油雾凝聚机理的模拟及实验研究

发布时间：2018-03-03 06:11

本文选题：油雾　切入点：碰撞凝聚　出处：《东北大学》2011年硕士论文　论文类型：学位论文

【摘要】：本课题对油雾凝聚机理的研究是通过凝缩嘴的凝聚效果来体现的,主要进行了理论分析、FLUENT数值模拟、实验研究等方面的探索。本文首先通过对油雾颗粒碰壁运动理论和油雾颗粒之间碰撞凝聚理论进行分析,得出影响油雾颗粒凝聚的重要标准是颗粒的韦伯数,从韦伯数的定义可知油雾颗粒的运动速度是影响韦伯数大小的一个重要参数。然后通过FLUENT软件进行仿真模拟油雾颗粒在不同结构凝缩嘴内的运动变化情况；并设计搭建试验台,通过正交实验找出影响凝缩嘴凝聚效果的三个因素的主次顺序。通过以上工作主要得出如下结论： (1)通过对三种不同结构的凝缩嘴进行FLUENT数值模拟,由模拟的粒径变化图可知,阶梯型凝缩嘴的凝聚效果最好,其次是直角型凝缩嘴,普通型凝缩嘴的凝聚效果要最差；对比粒径变化图,速度场图和压力场图可知,当凝缩嘴内的孔径由大突然收缩变小时,其压力会急剧减小,油雾颗粒速度增大,而此时油雾粒径也会迅速变大,说明油雾颗粒粒径的变化受油雾颗粒速度的影响比较大。 (2)通过对三组正交实验的数据进行分析处理,实验结果表明,随着油雾压力的增大,凝缩嘴的整体凝缩率是在不断下降的；孔径因素是影响凝缩嘴凝缩率的最主要因素,孔长因素随着油雾压力的增大其影响作用越来越小,材料因素是最次要因素；当油雾压力为10KPa时,凝缩嘴的整体凝缩率最高,且此时三因素的极差值有一个较好的梯度,便于区分主次因素,有利于选择不同类型的凝缩嘴。因此在实际应用中为了获得较好的凝缩效果,应使凝缩嘴入口处的油雾压力保持在10KPa左右较好。
[Abstract]:In this paper, the condensing mechanism of oil mist is studied through the condensing effect of condensate nozzle, mainly through the theoretical analysis of fluent numerical simulation, experimental research and other aspects of exploration. In this paper, the Weber number of oil mist particles is obtained by analyzing the theory of impingement motion of oil fog particles and the theory of collision condensation between oil fog particles. From the definition of Weber number, it can be seen that the velocity of oil mist particle is an important parameter that affects the size of Weber number. Then the motion change of oil fog particle in condensed mouth with different structure is simulated by FLUENT software, and the test bed is designed and built. The main and secondary order of the three factors affecting the condensing effect of condensate mouth is found by orthogonal experiment. The main conclusions are as follows:. 1) through the FLUENT numerical simulation of three kinds of condensed nozzles with different structures, the result shows that the agglomeration effect of the ladder condenser is the best, the right angle condensate is the second, and the common condenser is the worst. Compared with the particle size change diagram, velocity field diagram and pressure field diagram, it can be seen that when the aperture in the condensing mouth changes from a large sudden shrinkage to a smaller one, the pressure decreases sharply, the oil mist particle velocity increases, and the oil mist particle size increases rapidly. It shows that the variation of oil mist particle size is greatly affected by the oil mist particle velocity. 2) through the analysis and processing of the data of three groups of orthogonal experiments, the experimental results show that with the increase of oil mist pressure, the overall condensation rate of condensate nozzle is decreasing, and the factor of pore diameter is the most important factor affecting the condensing rate of condensate nozzle. With the increase of oil mist pressure, the effect of pore length factor becomes smaller and smaller, and the material factor is the most important factor, when the oil mist pressure is 10 KPA, the condensate rate is the highest, and the difference of the three factors has a good gradient. It is convenient to distinguish primary and secondary factors and to select different types of condenser. In order to obtain better condensing effect, the oil mist pressure at the entrance of condenser should be kept at about 10 KPA in practical application.
【学位授予单位】：东北大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH117

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