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The agitator tank is a type of reaction vessel widely used in various industries, such as chemical engineering. In this study, the structure of the three-layer blade agitator was optimized by controlling variables, and the changes in the fluid area and the suction rate of the self-suction blade during the agitation process were investigated. Using the numerical simulation analysis method, the rotation direction of the blades, the total height of the blades, and the position of the self-suction blade were changed as three factors. The FLUENT software was used to conduct simulation analysis on the agitators with different structures to obtain visualized data. The orthogonal experimental variance analysis was performed on the obtained data to determine the magnitude of the influence of each factor on the suction rate of the self-suction blade. The study found that among the three factors in this experiment, the position of the self-suction blade had the greatest impact on the suction rate, followed by the total height of the blades, and finally the rotation direction of the blades.

The exploitation of deep and ultra-deep oil and gas reservoirs has problems such as complex pressure system, narrow safety density window and high overflow risk. High-precision overflow monitoring methods help improve drilling efficiency. In this paper, high-frequency radar is proposed as a tool for monitoring the mud level of the tank, which is not affected by steam and can monitor the mud level with high precision. In view of the monitoring position, the numerical simulation method is used to calculate the surface of the mud tank, the actual size of the mud tank is scaled in equal proportions, the size of the agitator, the stirring speed and the inlet and outlet flow are numerically calculated, and the fluctuation characteristics and influencing factors of the dynamic mud surface are analyzed, and a reasonable monitoring position is analyzed. It is found that the mud surface in the center of the agitator decreases, the mud surface near the wall of the mud tank rises, The mud surface fluctuation is mainly affected by the stirring speed, the impeller diameter, and the mud height, and is less affected by inlet and outlet flow rates. Moreover, the lower the mud height, the greater the impact of the agitator; the higher the stirring speed the more intense the mud surface fluctuation; the larger the impeller diameter, the more intense the mud surface fluctuation. it was found that the mud surface near the wall between the two agitators is relatively stable, where is less affected by agitators and the mud height. It is recommended to place it at this position when using high-frequency radar for monitoring, aiming to improve the accuracy of-frequency radar mud surface monitoring.

Good solid-liquid mixing homogeneity and liquid level stability are necessary conditions for the preparation of high-quality composite materials. In this study, two rotor-stator agitators were utilized, including the cross-structure rotor-stator (CSRS) agitator and the half-cross structure rotor-stator (HCSRS) agitator. The performances of the two types of rotor-stator agitators and the conventional A200 (an axial-flow agitator) and Rushton (a radial-flow agitator) in the solid-liquid mixing operations were compared through CFD modeling, including the homogeneity, power consumption and liquid level stability. The Eulerian–Eulerian multi-fluid model coupling with the RNG k–ε turbulence model were used to simulate the granular flow and the turbulence effects. When the optimum solid-liquid mixing homogeneity was achieved in both conventional agitators, further increasing stirring speed would worsen the homogeneity significantly, while the two rotor-stator agitators still achieving good mixing homogeneity at the stirring speed of 600 rpm. The CSRS agitator attained the minimum standard deviation of particle concentration σ of 0.15, which was 42% smaller than that achieved by the A200 agitators. Moreover, the average liquid level velocity corresponding to the minimum σ obtained by the CSRS agitator was 0.31 m/s, which was less than half of those of the other three mixers.

The goal of this work was to evaluate the efficiency of two different agitation systems by measuring the nutrient distribution in a digester fed with renewable energy crops and animal manure. The study was carried out at the practical research biogas plant of Hohenheim University. A unique probe sampling system has been developed that allows probe sampling from the top of the concrete roof into different parts and heights of the digester. The samples were then analyzed in the laboratory for natural fatty acids concentrations. Three different agitation setups were chosen for evaluation at continuous stirring and feeding procedures. The results showed that the analysis approach for agitator optimization through direct measurement of the nutrients distribution in the digester is promising. The type of the agitators and the agitation regime showed significant differences on local concentrations of organic acids, which are not correlated to the dry matter content. Simultaneous measurements on electric energy consumption of the different agitator types verify that by using the slow-moving incline agitator with large propeller diameters in favor of the fast-moving submersible mixer with smaller propeller diameters, the savings potential rises up to 70% by maintaining the mixing quality.

High energy consumption in fluidized bed dryers (FBDs) remains a critical challenge for tea processing, largely due to poor fluidization quality of sticky, irregular, and non-uniform tea particles. To address this issue, this study investigated the potential of horizontal-axis rotary agitators to improve the hydrodynamics of a gas-solid FBD and reduce energy losses. Computational fluid dynamics (CFD) simulations were performed using the two-fluid model combined with the kinetic theory of granular flow (TFM-KTGF), focusing on key parameters including pressure drop, standard deviation of pressure drop, solid volume fraction distribution, and granular temperature. Some configurations were analyzed: a bed without an agitator, and beds equipped with rotary agitators of varying blade numbers (three and five) and diameters (200 mm and 300 mm) at different rotational speeds. The results demonstrated that introducing a horizontal-axis rotary agitator significantly improves fluidization. The largest rotary domain (five blades, 300 mm diameter) achieved the lowest pressure drop of 315,135 Pa at 6.28 rad/s, while also promoting more uniform solid distribution and increasing granular temperature up to 2.5 × 10⁻ 3  J/kg. The agitator enhanced particle circulation, expanded lean regions within the bed, and reduced dense packing, leading to improved gas-solid contact and reduced resistance to airflow. Furthermore, increasing the agitator speed decreased pressure drop and its standard deviation, while increasing the granular temperature, confirming the beneficial effect of enhanced stirring energy. This study highlights the effectiveness of horizontal-axis rotary agitators in enhancing the hydrodynamic performance of FBDs, offering a promising approach to improve energy efficiency and drying uniformity in tea production. The insights presented here can guide future design and optimization of industrial-scale dryers handling cohesive, irregular particles.

Grinding is a unit of operation of a pure mechanical process. An attritor is a grinder able to be used for fine or selective grinding. However, few studies have reported on the optimum design for the attritor. The attritor’s grinding characteristics and grinding effect depend not only on the operating conditions, but also on the geometry of the agitator. Therefore, we investigated the effect of the agitator shape on the grinding efficiency from the viewpoint of experiments, kinetic analysis, and discrete element method (DEM) simulations. We conducted grinding experiments with two different agitators. One was Agitator A, a traditional design with two pairs of 90° staggered mixing arms at the middle and bottom of the mixing shaft. The other was Agitator B, with a lower mixing arm inclined by 10° along the horizontal direction. We found that the grinding rate constant of Agitator B was approximately 40% greater than that of Agitator A. Although the size distribution of the particles was relatively dispersed after grinding with Agitator B, the distribution was concentrated mainly within two ranges (<0.5 mm and 2–4 mm) with Agitator A. These results and an elemental analysis of each size fraction suggested that the dominating grinding mode in Agitator A was surface grinding, whereas in Agitator B, it was bulk grinding. In terms of the influence of the agitator shape, the DEM simulation results showed that the kinetic energy of the grinding media in Agitator B was 0.0046 J/s, i.e., larger than the 0.0035 J/s obtained for Agitator A. A collision energy analysis showed that the dominating collision was between the media and wall in the tangential direction for both models. The collision energy of the media in Agitator B was larger than that of that in Agitator A. The results from the DEM simulation can help us evaluate the experimental results and infer the reasons why the grinding rate constant in Agitator B is larger than that in Agitator A.

Anaerobic digestion (AD) plays a crucial role in renewable energy production and waste management by converting organic waste into biogas and reduces greenhouse gas emissions. Optimized bioreactor performance depends on two main categories of factors: (1) reactor and geometric factors of agitator geometry, blade configuration, rotational speed, torque, power consumption, and the impeller-to-tank ration (d/D), and (2) fluid property factors of viscosity and flow characteristics, which relates turbulence, circulation patters, and stratification. Impeller power strongly influences nutrient distribution, gas exchange, and temperature uniformity within the reactor. While higher power inputs improve turbulence and prevent stratification, they also increase energy demand. This study evaluated fifteen blade configurations to determine the optimal fluid circulation using ANSYS 2024 R1 Fluent simulations. The bioreactor tank, with a diameter of 0.130 m and a height of 0.225 m, was tested at speeds ranging from 40 to 150 RPM. Among the single-blade configurations, the curved blade achieved the highest velocity at 0.521 m/s, generating localized circulations. The Rushton blade produced strong radial flows with a velocity of 0.364 m/s, while the propeller blade reached 0.254 m/s, supporting axial flow. In double-blade arrangements, the curved-propeller combination exhibited velocities between 0.261 and 0.342 m/s, enhancing fluid motion. The three-blade configurations resulted in the highest power consumption, ranging from 1.94 W to 1.99 W, with power increasing at higher RPMs and larger impeller sizes. However, torque values decreased over time. The most efficient mixing was achieved at moderate RPMs (80–120) and an impeller-to-tank diameter ratio (d/D) of approximately 0.75. These findings highlight the significance of blade selection in balancing mixing efficiency and energy consumption for scalable AD systems.

Mixing processes are becoming today a huge concern for industrialists in various domains like the pharmaceutical production, oil refining, food industry and manufacture of cosmetic products especially when the processes are related to the mixing of highly viscous products. So the choice of a stirring system for this category of products or fluids must be rigorously examined before use because of the flows which are laminar in the most cases, something that is not good to obtain homogeneous particles or suspensions after the mixing operation. This CFD study allows developing a new geometrical model of mechanical agitator with high performance for mixing of highly viscous fluids. It consists of a combination of two bladed and helical screw agitators. The investigations of the flow structure generated in the vessel are made by using the computer code ANSYS CFX (version 13.0), which allows us to realize and test the effectiveness of the new stirrer on the resulting mixture and power consumption.

Demand for fresh water increases day by day. Solar desalination is one of the promising technologies to meet this demand in an economical fashion which uses solar still. For the current study, single-basin single-slope conventional solar still and a modified single-basin single-slope solar still with inbuilt condenser and agitator were designed and fabricated. Both the stills were tested under the same ambient conditions to compare the performance. Through experimental results, it was found that modified still with inbuilt condenser and agitator had 98.69% more productivity than conventional solar still. Modified still productivity was recorded as 4.856 L/m 2 /day and that of conventional still was 2.44 L/m 2 /day. The agitation effect caused by the agitator in the modified still led to an increase in the rate of evaporation. The increase in condensing area for the same evaporation area of the modified still improved the condensation rate. These two synergized effects resulted in an overall performance improvement of the modified still over the conventional still. An energy analysis revealed that modified still is 24.42% more efficient than its counterpart. The energy efficiency of modified and conventional stills was calculated as 4.82% and 2.04% respectively.

Experimental studies on heat transfer coefficients were carried out of Newtonian and time dependent power law fluids in mechanically agitated vessel. Three different Non-Newtonian fluids containing 0.5%(n = 0.973), 1%(n = 0.851), 2%(n = 0.793) CMC (Carboxy Methylcellulose) and water were studied in the coil and 1, 2 and 4 percentages (n = 0.698) Non-Newtonian solutions of CMC in the test vessel. In this section of investigation we are focusing on heat transfer from wall to agitated vessel. In order to find results, the entire experimental data were discussed for jacketed vessel in three different impeller diameter and different speeds. It has been observed that a Modified Wilson plot is most appropriate for finding individual heat transfer coefficients. Data of 1, 2 and 4% CMC, for three impeller diameters, has been correlated and the overall heat transfer coefficient have been approximated with standard deviation 8.03%.