Research On Aerodynamic Characteristics Of Drying Centrifugal Fan And Heat-transfer Characteristic Of Heating Pipes In Rolling Washing Machine

In order to overcome resistance of long and narrow wind channel,high-head centrifugal fan is used to drive air fluid in drying system of washing drying machine.However,aerodynamic performance of centrifugal fan is limited because of long and narrow wind channel and its unreasonable outline,also,aerodynamic noise is enhanced.And heat transfer performance of heating tubes is weakened with low flow resistance due to smooth surface.In order to match the flow field characteristics of centrifugal fan and heat transfer characteristics,enhance aerodynamic performance and decrease aerodynamic noise generated by centrifugal fan,increase heat transfer performance of heating tubes,flow field and noise characteristics of centrifugal fan and heat transfer characteristics of heating tubes were studied with a research target of drying system for washing drying machine.First,numerical method was used to study operation condition and flow field of centrifugal fan in drying channel of washing drying machine with FLUENT software.Second,the influence factors of fan aerodynamic performance were found to be volute,volute tongue and flow channel outline by analyzing flow field information,and research was carried on to optimize aerodynamic performance combining with noise theory by changing these factors.Next,drying air channel was designed to match the centrifugal fan according to research results of aerodynamic performance and aerodynamic noise,and centrifugal fan total pressure of improved model was promoted by 23.05% compared with the original model,and a rise of efficiency by 20.11%,a decline of noise value by 3.61 dB(A).Last,numerical method was used to study relation between heat transfer performance of heating tubes and diameter,line spacing,column spacing,spread pattern,section shape and surface shape with improved model.Heat transfer performance of heating tubes was improved only with changing section shape or surface shape on condition of low flow resistance compared with original model.Besides,drying channels of improved and original model were made to assemble the centrifugal fan.And experiments were carried on to test their characteristic performance curves of all working conditions.The total pressure curve and efficiency curve of improved model were optimized greatly compared with original model.Aerodynamic noise of drying conditions was tested in a semi-anechoic chamber by assembling the two models to drying system of washing drying machine,the machine noise of improved model was decreased by 2.54 dB(A).Accuracy and reliability of numerical simulation method is proved by experimental results.