气固两相流饲料输送管道结构优化研究

Study on Structure Optimization of Feed Conveying Pipeline in Gas-Solid Two-phase Flow

目的针对饲料输送管道气固两相流对弯管壁面冲蚀磨损严重的问题,提出一种在弯管外侧加设辅助气流的新型结构。方法运用计算流体力学方法,采用离散相模型(Discrete Phase Model,DPM)研究普通和新型弯管的冲蚀磨损情况,模型的有效性通过普通弯管压降梯度实验加以验证。通过分析两种弯管的流场分布情况,进一步研究空气进口速度、颗粒质量流量和颗粒粒径等因素对弯管冲蚀磨损的影响。结果随着空气进口速度的增加,弯管的平均冲蚀磨损速率先减小、后增大,但新型弯管的平均冲蚀磨损速率降低了7.1%~8.5%,且当空气进口速度为35m/s时,平均冲蚀磨损速率最小。当颗粒质量流量增加时,弯管平均冲蚀磨损速率基本呈线性增长,但新型弯管平均冲蚀磨损速率的增长速率略小于普通弯管,且平均冲蚀磨损速率降低了8.2%~9.7%。当颗粒粒径增加时,弯管的平均冲蚀磨损速率先急剧增大、后平缓变化,但新型弯管平均冲蚀磨损速率降低了8.2%~17%。结论通过研究发现,弯管外侧均存在冲蚀磨损,但新型结构均能有效减小弯管的冲蚀磨损。颗粒质量流量对弯管冲蚀磨损的影响最大,且颗粒质量流量越大,平均冲蚀磨损速率越大。颗粒粒径对降低弯管冲蚀磨损的效果最好,且颗粒粒径越小,效果越佳。

Focusing on the serious erosion wear of the inner wall surface of the elbow caused by the gas-solid two-phase flow in feed conveying pipeline,a new structure with auxiliary air flow on the outside of the elbow was proposed.Based on computational fluid dynamics,the erosion wear of ordinary and new type elbows was studied by adopting discrete phase model(DPM).The validity of the model was verified by the pressure drop gradient experiment of ordinary elbow.By analyzing the flow field distribution of these two kinds of elbows,the effect of air inlet velocity,particle mass flow rate and particle size on the erosion wear of these two kinds of elbows was further studied.The results show that with increasing of air inlet velocity,the average erosion wear rate of these two kinds of elbows firstly decreased and then increased.However,the average erosion wear rate of the new type elbow decreased by 7.1%~8.5% compared with that of the ordinary.Moreover,when the air inlet velocity was 35 m/s,the average erosion wear rate of these two kinds of elbows was the lowest.With increasing of particle mass flow rate,the average erosion wear rate of these two kinds of elbows basically increased linearly.But the growth rate of the average erosion wear rate of the new type elbow was slightly lower than that of the ordinary elbow,and the average erosion wear rate of the new type of elbow was 8.2%~9.7% lower than that of the ordinary.With increasing of particle size,the average erosion wear rate of these two kinds of elbows firstly increased sharply and then changed gently.But the average erosion wear rate of the new type of elbow decreased by 8.2%~17% compared with that of the ordinary.It is found that erosion worn on the outside of these two kinds of elbows,but the new structure can effectively reduce the erosion wear of the elbow.The particle mass flow has the greatest impact on the erosion and wear of the elbow,and the larger the particle mass flow,the greater the average erosion and wear rate.The particle size has the best effect on reducing the erosion and wear of the elbow,and the smaller the particle size,the better the effect.