Study On Structure Optimization Of Fluid Mechanical Based On Digital Technology

As fluid media energy conversion machinery equipment, fluid mechanical is widely used in various fields of national economy and plays a very important role. With the continuous development of technology and global formation of manufacturing, the function of the fluid machinery is required continuously improved in various fields, digital technology is not only becoming a major innovation tool but also turning into effective means of shorten the product development cycle and improving performance of fluid machinery.In this paper, R40 axial fan is used as researched object, the blade of fan has been improved and it structural parameters were optimized based on digital technology.Firstly, one of the best airfoil on aerodynamic performance is choose and calculate the blade of fan using MATLAB program prepared by myself. The computational domain of fan is established, the turbulence model and the grid were examined. Influence to convergence results of the serial and parallel solver and different nodes are analyzed.Secondly, three-dimensional numerical simulation is conducted on the axial-flow fan with the FLUENT software; we simulate the flow field of axial-flow fan using Realizable k-εtwo equation turbulence models and SIMPLEC method and analysis the steady flow and unsteady flow field of the fan. We can get many important details of velocity and pressure distributions, many models of axial-flow fan are applied by changing some primary geometrical parameters that effect on the fan's performance, and then we can get the reason that each parameter affects on the axial-flow fan's performance. The results show that:total pressure increases as the installation angle; the maximum efficiency point is changed along the parabola; the maximum speed of outlet surface increases as motor speed, and Q-ηcurve is changed along Straight line; According to these results, structural parameters of fan are optimized. The fan efficiency has a maximum at angle of blade is 33.8°and motor speed is 1440rpm, then the maximum value is 0.7929. Finally, the finite element model of blade of R40 axial-flow fan has been built, using this model, the dynamic characteristics of blade has been analyzed with Ansys software. We can get the first 10 natural frequencies of blade under rated and resonant operating conditions, and get the harmonic response of exciting force. The results show that R40 axial-flow fan runs stable under resonant operating conditions, resonance does not occur; the larger rotation speed can increase the natural frequencies of blade; the blade has the maximum response of the exciting force at 120Hz.