CAJ | 학술논문

为了揭示叶片式抛送装置抛送物料时内部气流和物料复杂的流动特性以优化设计和指导运用，应用计算流体力学软件Fluent中的Mixture多相流模型、标准k-ε湍流模型与SIMPLEC算法，对抛送装置内气固两相流动进行了数值模拟，并将计算结果与抛送装置内物料运动的高速摄像试验结果进行了比较，物料速度的模拟值和高速摄像实测值基本吻合。在分析了物料运动规律基础上，对其叶片数、进料速度以及物料体积浓度的不同变化作了对比模拟。研究结果表明：数值模型可预测叶片式抛送装置的输送性能以及最佳喂入量；4叶片较3和5叶片更有利于抛送；进料速度对物料在叶轮区的体积分布规律影响较大，在最佳喂入量范围内，进料速度越大，出口处物料浓度越大，抛离速度也越大，装置输送性能越好；超过此范围时，随进料速度增大，进料口处物料浓度增大而出口处物料浓度减小，装置极易堵塞；进料口物料体积浓度的变化只影响抛送叶轮内以及圆形外壳出口区域的物料体积浓度，而对其物料速度分布规律及速度大小影响不大。该研究可为叶片式抛送装置工作参数优化提供参考。
위료게시협편식포송장치포송물료시내부기류화물료복잡적류동특성이우화설계화지도운용，응용계산류체역학연건Fluent중적Mixture다상류모형、표준k-ε단류모형여SIMPLEC산법，대포송장치내기고량상류동진행료수치모의，병장계산결과여포송장치내물료운동적고속섭상시험결과진행료비교，물료속도적모의치화고속섭상실측치기본문합。재분석료물료운동규률기출상，대기협편수、진료속도이급물료체적농도적불동변화작료대비모의。연구결과표명：수치모형가예측협편식포송장치적수송성능이급최가위입량；4협편교3화5협편경유리우포송；진료속도대물료재협륜구적체적분포규률영향교대，재최가위입량범위내，진료속도월대，출구처물료농도월대，포리속도야월대，장치수송성능월호；초과차범위시，수진료속도증대，진료구처물료농도증대이출구처물료농도감소，장치겁역도새；진료구물료체적농도적변화지영향포송협륜내이급원형외각출구구역적물료체적농도，이대기물료속도분포규률급속도대소영향불대。해연구가위협편식포송장치공작삼수우화제공삼고。
When an impeller blower is in operation, the materials in it are conveyed mainly by means of the paddle throwing and the airflow generated by a high-speed rotating impeller blowing. In order to reveal the influence of airflow in impeller blowers on material conveying, numerical models of the air flow in the impeller blowers using the computational fluid dynamics software Fluent were developed by some scholars at home and abroad. Basic characteristics of the airflow field were obtained, which would be useful for predicting the motion of the materials. However, the studies above mentioned aimed at airflow field only, without considering materials in it, so their conclusions were not accurate. To further study the solid-gas two-phase flow mechanism in an impeller blower, a three-dimensional simulation was performed for the solid-gas two-phase turbulent flow in the impeller blower by using FLUENT software with a mixture model and a standard k-ε turbulence model. In the numerical calculation, the finite volume method was used to discretize the governing equations. The SIMPLEC algorithm was applied for the solution of the discretized governing equations. For the calculated zones composed of rotating impeller and static housing, Moving Reference Frames (MRF) was used to simulate the two-phase flows in complex geometries. Comparisons between the simulated values and the measured values of materials velocity at the discharge vertical pipe by high-speed video in reference paper [4] were made, and the reliability of the numerical simulation was verified. Meanwhile, on the basis of the analysis of the law of materials flow, contrast simulations on variations in working parameters such as paddle numbers, impeller’s rotational speed, material-fed speed, and volume fraction of solid phase were carried out. It was concluded that:1) The mixture model was successfully applied to simulate the turbulent particle-gas two-phase flows in an impeller blower, and predict the conveying property of the impeller blower. 2) Impellers with 4 paddles were more favorable for throwing/blowing materials than 3 and 5 paddles, because the materials velocity distribution of the middle plane (Z=0) of the impeller and the discharge pipe with 4-paddle was more even than that of 3-paddle and 5-paddle ones, and fewer vortex flows were generated. Besides, the axial symmetry of 4-paddle impeller blower was better than that of 3-paddle and 5-paddle ones, with a fine balance at a high speed, especially. 3) Distributions of materials velocity in the impeller blower did not change much with the impeller’s rotational speed increasing, but the velocity of throwing/blowing materials changed much with it, and the higher the rotational speed was, the higher the velocity of throwing/blowing materials was. 4) An impeller’s rotational speed and volume fraction of solid phase at the inlet being equal, feeding velocity determines the quantity of material fed into the impeller blower, and affects the distribution of volume fraction of solid phase at the impeller zone; In the limiting feed quantity range, higher feeding velocity means a larger volume fraction of solid phase and a higher velocity of throwing/blowing materials at the outlet, and was more favorable for conveying materials. 5) The change of the volume fraction of solid phase at inlet has less influence on the distribution of materials velocity;it only affects the volume fraction of solid phase at the entire zone, and the volume fraction of solid phase at the entire zone increases with the increase of material volume fraction at the inlet.