Aim of study: Novel configurations of separation chamber are proposed to resolve the critical issue of separation in agro-industrial equipment.Area of study: Dept. of Mechanical and Biosystems Engineering, Urmia, IranMaterial and methods: Precise and instrumented experimentation has been conducted to calibrate the computational fluid dynamics (CFD) methodology in the modeling and simulating chickpea pod separation. Mechanisms were selected based on optimizing separation efficiency, relative purification and required airflow as a criterion for energy consumption.Main results: Applying a guiding blade and suction fans may potentially increase the separation efficiency while reducing the relative purification and required airflow. The highest separation efficiency (95%), the lowest required airflow (545 m³/h) and the lowest pressure drop (16.3 Pa), were obtained by such configuration. Furthermore, the highest relative purification of 90% was achieved when the mechanism was free of blade and fans.Research highlights: To integrate the advantages of the above-mentioned configurations, a series-type assembling them is proposed to preserve the separation efficiency and relative purification at the highest level, meanwhile reducing the required airflow. Also, 15% enhancement in the separation efficiency and 302.8 m³/h reductions in the airflow were found as a crucial finding. The high correlation of experimental and theoretical CFD results is the key point to motivate the researchers for extension of similar case projects.

Optimum design of the conveying process plays a key role in the enhancement of system performance. In this study, a critical section of a larvae killing system in wheat conveying was evaluated experimentally and numerically. Three elbow angles of 105, 120, and 135° according to physical constraints were assessed to achieve the best conveying condition. Computational fluid dynamics (CFD) was used to obtain numerical results. Also, the Reynolds stress model (RSM) and discrete phase method (DPM) were applied to simulate the turbulences and interaction between solid–gas phases, respectively. The results showed that a minimum pressure drop of 131 Pa occurred in the 120° configuration, and this configuration has the best development from the velocity magnitude viewpoint. Of note, the lowest vorticity magnitude (as a positive factor in safe conveying) was obtained for the 120° configuration in which the vorticity magnitude 63% less than 105°. Also, the contours of turbulence intensity and erosion, comprehensively investigated. Considering all aspects, the 120° configuration was selected as the optimum conveying angle in the larvae killing system. Practical applications The larvae killing system is the main part of the wheat conveying processes. The optimal condition of conveying could be obtained using new numerical methods. Computational fluid dynamics is a powerful method in the simulation of process phenomena. The results achieved from this research could be utilized for energy saving through decreasing the pressure drop, besides understanding of flow field within the system.

In this study, as a novelty, the reverse flow effect on a wheat flour cyclone performance was evaluated. A computational fluid dynamics (CFD) simulation was realized using a Reynolds stress turbulence model. Also, particle-air interactions were modeled applying a discrete phase model. Besides the experimental measurement, the numerical simulation was conducted in a main (without reverse flow) and six various reverse flow levels (I = 0.0385 m 3 s À1 , II = 0.0396 m 3 s À1 , III = 0.0484 m 3 s À1 , IV = 0.0583 m 3 s À1 , V = 0.0704 m 3 s À1 , and VI = 0.0836 m 3 s À1 ) by CFD. The validation between pressure drop in experimental data and numerical results revealed a good agreement with a maximum deviation of 8.2%. Cyclone performance including pressure drop and separation efficiency was assessed in the mentioned reverse flow levels. Moreover, velocity field, centrifugal force, and turbulence parameter were evaluated, comprehensively. It was found that the flour separation efficiency increased with enhancing the reverse flow level to IV = 0.0583 m 3 s À1 , but decreased with a sharp slope in the reverse levels of V = 0.0704 m 3 s À1 and VI = 0.0836 m 3 s À1 . Practical ApplicationsCyclone separators are widely used in various industries such as flour and cement.The various parameters of cyclones in a food processing unit effectively affect cyclone efficiency. Therefore, an innovative method for increasing cyclone performance is presented in this study. Computational fluid dynamics (CFD) is a powerful tool for simulation of the food processing phenomenon. Validation could be guaranteed by the usage of numerical results that are obtained from CFD simulations. The innovative methods can play a key role in decreasing energy usage by reducing the pressure drop and enhancing separation efficiency.

Cyclone is often used in the Industry due to its low maintenance costs, simple design, and ease of operation. This work presents both experimental and simulation evaluation on the effect of inlet velocity and mass flow rate on the performance of a wheat conveying cyclone. According to the great importance of the pressure drop and separation efficiency on the separation phenomenon in the cyclone, a comprehensive study has been conducted in this regard. A computational fluid dynamics (CFD) simulation was realized using a Reynolds stress turbulence model, and particle-air interactions were modeled using a discrete phase model. The result showed a good agreement between the measured value and CFD simulation on the pressure drop and tangential velocity with a maximum deviation of 6.8%. It was found that the separation efficiency increased with inlet velocity up to 16 m s−1 but decreased slightly at a velocity of 20 m s−1. The pressure drop increased proportionally with inlet velocity. However, optimum performance with the highest separation efficiency (99%) and acceptable pressure drop (416 Pa) was achieved at the inlet velocity of 16 m s−1 and mass flow rate of 0.01 kg s−1.

In the present study, imperative parameters including centrifugal force, erosion, streamline, strain rate, and wall shear are evaluated in a cyclone separator. The flaw of the cyclone surface due to erosion is an acute problem in the industry. According to the great importance of the centrifugal force on the separation phenomenon, a comprehensive study is conducted. A computational fluid dynamics (CFD) simulation is realized by applying a Reynolds stress turbulence model (RSM), and particle–air interactions were modeled using a discrete phase model (DPM). The result shows a good agreement between the experimental data and CFD simulation on the tangential velocity and pressure drop. The maximum deviation of the validation process is 6.8%. It is found that the centrifugal force within the cyclone is increased with an enhancement in the inlet velocity. The separation efficiency indicates an increase–decrease treatment in various inlet velocities with inlet velocity up to 16 m⋅s−1 but decreases slightly at a velocity of 20 m⋅s−1. The pressure increases proportionally with inlet velocity. The best performance with the highest separation efficiency (99%) and pressure drop (416 Pa) obtains at the inlet velocity of 16 m⋅s−1 and mass flow rate of 0.01 kg⋅s−1. In addition, the maximum erosion rate was created in the entrance and conical part of the cyclone.

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Optimal design of conveying path can be lead to decrease the reverse flow and blockage in the conveying processes. In the present study, the effects of four different initial pipe lengths of 190, 380, 570, and 760 mm in the larvae killing machine were evaluated, comprehensively. The numerical calculations were conducted by computational fluid dynamics. Also, the Discrete Phase Model (DPM) and Reynolds Stress Model (RSM) were utilized to model the solid–gas interactions and turbulence of the flow, respectively. According to the results, the minimum pressures drop resulted in configuration III with 159 Pa. A negative pressure field was created in the interior radius of the second elbow, which is due to the enhancement of velocity in this area and an enhancement in dynamic pressure. Moreover, the maximum and minimum vorticity magnitudes were obtained in configurations I and III, respectively. Finally, considering all conditions, configuration III was chosen as the best configuration. Practical Application The larvae killing machine is utilized to eliminate larvae from whet during conveying. The appropriate design of the piping system is a critical subject in this field. One of the powerful methods for designing the conveying system is computational fluid dynamics. The results of the study can reduce the pressure drop and increase the efficiency of the system and provide uniform conveying in this machine.

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