Investigation of the Performance of V-cut Turbines for Stirring Shear-thinning Fluids in a Cylindrical Vessel

Abstract

The impeller design is the most crucial parameter to enhance the performance of stirred tanks. The cut in the impeller blade is a new technique to save the energy of impellers in mixing vessels without increasing the mixing time or reducing the product quality. In this paper, the new technique of cut is applied for a disc turbine rotating in an unbaffled cylindrical tank. Effects of the V-cut shape are highlighted. Non-Newtonian shear-thinning fluids are considered for the three flow regimes (laminar, transient, and turbulent). Effects of the number of blades on the flow patterns, pumping rate (Nq) and power consumption (Np) are explored. From the obtained results, a recirculation loop of flow is observed at the tip of each blade for impellers with less than three blades. These recirculation loops disappear with the increased number of blades. Under laminar flow conditions, the obtained results also revealed a decrease in power consumption and an increase in the discharge flow rate with the rise of Reynolds number. However, almost any changes were observed for these parameters (Np and Nq) under turbulent flow conditions.

Complex fluid flow in annular space under the effects of mixed convection and rotating wall of the outer enclosure

“…This study was conducted with powerful CFD software, which proved its efficiency in the treatment of various complex phenomena. [49][50][51][52][53][54][55][56][57][58][59][60][61][62] In this numerical pattern work, we studied 100 and n = 0.6, 1, and 1.4 at Re = 20 and Pr = 50. In fact, the contours of streamlines determine the path of the flow within the space, from which it is possible to know the regions in which the thermal transfer is strong or weak.…”

“…This study was conducted with powerful CFD software, which proved its efficiency in the treatment of various complex phenomena 49–62 . In this numerical pattern work, we studied the effectiveness of thermal transfer under the influence of a set of related parameters stated here: size and arranging of inner cylinders, the rotational speed of the outer enclosure, and strength of thermal buoyancy the nature of the working fluid.…”

Thermophysics Analysis of Office Buildings with a Temperature–Humidity Coupling Strategy Under Hot-Arid Climatic Conditions

“…The computational fluid dynamics (CFD) method has proved its efficiency in various engineering applications and with complex geometries [56][57][58][59][60][61][62][63][64][65]. In this works, the CFD tool Fluent was used to perform the investigation.…”

Entropy and Hurst analysis for the determination of two-phase flow time series complexity

“…These works do not present a general application, since the proposed mathematical model depends on the physical and chemical phenomena of the system involved. There are studies that report aspects such as: The effect of some design parameters on the flow fields and energy consumption through CFD simulation (Youcefi et al, 2013); the effect on hydrodynamic parameters when using different eccentric impellers without baffles in a cylindrical tank (Hameur, 2016); the Effects of Baffles on a Vessel Stirred by a Rushton Turbine (Kamla et al, 2017); the hydrodynamic behavior of the agitation of a shear-thinning fluid in a cylindrical vessel (Ameur, 2020); the transitory behavior of CO2 in a gas cooler during variable startup conditions of a transcritical refrigeration system (Ituna, 2019); the rotating reference frame size for simulating amixing straight-blade impeller in a baffled stirred tank using an MRF approach (De la Concha et.al., 2019). These works show satisfactory evidence that allows to elucidate the viability of the CFD in the analysis of hydrodynamic parameters, which allows proposing this tool to study more complex phenomena such as mass transfer using the appropriate models for this purpose.…”