Improved Design Of Washing Pump In Household Dishwasher

Dishwasher is an electrical appliance which can replace manual cleaning of tableware,kitchen utensils and other items.The household penetration rate has reached50 to 70% in developed countries in Europe and the United States.There is also a very rapid growth in China in recent years.Foshan Shunde Midea Washing Appliances Mfg.Co.Ltd started to introduce technology of Italian Merloni to produce and develop dishwashers from 1998;and now it has experienced three stages from technology introduction,digestion and absorption,to independent research and development in the past 20 years.The current product categories are developed very completely and are sold all over the world.With the requirements increase of global energy-saving and emission-reduction,the dishwasher industry standards have also been continuously improved year by year among all countries,such as the European Union EN50242 and the energy efficiency label Directive(EU)1059/1016,stipulating from single cycle energy consumption,water consumption,cleaning rate,drying rate,noise,loading place settings and other indicators.The energy efficiency index also has a variety of performance level requirements.The mandatory implementation of domestic standard GB38383 about the dishwasher energy efficiency and water efficiency limit value and grade,and the expansion of new functions in Chinese market,both of which require a higher and higher performance requirements of the dishwasher.In order to meet these standard and function requirements,the corresponding core components and system have to be continuously optimized.The washing pump is the most important part among all performance affecting components.This paper takes the dishwasher washing pump as the research object,uses experiments and CFD numerical simulation methods to design and optimize the centrifugal pump impeller,volute,and heating tube.At the same time,the author design and build a closed micro centrifugal pump test platform to verify the performance improvement of the optimized washing pump.The main research work of this paper includes:First of all,this paper introduces the basic principles of the dishwasher and the domestic and foreign development of the washing pump industry in details.The author combines the company's product strategy development direction and the match relation between water flow system and dishwasher,deriving two directions to improve the pump performance,water heating before entering pump or after entering pump.Through the reliability test,the pre-heating way is quickly eliminated,and the integrated post-heating washing pump is selected as the final solution.Secondly,the author designs the main dimensions of the washing pump impeller by speed coefficient method,and optimizes the diameter and width of the impeller by the experimental way.At the same time,the author optimizes the volute through the CFD numerical simulation,and use the two-stage pressurization technology to improve the hydraulic performance of the pump,which is used for the first time in this filed.In addition,the author redesigns the existing integrated heating tube according to the industrial heating tube manufacturing level of the industry;Finally,the author finishes the experimental research about the hydraulic characteristics of the dishwasher washing pump.The closed-type miniature centrifugal pump test platform is built.This platform has high test accuracy and good reliability.The data acquisition system is used to avoid errors caused by human operation.This system is used to verify the optimization of the pump volute,and the results show that the hydraulic efficiency is improved to 150% comparing with the original pump.