Research On The Character Of Axial Cyclone Separator And Droplet Impact On The Wall

As an efficient separator equipment, with a small and simple structure, high pressure resistance, easy parallel and low pressure loss, the axial cyclone separation is widely used in the petrochemical, desalination and other industries. It can remove solid and liquid particles in the gas stream to improve the purity of the gas, collect valuable particles or protect downstream equipment. At present, the research about cyclone mainly focuses on conventional cyclone separator. To axial cyclone, the research is relatively rare. So understanding of the axial flow cyclone separator should to be strengthened. There is still much room for improvement of the structure. This paper studied an axial cyclone separator with experimental and numerical methods in detail.Firstly, this paper studied the pressure loss of cyclone with experiment using air as the working fluid. It mainly included two cases. First, the separator total pressure loss in different wind speeds. Second, the separator wall pressure distribution characteristics in different wind speeds. The results of the experiments show that: 1) the pressure loss coefficient of this cyclone is 7.5. Comparison of wall static pressure loss and the total pressure loss found that it will bring great error instead the total pressure loss of static pressure loss in a swirl device. 2)the dimensionless wall static pressure distribution is similar in the circumferential direction except a short distance place behind the blade. 3) the result of SSG model is more consistent with the experimental result.Secondly, this paper studied the single-phase and two-phase flow fields in the cyclone with numerical method. In the single-phase simulation, the pressure field, velocity field were studied and the influence of different structure to the pressure loss was also studied. In the two-phase simulation, the influence of different structure to the separation efficiency was studied and giving a simple formula of the separation efficiency. The results of the simulation show that: 1) the pressure field is centrosymmetric. The pressure loss increases with the increase of blades number, hub diameter, separation section length and inlet velocity and discrease of blade angle. Among them, blade angle and hub diameter are more important 2)the velocity field is centrosymmetric. The dimensionless tangential velocity distribution is the same although different inlet velocity. 3) separation efficiency increases with the increases of blades number, hub diameter, separation section length and inlet velocity and discrease of blade angle. Separation efficiency formula requires further improvement.Finally, this paper simulate the droplet impact on the axial cyclone wall with the VOF model. Only impacting horizontal and inclined wall were studied. For the former, the study is about the influence of the contact angle to the simulation included SCA, DCA and the contact angle provided by Hoffman function. For the later, the study is about the influence of different wall materials and inclined angle to the impacting. The results show that: 1) using k-?+VOF+dynamic contact angle model can get more accurately result. But the dynamic contact angle only can be got from experiment. The k-?+VOF+Hoffman function model is the best to simulate this phenomenon. 2) the contact angle has an important influence on droplet impacting on the inclined surface. A large contact angle can make the droplet slip on the inclined surface. 3) the larger the inclined angle is, the earlier the impacted droplet asymmetry is destroyed. The front spread factor is larger and the back spread factor is smaller on the surface with larger inclined angle.