Structure Improvement And Aerodynamics Study On Oval Leaves Of Fan In Subway

The fan in subway is one of the core equipment in underground ventilation system, and the rotating stall of the fan was a serious problem during the process of work. The rotating stall depends on leaf structure properties, air conditions and so on, so analyzing the aerodynamic characteristics and structure optimization of the fan have important theoretical and practical significance.Analysis of aerodynamic characteristics of the fan be done with three turbulence models which are ?-??RNG ?-??Realizable ?-? and two kinds of pressure velocity coupling algorithm which are SIMPLE and SIMPLEC algorithm. Relationship curve of between resistance coefficient and elevating force coefficient and. These relationship curves were compared with the actual wind tunnel test data. The result prove that combination of RNG ?-? model and SIMPLEC algorithm be close to the wind tunnel test data, and the study method of this paper was achieved.Analysis of dynamic characteristics of paddle was carried out. The distribution of velocity vector under different paddle consistency and the distribution of velocity vector of the paddle's tip region were achieved. The result proved that the paddle got a good performance under the paddle consistency was 0.5.Three dimensional model of oval impeller was established. The numerical simulation analysis of flow field in impeller was carried out, and the track lines of paddle's central section and hub were achieved. The result showed that the reason of the rotating stall was the eddy in the tip of paddle. Structural improvements was made, and the comparison showed that the difference between the max and min flow rate in the new paddle's central section reduced by 23%, and the deviation of fluid got better, the eddy in the tip of paddle mostly disappeared.The comparativist analysis of dynamic characteristics of the old and improved paddle were carried out. The distribution of velocity vector and the paddle's surface pressure and lift and drag coefficients graph were achieved. The result proved that the improved paddle reduced high speed range in the tip of paddle, and the rotating stall. In the blade head rotates outdated to 10°, blade aerodynamics leads to optimal, then lift to drag ratio of 16, which the angle of attack is 6°.