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Directed Energy Deposition (DED) processes necessitate a consistent material flow to the melt pool, typically achieved through pneumatic conveying of metal powder via thin pipes. This study aims to record and analyze the multiphase fluid–solid flow. An experimental setup utilizing a high-speed camera and specialized optics was constructed, and the flow through thin transparent pipes was recorded. The resulting information was analyzed and compared with coupled Computational Fluid Dynamics-Discrete Element Modeling (CFD-DEM) simulations, with special attention to the solids flow fluctuations. The proposed methodology shows a significant improvement in accuracy and reliability over existing approaches, particularly in capturing flow rate fluctuations and particle velocity distributions in small-scale systems. Moreover, it allows for accurately analyzing Particle Size Distribution (PSD) in the same setup. This paper details the experimental design, video analysis using particle tracking, and a novel method for deriving volumetric concentrations and flow rate from flat images. The findings confirm the accuracy of the CFD-DEM simulations and provide insights into the dynamics of pneumatic conveying and individual particle movement, with the potential to improve DED efficiency by reducing variability in material deposition rates. [ABSTRACT FROM AUTHOR]

The application of electrical capacitance tomography (ECT) for monitoring of industrial processes has been studied and proposed by many researchers. Examples can be found in monitoring of multiphase flows or mixing processes in reactors. Demonstrations of the functionality based on lab and test rig measurements have proven the potential of the proposed principles. This paper discusses the application of an ECT system in a heavy industries application. The harsh operating conditions in the industrial environment pose several challenges for the application of sophisticated measurement technology. This work addresses key aspects for the application of an ECT measurement system in such an environment. Specifically the electrical system design and the influence of the temperature are addressed. Relevant parameters and possible solutions are discussed. Furthermore the application of ECT as instrument for mass flow metering in pneumatic conveying processes is addressed. Supportive measurement studies from test rig experiments and comparative simulation studies are presented. Therefore, the paper provides a concise discussion on the application of ECT under harsh operating conditions, as well as the use of ECT as a measurement device for process measurement. The work concludes with a presentation of a measurement system in an industrial plant in which the proposed concepts were succesfully implemented. [ABSTRACT FROM AUTHOR]

A three-lobed helical pipe was installed downstream of the bend of a vertical-horizontal pneumatic pipeline. The swirl characteristics under different helical pipe structures were investigated. Results show that: (a) the maximum velocity region rotates quasiperiodically, and the smaller the pitch, the faster the rotation; (b) the 3D morphological changes of the axial velocity distribution in downstream sections are similar: from an arch to a pit and finally to a uniform flat top. The tangential velocity appears as a Rankine vortex near the wall; (c) the swirl decays rapidly along the downstream. The initial swirl intensity, proportional to the helical pipe length, increases first and then decreases with decreasing pitch, whereas the structural parameters have minimal effect on the swirl decay rate; (d) the helical tube remarkably increases the system energy consumption, and the total pressure drop is inversely proportional to the pitch and proportional to the length. [ABSTRACT FROM AUTHOR]

To investigate the system pressure drop distribution when conveying particle using different curvature radius pipes for the pneumatic conveying system, this paper measured the particle velocity distribution, particle-particle collision characteristics, collision energy loss, minimum pressure drop gas velocity, system pressure drop distribution, and power dissipation for R/D = 3.75, R/D = 5, and R/D = 6.25 pipes. Subsequently, the artificial neural network technique is used to predict the pressure drop of the pneumatic conveying system. It is found that the pressure drop of the system is lower when using the pipe with R/D = 6.25 for conveying particles. Compared to the pipe with R/D = 3.75, the reduction in power dissipation is 3.18 and 5.27% for conveying pellets when using R/D = 5 and R/D = 6.25 pipes, respectively. In addition, the energy loss of the system can be effectively reduced when using the pipe with R/D = 6.25 for conveying particles, which is more beneficial for the particles move in the pipe. The pressure drop model built with artificial neural network can predict the pressure drop value of the system more accurately within ±1.5%. [ABSTRACT FROM AUTHOR]

Data on pressure signals and gas flow rate signals was collected under various experimental conditions. A comparative analysis was conducted to investigate the gradient changes of the fluidizing gas, the supplemental gas, and the pressurizing gas. A three‐factor three‐level orthogonal experiment was carried out. The results demonstrated that the proper use of the fluidizing gas can enhance the steady condition of the conveying process. Increasing the flow rate of the supplemental gas can improve the steady flow pattern, while the pressurizing gas has the opposite effect. The degree of influence of these parameters on the steady condition of the conveying process was shown to follow the order of fluidizing gas valve opening, pressurizing gas valve opening, and regulating gas valve opening. [ABSTRACT FROM AUTHOR]

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Chemical Engineering (China) / Huaxue Gongcheng is the property of Hualu Engineering Science & Technology Co Ltd. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This paper takes the power source (gas–solid injector) of the large-sized particle pneumatic conveying system as the design object, builds the pure gas flow field experiment bed and particle pneumatic injection experiment bed, and establishes the dataset of the large-sized particle gas–solid injector of the injection experimental results. Constructed the simulation model of gas–solid injectors based on CFD-DEM coupling, and established the dataset of pure gas flow field injection and gas–solid injection simulation results under multiple evaluation indexes. These datasets are valuable for engineers and designers, providing a reference for designing gas–solid injectors and other pneumatic conveying devices.

The purpose of the present study is to simulate erosion on the aluminium plate with a cylindrical hole caused by solid particles after passing through 90° elbow, using the Computational Fluid Dynamics (CFD), the Discrete Phase Model (DPM), and erosion equations. Discrete trajectories of solid particles are calculated using the Lagrangian approach, while the simulation of the fluid was obtained by solving the fluid motion equation using the Eulerian approach. Supplementary sub-models are incorporated into the software to enhance the accuracy of particle trajectory calculations within the simulated geometry. These sub-models include collisions of solid particles with walls (stochastic model) and erosion model. The numerical simulation results obtained in this paper were compared with the existing experimental results from the group of authors, demonstrating a good match. The paper provides the main characteristics of the mathematical model, along with the interpretation of results and a discussion, with the key findings highlighted in the conclusion. The findings indicate that erosion process is significantly influenced by both the particle impact velocity and impact angle, which are key parameters in many erosion equations. Furthermore, it is observed that the velocity of the particles is consistently lower than the mean velocity of the air. Additionally, the angle at which the particles impact the aluminium plate is not always exactly 90° due to multiple collisions with the wall, signifying that the particles do not move exclusively vertically.

In order to solve the traditional feeding equipment can not meet the requirements of the operation of the breeding vessels, designed to meet the long-distance transportation of the farm workers, large feeding volume of the work requirements of the pneumatic conveying automatic feeding machine, to solve the feed particles clogging, crushing rate is high, the system has high energy consumption, can not be controlled by the speed and other issues, through the CFD-DEM method of analysis of the feed from the mouth to the mouth of the movement of the feed outlet process, the simulation results show that the simulation results show that in the initial stage of the feed movement, the pressure loss is large, after entering the bend, the feed basically becomes suspended, and there is no feed blockage in the whole process, and in the outlet, the feed is uniformly distributed. In the whole process, the feed and air velocity pressure are after the elbow to reach a stable state. Manufacturing prototype for test verification, in the experimental process did not find the phenomenon of feed clogging, and control the frequency converter so that the motor speed of 40 r/min to meet the 1.5 t/h feeding rate, by controlling the motor speed to achieve the function of controlling the feeding speed, it meets the application scenarios of breeding vessels. [ABSTRACT FROM AUTHOR]

Energy consumption is one of the important indicators of green development. The pressure drop and the particle kinetic energy loss in the pipe bend result in high energy consumption of wheat pneumatic conveying. In this paper, the CFD-DEM method is used to study the characteristics of flow field in horizontal pipe bend. The results show that the particles converge together under the force of the curved pipe wall to form a particle rope. With increasing pipe bend ratio R/D, the aggregation of particle bundles becomes stronger and the particle spiral phenomenon decreases. The particles impact the pipe wall at an angular position of θ = 30–60° around the bend, and their velocity decreases slowly under the friction resistance of the pipe wall. The velocity loss caused by particles impacting on the pipe wall increases with increasing initial velocity. When the particle mass flow rate is 1.26 kg/s and the gas velocity is 10 m/s, the pressure drop in the bend decreases and then increases with increasing R/D. The pressure drop of the bend is smallest for R/D = 2 and increases gradually with increasing gas-phase velocity. With increasing of R/D, the wall shear force between the particles and the bending pipe decreases and then increases, and the position of the maximum force moves towards the bottom of the bending pipe. The area over which the wall shear force acts continues to decrease because of the aggregation of particle bundles. The research results provide a theory for optimal design and application of pneumatic conveying equipment for wheat particles. [ABSTRACT FROM AUTHOR]

Pneumatic fly ash conveying systems in thermal power plants are often not able to transport ash as per their expected duty due to either variability of ash characteristics and/or inadequate system sizing resulting in generation loss and reduced ash utilization. This paper results from an ongoing investigation into the relationship between the physical characteristics of ash to some of the important design criteria, such as ash conveyability and flowability. Based on a comprehensive test program including the pneumatic conveying (in a pilot plant) and flow property testing of 23 ash samples obtained from five different power stations, predictions for conveyability and flowability have been made using bulk property characterization. Of all the different particle and bulk parameters investigated, the angle of repose has been found to be the most significant parameter linking conveyability and flowability. A newly developed design tool based on the angle of repose is expected to assist designers and operational engineers to predict the flow condition and appropriately size equipment/system with suitable operating parameters. [ABSTRACT FROM AUTHOR]

Accurate prediction of blockage conditions or the minimum transport boundary is essential for the reliable design and operation of a pneumatic powder conveying system. Many existing empirical models for minimum transport boundary do not consider essential powder properties and operating conditions, such as loose poured bulk density, particle size, and air density. Based on the conveying results of 13 different powders, this paper has developed a new empirical model for the minimum transport boundary. The model includes a Froude number based on particle size and bulk density and a dimensionless gas density term, which makes the model inherently adaptable to variations in powder properties and operating conditions. Results of validation show that the new model provides a significantly improved prediction of minimum Froude Number (in the range of 7 to 13% relative error only) compared to the existing models, which provided relative errors in the range of 19 to 67%. [ABSTRACT FROM AUTHOR]

This paper presents the results of ongoing research aimed at modeling the pressure drop in bends during pneumatic conveying of fine powders. Based on the test results of conveying fly ash and two grades of cement through three different radii of curvature of the bends, two different bend diameters, and two different locations of the test bend, a semi-empirical relationship was developed for bend loss with various pressure drop components modeled separately. The newly developed model was used to predict the bend loss for a solid loading ratio in the range of 51–170 (very dense phase). The proposed model exhibited a satisfactory level of prediction accuracy, with relative error percentages of less than 12.2% and 19.6% for the high and low solids loading ratios, respectively. [ABSTRACT FROM AUTHOR]

The intelligent pipeline pneumatic conveying method is a potentially efficient solution for the transportation of municipal solid waste (MSW). Due to the complex compositions and large volumes of MSW, the application of pneumatic conveying technology requires particular designs. However, the related research is limited. Here, we determined the physical properties of MSW by investigating their compositions. Specifically, we described the movement characteristics of waste under pneumatic conveying based on theoretical calculation, simulation, and preliminary trials. We obtained the key parameters during the pneumatic conveying of MSW including the no-load friction factor, the comprehensive resistance coefficient, the number of velocity heads lost and the shape factor of materials, which pave a way for the design of pneumatic conveying system. The obtained results provide supports for the research and development of waste pneumatic conveying technology. [ABSTRACT FROM AUTHOR]

The purpose of the present study is to simulate erosion on the aluminium plate with a cylindrical hole caused by solid particles after passing through 90° elbow, using the Computational Fluid Dynamics (CFD), the Discrete Phase Model (DPM), and erosion equations. Discrete trajectories of solid particles are calculated using the Lagrangian approach, while the simulation of the fluid was obtained by solving the fluid motion equation using the Eulerian approach. Supplementary sub-models are incorporated into the software to enhance the accuracy of particle trajectory calculations within the simulated geometry. These sub-models include collisions of solid particles with walls (stochastic model) and erosion model. The numerical simulation results obtained in this paper were compared with the existing experimental results from the group of authors, demonstrating a good match. The paper provides the main characteristics of the mathematical model, along with the interpretation of results and a discussion, with the key findings highlighted in the conclusion. The findings indicate that erosion process is significantly influenced by both the particle impact velocity and impact angle, which are key parameters in many erosion equations. Furthermore, it is observed that the velocity of the particles is consistently lower than the mean velocity of the air. Additionally, the angle at which the particles impact the aluminium plate is not always exactly 90° due to multiple collisions with the wall, signifying that the particles do not move exclusively vertically. [ABSTRACT FROM AUTHOR]

Directed Energy Deposition (DED) processes necessitate a consistent material flow to the melt pool, typically achieved through pneumatic conveying of metal powder via thin pipes. This study aims to record and analyze the multiphase fluid–solid flow. An experimental setup utilizing a high-speed camera and specialized optics was constructed, and the flow through thin transparent pipes was recorded. The resulting information was analyzed and compared with coupled Computational Fluid Dynamics-Discrete Element Modeling (CFD-DEM) simulations, with special attention to the solids flow fluctuations. The proposed methodology shows a significant improvement in accuracy and reliability over existing approaches, particularly in capturing flow rate fluctuations and particle velocity distributions in small-scale systems. Moreover, it allows for accurately analyzing Particle Size Distribution (PSD) in the same setup. This paper details the experimental design, video analysis using particle tracking, and a novel method for deriving volumetric concentrations and flow rate from flat images. The findings confirm the accuracy of the CFD-DEM simulations and provide insights into the dynamics of pneumatic conveying and individual particle movement, with the potential to improve DED efficiency by reducing variability in material deposition rates.

In the vacuum system of pneumatic conveying, the authors have proposed that a suction nozzle equipped with an injection pipe at the center would provide a highly dense, highly efficient method of transporting powder and particles. In this paper, we examined the effects of suction velocity and particle diameter on the loading ratio and the suction nozzle efficiency by attaching the injection port on the outer part of the suction nozzle. As a result, in the case of coarse particles within this experimental condition, the effect of suction velocity differs in both cases (the injection ports positioned at the center and outer part). This characteristic is explainable by the difference between fluidization phenomenon and aeration phenomenon. Under conditions that are not affected by the suction velocity, neither is affected by the particle diameter in both cases. [ABSTRACT FROM AUTHOR]

In order to reduce the crushing rate and energy consumption of corn kernels in the pneumatic conveying process, this paper firstly used the conveying wind speed, material-air ratio and corn kernel moisture content as the influencing factors in the conveying process to conduct single-factor simulation experiments. Then, a test platform was created for the pneumatic conveying of grain particles and an orthogonal test was conducted using the crushing rate and pipeline pressure drop as conveying performance indices. A regression equation model was then created that connected each test index to each factor in turn. Lastly, it was used the response surface method for multi-objective optimization to determine the ideal parameter combinations for the conveying wind speed, which was 25.42 m/s, the material to gas ratio, which was 10, and the moisture content, which was 13.912%. At this time, the corresponding pneumatic conveying indexes are 1.112% crushing rate, 8.725 kPa pressure drop, and 0.328 kg/s conveying capacity, which provide theoretical and experimental bases for the prevention of crushing and the reduction of energy consumption during the pneumatic conveying of grain particles. [ABSTRACT FROM AUTHOR]

Pneumatic conveying is a vital technology for delivering bulk solids, powders, and granular materials in various industries. Significant advances in pneumatic conveying technology have occurred in recent years, spurred by the demand for sustainable and energy-efficient industrial processes. This paper explores the current advances in pneumatic conveying technology and their implications for the industry. First, the principles of pneumatic conveying are discussed. Then, two significant advances in pneumatic conveying technology are highlighted. Schenck Process, for example, has created the Enhanced Dilute Phase Pneumatic Conveying (EDIP) system, the E-Finity continuous dense phase system, and high-pressure systems utilizing Lontra's LP2 Compressor Blower. Second, Palamatic Process provides dense-phase vacuum conveying cyclones as well as powder pumps for nonabrasive dense-phase vacuum conveying. Several research gaps in pneumatic conveying technology are identified in the paper, including the integration of artificial intelligence and machine learning, the optimization of multiphase flow behavior, energy efficiency and sustainability, material degradation, and particle damage, handling of cohesive and difficult-to-convey materials, scale-up and design optimization, and real-time monitoring and control systems. The future outlook highlights the potential of sustainable practices to advance pneumatic conveying technology further. The integration of these technologies can lead to improved performance, energy efficiency, and sustainability in pneumatic conveying systems. [ABSTRACT FROM AUTHOR]

The stable transportation of pulverized coal in the vertical pipe is significant for the operation of the gasifier. There are few studies on the flow characteristics and flow pattern transition of particles in vertical pipes with small diameters. This paper has modeled and analyzed the flow characteristic of powder in dense-phase pneumatic conveying through 25 mm vertical pipe using CFD. Firstly, the grid independence is verified to determine the optimal mesh size. Then, the influences of different solid loading ratios (SLRs) and conveying velocities on particle flow characteristics, flow stability, and flow pattern transition are investigated. The results show that the flow pattern in the vertical pipe changes from annular flow to uniform flow at high SLR and low conveying velocity. Moreover, the evolution regulation of resistance characteristics under different conveying velocities is further revealed. Considering the conveying stability and economic benefit, the most suitable conveying velocity is 6 m/s.

Pneumatic conveying of powders is an engineering process used for conveying dry granulate or powder material where energy consumption is a significant cost factor and contributes to greenhouse gas emissions. In this RD&I project, work was conducted to model pneumatic conveying and bulk characteristics of the particulate product being conveyed. Because pneumatic conveyance is highly empirical, general models are difficult to establish. Due to these limitations, evaluating energy efficiency is usually limited to a specific experimental range of conditions. This work is based on engineering optimization of a workflow with data from an industrial operation commanded by a Programmable Logic Controller (PLC) with a control algorithm, performing logical, sequential, and timed tasks for plant control. The PLC communicates with a Human–Machine Interface and a Supervision and Control System, which are the means of interaction through a graphical environment interface with the process operator. By applying mathematics to introduce a systematic method to select the gas (air) pressure and flow necessary to operate a pneumatic conveying system in dense phase mode, it has been shown, on an industrial scale of 10 t/h, the feasibility of controlling an efficient pneumatic conveying system manipulating only two input parameters. This allows operation at pre-determined conveying rates with lower operational expenditures. The same methodology can be explored for several other systems.

Dilute and dense conveying systems through pipelines are a common practice in our everyday life. It is used in many industries to convey a mixture of gas and solids from one location to another through pipes. Gas-solid transport is desirable in some industries but unwanted in others. Depending on the density, size, and shape, these solid particles may result in erosion and subsequent damage to piping and other equipment. Understanding the gas-solid two-phase flow dynamics can help develop efficient and cost-effective pipe transport systems, thereby mitigating the problems associated with the gas-solid two-phase flow. Models for estimating volumetric flow rates and other gas-solid two-phase flow properties are scarce as most are very complex, expensive, and unavailable proprietary commercial software. This study, therefore, developed a simple model using the general energy balance equation and relevant mixing theories for estimating the volumetric flow rate of natural gas-solid two-phase flow in horizontal pipes. The results from the model showed that the gas-solid flow rate is a function of pipe diameter, pressure drop, pipe length, solid volumetric concentration, solid-to-gas density ratio, and solid-to-gas friction factor ratio.

针对当前通用型称重料仓工艺烦琐和设备复杂的问题，以大豆为例，运用模块化集成设计理念，采用理论分析与仿真模拟相结合的方法，设计开发了一套集卸料器与料仓于一体的气固分离称重料仓。采用Solidworks三维建模软件将设备各部分构件建模，运用计算流体力学及离散项模型对气固分离称重料仓的关键结构进行分析。结果表明，设计的气固分离称重料仓在完成称重卸料的同时可分离轻杂，简化了称重卸料过程，新增的蝶阀模块可根据料仓内的物料量动态调整进出仓过程。综上，设计的气固分离称重料仓可用于气力输送大豆的称重卸料。 Aiming at the problems of the cumbersome process and complicated equipment of the current general-purpose weighing silo, taking soybean as an example, using the modular integrated design concept and the method of combining theoretical analysis and simulation, a set of gas-solid separation equipment for weighing silo integrating unloader and silo was designed and developed. The Solidworks 3D modeling software was used to model each part of the equipment. The key structure of the gas-solid separation equipment for weighing silo was analyzed by computational fluid dynamics and discrete phase model. The results showed that the designed gas-solid separation equipment for weighing silo could realize the separation of light impurities while completing weighing and discharge, and simplified weighing and discharge process. The newly added butterfly valve could dynamically adjust the process of inlet and outlet according to the amount of material in the silo. In conclusion, the designed gas-solid separation equipment for weighing silo can be used for weighing and unloading of pneumatically conveyed soybeans.

Pressure drop prediction model has been well concerned in pneumatic conveying system design. The Barth's additional pressure drop prediction model is one of the most widely accepted and applied models, in which the solid friction coefficient in horizontal straight pipe is particularly important. In this work, a regression model of solid friction coefficient was addressed on the basis of two dimensionless numbers (the inlet Froude number and the solid-gas loading ratio), which were conducted based on fly ash pneumatic conveying experiment data in a 16 m length pipeline. Then, the prediction accuracy of the regressed model was verified by the pressure drop of other pneumatic conveying pipeline system, 123 m and 139 m pipelines, respectively. The results show that solid friction coefficient gradually decreases with inlet Froude number, conversely, it increases with solid-gas loading ratio. And the regressed solid friction coefficient maintained relatively high accuracy in the prediction of pressure drop, for both fly ash pneumatic conveying pipelines of 16 m length and 123 m length. However, a different prediction accuracy appeared for the different loading ratio of 139 m length pipeline complete pneumatic conveying system. The pressure drop prediction accuracy sharply declines when solid-gas loading ratio is larger than 85. [Display omitted] • A regression model of the solid friction coefficient was conducted. • The model was addressed based on two dimensionless numbers. • The model maintained relatively high prediction accuracy for pressure drop. [ABSTRACT FROM AUTHOR]

In order to improve the performance and effect of pellet feed conveying, an automatic baiting machine with remote pneumatic conveying, which can be controlled centrally, and operated at regular time, quantity and speed, was designed to meet the working demand of large intensive deep-sea breeding vessels for baiting operation. The overall structure of the baiter was determined, the design of the key parts of the screw feeder was completed, and the discrete element simulation analysis of EDEM ( high performance bulk and granular material simulation software) was carried out. The simulation results show that the feed pellets in the device will not be clogged or stagnated during the process from generation to elimination. The feeding speed can be controlled by the rotational speed of the spiral shaft, and the feeding speed is stable. When the spiral shaft speed reaches 40 r/ min, the feeding speed of 1.5 t/h is satisfied. The design and a research provide reference and a basis for the design and performance optimization of the subsequent deep-sea culture feeding equipment. [ABSTRACT FROM AUTHOR]

To study the flow characteristics of particles in the vertical tube, the velocity is measured at the minimum pressure drop (MPD) by using a high-speed particle image velocimeter (PIV). Firstly, the pneumatic conveying system's pressure drop and the particle velocity characteristics in the vertical tube were investigated. Then, for the axial fluctuation velocity of the particles, the continuous wavelet transform, and one-dimensional discrete orthogonal wavelet decomposition are used to reveal the dynamic characteristics of the particles based on the time-frequency characteristics, the contribution of wavelet levels to the energy of particle fluctuations, the auto-correlation of each wavelet level and the probability distribution of wavelet levels. The results demonstrate that large-scale movement dominates particle movement in the vertical tube, whereas small-scale movement increases as conveying height rises. The energy contribution of the low-frequency wavelet level is larger, and this contribution decreases with the acceleration of the particles along the tube. The high-frequency wavelet level's auto-correlation coefficients decay more slowly and have a longer duration. At increasing wavelet levels, the skewness and kurtosis coefficients grow, and the departure of the Gaussian probability distribution becomes more obvious. [ABSTRACT FROM AUTHOR]

Copyright of Packaging & Food Machinery is the property of Packaging & Food Machinery Magazine and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study introduces a novel methodology to evaluate the behaviour of biomass material by examining the ratio of aeration and deaeration time constants. To this end, a series of tests were conducted on four different materials, namely, cottonseed, wood chips, wood pellets, and wheat straw, in order to investigate their aeration and deaeration behaviours. The study derives the aeration and deaeration pressure drop equations, and discusses the corresponding time constant expression. Subsequently, the four materials were conveyed in 12 m long batch-fed and continuous pneumatic conveying pipelines to examine their behaviour in longer pipelines. The results indicate that the aeration and deaeration time constants increased with an increase in air superficial velocity. However, the ratio of the aeration and deaeration time constants was identified as a unique number, where a value close to 1 indicates a higher likelihood of plug flow. On the basis of the results, cottonseed, with the lowest ratio of time constant, was more likely to form a stable plug flow in both batch-fed and continuous pneumatic conveying. Given the unique properties of biomass and the limited research on the pneumatic conveyance of biomass, this methodology represents a novel approach for predicting modes of flow in materials with complex properties. [ABSTRACT FROM AUTHOR]

This study investigates pneumatic conveying of four different biomass materials, namely cottonseeds, wood pellets, wood chips, and wheat straw. The performance of a previously proposed model for predicting pressure drop is evaluated using biomass materials. Results indicate that the model can predict pressure with an error range of 30 percent. To minimize the number of trial tests required, an optimization algorithm is proposed. The findings show that with a combination of three trial tests, there is a 60 percent probability of selecting the right subset for accurately predicting pressure drop for the entire range of tests. Further investigation of different training subsets suggests that increasing the number of tests from 3 to 7 can improve the probability from 60% to 90%. Moreover, thorough analysis of all three-element subsets in the entire series of tests reveals that when considering air mass flow rate as the input, having air mass flow rates that are not only closer in value but also lower increases the likelihood of selecting the correct subset for predicting pressure drop across the entire range. This advancement can help industries to design and optimize pneumatic conveying systems more effectively, leading to significant energy savings and improved operational performance. [ABSTRACT FROM AUTHOR]

Powder breakage during pneumatic conveying negatively affects the properties of dairy products and causes increased dusting, reduced wettability, and decreased product performance. In particular, particle breakage is a serious issue for fat-filled milk powder (FFMP) which, if it breaks, releases fat that causes odours and leads to sticky blocked pipes. In this work, a conveying rig (dilute phase, positive pressure) with 50 mm diameter food grade stainless steel pipes (1.5 m high and 5 m conveying distance with three 90° bends, two in the vertical plane and one in the horizontal plane) was built as the test system. The effects of operating conditions (conveying air velocity and solid loading rate) on the attrition of FFMP in a dilute phase conveying system were experimentally studied. Four quality characteristics were measured before and after conveying: bulk density, particle size distribution, wettability, and solubility, to access the influence of particle breakage. Conveying air speed shows a significant impact on powder breakage. As air speed increased, more breakage occurred, and the volume mean diameter D[4,3] decreased by around 50%, using the largest conveying air speed of 38 m/s. Bulk density increased accordingly whereas wettability decreased with an increase in air speed, resulting from the higher breakage rate. On other hand, improving the solid loading rate can further reduce the breakage level, but the positive effect is not as good as decreasing air speed.

To examine the flow characteristics of particles in the vertical tube corresponding to different curvature radius bends, the particle velocity is measured at the Minimum Pressure Drop (MPD) using a high-speed Particle Image Velocimeter (PIV). This experiment explores the effects of particle flow characteristics at different curvature radius bends and their corresponding vertical tubes with pressure drop, power consumption, the intensity of particle fluctuation velocity, power spectrum and time-frequency characteristics. It is observed that the pressure drop and power consumption can be reduced with the help of a large curvature radius bend. Besides, the reduction of particle velocity in the large curvature radius bend and its corresponding vertical tube is less, and the particle possesses a larger intensity of fluctuation velocity in its corresponding vertical tube. The particles in the vertical tube corresponding to the large curvature radius bend lead to large peaks of the power spectrum in the low-frequency region, which is closely linked to the pressure drop. Eventually, the dynamics of particles in a vertical tube are revealed from the perspective of time-frequency analysis by using a continuous wavelet transform.

Aiming at the problems of high energy consumption and particle breakage in the pneumatic conveying process of large-scale breeding enterprises, in this paper, based on the theoretical calculated value of particle suspension velocity, a computational fluid model and a discrete element model are established based on computational fluid dynamics (CFD) and discrete element method (DEM). Then, through the numerical simulation of gas-solid two-phase flow, the influence of four factors of conveying wind speed, particle mass flow rate, pipe diameter, and particle size on the velocity distribution of particles in a horizontal pipe, dynamic pressure change in the pipe, pressure drop in the pipe, and solid mass concentration are studied. The results show that the k-ε turbulence model can better simulate the movement of gas-solid two-phase flow, and through the analysis of the simulation, the influence of four different factors on the conveying characteristics is obtained, which provides a scientific basis for the construction of the conveying line. [ABSTRACT FROM AUTHOR]

In order to study the working mechanism and sowing effect of seed delivery pipes and their associated cavity seeders, the factors affecting the sowing test were first derived through pressure loss theory and force analysis of cotton seed particles in the gas-solid coupling field. Secondly, Ansys fluent was used to simulate the flow field of seed delivery pipe joints to study the effect of seed delivery pipe joints on the overall pressure loss and uniformity of air pressure distribution and to determine the optimal structure of seed delivery pipe joints. Then, the EDEM was simulated for the overall seed delivery pipe and its associated cavity seeders in the absence of positive pressure to analyze the transport pattern of each cotton seed. Finally, CFD-DEM gas-solid coupling simulation experiments were conducted on the center of two rows of seed delivery pipes and their connected cavity seeders to analyze the trajectory of cotton seeds under different rotational speeds of cavity seeders and different positive seed delivery pressures and to deeply analyze the causes of Multiple seeding and Miss-seeding. At the same time, the seeding performance was evaluated by coupling simulation values with single seeding rate and multiple seeding rate as seeding performance evaluation indexes and compared with bench test. The results show that in the coupling simulation, when the speed of the cavity seeders is 20~40 rev/min and the seed delivery tube is passed into 50~150 Pa positive pressure airflow, the single seeding rate is not less than 83.06%, and the missed seeding rate is not more than 9.23%. In the bench test, the single seeding rate was not less than 80.64%, and the missed seeding rate was not more than 9.86% under the same cavity seeders speed and positive pressure, and the results of the bench test and the simulation test were close and consistent, which verified the feasibility of the simulation. [ABSTRACT FROM AUTHOR]

The pressure drop and conveying stability caused by the bend significantly affect the pneumatic conveying process of stiff shotcrete, which is the key to solving the problem of long-distance transportation. In this paper, the effects of different air velocities (32 m/s, 36 m/s, 40 m/s), water-cement ratios (0.1, 0.2, and 0.3), and bending-diameter ratios (4, 12, and 20) on the pressure drop of the elbow R1 and conveying stability R2 are studied using the response surface method. The conveying stability is characterized by the pressure variation coefficient (C.V). The response surface graph aids in the intuitive analysis of the effects of these variables. The results show that the impact of air velocity on R1 and R2 is exceptionally significant, and the interaction of each factor on the response value is analyzed. The response value and the quadratic polynomial regression equation between the various factors are obtained in addition to the flow characteristics of stiff shotcrete under different working conditions. The relationship established by the statistical processing of the experimental results can provide some reference for specifying the pressure loss model of stiff shotcrete. [ABSTRACT FROM AUTHOR]

The flow mode changes from dense to dilute as fine particles are conveyed via long pipelines. Because multiple complex interactions are involved, the modeling and prediction of such a flow transition poses difficulties. In various fields of research, computational fluid dynamics (CFD) has been successfully employed to address the inadequacies of the theoretical method. Using the ANSYS 16.2 software and the Eulerian–Eulerian technique, a CFD model of gas–solid flow was developed in this research. The flow–mode transition through a pipeline section (length 30 m and bore 53 mm) was predicted using the model. Fly ash was employed as the conveying material. The contours of flow parameters such as void fraction, solid volume fraction, air velocity and particle velocity were examined in different cases of simulations. For each of the four cases, the air velocity at the outlet of the pipeline section was predicted and found to be within a reasonable error margin. [ABSTRACT FROM AUTHOR]

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Powder breakage during pneumatic conveying negatively affects the properties of dairy products and causes increased dusting, reduced wettability, and decreased product performance. In particular, particle breakage is a serious issue for fat-filled milk powder (FFMP) which, if it breaks, releases fat that causes odours and leads to sticky blocked pipes. In this work, a conveying rig (dilute phase, positive pressure) with 50 mm diameter food grade stainless steel pipes (1.5 m high and 5 m conveying distance with three 90° bends, two in the vertical plane and one in the horizontal plane) was built as the test system. The effects of operating conditions (conveying air velocity and solid loading rate) on the attrition of FFMP in a dilute phase conveying system were experimentally studied. Four quality characteristics were measured before and after conveying: bulk density, particle size distribution, wettability, and solubility, to access the influence of particle breakage. Conveying air speed shows a significant impact on powder breakage. As air speed increased, more breakage occurred, and the volume mean diameter D[4,3] decreased by around 50%, using the largest conveying air speed of 38 m/s. Bulk density increased accordingly whereas wettability decreased with an increase in air speed, resulting from the higher breakage rate. On other hand, improving the solid loading rate can further reduce the breakage level, but the positive effect is not as good as decreasing air speed. [ABSTRACT FROM AUTHOR]

Featured Application: Particle degradation of biomass materials can be a severe issue in transportation and material handling because of dust generated. Especially for pneumatic conveying systems, assessment of material degradation in such a large process can be challenging. In this study, the degradation of wood pellets and dry roasted coffee beans in a pneumatic conveyor was evaluated for high-speed impacts. The change in particle size and generation of fine particles were used as an indicating parameter for the degradation. A four-bends industrial scale conveying system was used for the degradation study in lean phase pneumatic conveying. The effects of operating parameters on the degradation were investigated, including the conveying velocity of particles and particle concentration. The experimental results showed that the degradation and the fines generation increased with an increase in particle velocity. An opposite trend was observed with an increased solid concentration in the pipeline. It was found that the two types of wood pellets traveled at different particle velocities with the same operating conditions, which resulted in significant differences in the degradation. Compared to the wood pellets, roasted coffee beans were found to travel at air velocity. In conclusion, the degradation in a pneumatic conveying system is complex and challenging to evaluate because there are many influential factors, such as the type of materials, equipment, and operation conditions. Early assessments in a laboratory will be beneficial to evaluate the degradation at all controlled operative conditions. [ABSTRACT FROM AUTHOR]

To reveal the flow characteristics of shotcrete during pneumatic transportation, the numerical simulation of the gas–solid flow of shotcrete in the pipeline transportation process was carried out based on a CFD-DEM coupling simulation method. When the particle diameter increased from 7 mm to 12 mm, the maximum wear depth of the pipeline increased from 1.48 × 10−6 mm to 4.58 × 10−6 mm. With an increase in particle diameter, the maximum wear depth of the pipeline increased. Moreover, the wear position gradually concentrated to a fixed area with the increase in particle diameter. In the wind speed range of this simulation study, when the wind speed increased from 42 m/s to 52 m/s, the maximum wear depth of the pipeline increased from 2.53 × 10−6 mm to 5.26 × 10−6 mm. The change in wind speed had little effect on the wear location of the pipeline. However, the wear depth of the pipeline increased with the increase in wind speed. When the curvature radius increased from 200 mm to 250 mm, the maximum wear depth decreased from 5.83 × 10−6 mm to 4.47 × 10−6 mm. When the curvature radius increased to 300 mm, the maximum wear depth increased to 6.58 × 10−6 mm. Finally, according to the law of pipeline wear and combined with the actual situation of pipeline wear in engineering, measures were put forward to prevent or reduce the degree of pipeline wear. [ABSTRACT FROM AUTHOR]

The scale of dry pulverized coal gasifier is restricted by the conveying capacity of single pipeline. In this paper, the flow characteristics of pulverized coal at different pipe diameters and operation parameters under high pressure are simulated to indicate flow stability and ultimate pipe diameter. Firstly, the numerical model is established and verified by the industrial data. The influences of conveying velocities and densities on the particle behavior are investigated to explore the flow regime and conveying stability. The flow characteristics and pattern transition regulation are discussed at different pipe diameters. The evolution mechanism of pressure drops in different straight pipes are analyzed. Also, the ultimate pipe diameter of gasifier is revealed at industrial operating parameters. [Display omitted] • The flow characteristics and pattern transition regulation are discussed at different pipe diameters. • The evolution mechanism of pressure drops in different straight pipes are analyzed. • The ultimate pipe diameter of gasifier at industrial operating parameters is revealed. [ABSTRACT FROM AUTHOR]

This paper will validate two basic concepts of numerical models for prediction of pressure change along the transport pipeline in the case of long distance and high capacity lignite ash pneumatic conveying. Application of various friction factor correlations and variation of given parameter, led to the total of fourteen different numerical models and program codes in FORTRAN. The input data for numerical models are based on comprehensive experimental research of high capacity and long distance Kolubara lignite fly ash pneumatic conveying system within 620 MWe thermal power plant unit under operating conditions. Numerical simulation results are validated against experimental data and subjected to statistical analysis methods. The functional dependence obtained by the least squares method was evaluated using mean squared deviation and correlation ratio. The predicted pressure changes show the best agreement, with the measured decrease of pressure amplitudes along the transport pipelines, for the model based on the momentum balance of air-ash mixture flow and friction factor correlation given by Dogin and Lebedev for the parameter A = 1.4∙10-6. This model achieved the best correlation ratio of 93.99% for Pipeline 1 and 91.33% for Pipeline 2, as well as the best mean squared deviation of 9.58% for Pipeline 1 and 13.66% for Pipeline 2. Also, the fanning friction factor values are fully consistent with previously examined cases available in the literature. Numerical simulation model can be used for prediction of the ash pneumatic conveying capacity and pressure drop for the specified transport pipeline. [ABSTRACT FROM AUTHOR]

Dilute and dense conveying systems through pipelines are a common practice in our everyday life. It is used in many industries to convey a mixture of gas and solids from one location to another through pipes. Gas-solid transport is desirable in some industries but unwanted in others. Depending on the density, size, and shape, these solid particles may result in erosion and subsequent damage to piping and other equipment. Understanding the gas-solid two-phase flow dynamics can help develop efficient and cost-effective pipe transport systems, thereby mitigating the problems associated with the gas-solid two-phase flow. Models for estimating volumetric flow rates and other gas-solid two-phase flow properties are scarce as most are very complex, expensive, and unavailable proprietary commercial software. This study, therefore, developed a simple model using the general energy balance equation and relevant mixing theories for estimating the volumetric flow rate of natural gas-solid two-phase flow in horizontal pipes. The results from the model showed that the gas-solid flow rate is a function of pipe diameter, pressure drop, pipe length, solid volumetric concentration, solid-to-gas density ratio, and solid-to-gas friction factor ratio. [ABSTRACT FROM AUTHOR]

During the crop harvesting process, it is important to obtain the crop yield quickly, accurately and in real time to accelerate the development of smart agriculture. This paper investigated a denoising method applicable to the impact-type sunflower yield sensor signal under the influence of complex noise background in the pneumatic seed delivery structure for a sunflower combine harvester. A signal processing method combining complementary ensemble empirical mode decomposition (CEEMD) and wavelet threshold denoising (WTD) based on an adaptive decomposition capability was proposed by analyzing the non-smoothness of the signal with the impact-type sunflower yield sensor signal in sunflower fields. CEEMD was used to decompose the sunflower seed impact analog signal and field impact-type sunflower yield sensor signal adaptively, and the high frequency components were processed by WTD. Finally the de-noised signal was obtained by reconstruction. An evaluation objective function of the denoising ability of the algorithm based on signal-noise ratio, root mean square error, smoothness and waveform similarity indexes with different weights was also constructed. The results showed that the evaluation objective functions of the simulated and measured signals after denoising by the CEEMD-WTD method are 1.9719 and 4.5318, respectively, which are better than the single denoising methods of EMD (1.5096 and 4.0012), EEMD (1.8248 and 4.0724), CEEMD (1.9516 and 4.3384), and WTD (1.8737 and 4.5294). This method provides a new idea for signal denoising of the impact-type sunflower yield sensor installed in the pneumatic seed delivery structure, and further provides theoretical support and technical references for the development of sunflower high-precision yield measurements in smart agriculture. [ABSTRACT FROM AUTHOR]

Pneumatic conveying is a vital technology for delivering bulk solids, powders, and granular materials in various industries. Significant advances in pneumatic conveying technology have occurred in recent years, spurred by the demand for sustainable and energy-efficient industrial processes. This paper explores the current advances in pneumatic conveying technology and their implications for the industry. First, the principles of pneumatic conveying are discussed. Then, two significant advances in pneumatic conveying technology are highlighted. Schenck Process, for example, has created the Enhanced Dilute Phase Pneumatic Conveying (EDIP) system, the E-Finity continuous dense phase system, and high-pressure systems utilizing Lontra’s LP2 Compressor Blower. Second, Palamatic Process provides dense-phase vacuum conveying cyclones as well as powder pumps for nonabrasive dense-phase vacuum conveying. Several research gaps in pneumatic conveying technology are identified in the paper, including the integration of artificial intelligence and machine learning, the optimization of multiphase flow behavior, energy efficiency and sustainability, material degradation, and particle damage, handling of cohesive and difficult-to-convey materials, scale-up and design optimization, and real-time monitoring and control systems. The future outlook highlights the potential of sustainable practices to advance pneumatic conveying technology further. The integration of these technologies can lead to improved performance, energy efficiency, and sustainability in pneumatic conveying systems.

To examine the flow characteristics of particles in the vertical tube corresponding to different curvature radius bends, the particle velocity is measured at the Minimum Pressure Drop (MPD) using a high-speed Particle Image Velocimeter (PIV). This experiment explores the effects of particle flow characteristics at different curvature radius bends and their corresponding vertical tubes with pressure drop, power consumption, the intensity of particle fluctuation velocity, power spectrum and time-frequency characteristics. It is observed that the pressure drop and power consumption can be reduced with the help of a large curvature radius bend. Besides, the reduction of particle velocity in the large curvature radius bend and its corresponding vertical tube is less, and the particle possesses a larger intensity of fluctuation velocity in its corresponding vertical tube. The particles in the vertical tube corresponding to the large curvature radius bend lead to large peaks of the power spectrum in the low-frequency region, which is closely linked to the pressure drop. Eventually, the dynamics of particles in a vertical tube are revealed from the perspective of time-frequency analysis by using a continuous wavelet transform. [ABSTRACT FROM AUTHOR]