Effects of Particle Stacking Angle on Heat Transfer Characteristics of Particles Close to the Wall

The primary energy demand increases, but a large amount of waste heat resources were not effectively used. To explore the influence of particle stacking structure on waste heat recovery process, CFD method was used to simulate. An unsteady heat transfer model of two particles was established, effect of particle stacking angle on heat transfer characteristics of the particles close to the wall under different initial temperature conditions was studied. Results show that: higher initial temperature, resulting in increased heat transfer time, the larger particle stacking angle causes the shortening of heat transfer time. When initial temperature is 1073 K, the average wall heat flux shows a trend of rapid decline first and then a slow one. At the same moment, the larger stacking angle causes smaller particle average temperature. The change of particle stacking angle shows a greater impact on the temperature of the particles close to adiabatic wall. The increase in the stacking angle resulting in better heat transfer characteristics between particles.

Experiment and Simulation of Impact Response of Woven CFRP Laminates with Diferent Stacking Angles

The ffects of different laying angles on impact resistance and damage types of woven carbon fibre-reinforced polymer(CFRP)laminates were studied.The drop harmmer impact test and simulation analysis of woven CFRP laminates at four different velocities were carried out by means of the combination of experiment and explicit finite element analysis.The effect of impact velocity on damage pattern and fracture of woven CFRP laminates with eight layers and four laying angles(0°,15°,30°,and 45°)was studied by drop weight impact test,and the damage area of woven CFRP larminates with different laying angles was measured by ultrasonic nondestructive testing method.A user-defined material model was developed based on LS-DYNA to simulate the impact behavior of woven CFRP laminates.A finite element simulation model was established to effectively predict the complex damage evolution of woven CFRP laminates under low-speed impact loading.Its effectiveness was verified by impact response and damage crack pattern.The energy absorption and impact force of the laminated plate increase gradually from 0°to 45°in the laying angle of woven fabric.With the increase of laying angle from 0°to 459,the length of fracture crack and the damage area increase.The developed model can accurately predict the impact properties of the composites.

Numerical investigation of non-spherical particle deposition characteristics on filter media

In the building environment,PM2.5 seriously affects people’s health and quality of life,so it is necessary to study the particle deposition characteristics.In addition,it is essential for a thorough investigation of the dust removal mechanism to understand the non-spherical particles deposition characteristics.The stacking angle experiment was used to calibrate the discrete element simulation parameters.And four simulation methods(CFD-DPM,CFD-DEM,API interface loading drag model based on EDEM software and EDEM simulation)were used to numerically simulate the non-spherical particles deposition characteristics.The optimal simulation method EDEM was applied to study the non-spherical particles deposition characteristics in filter media,which saves the calculation time obviously.On this basis,the particle parameters on the particle deposition characteristics of filter media were investigated.The results show that the deposition rate of non-spherical(special shape)particles with the same volume is basically consistent on the filter media,hence it is more realistic that the dust actual shape is simplified into the triangular-shaped particles.As the particle size increases,the number of deposited particles on the filter media decreases.And the larger the particle size,the more dispersed the distribution.It has a significant impact on the number of particles deposited on the filter media when the particle velocity is 0.1 m/s.The particle deposits to the lower part of the filter media in the form of a parabola and deviates from the outlet seriously at 0.1 m/s.Moreover,it has little effect on the number of particle deposition at the other velocities,and most particles are deposited on the upper part of the filter media with the increase of particle velocity.