Temat: flow pattern - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Simulations of flow patterns in silos with a cellular automaton: Part 1
Autorzy:: Kozicki, J.
Tejchman, J.
Tematy:: cellular automation
granular flow
flow pattern
insert
silo; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1965146.pdf Link otwiera się w nowym oknie
Opis:: A simplified cellular automaton was used to calculate the kinematics of non-cohesive granular materials during confined flow in silos. In this model, granular flow was assumed to be an upward propagation of holes through a lattice composed of cells representing single particles. Calculations were carried out with different silo shapes and inserts, transition probabilities, migration rules, outflow schemes, grid types, wall roughness and cell numbers. To visualize the calculation process, horizontal layers of various shades were introduced. The simulation results were compared with laboratory tests in model silos.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 2.

Tytuł:: Effect of flow orientation in experimental studies on FC-770 boiling heat transfer in asymmetrically heated minichannels
Autorzy:: Piasecka, Magdalena
Strąk, Kinga
Tematy:: heat transfer
flow boiling
minichannel
flow orientation
flow pattern; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czasopisma i Monografie PAN
Powiązania:: https://bibliotekanauki.pl/articles/59111913.pdf Link otwiera się w nowym oknie
Opis:: The article presents experimental results of boiling heat transfer during FC-770 flow in a group of five minichannels with a common heated wall. The flow orientation was changed from 0º to 180º, with a 15° increment. During the experiments, the temperature of its outer heated wall surface was measured by an infrared camera. At the same time, flow patterns were captured through the glass plate opposite the heated wall using a high-speed camera. The purpose of the calculations was to determine local heat transfer coefficients on the contact surface between the working fluid and the heated surface in the central minichannel, using a simplified 1D calculation method. The results in the form of dependences of the temperature of the heated wall and the heat transfer coefficient as a function of the distance from the channel inlet for various flow orientations were analysed. Furthermore, typical boiling curves and two-phase flow patterns were presented. The mean relative error of the heat transfer coefficient was determined for various flow orientation. The dependence of the void fraction as a function of heat flux was illustrated for various angles of minichannel inclination to the horizontal plane. It was observed that the void fraction increased with heat flux and with increasing angle of inclination of the minichannel to the horizontal plane.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 3.

Tytuł:: Application of stereology for assessment of two-phase flow structures
Autorzy:: Masiukiewicz, M.
Ulbrich, R.
Zając, D.
Tematy:: stereological analysis
two-phase flow pattern
pattern recognition; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/175510.pdf Link otwiera się w nowym oknie
Opis:: This paper describes a method for two-phase flow structures evaluation of gas-liquid mixture based on theoretical assumptions for the stereology in materials science. This assessment is based on the analysis of digital images, obtained with a high-speed camera. The bright field technique was used for process visualization. The images obtained during the visualisation were, in fact, projections of the structures. For the given recording conditions, the stereological analysis applied was based on the linear method and on the method of random and directed secants. The new methods of determining important parameters of two-phase flow were proposed on the basis of collected data. The parameters are as follows: the volume fraction, the interfacial area, the number of objects in one of the phases of the mixture and two other structural parameters of the selected two-phase fluid obtained from the analysis of the two-dimensional image (average length of chords for projected objects, average free distance for convex shapes from the projection).
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 4.

Tytuł:: The rectangular two-phase closed thermosyphon: A case study of two-phase internal flow patterns behaviour for heat performance
Autorzy:: Chompookham, Teerapat
Sichamnan, Surachet
Bhuwakietkumjohn, Nipon
Parametthanuwat, Thanya
Tematy:: internal flow
flow pattern
rectangular two-phase closed thermosyphon; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/240618.pdf Link otwiera się w nowym oknie
Opis:: This research explored different types of two-phase flow patterns that influenced heat transfer rate by assessing rectangular two-phase closed thermosyphon (RTPCT) made from glass with the sides of equal length of 25.2 mm, aspect ratio 5 and 20, evaporation temperature of 50, 70, and 90°C, working substance addition rate of 50% by volume of evaporator, and water inlet temperature at condensation of 20°C. Upon testing with aspect ratios 5, three flow patterns emerged which were: bubble flow, slug flow and churn flow respectively. As per the aspect ratio 20, four flow patterns were discovered which were: bubble flow, slug flow, churn flow and annular flow, respectively. Aspect ratio 5 pertains characteristic which resulted in a shorter evaporation rate of the RTPCT than that of the aspect ratio 20, thus, a shorter flow distance from the evaporator section to heat releaser was observed. Therefore, flow patterns at aspect ratio 5 exhibited a faster flow velocity than that of the aspect ratio 20. Furthermore, changes of flow pattern to the one that is important for heat transfer rate can be easily achieved. Churn flow was the most important type of the flow for heat transfer, followed by slug flow. Moreover, with aspect ratio 20, annular flow was the most important flow for the heat transfer, followed by churn flow, respectively. Throughout the test, average heat flux as obtained from the aspect ratio 5 were 1.51 and 0.74 kW/m2 which were higher than those of the aspect ratio 20. The highest heat flux at the operating temperature of the evaporator section was 90°C, which was equivalent to 2.60 and 1.52 kW/m2, respectively.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 5.

Tytuł:: The Fibrous Structure of the Bolt and Its Effect on the Joint Reliability
Autorzy:: Dubiel, Tomasz
Balawender, Tadeusz
Osetek, Mirosław
Tematy:: cold forging
bolts
fasteners
grain flow pattern; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2049126.pdf Link otwiera się w nowym oknie
Opis:: The use of cold forging is a widely used solution in many industries. One application is the manufacture of bolts and fasteners. The largest amounts of bolts are used in the automotive and machine industry. Those customers demand high standards of quality and reliability from producers based on ISO 9001 and IATF 16949. Also, the construction, agriculture and furniture industries are raising their expectations for deliveries from year to year. Automotive companies issue their standards specifying specific requirements for products. One of these standards is the aviation standard SAE USCAR 8-4; 2019, which speaks of a compatible arrangement of fibers in the bolt head and in the area of transition into the mandrel. The article presents the cold forging process of flange bolts. Obtaining a compatible, acceptable and incompatible grain flow pattern based of the above mantioned standard was presented. Then the results of FEM simulation were correlated with the performed experiment. The effect of incompatible grain flow system was discussed and presented as the crack initiating factor due to delta ferrite, hydrogen embrittlement, tempering embrittlement. The reliability of the connections was confirmed in the assembly test for yield stress on a schatz machine. The advantages of this method and the difference compared to the tensile test were presented.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 6.

Tytuł:: Verification of Dead Zones Generated in Bioreactors as a Proactive Stage in Bioreactor Design
Autorzy:: Al-Mashhadani, Mahmood K. H.
Tematy:: bioreactor
dead zone
flow pattern
mass transfer
modeling; Pokaż więcej
Wydawca:: Polskie Towarzystwo Inżynierii Ekologicznej
Powiązania:: https://bibliotekanauki.pl/articles/24201743.pdf Link otwiera się w nowym oknie
Opis:: The activity and growth of microorganisms for renewable energy production are still influenced by the dead zones created in bioreactors. These areas form a nutrient and thermal gradient, causing an abundance of food in certain areas compared to famines in other areas of same bioreactor. The current study is a step in identifying those dead zones, followed by another step in improving the flow of media inside the reactor. The results indicated that the inner parts of the bioreactor may be a crucial factor in the creation and spread of such dead zones. For example, the position of the disc-type diffuser contributes to the generation of those areas at the bottom of the reactor. It was inferred from the fluid movement in reactors using the annular-type diffuser proposed in the current study. The bubble size, gas mass flux, and radiuses of fillet, as the most important factors, were examined in both bioreactors. The results revealed a noticeable improvement in these parameters in this area of the reactor when the disc diffuser was replaced by the annular diffuser. For example, the average liquid velocity was recorded in the lower part of the modernized reactor at 0.0198 m/s, while the velocity was recorded in the conventional reactor at 0.00077 m/s under same bubbles diameter used in both reactors (0.125 mm). The inclusion of the effect of the presence of microorganisms in mathematical models was also addressed in the current study. The results showed that the amount of oxygen remaining at the bottom of the reactor after bio-consumption in the presence of the annular diffuser was higher than that in the conventional reactor. This clearly emphasizes the importance of the design of the internal parts of the bioreactor.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 7.

Tytuł:: Simulations of flow patterns in silos with a cellular automaton: Part 2
Autorzy:: Kozicki, J.
Tejchman, J.
Tematy:: cellular automation
collisions
density wave
granular flow
flow pattern
silo; Pokaż więcej
Wydawca:: Politechnika Gdańska
Powiązania:: https://bibliotekanauki.pl/articles/1965144.pdf Link otwiera się w nowym oknie
Opis:: An improved cellular automaton has been used to calculate the kinematics of non-cohesive granular materials during confined flow in mass and funnel flow model silos. In this model, based on a gas model of hydrodynamics, collisions and dissipation of particles were taken into account during granular flow. The model allowed for investigations of dilatant zones in granular material during silo flow.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 8.

Tytuł:: Energy of intrinsic mode function for gas-liquid flow pattern identification
Autorzy:: Sun, Z.
Gong, H.
Tematy:: gas-liquid flow pattern
flow-pattern map
pressure fluctuation
bluff body
signal energy
intrinsic mode function
empirical mode decomposition; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/221137.pdf Link otwiera się w nowym oknie
Opis:: Gas-liquid flows abound in a great variety of industrial processes. Correct recognition of the regimes of a gas-liquid flow is one of the most formidable challenges in multiphase flow measurement. Here we put forward a novel approach to the classification of gas-liquid flow patterns. In this method a flow-pattern map is constructed based on the average energy of intrinsic mode function and the volumetric void fraction of gas-liquid mixture. The intrinsic mode function is extracted from the pressure fluctuation across a bluff body using the empirical mode decomposition technique. Experiments adopting air and water as the working fluids are conducted in the bubble, plug, slug, and annular flow patterns at ambient temperature and atmospheric pressure. Verification tests indicate that the identification rate of the flow-pattern map developed exceeds 90%. This approach is appropriate for the gas-liquid flow pattern identification in practical applications.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 9.

Tytuł:: Physical Modelling of Tundish Slag Entrainment under Various Technological Conditions
Autorzy:: Michalek, K.
Gryc, K.
Socha, L.
Tkadlečková, M.
Saternus, M.
Pieprzyca, J.
Merder, T.
Pindor, L.
Tematy:: steelmaking
tundish
slag entrainment
flow pattern
physical modelling; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/351348.pdf Link otwiera się w nowym oknie
Opis:: This paper deals with the issue of physical modelling of vortexes creation and tundish slag entrainment over the mouth of the nozzle into the individual casting strands. Proper physical model is equivalent to the operational continuous casting machine No. 2 in TŘINECKÉ ŽELEZÁRNY, a.s. Physical modelling methodology and simulated operational conditions are shortly described. Physical modelling was used for the evaluation of current conditions of steel casting at the application of different impact pads in the tundish. Further, laboratory measurement on the physical model aiming the determination of exact critical periods of vortexes creation and study of the slag entrainment as a consequence of changes in surface level during the tundish refilling to standard level were realised. The obtained results were analysed and discussed.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Skocz do pozycji: 10.

Tytuł:: Does the life cycle affect earnings management and bankruptcy?
Autorzy:: Durana, Pavol
Michalkova, Lucia
Privara, Andrej
Marousek, Josef
Tumpach, Milos
Tematy:: earnings management
corporate life cycle
cash flow pattern
bankruptcy; Pokaż więcej
Wydawca:: Instytut Badań Gospodarczych
Powiązania:: https://bibliotekanauki.pl/articles/19233663.pdf Link otwiera się w nowym oknie
Opis:: Research background: Deteriorating economic conditions and a negative outlook increase the pressure on financial management and the need to show high financial performance. According to Positive Accounting Theory, the growing risk of bankruptcy is associated with the phenomenon of earnings management. Bankruptcy risk and the quality of reported profits, along with other aspects of financial performance, vary throughout the company's life cycle. Nevertheless, these factors or their interactions are investigated only to a very small extent. Purpose of the article: The aim of this study is to clarify the impact of corporate life cycle and bankruptcy on earnings management, in order to describe behaviour of companies at different stages of corporate life cycle. Methods: A hierarchical mixed model with a random time and industry effect was chosen as appropriate because it allows the investigation of multilevel data that is not independent. The sample covers the financial indicators of more than 33,000 Central European companies from 2015-2019. The non-sequential Dickinson model, company age, and three models of accrual earnings management were used as proxies for the company's life cycle and quality of reported profit. Findings & value added: Earnings management and bankruptcy risk have a U-shape, indicating that financially distressed firms reduce reported accounting profit at the Introduction, Decline and, to a lesser extent, at the Growth stage. Slovak and Czech companies manipulate profits to a similar extent, Hungarian companies increase accounting profit to a greatest extent than the surveyed countries by controlling bankruptcy - life cycle effect; however, the variability of accounting manipulations across industries has not been demonstrated. These findings imply that start-ups and declining businesses provide crooked financial statements to obtain more favourable debt covenants, and estimating discretionary accruals using life-cycle subsamples can improve the predictive power of accrual earnings management models.
Dostawca treści:: Biblioteka Nauki

Artykuł

na półce

Informacja

Wyszukujesz frazę "flow pattern" wg kryterium: Temat