|
|
Mercuryjie2008(金币+100, 翻译EPI+1): 非常感谢啊 2011-03-21 19:22:11
Flow field inside of cyclone dryer is very complicated, thus making the research extremely difficult. The gas tangentially flows into the drying body, which helps strengthen the transmission of gas-solid process, enhance the collision or friction between solid particles, increase the contact area between particles and air flow, and speed up the air drying process. Due to the cyclone board, gas-solid turbulent action becomes further intensified, which makes different scales of the particles dried homogeneously. At present, either theoretical or experimental studies about cyclone dryer are rare. Our paper is a preliminary research on this respect with the help of computer simulation and some experiments.
In this paper, we mainly take the computational fluid dynamics CFD methods to simulate the flow velocity field of gas-solid inside the dry body, and analyze the single-phase flow field, gas-solid flow field, particle volume fraction, particle motion track, the pressure loss.
Firstly, we assume three common turbulence simulation model - the standard model, RNG model, and Reynolds stress model (RSM model) to simulate fluid flow field, and find RSM model is more suitable by comparison, so we adopt the RSM model for gas-solid coupling calculation. By gas flow field simulation, we obtain axial, radial, tangential 3D velocity field distribution, finding tangential velocity is much larger than the others. Further analysis focus on principle of pressure distribution and its relationship with gas incoming speed.
Secondly, simulation on gas-solid flow is made. Euler coordinate RSM model is used for gas simulation, and two models are used for particles simulation - Euler coordinate hybrid model and Lagrange coordinate stochastic model. The mutual coupling is also taking into account during the computing process. Conclusions: ① The hybrid model simulation shows the solid particles distribution in the dryer, namely the volume fraction of solid particles increases along with the radial direction, and reach the highest on the wall. ② stochastic model shows the particle trajectories, indicating that the movement of particles in the dryer is randomness.
Finally, in order to get a better understanding of the dynamic characteristics of cyclone dryer, we detect the particles’ residence time in the dryer.
By comparing some experimental data and simulation results, we find they agree well, which proves the correctness of our simulation. And we believe our work has a certain reference value for further design or theoretical research.
正好我也是做模拟的，刚好看到了，顺便翻译一下。 |
|
回复此楼