Pneumatic conveying devices are commonly used in the fields of chemical industry, raw material transportation, and material processing. Elongated biomass particles are not evenly distributed in the lifting tube because biomass clumps during conveying. Pneumatic conveying test setup and measurement system were built in this paper in order to study the agglomeration behavior of elongated biomass particles in the lifting tube experimentally. Particle tracking velocimetry (PTV) was used to determine the area distribution and velocity distribution of particles at different apparent air velocities and mass flow rates. The results show that while keeping the mass flow rate constant at 46.50 g/s, the apparent gas velocity increased from 5.91 to 7.91 m/s and the maximum size of agglomerates decreased from 0.689 to 0.235. The apparent gas velocity was kept at 6.40 m/s, and the particle mass flow rate was adjusted from 56.50 to 16.20 g/s. The maximum size of the agglomerates was reduced to 0.115. Therefore, appropriately increasing the apparent gas velocity or decreasing the particle mass flow rate can improve the uniformity of the particle distribution in the lifting tube. The results would provide a reference for parameter adjustment of pneumatic conveying devices in industrial production.

The booming progress of biomass fuels in the enhancement of energy sustainability has been witnessed over the past few decades. Drying or moisture content reduction is a critical pretreatment step for the efficient utilization of wet biomass fuels whose improvement requires this study to focus on the effect of the transportation behavior of biomass fuels inside drying facilities. Experiments were performed under a variety of operating conditions in order to determine the residence time distribution (RTD) and flow characteristics of s‐liked biomass fuels in the process of transportation. A series of experiments are carried out in a rotary drum with different baffle structures, a length of 1850 mm and a diameter of 770 mm. Meanwhile, s‐liked and CO₂ expanded biomass particles were taken as standard and tracer materials. RTD and scattering and fallout angles are measured and studied under the conditions of different baffle heights (64‐184 mm), numbers (2‐8), installation slopes (70°‐110°), rectangular bend heights (24.8‐62.5 mm), and bend slopes (90°‐150°). The Taylor model can appropriately estimate the mean residence time (MRT) of particles in a rotating drum with variety of baffle structures, such as baffle height, number, and bend slope.

To examine the influence of liquid dynamic viscosity η on atomization and droplet evolution in a twin-fluid nozzle, experiments were conducted under air-injection conditions. Optical measurement methods were employed. Laser diffraction and high-speed imaging techniques were used. Water ( η _water = 1.00 mPaꞏs) and a flavoring liquid ( η _flavor = 2.35 mPaꞏs) were selected as the working fluids. The results show that the Sauter Mean Diameter (SMD) of droplets from both liquids decreased as the air injection pressure ( p _g ) increased from 0.10 MPa to 0.35 MPa. The liquid mass flow rate ( q _m ) was kept constant at q _m =15 kg/h. The SMD of atomized water remained lower than that of the flavoring liquid over the entire pressure range. The droplet size distribution further indicates that the low-viscosity water system produced a larger fraction of small droplets and a more concentrated size distribution. In contrast, the higher-viscosity flavoring liquid generated a greater proportion of larger droplets. Both the droplet exit velocity and the spray cone angle showed a similar trend as air injection pressure increased. The values first decreased and then increased. The spray angle of the water system remained larger than that of the flavoring liquid, indicating stronger radial dispersion. Overall, liquid dynamic viscosity significantly influences droplet refinement and spray dispersion characteristics. Liquids with different viscosities exhibit distinct atomization responses when the gas injection pressure varies.

Efficient and stable atomization is important for obtaining satisfactory spray performance. In this work, a high-viscosity flavor solution was atomized with a twin-fluid nozzle, and the role of air injection pressure was examined by combining laser diffraction measurement with high-speed visualization. The evaluation mainly involved droplet size distribution, Sauter mean diameter (SMD), apparent droplet velocity, and spray angle. When the liquid mass flow rate ( q _m ) was kept at 15 kg/h and the air injection pressure increased from 0.10 MPa to 0.35 MPa, the droplet population shifted progressively toward smaller sizes. The SMD also decreased, although the rate of reduction became weaker as the pressure continued to rise. At p _g =0.30–0.35 MPa, relatively fine atomization was achieved, with the SMD staying below 45 μm. In comparison, both the apparent droplet outlet velocity and the spray angle changed only within a narrow range throughout the tested conditions. Overall, the results indicate that raising the air injection pressure mainly improves droplet refinement, while its influence on droplet motion and spray spreading is comparatively limited. These observations help clarify the pressure-dependent atomization behavior of viscous flavor solution in a twin-fluid nozzle and can serve as a reference for selecting operating conditions in practical applications.