Structural optimization of corn circulating ventilator for grain storage silo based on CFD

Developments in vacuum storage technology present an opportunity to achieve significant improvements on protection, preservation and storage of agricultural commodities for residential and commercial use. Sub-baric storage is a environmental friendly, non-residue organic technology which provides chemical-free and insect contamination-free products. Due to creation of vacuum, there is a change in the environment inside the storage structure. This study therefore contributes an important knowledge and method in the development, fabrication and application of a sub baric storage bin (SBSB) as a best alternative to the commonly used traditional and modern storage structure. In its embodiment, the work focuses on the design and fabrication of the sub-baric storage bin to provide efficient storage of food grains by preventing the use of pesticides and insecticides and to reduce material loss during storage, a sub-baric storage bin of 500 kg capacity was designed and developed. The developed storage bin consists of storage chamber (500 kg), Vacuum pump, suction blower, grain inlet with pipe for loading, grain outlet for unloading, vacuum gauge, thermocouple, control panel, agitator, air filter, two inlet valves for gas infusion, vacuum release valve and SS mobile skid. The designed sub-baric storage bin is cylindrical in geometry with conical shape at bottom side and flat circular plate on top side and the storage bin has capacity of 500 kg to store food grains with hopper angle of 60°. The storage bin was designed in such a way that, it has provision for both bulk and bag storage and to work from 0-650 mm Hg vacuum. The developed SBSB was subjected to hydraulic pressure test and vacuum drop test to ensure a safe operation. It was observed that there was no implosion (compression) or explosion confirming to the fact that the design was adequate and also safe to operate. Also, there were no signs of bulging, buckling or any deformations observed in any of the components or the pipe lines, connections, fixtures or fasteners. Hence, it was concluded that the designed equipment could be operated safely at 650 mm Hg vacuum pressure satisfying all the applicable safety assurances and standards relevant to the industry.

To enhance the classification efficiency of hydrocyclones, this study introduces a novel hydrocyclone design featuring a composite curved-inlet-body structure. Through numerical simulations, the internal flow field characteristics of this structure are thoroughly investigated. The results reveal several key findings: when the diameter of the overflow tube is reduced below a critical threshold, the axial velocity exhibits predominantly downward movement within the outer cyclone, accompanied by substantial recirculation, leading to a loss of effective separation. Moreover, both static pressure and tangential velocity are largely independent of the insertion depth of the overflow tube. In contrast, the diameter of the bottom flow opening plays a crucial role in determining flow dynamics within the hydrocyclone. An excessively large or small bottom opening leads to flow instabilities, causing fluctuations that disrupt the uniformity of the flow field. Additionally, a small height-to-diameter ratio exacerbates flow instability, increasing turbulence intensity and resulting in irregular fluctuations in the LZVV. These findings provide important theoretical insights for the design of more efficient hydrocyclone separation structures.

The deformability of sheet metal drawing is influenced by many technology and die structure parameters. By orthogonal experiment, the main four factors effected the deformability of sheet metal drawing have been studied in the two-stage drawing respectively. The results have shown the influencing order and optimum parameters of key factors were varied in different multi-stage sheet metal drawing. The influencing order of the four factors in the first drawing was the blank-holder force > dies radius>the lubricants>the punch-nose radius. The second drawing was dies radius>the lubricants>the punch-nose radius >blank-holder force. The optimum technology and structure parameters have been also determined by the experiments in the paper.

Analysis and optimization of air distribution and ventilation performance in a generator hall using an innovative attached air supply mode

Improving the separation efficiency of the inclined oil/water separator, a new type of gravity separation equipment, is of great importance. In order to obtain a comprehensive understanding of the internal flow field of the separation process of oil and water within this separator, a numerical simulation based on Euler multiphase flow analysis and the realizable k-ε two equation turbulence model was executed using Fluent software. The optimal value ranges of the separator’s various structural parameters used in the numerical simulation were selected through orthogonal array experiments. A field experiment on the separator was conducted with optimized structural parameters in order to validate the reliability of the numerical simulation results. The research results indicated that the horizontal position of the dispenser, the hole number, and the diameter had significant effects on the oil/water separation efficiency, and that the longitudinal position of the dispenser and the position of the weir plate had insignificant effects on the oil/water separation efficiency. The optimal structural parameters obtained through the orthogonal array experiments resulted in an oil/water separation efficiency of up to 95%, which was 4.996% greater than that realized by the original structural parameters.

Proton exchange membrane fuel cell (PEMFC) has become one of the new energy vehicle powertrains due to its special advantages, such as no pollution to the environment, high energy efficiency and power density. In order to improve the performance, a three-dimensional simulation model of the actual PEMFC is constructed. Combined with the mathematical models such as the electrochemical model and current conservation model, the model is calibrated by experiments. When the working voltage is 0.64 V, the error of the simulation results is 0.73%, compared with the experimental data. Then, the Taguchi method is used to design a multi-factor and multi-level orthogonal experimental scheme of PEMFC. Based on the orthogonal experimental table, the effects of different anode wave channel distortion, gas diffusion layer thickness and gas diffusion layer porosity on the current density are studied with a simulation experiment. The influence of the above factors on the orthogonal experiment results is analyzed by the signal-to-noise ratio. The regression equation is obtained by calculating the orthogonal experimental data. The t-test results are greater than 3.49, which indicates that each independent variable in the regression equation is important. R2 test is 0.915, and the F test is 53.508, indicating that the regression equation is significant and the optimal and worst structural parameter combinations are predicted. The current density reaches 14,190.18 A/m2 under the optimal structure combination, which is 6.14% higher than the calibrated model. Single factor experiments are carried out on these three different structural parameters to verify the effectiveness of the Taguchi method, and the best combination of structural parameters is obtained.

PurposeSix-axis force sensors play an important role in civilian and military fields because of their multifunctionality. In the context of sensor structure design, sensitivity and sensitivity isotropy are often considered. This paper aims to study the possible relationship between the sensitivity/sensitivity isotropy and structural parameters of an 8/4–4 parallel six-axis force sensor. A comprehensive evaluation index and structural optimization design scheme are suggested in the end.Design/methodology/approachBased on the conditional number of the Jacobian matrix spectral norm, the sensitivity and sensitivity isotropy of the sensor are derived. Orthogonal experiments are used to determine the degree of primary and secondary factors that have a substantial effect on the sensor characteristics. The relationship between the performance indices and the structural parameters is analyzed by the performance atlas method. The comprehensive evaluation index lays the foundation for the structural optimization design of an 8/4–4 parallel six-axis force sensor.FindingsThe variation in each performance index of the sensor for each of the structural parameters is analyzed, and the structural parameters of the sensor with the desired performance indices can be easily selected from the performance atlases. A comprehensive performance evaluation index with a target value of 1 is proposed, and the overall influence of the structural parameters on the sensor performance index is investigated. A simulation example shows the feasibility of the proposed evaluation index.Originality/valueThe importance of each structural parameter of the 8/4–4 parallel six-axis force sensor is determined through orthogonal experiments in this paper. Relations among the structural parameters meeting the performance indices are derived and shown in the performance atlases. A comprehensive evaluation index is proposed to analyze the overall sensor performance.

Collision avoidance and robot path planning problems have emerged as a potential domain of robotics research of late because of their indispensable requirements in the field of manufacturing vis-a-vis material handling, such as picking and placing an object and loading/unloading a component to/from a machine or storage bins. This chapter focuses on palletization, a form of unitization in which a uniform load is stacked on a wooden pallet using a predetermined case pattern sequence and a given number of layers. In many kinds of proposed C-space construction approaches, several algorithms deal with the boundary of the C-obstacle analytically. Lozano Perez proposed the fundamentals of the C-space approach. When both the robot and obstacles have the shape of convex polygons, the Cobstacle boundary for an n-DOF manipulator is approximated by sets of n-1 dimensional slice planes, which are made from a one-dimensional slice plane. C. Zhao and his colleague proposed an algorithm to describe the C-obstacle as a set of parametric equations formulated from the mapping of the boundaries of the obstacles in a workspace. They use inverse pseudo kinematics to convert the obstacles in a workspace into a C-space. Debanik Roy studied path planning algorithms and their heuristics using the concept of visibility graph, and he presented an overview of the case study of robot path planning in an industrial environment in real time. Xiaojun and his colleague proposed a two-phase approach for C-obstacle construction and the collision detection of manipulators. This method is applicable to manipulators with various types of kinematic structures and geometric shapes. M. Pettersson and his coworkers proposed trajectory optimization method considering fatigue and thermal load of real robot. They also referred that the proposed method could be directly adapted to palletizing system. The issues of these papers, however, are for the operation of real industrial robot, and it is a part of entire palletizing system. Many other latest researches solely oriented towards path planning or modified apparatuses to improve the specified handling task have also been conducted. Studies on the total robot palletizing system, however, which integrates loading pattern optimization, robot OLP simulation, and path optimization, have yet to be systematically conducted. This study was dedicated to the development of OLP Simulation S/W for a robot palletizing system (Non-vision system), which means that this study prioritized the reflection of the 17

Many Fayoum Standard Weirs have been perforated by one, two or three pipes, to convey much water in downstream direction. Measurements of discharge with these structures are complicated due existence of the opening. In this research, an experimental study was carried out to investigate the flow over clear over fall weir with bottom opening. Nine weir models with different heights were tested in horizontal laboratory flume of 17 m length, 0.3 m width, and 0.5 m depth. Weir height is changed three times. For each one, the diameter of opening is changed three times. The downstream depth was changed to cover all the expected flow regimes of the pipe and the weir. These flow regimes are; free pipe-free weir, submerged pipe-free weir and submerged pipe-submerged weir. The results of flow over weir with opening were compared with those of weir without opening having the same dimensions. It was found that there is a large deviation between them. Multiple regression equations based on energy principal and dimensional analysis theory were developed for computing discharge over clear over fall weir with bottom opening. Also, values of discharge coefficients were estimated for combined flow over the weir and through the pipe. Then the total discharge can be computed by multiplying the discharge coefficient by the summation of theoretical weir discharge plus theoretical orifice discharge. Equations for computing the discharge of combination are awarded.

PurposeThe purpose of this paper is to provide an optimization schedule of structural parameters for the sound absorption performance of a cellular ceramic foam in the sound frequency range of 200–4,000 Hz.Design/methodology/approachThe cellular ceramic foam with porosity of about 60–75% and the pore size of about 1–7 mm was successfully prepared by using natural zeolite powder as the main raw material. For this ceramic foam, the sound absorption performance was measured, and the absorption structure was optimized by some important structural parameters. With orthogonal experiment, optimization of structural parameters was found for absorption performance. By means of the range analysis method, the main factor is known to influence the performance of ceramic foam.FindingsThe present ceramic foam may have good absorption performance although at relatively low frequencies of 400–4,000 Hz while structural parameters of sample are appropriately combined. With orthogonal experiment, optimization of structural parameters for the absorption performance was found to be as follows: sample thickness, 25 mm; porosity, 73.5%; pore size, 4–5 mm and air gap depth, 20 mm. To influence the performance, sample thickness is the main factor, air gap depth is the second and both of pore size and porosity would have a relatively slight effect.Originality/valueThis paper presents a method to optimize the structural parameters of a cellular ceramic foam for sound absorption performance by means of orthogonal experiment.

To optimized the structure parameters of steering gear assembled in low speed truck,an orthogonal experiment is designed within rang of variation of the structure parameters,under the guide of vehicle handing and stability comprehensive evaluation indexes.One optimum parameter group is obtained by analyzing the influence of structure parameters on evaluation indexes based on the simulation of the established and verified model of the truck steering system.The optimum parameters group is demonstrated can be benefit to the vehicle handing and stability through contrasting the original structure parameters,and achieving the objective of power steering gear structure parameters optimized analysis.

This article studies the influence of structural parameters of the optimization model for the gas–liquid mixing device of a fire truck (compressed air foam lift fire truck, model JP21/G2, made in China) on the liquid phase volume fraction, static pressure, velocity streamline, and the influence of smaller flow rates on the mixing effect. By using the computational fluid dynamics (CFD) software FLUENT 2021 R2, numerical simulations were conducted on the fluid domain model of the gas–liquid mixing device of the JP21/G2 fire truck. The changes in the mixing effect time dimension, liquid phase volume fraction, static pressure, and velocity streamline inside the gas–liquid mixing device were obtained. The optimal mixer structure combination in practical applications was inferred through orthogonal experiments, and the influence of flow rate on the optimal pipe diameter and shortest mixing distance was obtained through variable flow rate simulation experiments. The numerical simulation results show that the presence of bent pipes in the JP21/G2 real vehicle model hinders the gas–liquid mixing process. A straight pipe section of at least 8 m was added after the bent pipe to ensure the mixing effect. The optimal parameter combination for orthogonal experiments had an accurate value of 50°-50°-220 mm. Under the same pipe diameter, using a larger flow rate can achieve better mixing effects.

Electrode-assisted hydrodynamic arc breaking for efficient side-cutting of Ti2AlNb

The uniformity of the wheat distribution within and between rows has a significant effect on crop population structure, leading to decreased yield as nonuniformity increases. Traditional drills are influenced by soil porosity and flatness in the field, making accurate control of sowing depth and amount challenging and resulting in an uneven spatial distribution of gramineous seedlings. Precision cave-sowing technology effectively enhances wheat population distribution uniformity. However, owing to limitations in existing mechanical precision cave planters, their operational speed is lower than that of drill planters. To address these issues, this study designed an air-suction precision wheat seed dispenser, described its basic structure and working principle, and developed a seed mechanical model. A theoretical analysis was conducted on the working process and key components of the seed feeder. A suitable mould hole diameter was determined to be 1.6~2.0 mm, and the rotation speed range for the seed plate was found to be 65~85 r·min−1. Fluent simulations were used to determine the influence of orifice type on gas chamber flow fields; DEM-CFD-coupled simulation identified an appropriate negative pressure range of 2.6~3.4 kPa for optimal performance during seeding operations. Orthogonal experiments were carried out with mould hole diameter, negative pressure size, and seed plate speed as test factors alongside a qualification index, multiple sowing index, and missed sowing index as response indicators—leading to regression equation establishment, which yielded the optimal parameter combination: mould hole diameter at 1.8 mm; gas chamber negative pressure at 3.2 kPa; and a seed plate speed of 74 r·min−1, with the corresponding forwards speed of the machine being 7 km·h−1—resulting in a qualification index of 91.66%, multiple sowing index of 5.98%, and missed sowing index of 2.36%. This pneumatic suction type wheat precision seeder achieves equivalent operational speeds as traditional drills while enabling precision seeding.

Purpose – For machine tools, the machining performance is mainly determined by the rigidity of the machine structure. How to design a machine tool with high rigidity is always a challenge issue. The paper aims to discuss these issues. Design/methodology/approach – In this paper, the Computer Aided Engineering (CAE) technique is used to analyze the structure rigidity of a Computer-Numerical Control (CNC) turn-mill machining center. The considered structure parameters include static rigidity and vibration mode. Through the integral analyses of these two structure parameters in conjunction with the practical design experiences, an optimal structure is obtained. Findings – Comparisons between the original prototype and the suggested new design structure via CAE technique under the guide of these two stiffness parameters show a great improvement on the maximal deformation of the machine structure under the action of cutting forces. Originality/value – Through the proposed integrative examination of two structural parameters and the CAE technique, together with design experiences, an optimal CNC machine structure can be obtained.