Numerical Calculation Of Blade Cascade And The Back Flow Passage Of The Dust Extraction Fan

This paper take SCF-dust extraction fan as the object of study, it has revealed the actual flow state of the air in the interior of the fan and also discovered the spot and source where the energy lost through the steady numerical simulation of blade cascade and back flow passage flow field at specific conditions and unsteady numerical simulation at rated condition, and has put forward the method and the way to reduce the structure size and to raise efficiency of the fan according to these analysis. It has carried on the redesigning of the dust extraction fan finally, and also done the numerical simulation of the redesigned fan.First, this paper embarked from the basic flow governing equation, has inferred the governing equations set and used the Realizable k-εmodel to describe 3-D unsteady turbulent in the fan. Besides, the governing equations were discretized both in the time and the space domain. It used the unstructured tetrahedron unit to produce the computation grid on the geometric model of the dust extraction fan blade cascade and back flow passage flow field, and increased density in the area of blade channel and gaps which flow changed fiercely. It completed the steady numerical simulation of the dust extraction fan at specific conditions and unsteady numerical simulation at rated condition through give the velocity-inlet and pressure-outlet boundary condition. We have discovered the spot and source where the boundary layer separated and where vortex, the secondary flow and so on emerged through analysis the pressure field, the velocity field and the vorticity field's distributed characteristic on the typical section. Then we proposed the redesign plan of the dust extraction fan on the basis of the numerical results. By optimizing the design parameters, we completed the redesigning of the axial flow dust extraction fan and did the numerical simulation and performance prediction of the modified fan, have proved the feasibility and effectiveness of the modified design. Through the performance prediction, we can get that the optimized fan which apply 3-D flow theory not only improve the efficiency significantly but also have a more wider efficient area which is favorable for working on a variable condition. Moreover, this paper analyzed each design parameter such like attack angle, radial clearance, the number of blade and hub ratio quantitatively and theoretically.Finally, we draw the conclusion that the numerical calculation method has a high reliability through compared the characteristic performance curve with the test result. It can provide the basis for the optimal design and modified design of the dust extraction fan, not only can enhance the efficiency, but also can reduce the experimental time and economic cost. Therefore, it has a high theoretical value and practical significance of the numerical calculation of the blade cascade and the back flow passage of the dust extraction fan.