Air Distributor Research Articles

Improving used Lubricant Oil Burner Performance: Effect of Swirled Flow of Internally Distributor Type on the Combustion and Flue Gas Temperature and Emission

This study aimed to experimentally investigate the combustion characteristics of used lubricant oil (ULO). A simple cylindrical burner of the natural draft vaporizing type, equipped with an internal air distributor, was designed and fabricated to achieve this objective. The burner’s efficiency was evaluated based on combustion temperature, flue gas temperature, and concentration levels. The key feature of this burner lies in the swirled flow of air combustion and ULO vapor within the combustion chamber, facilitated by the swirled flow air distributor type. Various air-fuel ratios (ϕ), ranging from 0.5 to 4, were considered in characterizing the burner’s performance. The results revealed increased combustion and flue gas temperatures in the radial airflow types. The highest temperatures achieved using the radial flow type are 930 oC and 410 oC for combustion and exhaust gas temperature, respectively. In contrast, the combustion chamber and exhaust gas temperatures are 980 oC and 465 oC for the swirled flow type, respectively. It was found that there is a decrease in the emission of CO and CO2 by volume under optimum conditions. This decrement was attributed to the swirled flow effects, which promoted a better mixture of air combustion and ULO vapor during combustion.

Reaction Characteristics of Calcination and Decomposition of Phosphogypsum in a Bubbling Fluidized Bed.

A bubbling fluidized bed reactor is designed to investigate the high-temperature calcination and decomposition characteristics of phosphogypsum (PG). The reactor employs electric heating, and a lifting discharge tube is installed in the middle of the air distributor to allow flexible switching between batch and continuous feeding modes. The batch test results show that the solid-phase bed materials with a PG particle size of 0.27-0.55 mm and a coal particle size of 0.55-0.83 mm are found to have uniformly mixed at a PG/coal mass ratio of 5:1 and calcined at a high temperature of 1100 °C for 30 min. PG completely decomposes to yield mainly CaS and a small amount of Ca2(SiO4) as the solid-phase products. For the above-mentioned optimal process parameters, a 120 min thermal-state continuous test is conducted. Feeding and discharging are performed at intervals of 30 min to maintain the stability of the static bed height inside the reactor. The results indicate that the PG decomposition rate is higher than 92% in the batch and continuous tests. However, the continuous decomposition of PG has significant process advantages, such as a higher CaS yield (71.20%) compared to that in the batch mode (64.49%). Furthermore, PG undergoes agglomeration and bonding within the particles when heated, intensifying the formation of a Ca2(SiO4) eutectic.

Research on prepositioned air distribution and dust control devices for continuous mining faces

This study, based on the construction of a wind flow-dust two-phase coupled diffusion model, develops a novel method using a prepositioned air distributor to create an air curtain for dust control. This research involved the analysis of wind flow transportation patterns and dust diffusion mechanisms with varying structural parameters, and the verification of simulation results through field tests. The findings indicate that with the increase of the axial horizontal opening angle of the prepositioned air distributor, the wind speed of the air curtain decreases, while the size of the vortex field in the heading face area expands. Increasing the axial vertical opening angle enhances the strength of the vortex, leading to improved dust control abilities. The dust concentration at the rear of the tunnel initially decreases and then rises. Additionally, as the turning angle increases, the speed at which the wind flow diffuses towards the rear of the tunnel also rises. Compared with traditional ventilation methods, the dust reduction efficiency at the respiratory zone height is improved to over 94.0 %. The concentration of dust within the tunnel is significantly reduced, with approximately 98.9 % of the dust confined within a 10.0 m range from the heading face.

Numerical evaluation and optimization of volatiles distributors with different configurations for biomass chemical looping combustion

The rapid devolatilization of biomass in chemical looping combustion could form a local plume of volatiles, reducing contact between volatiles and oxygen carriers and thus lowering gas conversion. Hence, a novel concept called volatiles distributor (VD) has been recently proposed to enhance the mixing between the volatiles and oxygen carriers. However, the configurations of VD have significant effects on its performance. To optimize the configurations of VD, the impact of VD with different configurations has been investigated with respect to the mixing behaviors and the pathways of volatiles in this work using computational fluid dynamics (CFD) modeling with an Eulerian-Eulerian two-fluid model coupled with a two-step EMMS/bubbling drag model. Comparison to experimental results from a cold-flow fluidized bed demonstrates that the CFD model can provide quantitative predictions for the vertical pressure profiles and reasonable trends of horizontal gas distributions of the fluidized bed under various conditions. Conditions varied were the superficial gas velocity, the percentage of the simulated volatiles, primary air distributor, and configurations of VD. The CFD simulations of both original and new designs reveal that the performance of the VD can be improved by reducing the open area of the distribution holes of the VD near the injection port and increasing it further away from the injection port. An optimal configuration is proposed to achieve an even distribution of volatiles and avoid the leakage of volatiles from the bottom of the VD.

Numerical investigation of air flow characteristics for a compact 5 [formula omitted] 10 array tubular segmented-in-series solid oxide fuel cell stack

Tubular segmented-in-series solid oxide fuel cells (SIS-SOFCs) offer the advantages of high voltage, low current, easy sealing, and high thermal shock resistance. Tubular SIS-SOFCs can be assembled into a highly integrated power-generation stack module to increase the volumetric power density. This study investigated the air flow characteristics of a kilowatt-class tubular SIS-SOFC stack with a 5 × 10-cell array, each containing 59 segments. A three-dimensional stack model that considers practical stack structures, coupled electrochemical reactions, and the mass/momentum/heat transfer processes was developed. The results show that a large flow nonuniformity existed in the conventional tubular stack design, which resulted in a severe temperature distribution. Local hot spots at the marginal positions and circumferential temperature difference were found to be non-negligible. To improve the flow uniformity, an air distributor with optimized diameters at different positions was designed, and manifold parameters were adjusted to balance the flow resistance. The maximum temperature was reduced by 35 K and temperature uniformity was significantly improved.

Increasing Economic Efficiency When Creating a Dynamic Microclimate in Compressed Conditions of Production Premises

This work is devoted to increasing economic efficiency when using two-stream air distributors that form a swirled and flat stream while providing a dynamic microclimate in compressed conditions of industrial premises. The design of a two-jet air distributor is proposed, which forms a swirled and flat laying air jet, that provides intensive attenuation of air flow velocity and temperature in stationary and variable mode. Measures aimed at saving cold energy are considered, namely, air supply in a variable mode, use of the flooring effect, use of devices for intensification of tidal flow turbulence. A set of optimal measures for obtaining the maximum economic effect is determined. A method of development and calculation of inflow mechanical ventilation systems based on the specified air distributors is proposed. The economic evaluation of the use of air distribution devices proved that the use of a two-jet air distributor makes it possible to obtain some economic effect.

Pembuatan Tungku Pembakaran Logam

Current technological advances have produced many products that aim to make human work easier. One of them is an iron burning tool that uses a blower as a tool used to increase or enlarge the air or gas pressure that will flow into the combustion container (furnace). The blower used is a 2 inch snail blower as a tool to increase the air pressure so that the air that is supplied can enlarge the burning flame. The furnace used is a drum coated with heat-resistant cement which can withstand the heat of the combustion fire so that the furnace does not melt. The frame materials used are hollow iron measuring 40 x 40 and angle iron measuring 40x40. For combustion, it uses coal as the main fuel and the blower itself as an air distributor so that it can produce the desired fire. Based on the test results in a metal burning furnace, a temperature of 340°C can be obtained as planned so that by heating the metal, various types of equipment can be formed as desired

EMMS and Syamlal O’Brien Hydrodynamic Modelling for Uniform and Non-Uniform Air Distributor in a Bubbling Fluidized Bed: Numerical Analysis

EMMS and Syamlal O’Brien Hydrodynamic Modelling for Uniform and Non-Uniform Air Distributor in a Bubbling Fluidized Bed: Numerical Analysis

Improvement of airflow uniformity and noise reduction with optimized V-shape configuration of perforated plate in the air distributor

The air distributor is the end component of the ventilation system, and its performance directly determines the comfortable and pleasant feeling of the residence. A perforated plate can be added to the air distributor to convert dynamic pressure into static pressure first and then distribute the air flow, which provides better self-adjustment compared with the embedded guide vane structure. However, the perforated plate can lead to a contradiction between head loss, noise and distribution uniformity. To reconcile this problem, a novel V-shape configuration of the perforated plate was put forward in this study. The internal flow and aeroacoustic properties of different types of perforated plates were systematically studied, and a full-scale test platform was built to verify the flow characteristics. The effects of hole size and installation position of the perforated plate on the uniform distribution of air flow were analyzed by the parametric analysis method. Then, the sound pressure level of the optimized perforated plate air distributor was further analyzed. The results show that, with the optimized perforated plate structure, the uniform flow performance was improved by about 30% and the overall sound pressure level was reduced by up to 12 dB.

Characteristic research of regeneration process of particulate filter medium in vibrated fluidized bed

Abstract The vibrational fluidized bed is innovatively adopted to regenerate the particulate filter medium for the purification of crude synthesis gas from the coal gasification process. Characteristic research of vibrated fluidized beds during dust-containing particulate filter medium regeneration has been carried out. The ideal transport model of particulate filter medium on the distributor is established and verified by using experiments. The mean residence time of the particulate filter medium can be reduced by 72% from 5.5 to 1.5 min with an increase in the working frequency from 50 to 60 Hz. The thickness of the bed layer is linearly increased with the feeding rate of the particulate filter medium under ideal working conditions. The resistance models of the fluidizing air are built up and validated, and they can be used to calculate the pressure drop of the static bed layer of the particulate filter medium on the fluidizing air distributor, which is the maximum value of the dynamic bed layer with the same thickness. The fluidizing air makes the mean residence time of the particulate filter medium decrease by 50% and reduces the difference in the particulate mean residence time under different feeding-rate conditions. The regeneration effect of dust-containing filter medium particles in a vibrated fluidized bed is evaluated. Fluidizing air with superficial velocity ranging from 0 to 0.6~0.9 m·s–1 makes the regeneration efficiency increase from 29.41% to 70.59~88.24%. This article provides a reference for the industrial application of a vibrated fluidized bed for the particulate filter medium recycling system.

Drying of freshly harvested almonds using a stockpile heated and ambient air dryer (SHAD) with an air distributor -part 2

Drying of freshly harvested almonds using a stockpile heated and ambient air dryer (SHAD) with an air distributor -part 2

Design and optimization of an air distributor for an almond stockpile heated and ambient air dryer (SHAD) - Part 1

Design and optimization of an air distributor for an almond stockpile heated and ambient air dryer (SHAD) - Part 1

Study of bubble behavior in a gas–solid dense-phase fluidized bed based on deep learning

Fluidization characteristics and hydrodynamics of gas–solid fluidized beds are controlled by bubble properties. However, the existing conventional image segmentation methods are unable to effectively resolve the problems of overlap and background interference between small bubbles, and the segmentation performance for bubbles must still be enhanced. To study the bubble behavior of a gas–solid dense-phase fluidized bed, a two-dimensional fluidized bed with different air distributors was adopted. The application of deep learning to digital image analysis technology is to improve the precision and automation of bubble recognition. The DeepLab V3+ model incorporates multi-scale information, which is well-compatible with uncertain bubble boundary information while enhancing the segmentation effect. A pixel accuracy of 97.95% and a mean intersection over union (MIoU) of 80.91% for multi-group bubble image segmentation were achieved. In comparison to conventional threshold-based recognition methods, the accuracy of the deep learning method increased by up to 40.31% and the MIoU by up to 53.88%, demonstrating the great potential and application value of semantic segmentation in the study of the complex motion behavior of gas–solid sorting fluidized bed bubbles. The influence of the air distributor on the behavior of bubbles is verified. The results indicate that air distributor aperture directly influences bubble diameter, aspect ratio, and shape factor, with coalescence being the primary cause of bubble enlargement.

Optimizing Design and Operational Parameters for Enhanced Mixing and Hydrodynamics in Bubbling Fluidized Bed Gasifiers: An Experimental and CFD-Based Approach

An experimental investigation of hydrodynamics of gas-solid flow is carried out by engaging different designs of air distributor plates. An analysis of three different plates, i.e., perforated, 45° slotted and novel hybrid plate, revealed the difference in pressure drop and minimum fluidization velocities (Umf) for varying input operational variables. Umf is found to be lowest for perforated and highest for 45° slotted plate, whereas pressure drop is found to be highest for 45° slotted plate and lowest for novel hybrid distributor plate. The bubbles rise velocity ratio (Umf,b/Umf,f) is noticed minimum for 45° slotted plate due to relatively larger bubbles originating from the bigger slot openings and maximum for perforated distributor plate owing to smaller bubbles with dominant axial rise. Furthermore, the bed height rise ratio (h/L) is observed as a minimum for perforated distributor and maximum for 45° slotted plate due to larger bubbles through 45° slots rupturing the bed surface, causing more bed expansion. Furthermore, CFD analysis is also carried out to observe the insight flow dynamics using the distributor plates. The simulations use a two-fluid model (TFM) and K-Epsilon turbulence models. CFD model shows promising results in agreement with the experimental results. CFD results revealed that the lower portion enhanced lateral dispersion/mixing of solid particles due to 45° angular openings of an air inlet. In contrast, the perforated plate exhibited a straight upward motion of small air bubbles, causing no radial/lateral mixing. CFD results for the hybrid plate show the mixed axial as well as lateral mixing of solids by revealing velocity distribution; therefore, the novel hybrid plate is found to be an optimum distributor plate due to its lowest pressure drop, adequate Umf, intermediary bed height rise ratio and moderate bubble rise velocity ratio across the bed.

Numerical Optimization Study of the Resistance Coefficient of U-Shaped Air Distributor

In this paper, the optimization of the flow channel structure of the U-shaped air distributor is proposed. Fluent meshing was used to mesh the multipatch meshing of the original model of the grid air distributor, and then the CFD numerical simulation was carried out by using Fluent 2022R1 to obtain the internal air flow state of the air distributor flow channel. Through the orthogonal experimental design and a comprehensive analysis method, the optimal size structure for resistance performance is obtained as S = 60 mm, RL = 125 mm, L = 160 mm, D = 100 mm, the resistance coefficient of the new structure as 1.375, and the pressure loss as 56.87 Pa, by using 3D modeling software (SOLIDWORKS 2015) and Fluent. Compared with the initial scheme, the resistance coefficient and pressure loss are reduced by 3.03% and 6.29%, respectively. To summarize, the research in this paper offers a substantial contribution to the realm of energy conservation and emission abatement in ship air conditioning systems, simultaneously furnishing invaluable guidance for the design of air distributors.

Time-scaled study on the erosion in circulating fluidized bed based on CPFD method

In this paper, the erosion characteristics in a circulating fluidized bed (CFB) were investigated on time scale with Euler-Lagrange model based computational particle fluid dynamics (CPFD). By analyzing average erosion rate data, two different erosion characteristics were found. In addition to the common linear erosion caused by downflow particles, another type of erosion is characterized by step growth and is caused by upwelling particles. Linear erosion at the height of 0.1 m is close to that at 0.2 m from the air distributor, but the value of stepped erosion at 0.1 m is much greater than that at 0.2 m. The simulation results show that stepped erosion is the main cause of erosion in the simulated object, accounting for about 70% of the total erosion. The present numerical study implies that the special gas-solid flow of CFB will bring different characteristics of erosion, and the anti-wear method should be targeted at the causes of erosion.

Bubble dynamics properties of B-particles in a quasi-2D gas-solid fluidized bed: Computational particle fluid dynamics numerical simulation and post-processed by digital image analysis technique

Bubble dynamics properties play a crucial and significant role in the design and optimization of gas-solid fluidized beds. In this study, the bubble dynamics properties of four B-particles were investigated in a quasi-two-dimensional (quasi-2D) fluidized bed, including bubble equivalent diameter, bubble size distribution, average bubble density, bubble aspect ratio, bubble hold-up, bed expansion ratio, bubble radial position, and bubble velocity. The studies were performed by computational particle fluid dynamics (CPFD) numerical simulation and post-processed with digital image analysis (DIA) technique, at superficial gas velocities ranging from 2umf to 7umf. The simulated results shown that the CPFD simulation combining with DIA technique post-processing could be used as a reliable method for simulating bubble dynamics properties in quasi-2D gas-solid fluidized beds. However, it seemed not desirable for the simulation of bubble motion near the air distributor at higher superficial gas velocity from the simulated average bubble density distribution. The superficial gas velocity significantly affected the bubble equivalent diameter and evolution, while it had little influence on bubble size distribution and bubble aspect ratio distribution for the same particles. Both time-averaged bubble hold-up and bed expansion ratio increased with the increase of superficial gas velocity. Two core-annular flow structures could be found in the fluidized bed for all cases. The average bubble rising velocity increased with the increasing bubble equivalent diameter. For bubble lateral movement, the smaller bubbles might be more susceptible, and superficial gas velocity had a little influence on the absolute lateral velocity of bubbles. The simulated results presented a valuable and novel approach for studying bubble dynamics properties. The comprehensive understanding of bubble dynamics behaviors in quasi-2D gas-solid fluidized beds would provide support in the design, operation, and optimization of gas-solid fluidized bed reactors.

Experimental Study on Denitration Transformation of CFB Boiler Burning Fujian Anthracite

Two 75 t/h medium-temperature separated circulating fluidized bed boilers burning Fujian anthracite were upgraded with low NOx combustion (LNC). By reducing the effective cross-sectional area of the air distributor (from 13.43 m2 to 11.38 m2), improving the secondary air rate (from 40% to 45%), adjusting the secondary air supply method (adding a layer of upper secondary air, raising the height of the lower secondary air nozzle (0.4 m), and increasing the secondary air speed (from 48 m/s to 54 m/s), the reform of low nitrogen combustion was carried out. The transformation achieved remarkable results, i.e., the original NOx emission concentration can be controlled between 140–160 mg/m3 after the transformation, and the lowest value is below 120 mg/m3.

A novel method for evaluation of spatial characteristics in a gas solid separation fluidized bed

This study investigates the complex spatial characteristics of a gas-solid dense-phase fluidized bed for a separation system. A custom-designed perspex bed, equipped with multi small holes and different distributors, was used to explore gas-solid suspension characteristics. The results show that there is a certain spatial heterogeneity in the density of the gas-solid separation fluidized bed. The spatial heterogeneity of gas-solid fluidized beds is characterized by global and local dependence. An empirical model that predicts the relative solid mass flow rate was proposed. GeoDetector technology (including a factor detector, interaction detector, risk detector, and ecological detector) was first introduced to quantify the spatial characteristics of a gas-solid fluidized bed. The influence of each factor on the spatial heterogeneity of particle solid mass flow rate follows the order: axial position > gas velocity > radial position > air distributor. The interactive relationship between variables on the spatial characteristics of gas-solid separation fluidization shows a nonlinear enhancement.

Hydrodynamics Investigations of Kaffir Lime Leaves Drying in a Swirling Solar Drying Chamber with Inclined Slotted Angle Air Distributor

The present work aims to investigate the behavior of drying kaffir lime leaves in a swirling solar drying chamber (S-SDC) fitted with an inclined slotted angle air distributor. A distributor plated with inclined slotted angle was located at the air inlet at the bottom of the chamber. Experimental and numerical methods have been applied to analyze the efficiency of developed S-SDC assisted solar drying system based on the moisture content (MC), moisture content ratio (MR) and drying rate (DR) were examined. The experimental results showed that the S-SDC can reduce the moisture content of kaffir lime leaves more rapidly than a conventional solar drying chamber (CSDC). The S-SDC gave a higher DR and decreased drying time compared to that of C-SDC. The results also indicated that operation at higher air velocities resulted in a greater DR, especially at the beginning stage of the drying process. For the S-SDC, the reduced of MC, MR and DR at a high air velocity (v = 2.0 m/s) was better than at low air velocities (v = 0.5 and 1.0 m/s). Drying chamber efficiency is also observed at a higher air velocity of 2 m/s for both SSDC and CSDC. In addition, obtained experimental findings are in line with numerical results. The outcomes of this study present the potential of using the S-SDC compared to the C-SDC to be used in drying crops.