Print ISSN: 1681-6900

Online ISSN: 2412-0758

Keywords : hydrodynamic

Recent Development in Hydrodynamic and Heat Transfer Characteristics in the Three-phase Fluidized-bed System

Omar S. Mahdy; Amer A. Abdulrahmn; Jamal M. Ali

Engineering and Technology Journal, 2022, Volume 40, Issue 9, Pages 1-26
DOI: 10.30684/etj.2022.132506.1125

Gas–liquid-solid fluidized beds are broadly utilized in the petrochemical, pharmaceutical, refining, food, biotechnology, and environmental industries. Due to complex phenomena, such as the particle-particle, liquid-particle, particle-bubble interactions, complex hydrodynamics, and heat transfer of three-phase (gas-liquid-solid) fluidized beds, they are incompletely understood. The ability to accurately predict the essential characteristics of the fluidized-bed system, such as hydrodynamics, individual phase mixing, and heat transfer parameters, is necessary for its successful design and operation. This paper investigates the pressure drop, minimum fluidization velocity, phase holdup, heat-transfer coefficient of a fluidized bed reactor, heat transfer studies, CFD simulation, and the effect of these parameters on the extent of fluidization. Many variables (fluid flow rate, particle density and size, fluid inlet, and bed height) affect the fluidizing quality and performance of the fluidization process. The hydrodynamics parameters, mixing of phases, and the behavior of heat transfer with various modes of fluidization were investigated to predict hydrodynamics parameters. Several publications have demonstrated the utility of (CFD) in explaining the hydrodynamics, heat, and mass transfer of fluidized beds. Principles of measurement, details of the experimental configurations, and the applied techniques by various researchers are also presented. Feng's model was statistically validated using experimental data that was both time-averaged and time-dependent. Furthermore, this model successfully predicted the instantaneous flow structures, which should provide strategies for the best design, scale-up, and operation in fluidized bed columns. The divergence between the simulated and observed values can be reduced by better understanding the fluidized bed's nature.

2D Model to Investigate the Morphological and Hydraulic Changes of Meanders

Jaafar S. Maatooq; Luay K. Hameed

Engineering and Technology Journal, 2020, Volume 38, Issue 1, Pages 9-19
DOI: 10.30684/etj.v38i1A.95

River engineering investigations require some level of hydrodynamic and morphologic analysis. The detailed of the hydraulic and morphologic features through meander evolution can be recorded by the numerical model spatially and temporally. The Center for Computational Hydro-science and Engineering, two- dimensional model (CCHE2D V3.29) was adopted to investigate the hydraulic and morphologic changes through meander’s evolution. Through the experimental work, a series of experiments runs were carried out through combining different geometric and hydraulic parameters to produce different experiment conditions. These parameters are flow rate, bed slope, and different initial incised and wide channels for both rectangular and trapezoidal sections. The CCHE2D model was calibrated and verified using two sets of experimental data. According to the computed values of statistical indicators, BIAS, NSE, and MAE of 0.0084, 0.96, and 0.0132 respectively for water level simulation, and 0.007,0.94, and 0.0182 respectively for bed level simulation, the calibrated Manning’s roughness which gives an acceptable agreement between simulated and measured water and bed levels was 0.029. The verification results were evaluated by the same statistical indicators of BIAS, NSE, and MAE of 0.09, 0.81, and 0.018, respectively, as evidenced by the statistical indicators, values that the CCHE2D model was reasonably capable of simulating the hydraulic and morphological changes through meander evolution.

Hydrodynamics in a Trickle Bed Reactor

Muhammad Fadel Abd; Farah Talib Jasim; Luma Shihab Ahmed

Engineering and Technology Journal, 2013, Volume 31, Issue 15, Pages 2860-2875

Experimental investigations have been carried out to study the performance of
trickle bed reactor. The effect of key parameters that play predominate role in the
performance of trickle bed reactor was studied. A laboratory unit was constructed
for this purpose where a versatile reactor setup required " high pressure stainless
steel reactor of 0.05m i.d × 1.25m height", in which the hydrodynamic
experiments carried out under different operating condition namely, superficial gas
velocity and liquid velocity , reactor pressure, bed temperature .Air–water system
was used for hydrodynamic experiments pressure drop, dynamic liquid holdup, and
axial dispersion coefficients were estimated. The results also show that the
dynamic liquid holdup increases with increasing liquid velocity and decreases
with increasing superficial gas velocity and bed temperature. Axial dispersion
tends to increase with increasing superficial gas and liquid velocities while it
decreases with increasing bed temperature.