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- MakaleYalnız künye2026Scopus SJRQ2Hydrodynamic characterization and design evaluation of a conical spout–fluidized bed under geometric and gas-distribution effects
Çutay, Arif; Tozlu, Alperen; Özahi, Emrah
Spout–fluidized beds are widely used in gas–solid processing and thermal conversion applications because of their enhanced particle circulation, mixing, and heat-transfer characteristics. However, the combined effects of reactor geometry, distributor configuration, and gas-flow distribution on the hydrodynamic organization of conical spout–fluidized beds are still not sufficiently quantified from a design perspective. In this study, a three-dimensional transient numerical analysis was performed to assess the effects of cone angle, auxiliary-hole number, and auxiliary-to-total flow-rate ratio on gas–solid flow behavior in a conical spout–fluidized bed reactor. The simulations were carried out using an Eulerian–Eulerian two-fluid model coupled with the kinetic theory of granular flow and the Syamlal–O'Brien drag model. Three cone angles (50°, 60°, and 70°), three distributor configurations with 70, 140, and 210 auxiliary holes, and two auxiliary-to-total flow-rate ratios (Qf/QT≈0.15 and Qf/QT=0.43) were investigated. The hydrodynamic response was evaluated using particle velocity, voidage distribution, and two compact flow indices: the radial spout heterogeneity index (RSHI) and the axial spout regularity index (ASRI). The results show that the flow field is governed by a characteristic core–annulus structure consisting of a dilute, high-velocity spout core and a denser recirculating annulus. Increasing Qf/QT enhances auxiliary gas penetration, particle suspension, and radial expansion of the gas-penetrated region; however, it also increases RSHI and ASRI, particularly at lower cone angles, indicating stronger radial heterogeneity and axial irregularity. Increasing the cone angle from 50° to 70° reduces radial hydrodynamic heterogeneity and improves axial spout regularity, whereas the number of auxiliary holes has a secondary and configuration-dependent influence compared with the gas-flow distribution and cone angle. Overall, the findings indicate that the auxiliary-to-total flow-rate ratio primarily controls gas distribution and gas–solid momentum exchange, while the cone angle governs radial uniformity and axial spout regularity. The proposed RSHI–ASRI framework provides a design-oriented basis for comparing conical spout–fluidized bed configurations and selecting operating conditions according to the desired balance between gas–solid interaction intensity, radial uniformity, and axial spout regularity.
- MakaleAçık Erişim2021Scopus SJRQ1Forecasting outbreak of COVID-19 in Turkey; Comparison of Box–Jenkins, Brown's exponential smoothing and long short-term memory models
Guleryuz, Didem
The new coronavirus disease (COVID-19), which first appeared in China in December 2019, has pervaded throughout the world. Because the epidemic started later in Turkey than other European countries, it has the least number of deaths according to the current data. Outbreak management in COVID-19 is of great importance for public safety and public health. For this reason, prediction models can decide the precautionary warning to control the spread of the disease. Therefore, this study aims to develop a forecasting model, considering statistical data for Turkey. Box-Jenkins Methods (ARIMA), Brown's Exponential Smoothing model and RNN-LSTM are employed. ARIMA was selected with the lowest AIC values (12.0342, -2.51411, 12.0253, 3.67729, -4.24405, and 3.66077) as the best fit for the number of total case, the growth rate of total cases, the number of new cases, the number of total death, the growth rate of total deaths and the number of new deaths, respectively. The forecast values of the number of each indicator are stable over time. In the near future, it will not show an increasing trend in the number of cases for Turkey. In addition, the pandemic will become a steady state and an increase in mortality rates will not be expected between 17–31 May. ARIMA models can be used in fresh outbreak situations to ensure health and safety. It is vital to make quick and accurate decisions on the precautions for epidemic preparedness and management, so corrective and preventive actions can be updated considering obtained values.
AtıfScopus39WoS28OpenAlex47
İncele - MakaleYalnız künye2016Scopus SJRQ1Effect of sugar beet fiber concentrations on rheological properties of meat emulsions and their correlation with texture profile analysis
Ağar, Berrin; Gençcelep, Hüseyin; Saricaoğlu, Furkan Türker; Turhan, Sadettin
The effect of sugar beet fiber (SBF) concentration on the rheological properties of meat emulsions was determined. In addition, texture profile analysis (TPA) of cooked meat emulsions was carried out to find a possible relationship between the dynamic rheological data and TPA parameters. All studied emulsions exhibited non-Newtonian, pseudoplastic behavior since apparent viscosity decreased with increasing shear rate. The Ostwald–de Waele model was successfully used to describe the flow properties of meat emulsions (R2 > 0.913). Emulsion systems were characterized as weak gel-like macromolecular dispersions with storage modulus (G′) much greater than loss modulus (G″). A modified Cox–Merz rule was applied by multiplying angular frequency with shift factors (αSF). Material stiffness parameter (Aα) calculated from complex modulus (G*) increased as SBF concentration increased. Significant correlations among the material stiffness data and TPA parameters were observed. It was concluded that TPA parameters could be predicted by using dynamic shear tests, and hence, this will make possible to save time and cost for meat processors when manufacturing a product with acceptable structural or textural characteristics.
AtıfScopus55WoS48OpenAlex66İncele - DergiProcess Safety and Environmental Protection
- DergiFood and Bioproducts Processing
- DergiChemical Engineering Research and Design