CFD Analysis Of Multi-blade Centrifugal Fan And Some Program Development Work About Its Preprocess And Postprocess

Multi-blade centrifugal fan has been widely used for air-conditional system because of its high flow coefficient, high pressure coefficient, small size and low noise. It has gradually been an important technical means to predict the internal flow structure of fan by using an existing, mature, commercial CFD package.Based on the requirement of CFD application in modern turbo-machine and grasping GAMBIT that is a commercial preprocess code, the parameterized modeling program for multi-blade centrifugal fan utilizes OOP and database technologies to develop binding GAMBIT. By the parameterized modeling program, many kinds of multi-blade fans can be generated quickly, which helps to decline the time cost in developing new fans.With the developed program, about ten common multi-blade centrifugal fans are simulated by CFD at design flow condition. Compared with the real tests, a good agreement is found at designing flow condition. At the same time, the error sources affecting the accuracy of CFD are discussed. And then, on the forementioned base, a common fan is simulated at all flow condition, and a comprehensive visualization is successfully executed to gain detailed flow field information and clear understanding of the entire flow field throughout this multi-blade forward-curved centrifugal fan. Calculation results disclose that the flow in the fan shows complicated three-dimensional characteristics. On this base,the similar numerical methods are carried out to understand the basic flow physics and the effect of various parameters such as the motor, the width of the volute, the width of the impeller, the distender of the volute, the clearance, the blade outlet angle, inlet angle, the blade chord length and the number of the blade. The internal flow field and loss of the fans are predicted and discussed. Some instructive conclusions have been derived from the simulate results. Which will be helpful to improve the performance of multi-blade centrifugal fan.Finally, the development work of the program which is to draw fan performance curves and which is a"post-process"for CFD simulation is discussed. Mainly talks about the arithmetic, the structure and the executive process of the curve drawing system. Then discusses some problems and key techniques which are encountered during the development of the program.