Letteratura scientifica selezionata sul tema "Clogging behavior"
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Articoli di riviste sul tema "Clogging behavior"
1
Zhou, Bo, Di Wang, Tianzhi Wang e Yunkai Li. "Chemical Clogging Behavior in Drip Irrigation Systems Using Reclaimed Water". Transactions of the ASABE 61, n. 5 (2018): 1667–75. http://dx.doi.org/10.13031/trans.12902.
Testo completoAbstract (sommario):
Abstract. Reusing reclaimed water in agricultural irrigation has become an effective way to alleviate water shortages in agriculture. However, the multiple substances in reclaimed water and their coupling effects easily lead to emitter clogging when using drip irrigation technology. The microorganisms present in reclaimed effluents secrete extracellular substances and absorb large amounts of solid particles, ions, nutrients, and organic matter and thus become the main part of the clogging substance. Meanwhile, traditional drip irrigation systems converted from irrigation to both irrigation and fertilization and the water-fertilizer coupling effects result in more chemical precipitation. Determining whether the chemical process has a significant impact on clogging and understanding the mechanism of this process was considered a difficult and important research question. For this reason, an indoor experiment, under a controllable environment, for drip irrigation emitter clogging using both reclaimed water with three Ca2++Mg2+ concentrations and groundwater was carried out. Several precise testing methods, such as x-ray diffraction, were applied to identify the mineral components in the clogging substances, and their characteristics and impacts on clogging were systematically explored. The results indicated that the emitter clogging characteristics were coincident under different treatments when using reclaimed water, and chemical precipitates were found in all treatments. Higher Ca2++Mg2+ concentrations led to more serious emitter clogging. The discharge ratio variation and Christiansen coefficient of uniformity for the reclaimed water treatments were lower than those for the groundwater treatment. Meanwhile, the total weights of the clogging substances were 5.6% to 58.8% higher. There were sufficient mineral components in the clogging substances, and they were identified as quartz, silicate, carbonate, and salt. Their contents all showed significant linear correlations with the degree of emitter clogging (R2 > 0.64, p < 0.05), which indicated that mineral components increased as the system continued operation. Among them, salt and silicate were linearly correlated to quartz contents, as they mainly originated from the water used for drip irrigation. However, carbonate contents increased in an exponential pattern with quartz contents (R2 > 0.67, p < 0.01), which demonstrated that carbonate was the main mineral component formed during the clogging process and the key component that increased clogging. The results obtained in this study provided insights into the chemical clogging process and the targeted chemical precipitates to be dealt with when using reclaimed water for drip irrigation. Keywords: Chemical precipitation, Emitter, Microirrigation clogging, Reclaimed water application.
2
Jung, Jongwon, Hongsig Kang, Shuang Cindy Cao, Riyadh I. Al-Raoush, Khalid Alshibli e Joo Yong Lee. "Effects of Fine-Grained Particles’ Migration and Clogging in Porous Media on Gas Production from Hydrate-Bearing Sediments". Geofluids 2019 (23 maggio 2019): 1–11. http://dx.doi.org/10.1155/2019/5061216.
Testo completoAbstract (sommario):
The migration of fine particles in porous media has been studied for different applications, including gas production from hydrate-bearing sediments. The clogging behavior of fine particles is affected by fine particle-pore throat size ratio, fine particle concentration, ionic concentration of fluids, and single/multiphase fluid flow. While previous studies presented valuable results, the data are not enough to cover a broad range of particle types and sizes and pore throat size in natural hydrate-bearing sediments. This paper presents a novel micromodel to investigate the effects of fine particle-pore throat size ratio, fine concentration, ionic concentration of fluid, and single/multiphase fluid flow on clogging or bridging in porous media. The results show that (1) the concentration of fine particles required to form clogging and/or bridging in pores decreased with the decrease in fine particle-pore throat size ratio, (2) the effects of ionic concentration of fluid on clogging behaviors depend on the types of fine particles, and (3) fine particles prefer to accumulate along the deionized water- (DW-) CO2 interface and migrate together, which in turn easily causes clogging in pores. As a result, multiphase fluid flow during gas production from hydrate-bearing sediments could easily develop clogging in pore throats, where the relative permeability of DW-CO2 in porous media decreases. Accordingly, the relatively permeability of porous media should be evaluated by considering the clogging behavior of fines.
3
Liu, Yingchao, Jingbin Wang, Yanjun Liu, Lihong Li, Heng Zhou e Xuefeng She. "CFD-DEM simulation of powders clogging in a packed bed with lateral inlet". International Journal of Chemical Reactor Engineering 19, n. 3 (8 febbraio 2021): 251–59. http://dx.doi.org/10.1515/ijcre-2020-0215.
Testo completoAbstract (sommario):
Abstract Clogging behavior of powder particles in packed bed is a longstanding engineering challenge in many industrial processes, of particular interests to ironmaking reactors. In this work, a CFD-DEM model was developed to investigate the powders clogging in a packed bed with lateral inlet. The flow and clogging of powders of varying gas velocities flowing through the packed bed were studied. The results showed that two kinds of clogging powders inside the porous can be observed. One is mainly due to mechanical interactions between powder particles, which can create arches on packed bed and stop the flow. When the powders form a bridge across the pore throat of the orifice, the bottleneck of void space becomes the starting point for blockage formation. The other represents a part of clogging powders which is due to drag force and friction between one small particle rolling very slowly on the surface of large particles whose spacing is close to the diameter of powders. The powders distribution, mechanical behavior and pressure drop were also discussed. The findings of this work provides a fundamental understanding on clogging behavior of powders in a packed bed with lateral inlet, and is useful for industry processes’ understanding and optimization.
4
Guo, Wei, Xuedong Guo, Xing Chen, Yingsong Li, Zhun Li, Yin An e Wenting Dai. "Laboratory Evaluation of the Permeability Durability of Utilization of Oil Shale Waste as Fine Aggregate in Open Grade Friction Course in Seasonal Frozen Regions". Applied Sciences 10, n. 1 (6 gennaio 2020): 419. http://dx.doi.org/10.3390/app10010419.
Testo completoAbstract (sommario):
Open graded friction course (OGFC), as a highly permeable mixture, has the characteristics of good friction and splash-and-spray reduction during rainstorms. The limitations of the use of such mixtures include the fact that they are affected by poor durability, including strength and permeability durability issues. In a previous study, oil shale waste, as a fine aggregate in the mixture (with a particle size less than 4.75 mm), could effectively improve the overall properties of OGFC, but the permeability durability was not clear. Thus, a comprehensive investigation of the permeability durability of oil shale waste as a fine aggregate is essential to achieving a better understanding in order to promote its engineering application. In this paper, the long-term permeability when using oil shale waste as a fine aggregate in OGFC was systematically investigated based on a self-developed laboratory physical clogging procedure. The test results illustrated the effectiveness of the utilization of oil shale waste as a fine aggregate in terms of permeability durability. A comprehensive index of the clogging coefficient containing mass, porosity and permeability coefficient was proposed based on gray relation entropy theory, the physical clogging model of COF-OGFC (OGFC containing oil shale waste filler) was established and the clogging speed of COF-OGFC was quantified based on the Mistcherlich growth model. The analysis showed that there is an essential difference in the clogging behavior of permeable pavement in the spring and summer. The maximum clogging degree of the permeable pavement in summer is about 40% higher than that in spring, while the clogging rate is much lower than in the spring, at only about 14%, which indicates that the clogging behavior of permeable asphalt pavement in spring is mostly in the rapid clogging mode, and that in summer is mostly in a slow deposition clogging mode. Moreover, the test results showed that the most important influences on the spring clogging behavior of COF-OGFC were the sandy clogging materials and particle sizes ranging from 150 μm to 1180 μm, which can be used to provide a reference for the design of anti-slip sand.
5
Lu, Guoyang, Zijian He, Pengfei Liu, Zhihao He, Gaoyang Li, Hao Jiang e Markus Oeser. "Estimation of Hydraulic Properties in Permeable Pavement Subjected to Clogging Simulation". Advances in Civil Engineering 2022 (21 gennaio 2022): 1–13. http://dx.doi.org/10.1155/2022/5091895.
Testo completoAbstract (sommario):
Permeable pavements are often affected by pore clogging, which leads to their functional failure and reduced service life. However, the clogging mechanism and its impact on the permeability and complex pore microstructures in pervious pavement remain unclear. The aim of current study is to quantify the clogging behavior in pervious pavement materials and carry out investigations on the development of pore characteristics and permeability. Novel polyurethane-bound pervious mixture (PUPM) was adopted for comparative study in present research with conventional Porous Asphalt (PA). The Aachen Polishing Machine (APM) was selected to perfectly serve as a simulator for clogging process of pavement in the actual service condition. The permeability and pore microstructure of the pervious pavement material were then characterized by using the self-developed permeameter and X-ray Computed Tomography (CT) scanning, respectively. The development of pore characteristics in terms of clogging was experimentally illustrated. Based on the pore characteristics, the flow behavior of PUPM subjected to different clogging periods was predicted based on the developed non-Darcy flow model. The developed experiments and analysis can further strengthen the understanding of the clogging mechanism within the porous pavement material. The results can also serve for the optimization of the pervious pavement design in the engineering application.
6
Muehlbauer, Jeffrey D., Theodore A. Kennedy, Adam J. Copp e Thomas A. Sabol. "Deleterious effects of net clogging on the quantification of stream drift". Canadian Journal of Fisheries and Aquatic Sciences 74, n. 7 (luglio 2017): 1041–48. http://dx.doi.org/10.1139/cjfas-2016-0365.
Testo completoAbstract (sommario):
Drift studies are central to stream and river ecological research. However, a fundamental aspect of quantifying drift — how net clogging affects the accuracy of results — has been widely ignored. Utilizing approaches from plankton and suspended sediment studies in oceanography and hydrology, we examined the rate and dynamics of net clogging across a range of conditions. We found that nets clog nonlinearly over time and that suspended solid concentrations and net mesh size exerted a strong effect on clogging rates. Critically, net clogging introduced unpredictable biases in resultant data due to the inaccuracies in water volume estimates introduced by progressive clogging. This renders the widespread approach to linearly “correct” for clogging inadequate. Using a meta-analysis of 77 drift studies spanning 25 years, we demonstrate that the detrimental effects of net clogging are routinely unappreciated, even though the results of most of these studies were likely affected by clogging. We close by describing an approach for avoiding net clogging, which will increase the accuracy and reproducibility of results in future freshwater, lotic drift studies.
7
Alimohammadi, Hossein, Kristina Vassiljeva, Eduard Petlenkov, Martin Thalfeldt, Alo Mikola, Tuule Mall Kull e Ahmet Köse. "Gray Box Time Variant Clogging behaviour and Pressure Drop Prediction of the Air Filter in the HVAC System". E3S Web of Conferences 246 (2021): 10002. http://dx.doi.org/10.1051/e3sconf/202124610002.
Testo completoAbstract (sommario):
Identification and prediction of clogging behavior in heating, ventilation, and air conditioning (HVAC) filters is crucial to avoid issues such as system overheating, energy waste, lower indoor air quality, etc. Researchers are focusing more on the particle loading characteristics of a filter medium in a laboratory environment under steady-state conditions, fixed particle concentrations, area of porosity, dust feed and volumetric flow rate. However, recent research still shows uncertainties in modeling as well as the implementation problems of constructing the HVAC laboratory test bench and equipment. In addition, subjects such as non-uniform particle deposition depreciation of the condition and various type of mechanical filters such as fibrous, fabric, granular, and membrane filter or electrostatic filters which typically used in HVAC systems perform under some assumptions and still need more research. The studies become even more difficult acquiring a large number of time-varying and noisy signals. Another approach among studies is data-driven knowing that Building Automation System (BAS) is not equipped with appropriate sensor measuring the clogging, it is needed to drive the clogging mathematical model from the pressure drop signal. This paper bridges the gap between particle-size study and black box modeling of HVAC filter which has not received much attention from authors. The proposed method assumes that the pressure drop is the result of two time-varying functions; f(t), which represents the dynamics of clogging and, g(t), which refers to dynamics of remained terms. The exponential and polynomial of second order functions are proposed to express the clogging behavior. The software package based on Particle Swarm Optimization Artificial Bee Colony (PSOABC) algorithm, is developed and implemented to estimate the coefficients of the clogging functions based on smallest RMSE, high coefficient of correlation and acceptable tracking. Five Air Handling Unit (AHUs) are selected for practical verification of the model and the results show that the applied method can successfully predict clogging and pressure drop behaviour of HVAC filters.
8
Licciardello, Feliciana, Alessandro Sacco, Salvatore Barbagallo, Delia Ventura e Giuseppe Luigi Cirelli. "Evaluation of Different Methods to Assess the Hydraulic Behavior in Horizontal Treatment Wetlands". Water 12, n. 8 (14 agosto 2020): 2286. http://dx.doi.org/10.3390/w12082286.
Testo completoAbstract (sommario):
While there have been numerous studies on the rate and development of clogging in horizontal subsurface treatment wetlands (HSTWs) and, consequently, the effects on its hydraulic characteristics, research has not shown a clear understanding of the processes. The existing methods for measuring the impact of clogging provide limited information on the extension and degree of the phenomenon. This study aimed to evaluate the capacity of various measurement techniques to assess the degree and variation in space and time of clogging in HSTWs. Hydraulic conductivity at saturation (Ks) measurements were conducted using a newly implemented scheme, the drainage equation method, and traditional tracer tests, which were carried out in a full-scale HSTW system, located in Sicily, Italy, during 2019. After five years of operation, the results highlighted a severe decrease in Ks (<1000 m day−1) in the inlet zone (despite the fact that the filter gravel was replaced in 2017), a very high reduction of Ks along the central path inside the bed, a nonuniform flow through the HSTW, the presence of stagnant zones, and a reduction of the porosity of the bed gravel. Nonetheless, the mean values of the physical–chemical and bacteriological parameters at the hybrid treatment wetland (hybrid TW) outlet indicated that the partial clogging had no significant effect on the quality of the discharged water. Moreover, the results obtained using the different measurement techniques (in terms of both the Ks values and the flow distribution inside the bed) were consistent with each other and with results obtained previously for the same system. Finally, the most efficient combination of methods to assess clogging in HSTWs was identified.
9
Zhu, Fei, Xiangping Wu, Yijun Lu e Jiandong Huang. "Understanding Penetration Attenuation of Permeable Concrete: A Hybrid Artificial Intelligence Technique Based on Particle Swarm Optimization". Buildings 14, n. 4 (21 aprile 2024): 1173. http://dx.doi.org/10.3390/buildings14041173.
Testo completoAbstract (sommario):
Permeable concrete is a type of porous concrete with the special function of water permeability, but the permeability of permeable concrete will decrease gradually due to the clogging behavior arising from the surrounding environment. To reliably characterize the clogging behavior of permeable concrete, particle swarm optimization (PSO) and random forest (RF) hybrid artificial intelligence techniques were developed in this study to predict the permeability coefficient of permeable concrete and optimize the aggregate mix ratio of permeable concrete. Firstly, a reliable database was collected and established to characterize the input and output variables for the machine learning. Then, PSO and 10-fold cross-validation were used to optimize the hyperparameters of the RF model using the training and testing datasets. Finally, the accuracy of the developed model was verified by comparing the predicted value with the actual value of the permeability coefficients (R = 0.978 and RMSE = 1.3638 for the training dataset; R = 0.9734 and RMSE = 2.3246 for the testing dataset). The proposed model can provide reliable predictions of the clogging behavior that permeable concrete may face and the trend of its development.
10
Li, Weifu, Yi Wang, Weijian Wang, Ying Ren e Lifeng Zhang. "Dependence of the Clogging Possibility of the Submerged Entry Nozzle during Steel Continuous Casting Process on the Liquid Fraction of Non-Metallic Inclusions in the Molten Al-Killed Ca-Treated Steel". Metals 10, n. 9 (8 settembre 2020): 1205. http://dx.doi.org/10.3390/met10091205.
Testo completoAbstract (sommario):
In the current study, the nozzle clogging behavior and inclusion composition in Al-killed Ca-treated steels were observed to investigate the relationship between the liquid fraction of non-metallic inclusions and the clogging possibility of the submerged entry nozzle. Clogging materials were mainly MgO-Al2O3 with less than 20% liquid phases, while most of the inclusions were full liquid CaO-Al2O3-MgO in tundish at the casting temperature. Thus, it was proposed that the nozzle clogging can be effectively avoided by modification of solid inclusions to partial liquid ones rather than full liquid ones. There was a critical value of liquid fraction of inclusions causing the nozzle clogging. A critical condition of the inclusion attachment on the nozzle wall was a function of cosθN−S+cosθI−S<0. With the increase of T.Ca content in steel, the evolution route of inclusions was solid MgO-Al2O3→liquid CaO-Al2O3-MgO→solid CaS and CaO. To avoid the clogging of the submerged entry nozzle (SEN) under the current casting condition, the appropriate T.Ca concentration range in Al-killed Ca-treated steels can be enlarged from the 100% liquid inclusion zone of 10–14 ppm to the 20% liquid inclusion zone of 4–38 ppm.
Tesi sul tema "Clogging behavior"
1
Li, Yang. "Visualization and analysis of particle settling and clogging behavior in porous media". Electronic Thesis or Diss., Rennes, INSA, 2024. http://www.theses.fr/2024ISAR0003.
Testo completoAbstract (sommario):
La manière dont les particules en suspension se déposent et conduisent au colmatage des milieux poreux est cruciale pour de nombreux scénarios d’application. Cette recherche utilise un modèle de milieu poreux transparent pour visualiser la sédimentation et le dépôt des particules. L’utilisation d’un algorithme de détection de particules sur des images obtenues par caméra rapid permet de suivre leurs trajectoires et leurs vitesses. L’analyse du comportement mécanique de ces particules est menée en fonction de la taille des particules et de celle des pores. Premièrement, l’analyse a montré que la gravité régit le mouvement d’une seule particule. Les trajectoires d’une particule injectée à différentes positions se rejoignent une fois qu’elles aient passé les premiers obstacles. Chaque trajectoire contourne les obstacles tout en conservant un mouvement globalement vertical d’infiltration profonde. Quant à la vitesse, elle est influencée par la présence d’obstacles et celle du fluide. Ensuite, l’injection d’un nombre croissant de particules a permis de montrer un nombre critique de particules au-delà duquel les particules s’accumulent dans le milieu poreux. Ce nombre critique dépend du rapport des tailles des particules et des pores. Cette accumulation de particules conduirait au colmatage du milieu poreux caractérisé par un flux sortant de particules nul. Le comptage du nombre de cas de colmatage parmi les nombreux essais réalisés a permis de quantifier la probabilité de colmatage selon le nombre de particules injectées et selon le rapport de taillesHow suspended particles deposit and lead to clogging in a porous medium is crucial for many application scenarios. This research uses a transparent model of porous medium to visualize particle behaviors. The use of a particle detection algorithm on highspeed camera images enables us to track particle trajectories and velocities. The particle mechanical behavior is analyzed at different size ratios (particle size divided by pore size). Firstly, analysis has shown that gravity governs the single particle motion. The trajectories of a particle injected at different positions converge once it has passed the first obstacles. Each trajectory bypasses the obstacles while maintaining an overall vertical motion of deep infiltration. Velocity is influenced by the presence of obstacles and the fluid itself. Next, the injection of an increasing number of particles has demonstrated a critical number of particles beyond which particles accumulate in the porous medium. This critical number depends on the size ratio. This accumulation would lead to clogging and can be characterized by zero particle outflow. By counting the number of clogging cases over multiple tests, we can quantify the probability of clogging as a function of the number of particles injected and the particle size ratio
2
Ni, Peiyuan. "A Study on Particle Motion and Deposition Rate : Application in Steel Flows". Doctoral thesis, KTH, Tillämpad processmetallurgi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-161915.
Testo completoAbstract (sommario):
Non-metallic inclusions in molten steel have received worldwide attention due to their serious influence on both the steel product quality and the steel production process. These inclusions may come from the de-oxidation process, the re-oxidation by air and/or slag due to an entrainment during steel transfer, and so on. The presence of some inclusion types can cause a termination of a casting process by clogging a nozzle. Thus, a good knowledge of the inclusion behavior and deposition rate in steel flows is really important to understand phenomena such as nozzle clogging. In this thesis, inclusion behaviors and deposition rates in steel flows were investigated by using mathematical simulations and validation by experiments. A ladle teeming process was simulated and Ce2O3 inclusion behavior during a teeming stage was studied. A Lagrangian method was used to track the inclusions in a steel flow and to compare the behaviors of inclusions of different sizes. In addition, a statistical analysis was conducted by the use of a stochastic turbulence model to investigate the behaviors of different-sized inclusions in different nozzle regions. The results show that inclusions with a diameter smaller than 20 μm were found to have similar trajectories and velocity distributions in the nozzle. The inertia force and buoyancy force were found to play an important role for the behavior of large-size inclusions or clusters. The statistical analysis results indicate that the region close to the connection region of the straight pipe and the expanding part of the nozzle seems to be very sensitive for an inclusion deposition. In order to know the deposition rate of non-metallic inclusions, an improved Eulerian particle deposition model was developed and subsequently used to predict the deposition rate of inclusions. It accounts for the differences in properties between air and liquid metals and considers Brownian and turbulent diffusion, turbophoresis and thermophoresis as transport mechanisms. A CFD model was firstly built up to obtain the friction velocity caused by a fluid flow. Then, the friction velocity was put into the deposition model to calculate the deposition rate. For the case of inclusion/particle deposition in vertical steel flows, effects on the deposition rate of parameters such as steel flow rate, particle diameter, particle density, wall roughness and temperature gradient near a wall were investigated. The results show that the steel flow rate/friction velocity has a very important influence on the rate of the deposition of large particles, for which turbophoresis is the main deposition mechanism. For small particles, both the wall roughness and thermophoresis have a significant influence on the particle deposition rate. The extended Eulerian model was thereafter used to predict the inclusion deposition rate in a submerged entry nozzle (SEN). Deposition rates of different-size inclusions in the SEN were obtained. The result shows that the steel flow is non-uniform in the SEN of the tundish. This leads to an uneven distribution of the inclusion deposition rates at different locations of the inner wall of the SEN. A large deposition rate was found to occur at the regions near the SEN inlet, the SEN bottom and the upper region of two SEN ports. For the case of an inclusion/particle deposition in horizontal straight channel flows, the deposition rates of particles at different locations of a horizontal straight pipe cross- section were found to be different due to the influence of gravity and buoyancy. For small particles with a small particle relaxation time, the gravity separation is important for their deposition behaviors at high and low parts of the horizontal pipe compared to the turbophoresis. For large particles with a large particle relaxation time, turbophoresis is the dominating deposition mechanism.QC 20150326
3
Mitchell, Ged. "An investigation into the factors affecting the behaviour of Highway Filter Drains, with a particular emphasis on the Scottish Trunk Road Network". Thesis, Abertay University, 2017. https://rke.abertay.ac.uk/en/studentTheses/768779b0-366a-434d-a28d-e9313885d37b.
Testo completoAbstract (sommario):
Approximately 1500 km (43%) of the strategic Scottish trunk road network drainage asset takes the form of Highway Filter Drains (HFDs). However, despite their popularity, they are prone to clogging, therefore they have an estimated operational life-cycle of ten-years. This research was undertaken to investigate the complex inter-relationship between catchment characteristics, road dynamics and the physical characteristics of the road to establish the key factors that govern the generation and spatial variability of Road-Deposited-Sediment (RDS). The aim being to establish the impact RDS Particle Size Distribution (PSD) has on clogging and the operational life-cycle of HFDs. The research adopted an integrated approach, incorporating: (i) a Field Study to investigate RDS PSD grading envelopes across the Scottish trunk road network, (ii) a HFD Field Survey (HFD-FS) to investigate the current condition of HFDs across a range of catchments, (iii) a HFD Field Study to establish whether, or not, graded stone PSD envelopes comply with specification requirements when first placed in the trench, (iv) 3 HFD Field Studies to assess the level of risk of system failure through evaluating the causes and quantifying the individual, cumulative and influencing factors which contribute to the evolution of clogging in HFDs, and (v) a Field Study utilising Ground Penetrating Radar data to explore why stratified (clogged) layers evolve within some HFDs. Based on the results of this research, design and maintenance procedures were then identified to improve the performance of HFDs. Results established that Scottish trunk roads operate under variable catchment characteristics and road dynamics, with the condition and specification of the road surface, volume of traffic, road geometry, number of running lanes and adjacent land use governing the generation and spatial variability of RDS. Five of the nine trunk road RDS PSD profiles shared a peak particle diameter of 425 μm, two had a peak of 600 μm, one had a peak of 1180 μm and one resulted in a peak of 2120 μm. Particles >1000 μm were mostly mineral or asphalt and it was shown that there is a direct link between the factors that govern the generation and spatial variability of RDS and those that govern the evolution of clogging and actual operational life-cycle of HFDs. The HFD-FS revealed that 69% were assigned Filter Drain Condition Index ratings of 3 or below, which identifies these as having exceeded the ten-year estimated operational life-cycle. 94% of those deemed to have reached the end of their operational life-cycle were over-the-edge (OTE) HFDs, which supports the assertion that pre-treatment would increase their operational life-cycle. Results also established that introducing a kerb-line and gully-pots or grass-strip between the road and the HFD significantly reduced the indices of particle size composition d50 and d90 and percentage of RDS retained at depths spanning 0 - 400 mm, compared to OTE HFDs with comparable catchment characteristics and road dynamics. Based on these results, the operational life-cycle of HFDs with a kerb-line and gully-pots and OTE HFDs with a grass-strip can be expected to exceed twenty-years, if catchment characteristics and road dynamics are representative of those in this study. This research also identified that compacting Type B graded stone with ‘heavy vibrating machinery’ during construction could potentially contribute to clogging. It was also established that HFD harrowing may exacerbate clogging because the process of disintegrating the cake-layer mobilises an otherwise rigid and compacted RDS mass and this is more likely to penetrate deeper into the HFD and inundate the HFD during a storm event. These findings indicate that current HFD construction and maintenance practice could have a detrimental impact on the effective operational life-cycle of HFDs. Overall, this research study has demonstrated that there are considerable uncertainties related to PSD grading envelopes and percentage of RDS migrating from roads to HFDs. It is clear therefore that one of the most notable findings of this research is that given the scale of strategic trunk road networks, assuming a single HFD operational life-cycle profile, for a trunk road or trunk road network, is highly unlikely to be representative of a HFD at the local level. It follows then that the widely accepted estimated ten-year operational life-cycle for HFDs, does not reflect the actual operational life-cycle of HFDs.
4
Chen, Shiu Yet, e 陳仕岳. "A study on clogging behavior of the nonwoven geotextile using gradient ratio test". Thesis, 1996. http://ndltd.ncl.edu.tw/handle/42788984171428252191.
Testo completo
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Hou, Hung Chia, e 侯宏佳. "A study on clogging behavior of the nonwoven geotextile by using electronic micro pore water pressure sensor". Thesis, 1997. http://ndltd.ncl.edu.tw/handle/63437987471822312322.
Testo completoAbstract (sommario):
碩士中原大學
土木工程學系研究所
86
Clogging potential is a major concern when geotextile is used in filtration/drainage systems. Various methods are available for determining the clogging potential of geotextile. Gradient ratio test (GR test) is widely applied for its convenience and shorter test duration. Chang and Nieh (1996) reviewed the conventional GR test and raised several recommendations for improving performance. Based on Chang and Nieh’s recommendations, S.Y. Chen (1996) devised a modified gradient ratio device that provides better performance of water pressure distribution over the specimen. Electronic micro pore water pressure sensor developed by the China Nanjing Hydraulic Research Institute is used instead of conventional implanted measuring tube for the study of the re-distribution of fine soil granules after the GR test. The anterior portion of the lead tube of the sensor is made of ceramic porous stone that can eliminate the interference of fine granules with interface material. The use of electronic water pressure sensor not only prevents undesirable effects during specimen preparation but also during the removal of bubbles. More importantly, it senses the water pressure distribution instantaneously. Findings indicate that for fine contents over 30%, blinding phenomenon may occur at any layer of the specimen, rather than in the 2.54cm layer above the geotextile. After the GR test, soil specimen in the 2.54cm layer above the geotextile is collected for analysis. Results reveal that the distribution of size of lost soil particles is related to the pore size of the geotextile. Findings also indicate that higher fine contents require a longer time to reach the stable state of the GR value.
Capitoli di libri sul tema "Clogging behavior"
1
Lu, Guoyang, Guoxiang Zhou, Dawei Wang, Jing Zhong e Markus Oeser. "Numerical Evaluation on the Filtration and Clogging Behavior of Porous Pavement". In Proceedings of GeoShanghai 2018 International Conference: Multi-physics Processes in Soil Mechanics and Advances in Geotechnical Testing, 201–9. Singapore: Springer Singapore, 2018. http://dx.doi.org/10.1007/978-981-13-0095-0_23.
Testo completo
2
Liu, Fenggang, Qiuyue Zhou, Lifeng Zhang e Ying Ren. "Observation on Clogging Behavior of Submerged Entry Nozzle of Al–Killed Steels". In The Minerals, Metals & Materials Series, 315–21. Cham: Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-92388-4_28.
Testo completo
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Dudczig, Steffen, Enrico Storti e Christos G. Aneziris. "Registration of Filtration Efficiency of Active or Reactive Filters in Contact with Steel Melt in a Steel Casting Simulator". In Multifunctional Ceramic Filter Systems for Metal Melt Filtration, 489–517. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_19.
Testo completoAbstract (sommario):
AbstractAspecial metal-casting simulator allowed to investigate the behavior of nozzles and filters in contact with a steel melt under controlled atmosphere. First, the clogging of carbon-bonded alumina nozzles with different active or reactive coatings was evaluated by introducing exogenous inclusions while monitoring the changes in melt flow with time. In addition, the microstructure of the nozzles was investigated by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy to assess the coating decomposition and phase transformations. In further approaches, endogenous inclusions were generated in situ by pre-oxidizing and deoxidizing the steel melt. Filters with different active and reactive coatings were immersed for different times in order to investigate the evolution of newly formed phases on the filter surface as well as characterize their cleaning performance based on the analysis of the solidified steel. The inclusions in the frozen steel melt were characterized with the aid of an automatic SEM – ASPEX-system, which identified the chemistry as well as the size and population of the inclusions. In the last approach, investigations of a new combined refining process based on the immersion of reactive filters and a subsequent filtration via carbon-free active filters was investigated, in order to remove the remaining clusters of inclusions.
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Wetzig, Tony, Andreas Baaske, Sven Karrasch, Steffen Dudczig e Christos G. Aneziris. "Cleanness of Molten Steel—Active and Reactive, Exchangeable Filter Systems for the Continuous Casting of Steel". In Multifunctional Ceramic Filter Systems for Metal Melt Filtration, 741–68. Cham: Springer International Publishing, 2024. http://dx.doi.org/10.1007/978-3-031-40930-1_29.
Testo completoAbstract (sommario):
AbstractThe filtration of steel melts in the continuous casting of steel is of special interest in order to meet the ever-increasing purity requirements regarding the metal’s purity. Due to the high mass flow and the high casting duration, the application of in-built filters in the tundish system is rather challenging, especially regarding the filter capacity. In the framework of this contribution, a new concept involving the immersion of filters into the steel melt from above the tundish was investigated. This approach allows for the flexible exchange of used filters without interruption of the underlying process. At the Institute of Ceramics, Refractories and Composite Materials, carbon-bonded alumina filters on the basis of established slurry compositions and modified replication techniques were scaled up for the industrial application in continuous casting of steel. The best property profile was observed for a triple coating approach based on centrifugation, dip coating and spray coating. In the tundish of a steel casting simulator, a lab-scale casting test was conducted in order to check the thermos-mechanical behavior of the filter in contact with molten steel. After the successful evaluation in lab scale, the filters were tested in industrial trials in cooperation with the company thyssenkrupp Steel Europe AG. A ladle casting with immersed filter lasted approximately 45 min with a static casting speed of 8 to 10 t/min and a melt temperature of above 1550 °C. The filters were analyzed for inclusions and potential damage at the Institute of Ceramics, Refractories and Composite Materials. Dense clogging layers on the filter surface were identified as in-situ layers as usually observed in lab-scale steel casting simulator tests in consequence of reactive filtration effects. Furthermore, inclusion clusters which were removed at the filter bottom due to the direct inflow in consequence of the buoyancy were observed as signs of active filtration. A further alternative to foam filters is presented by gel-cast spaghetti filter structures with mechanically robust full-strut structure. In the subproject T01K, the gel casting process was optimized in order to realize the necessary upscaling of the components. With the aid of alginate-based gel casting, spaghetti filter with organized lattice structures were manufactured and tested. Steel casting simulator trials showed favorable behavior in contact with the melt.
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Doan, Thao, Buddhima Indraratna, Thanh T. Nguyen e Cholachat Rujikiatkamjorn. "A Coupled CFD-DEM Approach to Examine Clogging Behaviour of Granular Medium by Fines". In Lecture Notes in Civil Engineering, 1–9. Singapore: Springer Nature Singapore, 2024. http://dx.doi.org/10.1007/978-981-97-8233-8_1.
Testo completo
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Henle, Christine A., e Uma Kedharnath. "Cyberloafing in the Workplace". In Encyclopedia of Cyber Behavior, 560–73. IGI Global, 2012. http://dx.doi.org/10.4018/978-1-4666-0315-8.ch048.
Testo completoAbstract (sommario):
Cyberloafing is employees’ intentional use of Internet technology during work hours for personal purposes. This can include surfing non-work related Internet sites, sending personal emails, online gaming, or social networking. Given the prevalence of cyberloafing and its negative consequences (e.g., reduced productivity, network clogging, security breaches), organizations have responded by implementing Internet use policies, filtering or monitoring Internet activity, and disciplining policy violators. Recently, attention has shifted away from identifying methods to limit cyberloafing to pinpointing the causes of cyberloafing. This emerging research suggests that employees are more likely to cyberloaf when they are treated unfairly, have certain characteristics like external locus of control or higher work status, have positive attitudes toward cyberloafing, or there are norms supporting it. The authors offer directions for future research that include exploring the possibility that cyberloafing can lead to positive outcomes like increased job performance, reduced stress, and work-life balance.
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Lim, Emiko, T. Fwa e K. Tan. "Laboratory evaluation of clogging behavior of porous asphalt pavements". In Bituminous Mixtures and Pavements VI, 287–92. CRC Press, 2015. http://dx.doi.org/10.1201/b18538-42.
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TOUCH, N., N. SHINYA, T. HIBINO e S. FUKUOKA. "CAPTURE AND CLOGGING BEHAVIOR OF ORGANIC MUD IN SAND BEDS". In Asian And Pacific Coasts 2011, 1030–37. WORLD SCIENTIFIC, 2011. http://dx.doi.org/10.1142/9789814366489_0122.
Testo completoAtti di convegni sul tema "Clogging behavior"
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Beck, David, Yvonne Holzbauer e Paul Uwe Thamsen. "Different Clogging Behavior of Wastewater Pumps". In ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-65422.
Testo completoAbstract (sommario):
Abstract The transport of wastewater presents operators with increasing challenges for their wastewater pumps due to an increasing proportion of tear-resistant fibrous materials and new types of hygiene articles (e.g. wet wipes) in the wastewater. This paper describes the different clogging behavior of wastewater pumps, which were recorded during the functional performance tests. In addition to the findings of the points susceptible to clogging, the maximum uptake of solids by an impeller is also discussed. The maximum uptake of solids is defined as the degree of saturation. Furthermore, it is shown to what extent the different clogging behavior influence the hydraulic performance and the resulting efficiency changes. In these tests, it became apparent that wastewater pumps react very differently to clogging. On the one hand, it can lead to a reduction in hydraulic function, which reduces the efficiency of the system. A distinction must be made here as to whether the pumps with a certain number of solids, a defined degree of saturation, retain their function or are brought to a standstill. On the other hand, the hydraulic performance can remain almost constant or, in some cases, be increased despite the clogging that occurs, but this is accompanied by an increased power requirement and can thus reduce the service life and the efficiency of the system.
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Müller, Enrico, Thomas Pensler e Paul Uwe Thamsen. "Clogging Behavior of Different Impeller Types of Sewage Pumps at Speed Variation". In ASME 2022 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fedsm2022-87023.
Testo completoAbstract (sommario):
Abstract Nonwoven wet wipes are the most hazardous substances that cause clogging of sewage pumps, due to the increasing amount of wet wipes in sewer systems. The clogging of sewage pumps causes a considerable additional economic expense every year, which can be avoided by well-functioning sewage pumps. An additional problem to be considered is the reduced water consumption, which increases the concentration with the increased use of wet wipes in the wastewater. With demand-driven pumping of wastewater due to large diurnal fluctuations, pumps are speed-controlled as the price of frequency converters decreases. The current advice when speed variation in wastewater pumps are used, affects the minimum velocity in the pipes. The study investigates how speed influences the clogging phenomena of wastewater pumps. The pumps have been approved at a test stand in a laboratory that is designed for functional tests on wastewater pumps. During the test the operating behavior is logged and indicates how clogging influences the pumping performance. Those tests have been done for a long-time performance test, in which the wastewater is pumped in a loop for 60 Minutes. During the test procedure the clogging is observed with a high speed camera, so that the clogging on the impeller can be visualized. This helps to understand the clogging and self-cleaning ability of impellers better. The behavior of the susceptibility to clogging of the wastewater pumps was very different. The type of impeller as well the speed are the most influencing characteristics that influence clogging.
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Jung, Jongwon, Shuang Cao, Riyadh Al-Raoush e Khalid Alshibli. "Fines migration and clogging behavior in methane hydratebearing sediments". In Qatar Foundation Annual Research Conference Proceedings. Hamad bin Khalifa University Press (HBKU Press), 2018. http://dx.doi.org/10.5339/qfarc.2018.eepd710.
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Gerlach, Angela, Dorian Perlitz, Flemming Lykholt-Ustrup, Christian Brix Jacobsen e Paul Uwe Thamsen. "The Clogging Behavior of a Vortex Pump: An Experimental Study on the Influence of Impeller Designs". In ASME 2017 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2017. http://dx.doi.org/10.1115/fedsm2017-69021.
Testo completoAbstract (sommario):
This paper analyzes the clogging behavior of a vortex pump with different impeller designs. The influence of blade outlet angle, blade number, and impeller diameter were tested. Non-woven textiles in different concentrations served as the clogging material. The results suggest that a smaller outlet blade angle, a higher blade number, and a larger impeller diameter allow pumping more textiles. Impellers that were capable of pumping more textiles, however, were less efficient. Overall, pumping textiles causes efficiency losses. However, this could not be only related to increased power consumption. Flow rates under clogging operation were close to the flow rates under clear water operation irrespective of the amount of clogging material and the impellers design. Further, in all tests clogging material accumulated at the suction mouth in the casing.
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Beck, David, e Paul Uwe Thamsen. "Optimization of a Closed 2-Channel Impeller With Experimental and Optical Support". In ASME 2024 Fluids Engineering Division Summer Meeting collocated with the ASME 2024 Heat Transfer Summer Conference and the ASME 2024 18th International Conference on Energy Sustainability. American Society of Mechanical Engineers, 2024. http://dx.doi.org/10.1115/fedsm2024-131002.
Testo completoAbstract (sommario):
Abstract Due to the high number of solids in wastewater and the resulting increased susceptibility to clogging for wastewater pumps, wastewater impellers are classically designed with a low number of blades as semi-open or closed impellers. In addition to higher possible efficiencies, the closed impellers also have an advantage in terms of resistance to wear compared to semi-open impellers. However, the closed 2-channel impellers have not yet been able to demonstrate good resistance to clogging by fibrous materials. Based on an already tested impeller (MOD 0), two further modifications are discussed in this publication, which show significant improvements in clogging behavior with the help of a optimization methodology. These are mainly achieved in the first modification (MOD 1) by a strongly thickened blade geometry, which can already achieve an initial improvement in clogging susceptibility. The second modification (MOD 2) takes up this thickened blade, whereby the concave suction side of the blade is made convex. This also significantly improves the slipping behavior of the dusters, resulting in a closed 2-channel impeller with a low susceptibility to clogging.
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Beck, David, Florian Brokhausen e Paul Uwe Thamsen. "Time-Resolved Measurements for the Detection of Clogging Mechanisms". In ASME 2022 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/fedsm2022-86961.
Testo completoAbstract (sommario):
Abstract The effects of clogging in pumps are manifold and change over time. This is demonstrated with time-resolved observations of the operating data on a test rig at the chair of fluid system dynamics of the Technische Universität Berlin. On the test rig, the head, flow, power consumption and efficiency of different pumps operating with artificial wastewater are recorded. In the data, different clogging behavior reflect in the operating parameters. There are three major clogging-induced characteristics to be differentiated in the time-resolved measurements. For some aggregates there is a rapid drop in the hydraulic parameters right from the start due to initial clogging, with following stagnating performance. This is showcased on a semi-open two-channel impeller, where efficiency drops by 40 % at the very beginning of the measurement and subsequently stagnates. In other cases, like demonstrated here on a closed two-channel impeller, the operating parameters decline continuously over the entire measurement period due to increasing clogging. In the showcased example, the efficiency drops by over 40% in the first six minutes of the measurement due to initial clogging and keeps declining till the end for another 6%. Lastly, there are cases where self-cleansing mechanisms are identified. It is further shown that this phenomenon also highly varies in its timing and hydraulic effects. Finally, it is concluded that all operating parameters must be monitored to generate sufficient knowledge about the clogging behavior of a given aggregate. Additionally, longer observation times are necessary to sufficiently identify effects like the self-cleansing of an impeller.
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Tilcher, David Konstantin, Michael Pöhler e Paul Uwe Thamsen. "Ball Passage and Impeller Types Do Not Characterize the Functional Performance of a Sewage Pump". In ASME 2020 Fluids Engineering Division Summer Meeting collocated with the ASME 2020 Heat Transfer Summer Conference and the ASME 2020 18th International Conference on Nanochannels, Microchannels, and Minichannels. American Society of Mechanical Engineers, 2020. http://dx.doi.org/10.1115/fedsm2020-20208.
Testo completoAbstract (sommario):
Abstract During the development of sewage pumps their functionality and efficiency have been continuously improved. Different impeller types have been developed; types to reduce clogging, types for associated maintenance during the various stages of the wastewater transport system, and types to increase the efficiency of the pumps. In the current market, energy requirements and efficiency play an increasingly important role. The design of pump impellers with the aim of improving efficiency may increase the susceptibility of clogging. So far there is no test describing both the energy efficiency and the wastewater pumping functionality. Operators can only describe in tenders, a desired efficiency and the indication of plausible experience with respect to the impeller geometry: the impeller shape and the ball passage. It is generally assumed that the susceptibility of clogging can be derived from the impeller shape and the ball passage (or freely passable space). Under this assumption, the vortex impeller should have the lowest susceptibility to clogging. With single and dual-channel impellers, accordingly, the largest possible ball passage points to a low susceptibility of clogging. Both, the hydraulically disadvantageous form of the vortex impeller and an enlargement of the ball passages beyond the hydraulic requirements leads to a significant reduction of efficiency. Generally, it is inferred from these circumstances that clog-free pumps are associated with low efficiency. This assumption, which is also found in the literature, requires a uniform test procedure for the objective assessment of the clogging behavior of sewage pumps. Such a test did not exist. At the Chair of fluid system dynamics, TU Berlin a test stand was developed to examine such assumptions to investigate the functionality and the clogging behavior of sewage pumps. More than 30 different wastewater pumps were tested in this procedure. The results may suggest a correlation between the susceptibility to clogging and the shape of the impeller or ball passage of various sewage pumps. Based on investigations already carried out at the Chair of fluid system dynamics, TU Berlin, the following conclusions are drawn from the measurements: • the superordinate impeller form (Vortex, Channel, etc.) gives no evidence about the susceptibility to blockages, • the ball passage does not indicate the susceptibility to blockages. From these observations it can be deduced: • a sewage pump with an appropriate efficiency may have a low susceptibility to clogging. It can therefore be concluded that the ball passage and the type of impeller are not appropriate parameters to characterize the functional performance of a sewage pump.
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Müller, Enrico, Thomas Pensler e Paul Uwe Thamsen. "Effect of Speed Variation on Clogging of Sewage Pumps". In ASME 2021 Fluids Engineering Division Summer Meeting. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/fedsm2021-65515.
Testo completoAbstract (sommario):
Abstract Pump clogging is a well-known problem due to the increasing amount of nonwoven wet wipes in the wastewater system. In addition, the usage of water decreases which causes higher concentration of solids in the wastewater. Based on the high variation of sewage flow many operators of sewer systems and sewage pumping stations were motivated to act that the wastewater is pumped as needed. It means that with reducing costs of frequency-controlled drives the usage of pumps with speed variation became a more state of the art application. The current operation mode when speed variation in wastewater pumps are used, affects the pumping of sewage water depending on inflow and the minimum velocity in the pipes. Until now, there is no answer which functionality and clogging occurs in the pump when speed changes. The study investigates how speed influences the clogging phenomena of wastewater pumps. The pumps have been approved at a test stand in a laboratory that is designed for proving wastewater pumps. The test includes several speeds with different quantities of wipes in a short-time and long-time functional performance test. The effects on the pumps and their clogging behavior are very different.
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Brunin, Olivier, e Geoffrey Deotto. "Loads Applied to Clogged Steam Generators Internal Structures". In ASME 2009 Pressure Vessels and Piping Conference. ASMEDC, 2009. http://dx.doi.org/10.1115/pvp2009-77140.
Testo completoAbstract (sommario):
During their commissioning, steam generators are clean, which means there is no fouling of the heat transfer surface of tubes and no clogging of the flow area on the secondary side. Then sludge appears steadily at a slow pace during operation. Sludge initiates a partial loss of cooling capacity which is modeled by a fouling factor and which mainly results in vapor pressure decrease. Sludge also initiates a reduction of the secondary side flow area, known as clogging. Four safety-related issues are dependant on clogging [1]: the secondary water mass balance, the thermohydraulics oscillations, the tube vibration risk and the resistance of internal structures. This paper focuses on the last of these issues. A numerical application, based on the modeling of a fictitious steam generator, is detailed in this presentation. The order of magnitude is an 8-times increase of the loads in normal operating conditions in case of a typical 60% clogging ratio of the upper tube support plate, and a 12-times increase in case of incidental depressurization transient. These theoretical results emphasize the need to take these loads properly into account in the checking of the mechanical behavior of the internal structure of the steam generators in operation in case of significant sludge deposits.
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Cowart, Jim, Patrick Moore, Harrison Yosten, Leonard Hamilton e Dianne Luning Prak. "Diesel Engine Acoustic Emission Airflow Clogging Diagnostics With Machine Learning". In ASME 2018 Internal Combustion Engine Division Fall Technical Conference. American Society of Mechanical Engineers, 2018. http://dx.doi.org/10.1115/icef2018-9601.
Testo completoAbstract (sommario):
A diesel engine electrical generator set (’gen-set’) was instrumented with in-cylinder indicating sensors as well as acoustic emission microphones near the engine. Air filter clogging was emulated by progressive restriction of the engine’s inlet air flow path during which comprehensive engine and acoustic data were collected. Fast Fourier Transforms (FFTs) were analyzed on the acoustic data. Dominant FFT peaks were then applied to supervised machine learning neural network analysis with MATLAB based tools. The progressive detection of the air path clogging was audibly determined with correlation coefficients greater than 95% on test data sets for various FFT minimum intensity thresholds. Further, unsupervised machine learning Self Organizing Maps (SOMs) were produced during normal-baseline operation of the engine. Application of the degrading air flow engine sound data was then applied to the normal-baseline operation SOM. The quantization error of the degraded engine data showed clear statistical differentiation from the normal operation data map. This unsupervised SOM based approach does not know the engine degradation behavior in advance, yet shows clear promise as a method to monitor and detect changing engine operation. Companion in-cylinder combustion data additionally shows the degrading nature of the engine’s combustion with progressive airflow restriction (richer and lower density combustion).
Rapporti di organizzazioni sul tema "Clogging behavior"
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Seginer, Ido, Louis D. Albright e Robert W. Langhans. On-line Fault Detection and Diagnosis for Greenhouse Environmental Control. United States Department of Agriculture, febbraio 2001. http://dx.doi.org/10.32747/2001.7575271.bard.
Testo completoAbstract (sommario):
Background Early detection and identification of faulty greenhouse operation is essential, if losses are to be minimized by taking immediate corrective actions. Automatic detection and identification would also free the greenhouse manager to tend to his other business. Original objectives The general objective was to develop a method, or methods, for the detection, identification and accommodation of faults in the greenhouse. More specific objectives were as follows: 1. Develop accurate systems models, which will enable the detection of small deviations from normal behavior (of sensors, control, structure and crop). 2. Using these models, develop algorithms for an early detection of deviations from the normal. 3. Develop identifying procedures for the most important faults. 4. Develop accommodation procedures while awaiting a repair. The Technion team focused on the shoot environment and the Cornell University team focused on the root environment. Achievements Models: Accurate models were developed for both shoot and root environment in the greenhouse, utilizing neural networks, sometimes combined with robust physical models (hybrid models). Suitable adaptation methods were also successfully developed. The accuracy was sufficient to allow detection of frequently occurring sensor and equipment faults from common measurements. A large data base, covering a wide range of weather conditions, is required for best results. This data base can be created from in-situ routine measurements. Detection and isolation: A robust detection and isolation (formerly referred to as 'identification') method has been developed, which is capable of separating the effect of faults from model inaccuracies and disturbance effects. Sensor and equipment faults: Good detection capabilities have been demonstrated for sensor and equipment failures in both the shoot and root environment. Water stress detection: An excitation method of the shoot environment has been developed, which successfully detected water stress, as soon as the transpiration rate dropped from its normal level. Due to unavailability of suitable monitoring equipment for the root environment, crop faults could not be detected from measurements in the root zone. Dust: The effect of screen clogging by dust has been quantified. Implications Sensor and equipment fault detection and isolation is at a stage where it could be introduced into well equipped and maintained commercial greenhouses on a trial basis. Detection of crop problems requires further work. Dr. Peleg was primarily responsible for developing and implementing the innovative data analysis tools. The cooperation was particularly enhanced by Dr. Peleg's three summer sabbaticals at the ARS, Northem Plains Agricultural Research Laboratory, in Sidney, Montana. Switching from multi-band to hyperspectral remote sensing technology during the last 2 years of the project was advantageous by expanding the scope of detected plant growth attributes e.g. Yield, Leaf Nitrate, Biomass and Sugar Content of sugar beets. However, it disrupted the continuity of the project which was originally planned on a 2 year crop rotation cycle of sugar beets and multiple crops (com and wheat), as commonly planted in eastern Montana. Consequently, at the end of the second year we submitted a continuation BARD proposal which was turned down for funding. This severely hampered our ability to validate our findings as originally planned in a 4-year crop rotation cycle. Thankfully, BARD consented to our request for a one year extension of the project without additional funding. This enabled us to develop most of the methodology for implementing and running the hyperspectral remote sensing system and develop the new analytical tools for solving the non-repeatability problem and analyzing the huge hyperspectral image cube datasets. However, without validation of these tools over a ful14-year crop rotation cycle this project shall remain essentially unfinished. Should the findings of this report prompt the BARD management to encourage us to resubmit our continuation research proposal, we shall be happy to do so.