s):  
Hongzhou Xu ◽  
Kevin Liu ◽  
Michael Fox
Keyword(s):  
Pressure Ratio ◽  
Leading Edge ◽  
Bimodal Distribution ◽  
Solid Particles ◽  
Medium Size ◽  
Air Filtration ◽  
Engine Operation ◽  
Coating Layers ◽  
Pass Through ◽  
Cooling Air

Abstract Gas turbine nozzle cooling often uses inserts to intentionally distribute cool air through impingement holes to hot spots, especially at leading edge regions of stage-1 nozzles. Owing to the variations of engine operation environment, inlet air filtration systems, upstream component surface coating layers, and oil/air sealing material choices, solid particles could enter the engine from outside or be generated inside from rotor rubbing, seal debris, peeled off coating layers or rusty surfaces, etc. These particles and their agglomerates can be carried by airflow to enter nozzle inserts and clog impingement holes, which may reduce cooling air significantly, resulting in severe engine failures. To reduce the risk of insert clogging, particle separation devices and filtration mesh screens have been implemented in front of nozzle inlets to prevent larger particles from entering. Therefore, designing appropriate nozzle insert hole sizes becomes very critical to let smaller particles pass through and exhaust from the nozzle exit. This experimental study focuses on finding a correlation between the impingement hole sizes of a nozzle insert and their clogged areas caused by seeded fine and medium size particles of Fe2O3 under specific pressure ratios. A nozzle insert was first chosen, and a single row of cylindrical impingement holes was machined at the leading edge of the insert. Measurements were conducted in a pressurized vessel at Reynolds numbers from 7,000 to 62,000 and pressure ratios from 1.01 to 1.10. Results indicate that insert clogging is a strong function of the hole size, particle size, and pressure ratio. The tested particles showed a bimodal distribution of fine and medium sizes, and the medium size particles played a major role in clogging holes. A clogging diagram with 3 zones (fully clogged zone, partially clogged zone, and no clogging zone) is generated from the test data, which can provide important design criteria for sizing the insert leading edge impingement holes to reduce the risk of clogging.

A New Instrument in Cavitation Research: The Cavitation Susceptibility Meter

1982 ◽  
Vol 104 (2) ◽  
pp. 136-141 ◽  
Author(s):  
D. M. Oldenziel
Keyword(s):  
Tensile Strength ◽  
Vapor Pressure ◽  
Liquid Flow ◽  
Gas Bubbles ◽  
Solid Particles ◽  
Gas Content ◽  
Dissolved Gas ◽  
New Instrument ◽  
Pass Through ◽  
Onset Of Cavitation

The rate of cavitation in liquid flow appears to be linked to the concentration and size distribution of gas bubbles and “weak” nuclei in the liquid used, as well as to the dissolved gas content. Consequently, the onset of cavitation is related to the tensile strength of the liquid, rather than the vapor pressure. The tensile strength of the liquid depends on the amount of gas in gas pockets (i.e., gas bubbles and gas absorbed at solid particles) suspended in the liquid and the shape of these gas pockets. An instrument will be described, which measures the tensile strength in a direct way. In this method a sample of liquid is made to pass through a pressure well, the minimum pressure of which can be adjusted.

scholarly journals WIND WAVES TRANSMISSION THROUGH POROUS BREAKWATER

1980 ◽  
Vol 1 (17) ◽  
pp. 18
Author(s):  
Stanislaw R. Massel ◽  
Piotr Butowski
Keyword(s):  
Average Rate ◽  
Wind Waves ◽  
Mass Term ◽  
Momentum Equation ◽  
Solid Particles ◽  
Long Waves ◽  
Experimental Investigations ◽  
Inertia Force ◽  
Rigorous Approach ◽  
In Series

Rubble - mound breakwaters are designed to protect exposed marine areas from excessive wave activity. The resulting interaction of the incident waves with the rubble units is extremely complex due to the variable reflective and frietional properties of the permeable structure. In the past decade considerable effort has been expended to derive rational methods for of such type structure. The theoretical and experimental investigations have been focused especoialy on the prediction of the reflection and transmission of regular waves incident to breakwater. Sollitt and Cross /^^^Z/ presented the analytical approach to the problem based on the assumption that the original nonlinear governing equation of the wave motion into porous media may be replaced by a linear one so as to give the same average rate of dissipation/Lorentz approximation/. Under the assumption that severe wave conditions for most breakwaters correspond to relatively long waves, the considerably simple solutions were developed by Kondo and Toma /1972/ and in series of papers by Madsen and co-authors /\97k, 1977, 1978/. Madsen s solutions follows rather a physical than mathematical rigorous approach to the problem. The momentum equation evaluated him explains the influence of the inertia force associated with the unsteady flow around the solid particles. Very careful analytical examination of this problem for the long waves past the narrow gaps and holes has been presented by Mei at al. /197**/. The study indicate that apparent mass term can be ignored in most practical cases.

Farmers, Fishers, and Sportsmen

2001 ◽  
Author(s):  
John T. Cumbler
Keyword(s):  
New England ◽  
Rural Areas ◽  
Turn Of The Century ◽  
Connecticut River ◽  
Edward Bellamy ◽  
The North ◽  
Fictitious Character ◽  
New City ◽  
The City ◽  
The Town

At the end of the nineteenth century, Edward Bellamy, one of the Connecticut River Valley’s most famous literary residents, created a fictional character who wanted to avoid “industrial existence” and instead “all day to climb these mighty hills, feeling their strength” and to “happen upon little brooks in hidden valleys.” Bellamy planned for his protagonist “to breathe all day long the forest air loaded with the perfume of the forest trees.” The wanderings of this turn-of-the-century fictitious character through thick forests and deserted hills reflects the changes engendered in the valley with the coming of industrial cities and the abandonment of hillside farms. When Bellamy was born in 1850 at Chicopee Falls in western Massachusetts, the region was in the process of deforestation and had few areas that were not intensely farmed. Yet as Bellamy himself noted in an 1890 letter to the North American Review, “the abandonment of the farm for the town” had become all too common. Deserted farms became one of the themes Bellamy sketched out in his notes for the novel. Bellamy had his character live in an “abandoned farmhouse. . . . The farmhouse was one of the thousands of deserted farms that haunted the roadsides of the sterile back districts of New England.” In viewing the depopulated countryside as a retreat from industrial existence, Bellamy’s character represented the fate of late-nineteenthand early-twentieth-century New Englanders. Increasingly, urbanized New Englanders began to look to rural areas not as sources of food or resources of necessity but as places to contemplate nature and practice fishing and hunting as sport. As rural areas, particularly on the hills and up the valleys, became less populated, farmers there lost much of their political voice. New city voices now became more important in the conversation about resource conservation. What farmers saw as abandoned and ruined farms, urban and suburban naturalists saw as rural retreats from the tensions and pollution of the cities. For these interlopers, rural New England represented a romantic ideal of a past they or their ances tors put behind them when they moved to the city.

Influence of the presence of open three-dimensional fiber structures on solid liquid cake filtration of limestone

2020 ◽  
pp. 152808372094927
Author(s):  
Markus Babin ◽  
Bo Liu ◽  
Gernot Krammer
Keyword(s):  
Filter Cake ◽  
Fine Particles ◽  
Three Dimensional ◽  
Solid Particles ◽  
Filter Medium ◽  
Dimensional Structure ◽  
Cake Filtration ◽  
Air Blowing ◽  
Pass Through ◽  
Set Up

Solid particles in a suspension can be separated effectively through cake filtration where the filter medium is decisive particularly during the initial stage when particle breakthrough can be high. To improve the filtrate quality and throughput, filtration aid additives are used, which are known to alter filter cake structure and thus reduce flow resistance but, in forming clusters, also stabilize fine particles that would otherwise pass through the filter (cake) easily. However, filter aids are costly, increase the complexity of the system and may have adverse effects for subsequent mechanical drying and washing. Instead of supplying additives, four alternative filter media were tested exhibiting an open, three-dimensional structure that reached deeply into the depth of the forming filter cake. An aqueous limestone suspension was investigated in a conventional laboratory test unit. Composite filter medium set-up delivered up to 15% faster filtration. The results indicate that the fiber structures give better performance that reach far into the cake and are oriented not only axially but also radially. In contrary to the initial hypothesis that an axial fiber structure would produce additional drainage channels along the surface of these fibers and thus support but deliquoring, the actual deliquoring performance with air blowing appeared to be slightly less efficient. Although not investigated yet, cake discharge with a 3-D filter layer present poses an additional challenge, rendering the concept of composite filters unpractical.

Particle Transmission Through a Turbo Pump

1998 ◽  
Vol 41 (3) ◽  
pp. 31-34 ◽  
Author(s):  
Patrick Kinney ◽  
David Pui ◽  
Benjanin Liu
Keyword(s):  
Atmospheric Pressure ◽  
Vacuum Pump ◽  
Solid Particles ◽  
Vacuum System ◽  
Small Particles ◽  
Particle Detectors ◽  
Pass Through ◽  
Turbo Pump

Experiments were performed to determine if small particles are capable of passing through a turbo-molecular vacuum pump. A test aerosol was generated at atmospheric pressure and injected into the vacuum system upstream of the turbo pump. Particles were measured immediately upstream and downstream of the turbo pump using two laser-based vacuum particle detectors. Tests were performed with solid and liquid particles. Solid particles were found to pass through the pump, although the efficiency of transmission is not known. Liquid particles did not pass through the pump. These results indicate that vacuum particle counters employed downstream of turbo pumps may be sensitive to upstream particle levels.

Effects of Hydroxyapatite/Silk Fibroin/Chitosan Ratio on Physical Properties of Scaffold for Tissue Engineering Application

2016 ◽  
Vol 872 ◽  
pp. 261-265 ◽  
Author(s):  
Wassanai Wattanutchariya ◽  
Atitaya Oonjai ◽  
Kittiya Thunsiri
Keyword(s):  
Tissue Engineering ◽  
Physical Properties ◽  
Pore Structure ◽  
Silk Fibroin ◽  
Engineering Application ◽  
Porous Scaffolds ◽  
Tissue Engineering Application ◽  
Pass Through ◽  
Near Future ◽  
Interconnected Pore

This study reports the effects of the mixing ratio of hydroxyapatite (HA), silk fibroin (SF) and chitosan (CS) on the physical properties of the scaffold used in tissue engineering. Experimental design based on mixture design was implemented to investigate the degradation rate of the scaffolds fabricated from various ratios of those biomaterials. Furthermore, pore morphology and pore size were evaluated to confirm the compatibility of the scaffold topography for cell growth and adhesion. The results from the study showed that all ratios, except pure HA solution, can be fabricated into porous scaffolds with an interconnected pore structure and appropriate pore sizes to allow all types of human cells to pass through. Furthermore, the scaffold solutions with high CS ratio resulted in a uniform pore structure and lower rates of biodegradation. Therefore, CS is recommended as the main structure because it provides the highest resistance to biodegradation. The scaffolds from various ratios may be applied for different tissue replacements in the near future.

scholarly journals Energy Valuation of Animal Excrement in the Production of Biogas: Study of the Biomethanation of Rabbit Dungs in Laboratory in Senegal

2018 ◽  
Vol 1 (2) ◽  
Keyword(s):  
Climate Change ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Rural Areas ◽  
Energy Production ◽  
Fish Farming ◽  
Methane Yield ◽  
Controlled Environments ◽  
Pass Through

Domestic biogas is increasingly seen as an alternative solution to the access to energy in rural areas in Africa. However, incubation will necessarily pass through the use of accessible substrates and high methanogenic power. The aim of this study is to produce biogas based on rabbit dungs in semi-controlled environments. The methodology used is essentially based on the determination of the methanogenic potential of rabbit dungs, dungs co-digested with sludge and market waste and the methane yield. The assessment of the production of the different mixtures in the laboratory shows that it is the combination of dungs and market waste which gives the best methane yield with 85.8%, followed by combinations of dungs and sludge, dungs and sewage sludge which respectively produce 66.5% and 66.2% of methane. Finally, the dungs alone recorded a 50% yield of methane. The biofertilizers obtained from the anaerobic digestion of dungs can be valued as a fertilizer in agriculture and as a nutrient in fish farming. Thereby, the valorization of rabbit dungs in the production of biogas can open interesting perspectives in energy production and in the fight against climate change (greenhouse gas).

scholarly journals A Case Study on Settling Process in Inclined-Tube Gravity Sedimentation Tank for Drip Irrigation with the Yellow River Water

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1685 ◽  
Author(s):  
Keyuan Wang ◽  
Yunkai Li ◽  
Shumei Ren ◽  
Peiling Yang
Keyword(s):  
River Water ◽  
Drip Irrigation ◽  
Yellow River ◽  
Fine Sediment ◽  
The Yellow River ◽  
Sedimentation Tank ◽  
Inclined Tube ◽  
Gravity Sedimentation ◽  
Tank Bottom ◽  
Settling Process

A sedimentation tank which can remove fine sediment with low cost and high efficiency is of great significance for the wide application of drip irrigation techniques with the Yellow River water. In this study, the settling process of an inclined-tube gravity sedimentation tank which has high removal efficiency for fine particles in practice was thoroughly investigated. The sediment concentration distribution in the tank was measured by an optical back-scattering turbidimeter. The sediment thickness at the tank bottom was also measured. In addition, the size grading of sediment deposited at different positions on the tank bottom and at different heights in the inclined tubes was also measured by a laser particle size analyzer. It was found that the removal efficiency of fine sediment was 64.7–69.7% in the inclined-tube gravity sedimentation tank, which was higher than that of the sedimentation tank without inclined tubes (with a sediment removal rate of 20.7–32%). The sediment was mainly deposited in the flow adjustment area and settlement area with inclined tubes. A suitable height for the inclined tubes was 70–90 cm. In addition, the water inlet, baffle, and overflow weir in the tank negatively affected the fine sediment settling in two experiment cases. The experimental results enhance our understanding of the sedimentation characteristics in the tank, and indicate the direction for the subsequent structural optimization of the tank.

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