【作者】 赵丽娟；

【导师】 张志军；

【作者基本信息】 东北大学 ， 机械工程（专业学位）， 2020， 硕士

【摘要】 随着工业的发展,粉尘污染导致的环境问题日益严重。二氧化硅粉体在化工生产中有着广泛应用,将二氧化硅粉体加入乙二醇溶液中形成分散液,广泛应用于涂料、橡胶、皮革、塑料、印刷、纺织等行业中,具有增稠、触变等作用。二氧化硅粉体加料的过程中会产生大量粉尘,会导致长期工作的工人形成硅肺。针对二氧化硅粉体加料产生大量粉尘的现象,本课题引入射流泵,射流泵喷嘴出口处产生的负压能够有效抑制粉尘。为了进一步探究射流泵的效果,本文借助Fluent软件分别对二氧化硅粉体加料过程和射流泵内部流场进行数值模拟研究。本文的研究工作主要包括以下几点:(1)对粉体填料扬尘机理进行分析。通过相关公式计算和理论推导,探究了流场内粉体颗粒的受力情况,二氧化硅粉体加料过程中与空气相互作用,当粉体颗粒受到的气流阻力大于浮重时,粉体颗粒受力大于零,形成粉尘。(2)对二氧化硅粉体加料产生粉尘的过程进行数值模拟。借助Fluent软件对加料罐内部流场进行数值模拟,模拟了二氧化硅粉体加料质量流量对产生粉尘的影响。结果表明:质量流量越大,产生的粉尘量越多。(3)对液气射流泵内部流场进行模拟分析。采用乙二醇溶液为工作流体,利用Fluent软件模拟液气射流泵的内部流场,获得了内部流场的速度、压力等分布情况。研究了不同质量分数的乙二醇溶液作为工作流体对液气射流泵喷射性能的影响。结果表明:随着乙二醇溶液质量分数的增加,液体的粘度逐渐增加,导致引射系数逐渐减小。(4)模拟研究操作参数和结构参数对射流泵喷射性能的影响。①模拟研究了混合流体出口压力和工作流体进口压力对射流泵性能的影响。结果表明:随着混合流体出口压力的增加,引射系数逐渐减小,甚至出现回流现象;随着工作流体进口压力的增加,引射系数逐渐增加。②模拟研究了面积比和喷嘴距对射流泵性能的影响。结果表明:面积比存在最优值,最优值为4;喷嘴距存在最优值,本文建立的模型最优喷嘴距为70mm。(5)射流泵实验研究。对液气射流泵进行了实验研究,验证操作参数对射流泵性能的影响。结果表明:混合流体出口压力和工作流体进口压力对射流泵性能的影响与实验结果趋于一致,验证了模型的可靠性。更多还原

【Abstract】 With the development of industry,environmental problems caused by dust pollution have become increasingly serious.Silica powder is widely used in chemical production.Silica powder is widely used in chemical production.Silica powder is added into glycol solution to form dispersion,which is widely used in coating,rubber,leather,plastic,printing,textile and other industries,with thickening,thixotropy and other functions.A large amount of dust will be generated during the silica powder feeding process,which will cause long-term workers to form silicosis.Aiming at the phenomenon that a large amount of dust is generated by the feeding of silica powder,this topic introduces a jet pump.The negative pressure generated at the jet pump nozzle outlet can effectively suppress the dust.In order to further explore the effect of the jet pump,this paper uses Fluent software to numerically study the silica powder feeding process and the internal flow field of the jet pump.The research work in this paper mainly includes the following points:(1)Analysis of dusting mechanism of powder filler.Through the calculation of related formulas and theoretical derivation,the force of powder particles in the flow field was explored.The silica powder interacted with air during the feeding process.When the resistance of the powder particles to the airflow was greater than the floating weight,the powder particles When the force is greater than zero,dust is formed.(2)Numerical simulation of the process of dust generation from the addition of silica powder.With the help of Fluent software,the internal flow field of the feeding tank was numerically simulated,and the effect of the silica powder powder mass flow on the generation of dust was simulated.The results show that the larger the mass flow,the more dust is generated.(3)Simulation analysis of the internal flow field of the liquid-gas jet pump.The ethylene glycol solution was used as the working fluid,and the internal flow field of the liquid-gas jet pump was simulated by Fluent software,and the distribution of the speed and pressure of the internal flow field was obtained.The effects of different mass fractions of glycol solutions as working fluids on the jet performance of liquid-gas jet pumps were studied.The results show that as the mass fraction of the ethylene glycol solution increases,the viscosity of the liquid gradually increases,leading to a gradual decrease of the ejection coefficient.(4)The effects of operating parameters and structural parameters on the injection performance of the jet pump are simulated.① The effects of mixed fluid outlet pressure and working fluid inlet pressure on the performance of jet pumps were simulated.The results show that as the outlet pressure of the mixed fluid increases,the ejection coefficient gradually decreases,and even the phenomenon of backflow occurs;as the inlet pressure of the working fluid increases,the ejection coefficient gradually increases.② The effects of area ratio and nozzle distance on the performance of the jet pump were simulated.The results show that there is an optimal value for the area ratio and the optimal value is 4;there is an optimal value for the nozzle distance.The optimal nozzle distance of the model established in this paper is 70mm.(5)Experimental research on jet pump.An experimental study of the liquid-gas jet pump was performed to verify the effect of operating parameters on the performance of the jet pump.The results show that the influence of the mixed fluid outlet pressure and the working fluid inlet pressure on the performance of the jet pump tends to be consistent with the experimental results,which verifies the reliability of the model.更多还原