Axial gas mixing in conical spouted beds with high density particles

Conical spouted beds operating with high-density particles (ρp > 2500 kg/m3) have recently gained attention because of their potential use as nuclear fuel coaters for next-generation nuclear reactors. In the literature, the number of axial gas mixing studies in conical and conical-cylindrical spouted beds is very limited and all axial mixing studies were carried out with relatively light particles (ρp ≤ 2500 kg/m3). Therefore, the objective of this study was to generate experimental data that can be used to explain the gas axial mixing behavior in conical spouted beds operating with both low- and high-density particles. Experiments were conducted in two (γ = 30°, 60°) conical spouted beds with three different types of particles: zirconia (ρp = 6050 kg/m3), zirconia toughened alumina (ρp = 3700 kg/m3) and glass beads (ρp = 2460 kg/m3). In order to be able to compare experimental data obtained at different conditions, a 1-D convection-diffusion gas mixing model originally developed by San José et al. (1995) was implemented to determine the axial dispersion coefficients. The results show that the axial dispersion coefficients range between 1.75×10−2 m2/s and 9.35×10−2 m2/s, increase with superficial gas velocity and are higher than the corresponding dispersion coefficients of fixed beds, lower than the dispersion coefficients of fluidized beds and in the same range with the cylindrical spouted beds reported in the literature. The corresponding Peclet numbers were in the range of 0.6–7.8 for all operating conditions and slightly higher Peclet numbers were obtained with glass beads indicating the relative importance of gas convective transport over gas dispersion for light particles compared to heavy particles.


Gas mixing in conical spouted beds
Doğan, Neslin; Külah, Görkem; Department of Chemical Engineering (2020-12-28)
Conical spouted beds are relatively new generation gas-solid flow reactors used in various applications such as drying, catalytic polymerization, treatment of wastes, particle coating and chemical vapor deposition due to their advantages over cylindrical spouted beds. For complete characterization of conical spouted beds, determination of the local flow structure based on gas velocity and gas mixing is of paramount importance. There are limited studies on local gas behavior in conical spouted beds, especial...
Particle Velocity, Solids Hold-Up, and Solids Flux Distributions in Conical Spouted Beds Operating with Heavy Particles
Külah, Görkem; KÖKSAL, MURAT (American Chemical Society (ACS), 2016-03-23)
Conical spouted beds operating with high density particles have recently gained attention because of their potential use as nuclear fuel coaters for next-generation nuclear reactors. To design, scale-up, and manufacture these coaters, detailed investigation of local flow structure is of paramount importance. Therefore, in this study, local instantaneous particle velocity and solids hold-up and flux measurements were carried out in spouted beds having a wide range of cone angles (30, 45, 60) using zirconia p...
CFD Simulations of Hydrodynamics of Conical Spouted Bed Nuclear Fuel Coaters
Lule, Senem Senturk; Çolak, Üner; KÖKSAL, MURAT; Külah, Görkem (2015-06-01)
The ability of the two fluid method (TFM) to predict the gas-solid flow phenomenon in conical spouted beds operated with high density (6050kgm(-3)) particles simulating the nuclear fuel coating conditions is investigated. The effects of geometric and operational factors, such as conical angle and static bed height, are also assessed. The results show that TFM predicts the time-averaged bed pressure drop quite well. The qualitative variation of the particle velocity, solids volume fraction, and axial particl...
Catalytic methanolysis of hydrazine borane: a new and efficient hydrogen generation system under mild conditions
Karahan, Senem; Zahmakıran, Mehmet; Özkar, Saim (2012-01-01)
Safe and efficient hydrogen storage is a major obstacle for using hydrogen as an energy carrier. Therefore, intensive efforts have been focused on the development of new materials for chemical hydrogen storage. Of particular importance, hydrazine borane (N2H4BH3) is emerging as one of the most promising solid hydrogen carriers due to its high gravimetric hydrogen storage capacity (15.4 wt%) and low molecular weight. Herein, we report metal catalyzed methanolysis of hydrazine borane (N2H4BH3, HB) as a fast h...
Analytic modelling of multi-junction solar cells via multi-diodes
Schuster, Christian Stefano; Koc, Mehmet; Yerci, Selçuk (2022-01-01)
Laboratory efficiencies and estimated costs alone cannot assess the extent to which photovoltaics (PV) is expanding. For outdoor operation, PV technologies also need realistic yet effective methods of yield evaluation. Here, we propose an analytical approach for calculating the power output of series, parallel, and independently connected multi-junction solar cells. It uses a fast search algorithm for the maximum power point suitable for data-driven tasks. Our approach enables us to model the sub-cells of a...
Citation Formats
N. Güler, M. KÖKSAL, and G. Külah, “Axial gas mixing in conical spouted beds with high density particles,” Particuology, vol. 81, pp. 45–57, 2023, Accessed: 00, 2023. [Online]. Available: