The Study Of Drag Reduction In The Spiral Cyclone

The spiral cyclone is a kind of cyclone which is characterized by having a continuous spiral channel in its body. The pressure drop in the center of the spiral cyclone amounts to more than a half of the total pressure drop in the spiral cyclone. In this article, in order to study the optimal device of drag reduction, a method of numerical simulation for the internal flow in the spiral cyclone is developed and used to study the effect of the reducing pressure drop stick and air deflector, when they are settled in the center of the spiral cyclone.Compared with the experiment, the numerical simulation has the advantage of convenience and low cost, moreover, it could be used to study the influence of structure parameters on internal flow and flow drag easily. In this article, firstly, the gas flow in a spiral cyclone is numerical simulated when no drag reducing instrument is settled in its body. Secondly, the reducing pressure drop sticks with different size and an air deflector are involved. At last, the results of the numerical simulation are analyzed.The results of numerical simulation show that:if a reducing pressure drop stick with proper size is settled in the center of the spiral cyclone, it can reduce the pressure drop efficiently, on the contrary, if the size is not proper it can increase the pressure drop; there is an optimization size for the reducing pressure drop stick, if the reducing pressure drop stick with an optimization size is involved, the effect of drag reduction could be maximum. It is also found that:when a reducing pressure drop stick and an air deflector are involved simultaneously, the effect of the drag reduction could be better.The mechanism of the drag reduction when an reducing pressure drop stick is involved in the spiral cyclone have some similarities as it is involved in conventional cyclones, the mechanism is that the effect of drag reduction could be achieved because the reducing pressure drop stick could change the structure of the flow field and depress the turbulence dissipation in the cyclone. The decrease of turbulence dissipation is the essential reason of the drag reduction. Through the comparison of the disciplines which are obtained by other researchers and the analysis of the distribution of velocity and static pressure, the drag reduction effect which is realized by the drag reduction methods which are involved in this article could be demonstrated to be reasonable.