Search Results (4)

The high energy consumption of conventional mixers equipped with active mixing elements necessitates the development of more efficient technologies for mixing bulk materials and feed mixtures. This study presents a gravity-driven mixing approach based on the rotation of an inclined cylindrical chamber, eliminating the need for active mixing elements. During chamber rotation, the mixture components move toward both end walls while simultaneously undergoing a circular motion along the inner cylindrical surface. This movement intensifies the mixing process and reduces energy consumption, thereby providing an energy-efficient gravity-based mixing approach that operates without active mixing elements. Laboratory experiments were conducted to determine the key physical and mechanical properties of the sapropel, organic fertilizer, and compound feed (formulation K-60-1). The measured values were as follows: velocity on an inclined steel surface, 0.65–1.21 m/s; coefficient of friction, 0.40–0.91; bulk density, 453–1166 kg/m³; and angle of repose, 36–39°. The experimental results confirmed the validity and adequacy of the developed analytical relationships. A structural and technological design of the gravity mixer was developed, and an experimental prototype was manufactured. Analytical relationships were obtained to determine the critical rotational speed of the chamber, particle movement velocity, and the power required for the mixing process. Under optimal operating conditions, the mixture uniformity reached 95.7% after 4 min of mixing. The mixer productivity was 0.95 t/h, while the specific energy consumption was 0.5 kWh/t, which is 2.5 times lower than that of conventional mixers equipped with active mixing elements. The obtained results confirm the feasibility and effectiveness of the proposed gravity-based mixing method for the preparation of feed and organomineral mixtures under the operating conditions of small-scale farms. Full article

Conical diffusers perform a variety of critical functions in final products (gas, hydraulic, and wind turbines, ejectors, gasifiers, combustion chambers, etc.). The purpose of this study was to experimentally study the flow distribution features in a vertical conical diffuser with different technical air supply methods to find directions for optimal movement organization. The vertical diffuser (apparatus) consisted of a conical section with an opening angle of 30° and a cylindrical section. The scientific results were obtained based on an experimental stand and the thermal imaging method. The article presents simplified equations of continuity and momentum balance for the system under consideration. Two methods of air supply to the diffuser were investigated: air supply through a single duct and air supply through 4 nozzles installed at different angles of 45°, 60°, and 70°. The experiments were carried out for stationary air movement with volumetric flow consumption through the system from 0.0018 m³/s to 0.006 m³/s. The Reynolds number for the air flow at the diffuser inlet ranged from 10,500 to 106,000. Significant differences in the flow structure for air supply to a diffuser through a single duct and nozzles were identified. The possibility of controlling the flow structure in a vertical diffuser by varying the inclination of the supply nozzles was demonstrated. Four characteristic patterns of air distribution in the diffuser were obtained: firstly, a pronounced central flow through the entire apparatus with a noticeable deviation of the flow to the right side; secondly, a local (from 30 to 75% of the apparatus height), central flow in the diffuser; thirdly, active air movement in the lower part of the diffuser with subsequent flow along the side walls of the apparatus; fourthly, multidirectional flow movement throughout the entire volume of the diffuser. Full article

Ocean wave energy has emerged as a promising source in the pursuit of sustainable energy solutions, with Oscillating Water Column (OWC) systems standing out due to their simplicity and potential. This study analyzes how the geometric and physical parameters of the OWC chamber influence internal airflow dynamics, a key factor in the performance of the Wells turbine. The methodology includes a mathematical approximation, the definition of chamber geometry, and the design parameters of both the chamber and the Wells turbine. Three configurations were evaluated using Computational Fluid Dynamic (CFD) simulations. The impact of key variables such as chamber inclination and cross-sectional shape on air velocity and pressure at the turbine inlet was assessed. The results indicate that, among cylindrical, inclined cylindrical, and rectangular configurations, the inclined cylindrical chamber design significantly enhances airflow stability and turbine efficiency. These findings offer valuable insights for enhancing the overall performance of OWC based energy systems. Full article

To meet the requirements of trellis grape crop root irrigation, spraying pesticides on branches and leaves, an integrated sprinkler was designed, which relies on the flow pressure to change the irrigation water and spray pesticide working modes. The structural parameters that affect the hydraulic performance were selected based on the working principle of the sprinkler. The key parameters for the irrigation mode included diversion hole inclination angle, refractive cone angle, refractive cone length, and cone hole distance. The key parameters for the spray pesticide mode included diversion chute width, the number of diversion chutes, the diversion chute inclination angle, the rotary acceleration chamber height, and the nozzle outlet cylindrical section length. The central composite design response surface tests of the water–pesticide integrated sprinkler were carried out; the analysis of variance and regression analysis were selected; the main influence rules and interactions of key structural parameters on irrigation performance and pesticide spraying performance of sprinkler irrigation system were obtained. The optimal parameters of the water–pesticide integrated sprinkler were: the diversion hole inclination angle is 20.8°, the refractive cone angle is 123.7°, the refractive cone length is 8.8 mm, the cone hole distance is 3.6 mm, the diversion chute width is 2.5 mm, the number of diversion chutes is 2, the diversion chute inclination angle is 10°, the rotary acceleration chamber height is 1.3 mm, and the nozzle outlet cylindrical section length is 0.7 mm. The irrigation hydraulic performance of the wetted radius is 3.4 m, the average irrigation application rate is 0.65 mm/h, and the uniformity coefficient is 88%. The spraying pesticide performance of the droplet volume mid-diameter is 200.2 μm, the droplet spectrum width is 2.2, and the droplet coverage is 9.4%. Full article