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.

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.

Irreversible erosion damage of the hearth lining determines the campaign life of a blast furnace (BF). Among the factors involved, structural thermal stress resulting from both internal and external temperature differences and external constraints is a key mechanism in the damage to the hearth lining. Based on a thermal–fluid–structural coupling model that accounts for molten iron flow and solidification, this study, building on thermal stress analysis of the hearth lining, proposes a method to determine the critical strength-based erosion boundary of the lining, using the compressive strength of carbon bricks as the criterion. It also investigates the influence of factors such as dead iron layer depth, tapping productivity, and molten iron temperature on the thermal stress-driven erosion boundary. The findings reveal that the depth of the dead iron layer determines the morphology of the hearth lining’s erosion. With increasing depth, the erosion pattern transitions from an elephant foot profile to a wide-face profile, while the radial erosion depth first increases and then decreases. Both increased tapping productivity and elevated molten iron temperature do not change the erosion shape but aggravate the erosion degree and induce axial displacement of the erosion zone. The research findings are of great significance for deepening the understanding of thermal stress damage in the hearth lining and provide an effective reference for long-term hearth design. Subsequent validation with a large amount of industrial data will further enhance the practical applicability of the proposed method.

The service state of the blast furnace (BF) hearth directly determines the furnace’s lifespan, and its failure carries significant economic and safety risks. The safe service state of the BF hearth depends on three key parameters: the chemical dissolution rate of the carbonaceous lining, the growth thickness of the solidified iron protective layer (SIPL), and the stress state of the lining material under thermal-mechanical loads. Based on the actual hearth operating conditions, this study established a three-dimensional thermal-fluid-concentration-structure coupling simulation model for the locally eroded hearth. This model considers conjugate heat transfer, carbonaceous concentration transport, molten iron solidification, and thermal stress in refractory materials. It systematically analyzes the influence of the deadman state parameters (floating height, bottom diameter, angle of repose, and bottom shape) on the safety of the hearth lining. The results show that increasing the deadman floating height and controlling its bottom diameter and angle of repose at a low level can effectively promote the formation of the SIPL, homogenize thermal stress, and inhibit carbon dissolution, thereby significantly delaying the lining erosion process. Compared with the flat-bottom deadman, the spherical-bottom deadman offers advantages in thickening the SIPL, reducing thermal stress, and lowering carbon dissolution loss, thereby effectively extending the hearth lifespan. The research findings provide important theoretical basis and operational guidance for the long-life operation of BF hearths.

The geometric anisotropy of non-spherical particles significantly impacts the multi-scale particle–fluid coupling mechanisms and heat transfer laws within spouted beds. This study proposes five modeling schemes based on coke particles' three-dimensional (3D) scanned morphologies and determines the optimal solution through experimental and numerical validations. The difference in computational accuracy between scanning modeling and the multi-sphere method of modeling particles is compared. By employing the discrete element method-computational fluid dynamics approach, the mechanical and heat transfer characteristics among scanned particles (P1-R), de-concave particles (P1-J), and spherical particles (P1-SP) in the spouted bed are investigated and the variations among six types of scanned particles are further compared. The results demonstrate that scanned particles exhibit superior computational accuracy over multi-sphere modeling approaches for complex granular systems. The P1-SP exhibits the highest contact force and overlap, P1-R forms narrow gas channels, and P1-J creates funnel-shaped gas channels. Particle shape influences thermal transport by modulating the packing density: P1-SP demonstrates the most uniform temperature distribution and the highest convective efficiency, P1-J shows optimal temperature symmetry despite hindered thermal diffusion due to high packing density on both sides, and P1-R performs intermediately. P1-SP and P1-R exhibit periodic clogging–unclogging behavior within the gas channels, causing synchronous gas flow parameters and volume fraction fluctuations. The temperature field initially rises and then decreases along the bed height, with the highest temperatures in the central jet region gradually decreasing toward the sides and deflections in the gas channels, resulting in local temperature asymmetries.