Pulsating Air Flow Research Articles

The Influence of Gas-Dynamic Non-Stationarity of Air Flow on the Heat Transfer Coefficient in Round and Triangular Straight Pipes with Different Turbulence Intensities

Unsteady gas-dynamic phenomena in pipelines of complex configuration are widespread in heat exchange and power equipment. Therefore, studying the heat transfer level of pulsating air flows in round and triangular pipes with different turbulence intensities is a relevant and significant task for the development of science and technology. The studies were conducted on a laboratory stand based on the thermal anemometry method and an automated system for collecting and processing experimental data. Rectilinear round and triangular pipes with identical cross-sectional areas were used in the work. Flow pulsations from 3 to 15.8 Hz were generated by means of a rotating flap. The turbulence intensity (TI) of the pulsating flows varied from 0.03 to 0.15 by installing stationary flat turbulators. The working medium was air with a temperature of 22 ± 1 °C moving at a speed from 5 to 75 m/s. It was established that the presence of gas-dynamic unsteadiness leads to an increase in the TI by 47–72% in a round pipe and by 36–86% in a triangular pipe. The presence of gas-dynamic unsteadiness causes a heat transfer intensification in a round pipe by 26–35.5% and by 24–36% in a triangular pipe. It was shown that a significant increase in the TI of pulsating flows leads to an increase in the heat transfer coefficient by 11–16% in a round pipe and a decrease in the heat transfer coefficient by 7–24% in a triangular pipe. The obtained results can be used in the design of heat exchangers and gas exchange systems in power machines, as well as in the creation of devices and apparatuses of pulse action.

Gas dynamics and heat exchange of stationary and pulsating air flows during cylinder filling process through different configurations of the cylinder head channel (applicable to piston engines)

Piston machines are used in distributed generation, are in demand as auxiliary energy sources in hybrid systems and are indispensable devices in compressor technology. The purpose of this article is to develop a method for improving the quality of the cylinder filling process based on an experimental study of the gas dynamics and heat transfer of stationary and pulsating flows in an intake system with profiled channels in a piston machine's cylinder head. Experiments were carried out on full-scale models of piston machines with thermal anemometry and thermal imaging. The article examines three cross-sectional shapes for the intake port in the cylinder head: circle (basic design), square and triangle. It is established that profiled channels in a piston machine's intake system have a significant impact on the gas-dynamic, flow and heat-exchange characteristics of both stationary and pulsating air flows. It is shown that the use of profiled channels leads to a more uniform distribution of air flow throughout the entire cylinder volume and a significant reduction in stagnation zones, which should lead to a reduction in specific fuel consumption. It is established that air flow through an intake system with square and triangular ducts increases up to 30 % compared to the basic system, which should lead to an increase in power. It is found that the use of square and triangular channels leads to an increase in the flow turbulence intensity by 3…30 % and an increase in the heat transfer coefficient to 25 % in a piston machine's intake system. On the practical side, the installation of a cylinder head with profiled channels should improve the technical, economic and environmental characteristics of piston machines.

Experimental study on the periodic pulsating ventilation by fluidic oscillator on pollutant dispersion and ventilation performance in enclosed environment

Ventilation plays an essential role in creating healthy and comfortable indoor environment, while adopting unsteady airflow field has the potential to improve the indoor air mixing effect, which is conducive to the dispersion and eventually the discharge of indoor pollutants. A fluidic oscillator capable of producing periodic pulsating airflow is employed to conduct a ventilation experiment to test the performance of such unsteady flow regime. The distribution of indoor pollutants at different source locations is compared under both steady and unsteady ventilation mode. The assessment of the fluidic oscillator ventilation system performance in eliminating pollutants involves the concentration exceedance rate, the decay of indoor pollutant concentration, and the resultant ventilation efficiency. At a relatively lower air supply rate, the fluidic oscillator device can enhance indoor air mixing, leading to a reduction of the peak indoor pollutant concentration. Additionally, the fluidic oscillator air terminal significantly prolongs the time needed to reach the pollutant concentration threshold, increases ventilation efficiency, and improves indoor air quality.

Energy and exergy analysis of drying of potash particles in a pulsation-assisted fluidized bed

Potash particles exhibit cohesiveness and hygroscopic behavior in the presence of moisture. During the drying of wet potash particles, solid bridges form, and the agglomeration behavior of such particles reduces the efficiency of drying. In this work, pulsed airflow was employed to break agglomeration and eliminate channeling in a fluidized bed with wet potash particles. The effect of different operating conditions including inlet drying gas temperature (40 °C, 50 °C, and 60 °C) and pulsation frequency (1.0 Hz and 2.0 Hz) on the energy and exergy efficiency of fluidized bed drying of potash particles was investigated. A drying model based on the thin-layer theory was employed to correlate the experimental data of drying of potash particles. The results showed that the highest energy and exergy efficiency of potash drying, 28.6% and 27.8%, respectively, was achieved when the fluidized drying of potash particles was operated at lower temperatures and close to the natural frequency of the fluidized bed system.

Elutriation of fine particles in a pulsed fluidized bed

This paper reported on fine particle elutriation for two different static bed heights of 25 cm and 30 cm in a pulsed fluidized bed. The effects of three types of flow including continuous airflow, on-off pulsed airflow, and pulsed airflow imposed on continuous airflow were investigated. Observations showed that the elutriation fraction extremely increased with gas temporal average velocity and static bed height for continuous airflow, while for pulsed and mixed flows at the same condition the increase was not considerable. The effect of pulse frequency from 0.033 Hz to 0.1 Hz as an optimum range led to an extreme reduction loss of particles for pulsed and mixed airflows compared to continuous airflow even at high gas temporal average velocities. The elutriation rate of mixed airflow at 0.033 Hz and 3Umf for 30 cm static bed height on average was 75% and 35.3% less than continuous and pulsed airflows, respectively.

MATHEMATICAL MODELING OF THE PROCESS OF MOVEMENT OF GRAIN MATERIAL ON THE SURFACE OF A SIEVE OF A VIBRATING PNEUMATIC PULSE SEPARATOR

The results of a theoretical study of the movement of grain material on the surface of a unfailing sieve of a vibrating pulse separator are presented. The paper presents the power and kinematic model, geometric characteristics of the surface of the sieve of a vibrating pneumatic pulse separator in static, and kinematic processing parameters. Calculations based on the proposed model allow determining the forces of movement, velocity, and acceleration of seeds in the grain medium under the combined action of vibrations and pneumatic pulse flow. The following conclusions were drawn as a result of the research and analysis of the generated forces according to the developed mathematical model: the greatest influence on the process of moving grain material, both in the horizontal and vertical directions, is exerted by the force of impulse (pulsation) of the air flow, the pressure force above the overlying layers of grain material (for seeds in the middle part and on the surface of the sieve without a dip), friction forces, seed weight, and the Archimedean force; in order to intensify the process of fractionation of the grain medium, increase the productivity of the vibrating pneumatic pulse separator, it is necessary to increase the force of the pulsating air flow, the inertia of the oscillatory motion, friction and lateral pressure on the seeds in the grain medium. To solve this problem, it is necessary to optimize the amplitudes and frequencies of oscillations of the unfailing sieve of the vibrating pneumatic pulse separator. The analysis of the mathematical model showed the feasibility of using a vibrating unfailing sieve surface with the simultaneous interaction of the injecting pulsating air flow under the sieve to separate grain material by seed density. It has been established that in order to intensify the separation of grain material into fractions, while increasing the productivity of the technical means, it is necessary to increase the force of the pulsating air flow, friction forces, and lateral pressure. The dynamic model of the movement of grain material displacement and recombination is scientifically substantiated and technological recommendations for the separation of grain material into fractions by seed density using the proposed technical means of a vibrating pneumatic pulse separator with the use of a patented method of its separation are developed.

The Effectiveness of Film Cooling with Injection of Pulsating Air Flow (Review)

The Effectiveness of Film Cooling with Injection of Pulsating Air Flow (Review)

An Examination of Heat Transfer Dynamics in Pulsating Air Flow within Pipes: Implications for Automotive Exhaust Engines

The detailed understanding of heat transfer in the pulsating airflow in the pipe is critical to reducing heat losses in the engine exhaust stream and improving catalyst performance. In the present investigation, we have scrutinized the impact of pulsation frequencies ranging from 0-90 Hz on the flow velocity field and the consequent heat transfer through a horizontal pipe wall. The Nusselt numbers were evaluated at three distinct cross-sectional points moving from upstream to downstream, by systematically modulating the frequency. Temporal variations in the velocity field and temperature were captured utilizing particle image velocimetry (PIV) and dual-thermocouple probes, respectively. Intriguingly, while the Nusselt number for steady flow at 0 Hz closely adhered to Gnielinski’s equation, the pulsating flow demonstrated a peak between 25-35 Hz, a pattern not predicted by the prevailing quasi-steady-state theory. The observed frequency response of turbulence was found to be congruous with the Nusselt number, indicating that the heightened heat transfer at frequencies of 25-35 Hz could be attributed to the enhanced turbulence and the temperature gradient between the fluid and the wall surface during the deceleration phase in the hysteresis of turbulence in the pulsating flow. The unique frequency characteristics of heat transfer that were uncovered in this study, with respect to both flow velocity and temperature, offer valuable insights for devising strategies to mitigate heat loss during ignition and idling. Furthermore, these findings provide robust benchmarks for validating numerical simulations of pulsating flows in real-life automotive engines.

Wet fluidization characterization of potash particles in a pulsation-assisted fluidized bed

In order to improve fluidization behavior, pulsed airflow was employed to break agglomeration and eliminate channeling in a fluidized bed with wet potash particles. The effects of pulsation frequency, pulsed air to continuous flow ratio (r), and inlet relative humidity of the air on bubbling behavior were investigated via an electrical capacitance tomography system. A frequency of 1.0 Hz and an r of 0.33 with 0.1 s opening time were found to be the optimum condition, leading to the lowest minimum fluidization velocity (umf) and generation of homogeneous bubbles in size and shape. A new theoretical model was developed to predict the umf of wet particles in a fluidized bed by considering both the liquid bridge force and resonant force resulting from the pulsation. Average absolute deviation percentage values between the predicted umf and the experimental data were 13.8 and 20.7 for the dry and wet particles, respectively, indicating good agreement.

Programmable pulsed aerodynamic printing for multi-interface composite manufacturing

•Wide Z number soft material printing •Active programmable droplet preparation •Multi-interface composite manufacturing Droplet-based printing is increasingly popular for flexible sensors, soft robotics, bioprinting, and bioinspired structures. However, programmable multi-interface droplet printing with a wide Z number (reciprocal of the Ohnesorge number) remains challenging. We present a method, programmable pulsed aerodynamic printing (PPAP), for patterning soft materials with extensive material compatibility and multi-scale and multi-interface properties. PPAP utilizes programmable pulsed airflow to shear pendant droplets at the nozzle orifice, covering a broad range of parameter domains. Owing to its co-flow configuration, PPAP can accurately print droplets with shell-core, Janus, and combined morphologies. The multi-interface droplet size is independent of its physicochemical parameters and can be predicted by the scaling law. Demonstrations include multi-scale, multi-interface composites: cell-loaded annular particles, liquid metal circuits, laser stimuli-responsive microcapsules, calcium alginate elastomers, and 3D multi-interface clusters. PPAP may promote the development of micro-nano functional structures and devices. Droplet-based printing is increasingly popular for flexible sensors, soft robotics, bioprinting, and bioinspired structures. However, programmable multi-interface droplet printing with a wide Z number (reciprocal of the Ohnesorge number) remains challenging. We present a method, programmable pulsed aerodynamic printing (PPAP), for patterning soft materials with extensive material compatibility and multi-scale and multi-interface properties. PPAP utilizes programmable pulsed airflow to shear pendant droplets at the nozzle orifice, covering a broad range of parameter domains. Owing to its co-flow configuration, PPAP can accurately print droplets with shell-core, Janus, and combined morphologies. The multi-interface droplet size is independent of its physicochemical parameters and can be predicted by the scaling law. Demonstrations include multi-scale, multi-interface composites: cell-loaded annular particles, liquid metal circuits, laser stimuli-responsive microcapsules, calcium alginate elastomers, and 3D multi-interface clusters. PPAP may promote the development of micro-nano functional structures and devices.

Preparation and Analysis of Experimental Findings on the Thermal and Mechanical Characteristics of Pulsating Gas Flows in the Intake System of a Piston Engine for Modelling and Machine Learning

Today, reciprocating internal combustion engines are used in many branches of the economy (power engineering, machine engineering, transportation, and others). In order for piston engines to meet stringent environmental and economic regulations, it is necessary to develop complex and accurate control systems for the physical processes in engine elements based on digital twins, machine learning, and artificial intelligence algorithms. This article is aimed at preparing and analysing experimental data on the gas dynamics and heat transfer of pulsating air flows in a piston engine’s intake system for modelling and machine learning. The key studies were carried out on a full-scale model of a single-cylinder piston engine under dynamic conditions. Some experimental findings on the gas-dynamic and heat-exchange characteristics of the flows were obtained with the thermal anemometry method and a corresponding measuring system. The effects of the inlet channel diameter on the air flow, the intensity of turbulence, and the heat transfer coefficient of pulsating air flows in a piston engine’s inlet system are shown. A mathematical description of the dependences of the turbulence intensity, heat transfer coefficient, and Nusselt number on operation factors (crankshaft speed, air flow velocity, Reynolds number) and the inlet channel’s geometric dimensions are proposed. Based on the mathematical modelling of the thermodynamic cycle, the operational and environmental performance of a piston engine with intake systems containing channels with different diameters were assessed. The presented data could be useful for refining engineering calculations and mathematical models, as well as for developing digital twins and engine control systems.

Regulating the Gas–Liquid Slug Flow in Microchannels through High-Frequency Pulsatile Perturbations

The gas–liquid slug flow that is characterized with alternate formation of gas and liquid segments has been widely applied for chemical synthesis and analysis. For its applications, it is essential to precisely control the gas and liquid slug lengths. However, using the passive method, the bubble/droplet generation frequency and their sizes are influenced by multiple parameters including the channel dimension, fluid physical properties, the gas-to-liquid flow rate ratio, and so forth and hence lack control flexibility. In this work, an active approach using pulsatile perturbations to control the gas–liquid slug flow is demonstrated. A rotating valve is applied to produce a high-frequency pulsating air flow. Under its influence, either Taylor bubbles in a hydrophilic channel or liquid-in-gas droplets in a hydrophobic channel can be generated synchronously with the flow pulsation. Therefore, the gas and liquid slug lengths can be independently tuned via the air inlet pressure and the liquid flow rate, respectively. The maximum generation frequency is up to ∼1300 Hz. In addition, the effects of the pulsation frequency, the pulse duty ratio, and the liquid viscosity are also investigated. This technique provides an efficient method to regulate the gas–liquid slug flow in multiphase microreactors or microfluidic analytical systems.

Dust dispersion during the pulse-jet cleaning process with the diffuser effect of the cartridge filter.

A special conical diffuser was presented and fixed on the top of the filter cartridge to improve the flow field. The existence of the diffuser can disperse the jet flow from the nozzle, and the high-speed airflow can act on more areas of the filter cartridge, including the top area of the filter cartridge. To improve the cleaning efficiency, the present study is aimed at optimizing the structure of the filter cartridge. The DPM model was used to simulate the dust dispersion process and the falling dust sedimentation from the filter under the action of the pulsed airflow. To validate the established model, the pressure values at the monitoring points were analyzed and compared with the related experimental results. It is found that the pressure values are consistent with the experimental results. Moreover, the installation distance and the size of the diffuser were studied and their influence on the dust distribution on the surface of the filter cartridge. It is found that the dust removal effect is relatively better when the installation distance is 90mm and the size radius is 25mm. The maximum dust concentration can be reduced by 15mg/m3. The present research results can provide theoretical guidance for the cleaning process of the filter cartridge and finally improve the dust-removal efficiency of the dust collector.

Exploratory Investigation of the Effects of Tactile Stimulation Using Air Pressure at the Auricular Vagus Nerve on Heart Rate Variability.

To explore the effects of tactile stimulation using air pressure at the auricular branch of the vagus nerve on autonomic activity in healthy individuals. Three types of tactile stimulation were used in this study: continuous low-amplitude, continuous high-amplitude, and pulsed airflow. The tactile stimulations were provided to the cymba concha to investigate autonomic activity in 22 healthy participants. The mean heart rate (HR) and parameters of HR variability, including the standard deviation of R-R intervals (SDNN) and root mean square of successive R-R interval differences (RMSSD) were compared at baseline, stimulation, and recovery periods. Two-way repeated measures ANOVA indicated a significant main effect of time on HR (p=0.001), SDNN (p=0.003), and RMSSD (p<0.001). These parameters showed significant differences between baseline and stimulation periods and baseline and recovery periods in the post-hoc analyses. There were no significant differences in the changes induced by stimulation type and the interaction between time and stimulation type for all parameters. One-way repeated measures ANOVA showed that HR, SDNN, and RMSSD did not differ significantly among the three time periods during sham stimulation. Parasympathetic activity can be enhanced by auricular tactile stimulation using air pressure, targeting the cymba concha. Further studies are warranted to investigate the optimal stimulation parameters for potential clinical significance.

Математичне моделювання та результати експериментальних досліджень процесу вібропневмоімпульсного поділу насіння за густиною

The results of the mathematical simulation of the movement of grain material on the surface of the perforated deck of the vibro-pneumatic-impulse separator have been presented. Both force and kinematic models were employed, considering the geometric characteristics of the perforated deck surface in dynamic interaction with the kinematic indicators of processing. The calculations based on the proposed model allow for determining the trajectories of movement, velocities, and accelerations of the grain seeds within the grain medium under the combined action of vibrations and the pneumatic-impulse flow. As a result of the scientific research and analysis of the forces created according to the developed mathematical model, it has been established that the most significant influence on the process of grain material movement, both in the horizontal and vertical directions, is exerted by the impulse force (pulsations) of the air flow, the pressure force of the underlying layers of the grain medium (for seeds in the middle part and on the surface of the perforated deck), frictional forces, the weight of the seeds, and the Archimedean force. Therefore, in order to intensify the process of fractionation of the grain medium and increase the specific productivity of the vibro-pneumatic-impulse separator, it is necessary to increase the force of the pulsating air flow, the force of inertia of the oscillatory motion, friction, and lateral pressure on the seeds within the grain medium.

Modeling the process of grain separation by density in a combined vibro-pneumatic and air-gravity unit

It was established that the method of intensifying the course of the work process is the organization of supplying the layer with a pulsating flow of air. Using a pulsating air flow, it is possible to change the magnitude of the aerodynamic effect on the grain mass by changing the magnitude of the force pulse under conditions of constant speed. At the same time, the effect of the pulsating flow on the ability to move grains of different mass (density) will be different, which can intensify the separation of seeds by density. The study of the combined effect of vibrations and pulsating air flow on the stratification of the grain flow and separation by density is an important scientific and technical task. The conducted analysis of publications revealed a promising possibility of using serial vibrating screen machines with a pneumatic system for the preparation of combined machines with a pneumatic system for the preparation of high-quality seeds, instead of vibro-pneumatic tables. To study the efficiency of the combined use of vibropneumoliquefied and pneumogravitational movement of the material. It is substantiated that the intensifying effect of the pulsating flow consists in the different force of influence on light and heavy grains. The mathematical description of the process of separation of loose material by density is based on the equations of motion of a particle in an oscillating medium, which is valid for any continuous medium that has the property of inertness. Formulated mathematical models of the processes of movement of components of grain material in the vibro-liquefied layer and in the air channel of the vibro-pneumocleaning machine will allow to determine the trajectories of the movement of grains in the working zones and, based on their analysis, to justify the parameters of the working bodies. The approbation of the mathematical description of the processes of separation of the components of grain material confirmed the increase in the efficiency of the use of pulsating flows for the separation of grain by density.

Unsteady gas dynamics and local heat transfer of pulsating flows in profiled channels mainly to the intake system of a reciprocating engine

• The secondary vortex flows of pulsating flows in profiled channels were analysed. • The turbulence intensity of pulsating flows in profiled channels was determined. • The effects of profiled channels on heat transfer in an engine intake system have been established. • An assessment of the key indicators of a diesel engine with a profiled intake system was performed. This article presents the results of experimental research into the gas dynamics and heat transfer of pulsating air flows in an intake system with square and triangular channels, as well as data from bench tests of a diesel engine. The research was carried out on both a full-scale model of a piston engine and a test bench with a diesel engine. In the first stage, some detailed data on the gas-dynamic and heat exchange characteristics of pulsating flows in the intake system were obtained. It is shown that the gas-dynamic effects typical of square and triangular channels have a significant impact on the flow and heat-transfer characteristics. It is established that the intensity of the turbulence of pulsating flows increases to 22% in the intake system with profiled channels (increased small-scale turbulence), while the amplitudes of the spectrum of flow velocity functions decrease to 33% (suppression of large-scale oscillations). It is shown that a square or triangular channel in the intake system leads to an increase in air mass flow in the range of 5% to 12% compared to the base system. It was found that the increase in the heat transfer coefficient is from 3% to 25% when profiled channels are used. In the second stage, bench tests of a diesel engine with different intake system configurations were carried out to evaluate the technical and economic performance. It is established that the use of profiled channels in the intake system leads to an increase in diesel power of up to 15% compared to the basic modification (while the engine efficiency remains unchanged). The data obtained supplement existing information on the gas-dynamic and heat-exchange characteristics of pulsating flows in profiled channels and can be used in the development of new designs for piston engine intake systems.

An experimental study on heat transfer of pulsating air flow in metal foam subjected to constant heat flux

In this study, the effect of pulsating air flow on heat transfer was investigated experimentally, while constant heat flux was applied with an electric heater to the side surface of the cylindrical duct with metal foam inside. Reynolds numbers in the range of 5932–8592 were studied at three different fan speeds. Pulsating flow experiments were carried out in the range of 12.0–27.9 Womersley numbers. It has been observed that the surface and air temperatures are not affected by the flow frequencies in this range and are independent of time. With the data obtained, Nusselt number values were calculated for the fully developed region, and the Nusselt number ratio was defined in order to compare the steady flow with the pulsating flow. Nusselt correlation was established for the fully developed region depending on the Reynolds number and the Womersley number in the studied range. It has been determined that the effect of frequency on the heat transfer in the case of pulsating flow is weak, but the heat transfer tends to decrease as the frequency increases.

Structural optimization of disperser in polymer flooding distribution tank based on venturi pulse injection

ABSTRACT Polymer was carried by liquid in conventional polymer dispensing tank of polymer flooding in oilfield. Polymer particles often gather in the process of polymer blending, resulting in blockage of ground pipelines and formation. To reduce this phenomenon, finite element method was used. Optimization of polymer tank carrier based on venturi tube gas pulse injection. The polymer particles were carried into the liquid distribution tank by the injection method of pulse airflow to realize efficient carrying. Study on the effect of different pulse intensity and pulse waveform on cohesion. The results showed that the combined effect of strong pulse difference and pulse gap could make the airflow have strong carrying capacity for difficultly migrated polymer particles. Optimized the shortest pulse time and got the shortest time of triangle wave, sawtooth wave, square wave, and sine wave under simulated conditions. Time was 5.1 s, 6.3 s, 6.2 s, 6.2 s, respectively. The corresponding pulse frequencies were 20 times/s, 15 times/s, 10 times/s and 30 times/s, respectively. Properly increasing pulse intensity could enhance the carrying capacity of pulse airflow to polymer and reduced the carrying time of polymer. The optimal pulse parameters were triangular wave with pulse intensity of about 120 m/s and pulsed frequency of 20 times/s. Established the phenomenon and reason of indoor experiment. The viscosity of polymer solution after stirring was higher than that of liquid flow carried by gas phase pulse. This shows that the polymer system was more fully dissolved under the condition of gas phase pulse carrying. Pulsed airflow injection could effectively reduce polymer aggregation and shear action of agitator to protect polymer structure. Pulse airflow injection also plays an important role in safe operation of ground pipelines and stable seepage in porous media.

Separation behaviour of polypropylene mixed particles under the coupling of vibration and airflow

Granular matter is a disordered system composed of a large number of particles, which appears as a complex physical phenomenon under external excitation. To study the separation behaviour of polypropylene particles, the separation of particles under various excitation methods was simulated based on the DEM-CFD coupling method. The results showed that polypropylene particles did not show Reverse Brazil Nut Separation under the single excitation of either vertical vibration or pulsed airflow, while under the double excitation of vertical vibration and constant airflow, the large particles located in the upper layer of small particles started to sink and formed Reverse Brazil Nut Separation. By analysing the change of voidage in particle bed, the explanation of the change of particle separation state by filling theory is verified. The airflow velocity increased from 15 m·s−1 to 21 m·s−1, and the volume concentration of large particles at the bottom increased by 27.615%, which promoted the formation of Reverse Brazil Nut Separation. The frequency and amplitude increased to 15 Hz, 20 mm or decreased to 5 Hz, 5 mm, respectively, and the volume concentration of large particles at the bottom decreased by 22.025%, 23.807% and 46.712%, 59.003%, indicating that too large or too small vibration acceleration would inhibit the formation of Reverse Brazil Nut Separation. In addition, changing the shape of the container or increasing the filling rate of particles in the container can eliminate the phenomenon of small particles accumulating in the corner.