Temat: suction - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Model tests on characteristic of suction caissons in saturated fine sand under intermittent loading
Autorzy:: Shi, P.
Tematy:: intermittent suction installation
model test
sand
suction caisson; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/258534.pdf Link otwiera się w nowym oknie
Opis:: Suction caissons are often used for the caissons of both offshore oil platforms and offshore wind power projects because of their advantages of simple construction, economical cost, and reusability. In this study, model tests were conducted in sand in order to investigate the effects of the caisson installation method on the penetration depth and the critical suction. Results of the test program showed that the method of changing the frequency of suction during different stages of the process can increase the penetration depth of the caisson. Combining with the deformation of the soil body inside and outside the caisson, the existing method for calculating the critical suction is modified, and the critical suction calculation equation of the discontinuous penetration test is proposed. Based on the test results, the calculation equation of the soil heave height can be more accurate predicted. The analysis results verify that the calculation method and the actual results are in good agreement.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Validating full cavitation model with an experimental centrifugal pump
Autorzy:: Li, W., -G.
Tematy:: centrifugal pump
cavitation
incipient cavitatio
suction performance
net positive suction head required
net positive suction head available
CFD; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1954444.pdf Link otwiera się w nowym oknie
Opis:: The full cavitation model is increasingly applied in the cavitating flow simulation and the cavitation performance prediction of a centrifugal pump to improve or optimize its hydraulic design. Since the model involves surface tension and non-condensable gas content, it can be potentially applied in predicting cavitation behaviour of a centrifugal pump when handling viscous oils that possess different surface tension and gas content than water. However, the model has not been validated extensively against experimental incipient cavitation and NPSHr (net positive suction head required) data so far. In the paper, the cavitation performance of an experimental centrifugal pump is investigated using the CFD code and the full cavitation model when pumping water. The incipient cavitation number-flow rate curve and head-NPSHa (net positive suction head available) relationship are established and compared with experimental observations. The relationship between the head and integrated vapour-liquid volume ratio in the impeller is argued. The influence of the non-condensable gas content and turbulence model on the head-NPSHa curve is clarified. The cavity pattern predicted is compared with the visualized one. The computational methods adopted and the results achieved here can be useful for the cavitation performance prediction of a centrifugal pump in engineering.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Evaluation of expansivity of Neogene clays and glacial tills from cental Poland (Warszawa area) on the basis of suction tests
Autorzy:: Wójcik, Emilia
Izdebska-Mucha, Dorota
Wydawca:: Polish Geological Institute - National Research Institute
Opis:: This paper presents the characteristics of the expansivity and quantitative prediction of heave of clay soils from Poland based on suction testing. Eleven Neogene clays and six glacial tills, differing in genesis and plasticity, were analysed to identify the expansive potential using eight empirical methods. The laboratory studies included measurements of soil-water characteristic curves and soil index properties. Data from water content, volume and suction measurements served to determine the suction compression index Ch and the suction-water content index delta h/delta w of the soils examined. The values of these indices are clearly dependent on the clay fraction content in tested soils. Compared with glacial tills, Neogene clays are expected to exhibit greater changes in volume due to changes in soil suction. Comparative results of the evaluation of expansivity suggest that the chosen classification methodologies provided consistent expansion ratings for glacial tills, while the values for Neogene clays vary from low to very high. The lowest expansivity classes have been obtained from evaluation based on soil suction. The McKeen (1992) method has been adopted for calculations of the potential field heave of Neogene clays and glacial tills. In order to provide a rational estimation of expansive soil behavior, specialists should take into consideration the specific site and design features.
Dostawca treści:: Repozytorium Centrum Otwartej Nauki

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Skocz do pozycji: 4.

Tytuł:: Evaluation of expansivity of Neogene clays and glacial tills from central Poland on the basis of suction tests
Autorzy:: Izdebska-Mucha, D.
Wójcik, E.
Tematy:: expansive soil
neogene clays
glacial tills
suction
suction compression index
heave; Pokaż więcej
Wydawca:: Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Powiązania:: https://bibliotekanauki.pl/articles/2059660.pdf Link otwiera się w nowym oknie
Opis:: This paper presents the characteristics of the expansivity and quantitative prediction of heave of clay soils from Poland based on suction testing. 11 Neogene clays and 6 glacial tills, differing in genesis and plasticity, were analyzed to identify the expansive potential using eight empirical methods. The laboratory studies included measurements of soil-water characteristic curves and soil index properties. Data from water content, volume and suction measurements served to determine the suction compression index Ch and the suction-water content index Dh/Dw of the soils examined. The values of these indices are clearly dependent of the clay fraction content in tested soils. Compared with glacial tills, Neogene clays are expected to exhibit larger changes in volume due to changes in soil suction. Comparative results of the evaluation of expansivity suggest that the chosen classification methodologies provided consistent expansion ratings for glacial tills, while values for Neogene clays vary from low to very high. The lowest expansivity classes have been obtained from evaluation based on soil suction. The McKeen (1992) method has been adopted for calculations of the potential field heave of Neogene clays and glacial tills. In order to provide a rational estimation of expansive soil behavior, specialists should take into consideration the specific site and design features.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The effects of cavity geometry on an aspirated compressor cascade
Autorzy:: Guo, S.
Lu, H.-W.
Liu, J.
Wu, C.-J.
Tematy:: highly loaded compressor cascade
boundary layer suction
suction flow distribution
off-take cavity; Pokaż więcej
Wydawca:: Polskie Towarzystwo Mechaniki Teoretycznej i Stosowanej
Powiązania:: https://bibliotekanauki.pl/articles/280871.pdf Link otwiera się w nowym oknie
Opis:: The impact of the bleed off-take cavity within aspirated blades on the aerodynamic perfor- mance of a highly loaded compressor cascade was explored. Three-dimensional Navier-Stokes simulations were conducted in rectangular compressor cascades after validation against expe- rimental results were done. Five different off-take configurations with varying suction loca- tion were numerically evaluated. The results show that the regularities of the suction flow distribution on the suction slot inlet greatly influence the benefits of boundary layer suction. The distribution style greatly depends not only on the flow condition of the blade passage, but also on the realization of the suction process and the geometry of the cavity inside the aspirated blade. The low kinetic fluid in the endwall region compared with that around the midspan is usually prone to be sucked into the suction slot. The distribution of the suc- tion mass flow along the spanwise direction would be symmetrical if the suction position is properly selected and the inside off-take cavity is well designed, even though the bleeding system has been simplified to be asymmetrical as employed in the present document.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Selection of main engines for hopper suction dredgers with the use of probability models
Autorzy:: Bocheński, D.
Tematy:: hoppers suction dredgers
main engines
design; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/258778.pdf Link otwiera się w nowym oknie
Opis:: This paper presents a new original method of selection of main engines for hopper suction dredgers with regard to probabilistic models. It was proposed to use the normal distribution to describe the operational loads of the main receivers. The principles for determination of parameters of load distribution and design power of the main engines were formulated. Lastly, the principles of selection of the size and number of main engines has been proposed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: The Pull-out Capacity of Suction Caissons in Model Investigations
Autorzy:: Sawicki, A.
Wachowski, Ł.
Kulczykowski, M.
Tematy:: suction caissons
pull-out resistance
model investigations; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Powiązania:: https://bibliotekanauki.pl/articles/241065.pdf Link otwiera się w nowym oknie
Opis:: A small-scale model experiment on the pull-out resistance of suction caissons is described. The pull-out force and suction developed within the caisson in the extraction process were recorded during the experiment. A simple breakout model, together with an elementary static formulae, is applied to predict the results obtained experimentally. There is a reasonably good agreement between the experimental results and predictions. An extensive discussion of the approach applied is included. The analysis presented in this paper is original, as it differs from other approaches mentioned in this paper, and leads to acceptable predictions. At the end, the results are also compared with another approach for predicting the capacity of suction caissons.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Influence of dredger power plant type and dredger size on output of power plant installed on trailing suction hopper dredger
Autorzy:: Bocheński, D.
Tematy:: trailing suction hopper dredgers
ship power plants; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/2073663.pdf Link otwiera się w nowym oknie
Opis:: This paper presents results of investigations dealing with influence of parameters characterizing size of trailing suction hopper dredger as well as type of power system on magnitude of total output of combustion engines installed in dredger power plant.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Technical and economic analysis of the impact of compressors installed at well clusters
Autorzy:: Foidas, I.
Stefanescu, D. P.
Tematy:: dynamic pressures
suction pressures
group compressor
cash flow; Pokaż więcej
Wydawca:: Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Powiązania:: https://bibliotekanauki.pl/articles/298607.pdf Link otwiera się w nowym oknie
Opis:: The current stage of mature gas fields exploitation is characterized by increasing the efforts for maintaining the wells in production, in order to maximize the gas recovery factor in conditions of economic profitability. In this respect, a permanent concern of the specialists in this domain is represented by the adjustment of the compression capacities with the dynamics of the energetic parameters of every well belonging to these fields. This assumes the compression units installing as close to the well head in order to decrease the dynamic pressure, allowing the gas ratę increasing. On the other hand, decreasing the dynamic pressure at the well head, results also in reducing the minimum gas rate necessary for removal the liquid accumulated at the wells bottom, avoiding thereby the risk of the wells flooding. The pilot project of installing the portable compressors at the level of some gas groups operated by Romgaz, was a real success, the future perspectives regarding the production enhancing and revenue growth, based on this technology, being certainly.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Aphids of the genus Diuraphis caught by Johnson suction trap in Poznan, Poland
Autorzy:: Strazynski, P.
Ruszkowska, M.
Krowczynska, A.
Tematy:: aphid
Diuraphis
Johnson suction trap
Poznan city
Polska; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/65082.pdf Link otwiera się w nowym oknie
Opis:: In 1973–2011 in Poznań, aphid catches were carried out using Johnson’s suction trap. Since then the suction trap located at the Institute of Plant Protection – National Research Institute in Poznań has continuously recorded the daily and seasonal dynamics of aphid flights. The collected results has been used to establish one of the largest databases of this type in Europe. The data also allow tracking changes in aphid biodiversity under the changing climatic conditions. Three aphid species of Diuraphis spp. were identified: D. muehlei (Börner, 1950) – in 1974, D. bromicola (Hille Ris Lambers, 1959) – in 1988, D. noxia (Kurdjumov, 1913) – in 2003 as a result of systematic and long-term aphid collections. The occurrence of D. noxia presents a particular risk to cereal crops in Poland. This expansive aphid species that originates from Asia and the Mediterranean is a vector of Barley yellow dwarf viruses (BYDV), and has become one of the most important pest of wheat and barley in the world. Changes in climatic conditions that have been observed in recent years in Poland such as hot summer, long and warm autumn, mild winter seem to be optimal for occurrence and development of aphid species from warmer parts of Europe.
Dostawca treści:: Biblioteka Nauki

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