| Centrifugal fans are widely used in industry, agriculture and daily life. High energyconsumption and noise make it a target of scientists and engineers. Modern numericaltechniques combined with experimental research are now used in improving the traditionalcentrifugal fan products, aiming at analyzing the internal flow and forecast externalcharacteristics of centrifugal fans. Thus take effective measures to improve the efficiencyof the centrifugal fans to achieve the purpose of using energy efficiently.A three dimensional numerical simulation is done on a largely produced cabinetcentrifugal fan. Standard k-ε viscous model and SIMPLE algorithm are selected. Velocityinlet and outflow are used as boundary conditions. Curves of the performance test are usedto validate the accuracy of the simulation. Images of the internal flow loss in the cabinetcentrifugal fan are presented. Causes of flow losses are described based on the images,such as flow separation, leakage and secondary flow. After analysis of the flow losses wedecided to make changes on the position of the volute tongue. Result of the simulation onthe improved machine provides a2.63%increase in internal efficiency and a betteroutflow condition.Small multi-blade centrifugal fans are widely used in household appliances, such aswall mounted boiler. Another numerical simulation is done on a multi-blade centrifugalfan in order to increase its efficiency. Standard k-ε viscous model and SIMPLE algorithmas well as velocity inlet and outflow boundary conditions are used in the simulation. Basedon the analysis of the results, blade installation angle is adjusted. The adjustment brings anincrease in total pressure and efficiency.Steady and unsteady numerical simulations are done on two types of centrifugal fans.Results of numerical simulations and experiments are in good agreement. The analysismethod and results are useful to improvements on similar fans. |
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