In mechanized rice harvesting, the performance of the cleaning device is one of the important factors that affect the overall efficiency of the combine-harvester. To study the influence of different parameters on the cleaning efficiency, the influence of airflow velocity and the inclination angle on the cleaning effect was analyzed. Both simulation and experimental results prove that the increase of airflow velocity and the inclination angle will reduce the impurity rate of rice and increase the entrainment loss rate. The addition of a vibrating sieve to the device reduces the trash rate of rice, but the entrained loss rate increases accordingly. After tilting the sieve surface by 10°, a reduction in both the impurity rate and the entrainment loss rate of rice was found in combination with the force analysis of the particles on the sieve surface. The effect of the device structure on the internal flow field distribution was analyzed by comparing the eddy viscosity and velocity flow lines inside the three scavenging device structures. Simulation after calibration of rice moisture content revealed that humid rice cleaning was not effective.

The life of the hearth is the main limiting link of the campaign of a blast furnace. As the equipment for holding molten iron in the furnace, the high-temperature molten iron is in direct contact with the refractory, which makes the refractory have a larger temperature increase. If the temperature gradient inside the refractory is large, it generates large thermal stress and causes the refractory to crack. Blast furnace gas and molten iron intrude into the gap, which directly causes melting erosion and other chemical erosion with carbon bricks. It aggravates the erosion degree of the furnace and seriously affects the production life of the furnace. Therefore, the furnace often occurs with different types of severe depression erosion in the late service of the blast furnace. In this study, the calculation model of the thermal fluid-solid coupling considering the molten iron flow and the solidification of molten iron was established. This calculation model was applied to study thermal stresses in the furnace with severe erosion. Based on the calculation model, the effect of blast furnace production parameters and deadman condition on thermal stresses in the furnace with severe depression erosion were analyzed, including tapping productivity, tapping temperature, cooling intensity, and deadman geometry. The research results are of great significance for prolonging the safe production life of blast furnaces.

The blast furnace (BF) hearth is critical for determining the life of a BF. Irreversibly eroded hearths can be caused by high-temperature molten iron erosion, alkali metal corrosion, and thermal stress. When serious depression erosion occurs in the hearth, furnace protection measures can prevent the erosion from expanding and ensure the safe operation of the BF. At present, furnace protection measures and furnace protection strength are mostly selected based on engineering experience. In this paper, a three-dimensional (3D) computational fluid dynamics (CFD) numerical model of BF hearth with elephant-type depression erosion was established to predict and evaluate the effect of furnace protection measures. At the same time, the phase change behavior of hot iron solidification was also considered. A numerical model was used to analyze common furnace protection measures such as increasing furnace hearth cooling, closing the tuyere, reducing the tapping productivity, and reducing the tapping temperature. The calculation results are consistent with actual furnace protection experience.

Blast Furnace (BF) is the primary production equipment for modern ironmaking, and the hearth is a crucial part of the BF where high-temperature molten iron is periodically stored. The deadman, located within the hearth, poses a significant obstruction to the flow of molten iron. Changes in the state of the deadman directly affect the flow and discharge behavior of molten iron within the hearth, subsequently influencing the lifespan of the hearth. This study develops a three-dimensional Computational Fluid Dynamics (CFD) model that incorporates the flow of molten iron and the solidification phase transition within the blast furnace hearth. Using the skull’s thickness in the erosion area as an evaluation index, it investigates the effects of deadman parameters, such as floating height, maximum diameter, eccentricity, porosity, and bottom shape, on the hearth’s erosion area. Additionally, considering the iron flow velocity and furnace wall temperature, the study offers suggestions for the comprehensive protection of the furnace hearth. The findings revealed that maintaining a higher floating height of the deadman is beneficial for the comprehensive safety of the hearth. When the deadman is eccentric towards the erosion direction, its volume increases, or its porosity decreases, the thickness of the skull in the erosion area will decrease, posing potential safety hazards to the operation of the BF hearth. The deadman with a spherical bottom, in both its seated and floating states, results in a stable thickness of the skull in the erosion area, which is favorable for extending the service life of the hearth.

This study developed a gravel soil granular bed model using the discrete element method, elaborating on the core barrel drilling process by integrating bond-breaking and particle flow patterns. A quantitative description of the drilling process is achieved by defining bond-breaking efficiency. The results indicate that the force on particles near the drill tooth is the greatest, and this force increases with the core barrel feed rate, which enhances drilling efficiency and exacerbates wear on the drill tooth and guide bars. An increase in rotational speed raises the force on the particles in the boundary region, leading to deeper wear of the guide bar; however, the enlargement of particle voids near the drill tooth mitigates wear. Additionally, a coupled discrete element method and finite element method are developed to analyse the effects of drilling parameters on drill tooth deformation, revealing that the design of the open hole at the top of the drill can effectively reduce the maximum equivalent stress and wear depth. The conclusions drawn contribute to understanding particle mechanics, the particle bonding damage mechanism, and drilling mechanical behavior, providing a reference for optimizing drilling operations and drill design.