| Counter-rotating axial flow fan is more special project of axial flow fan, the internal flow structure in the special cascade stages worthy researching .For 1990's, domestic's research for Counter-rotating axial flow fan is very active. The emphasis of the research is mainly to manufacture for the well ventilated machine product of new high-efficiency and low noise, optimal design and simulating calculation etc.. Because the current optimal design using CFD just carry on the calculation of different stages, did not carry on the whole analysis; and absence of the interference influence between stages and Performance Prediction of the whole machine. Author hopes to simulate the inner flow field of counter-rotating fan with a commercial CFD software—Fluent to provide the feasibility project for optimal design. In this thesis, take the aerodynamics analysis about velocity triangle of counter-rotating axial flow fan,put forward a kind of basic design way combined with the structure characteristics of Counter-rotating axial flow fan, at last put the technological process of optimum design based on FLUENT . Numerical simulation using FLUENT software based on solving 3d Reynolds average steady Navier-Stocks equations with Realizable K-e turbulent model and continuous plane for mixing treatment has been used to study the internal flow of the model OBB-84-84B counter-rotating axial flow fan. Compared the experiments Performance of the fan with numerical results, the numerical error in 5% proved the validity of the calculation. Study the interactions of Rotor/rotor through the effect of the first stage rotor's wakes. Combined the simulated results and the structure characteristics of counter-rotating fan, showed flow fields of the S1, S3 plane and disclosed the phenomenon and mechanism of interactions in fans. At same time study the match of two stage of counter-rotating fan. Discuss the influence of various axial distances and ratios of speed to the fans. In the end, point out the directions and methods of profound research through the CFD analytical result and present state of counter-rotating axial flow fan. |
