Optimum Design And Experimental Study Of Self-suction Pulse Sprinkler For Intelligent Toilet

With the improvement of living standards,smart toilets are becoming more and more popular among consumers.Cleaning nozzle is the core component of intelligent toilet,which plays a decisive role in the performance of intelligent toilet.As the latest product in cleaning sprinkler,self-suction pulse sprinkler has the advantages of simple structure,large cleaning area and good cleaning comfort.However,the performance of self-suction pulse sprinkler is greatly affected by its structural parameters.In addition,the domestic researchers have less research on self-suction pulse sprinkler for intelligent toilet and the foreign technology is confidential,which makes the self-suction pulse sprinkler for intelligent toilet produced and manufactured by domestic enterprises have many problems,such as pulse instability,less striking force,poor cleaning comfort and lack of performance test equipment.In this paper,a self-suction pulse sprinkler was designed according to the actual demand and taken as the research object,a multi-functional performance testing device for self-suction pulse sprinkler was designed and built.By means of the combination of experimental test and numerical calculation to research the influence of the self-suction pulse sprinklers structure parameters on the performance of the sprinkler in depth and meticulously.By basing on the response surface method to optimize the self-suction pulse sprinkler,and coMPare the performances of sprinklers before and after.The main work and research results are as follows:1.Summarize the current research status of self-suction pulse sprinkler,and systematically summarize the related research and optimization methods of self-suction pulse sprinkler.2.Designing and building a multi-functional performance testing device for self-suction pulse sprinkler,and developing a cleanliness analysis software,which realized the measurement and analysis of flow characteristics,iMPact force and cleanliness rate of self-suction pulse sprinkler.The test results show that:(1)the model nozzle can generate catch-up flow,but there is no obvious periodicity.(2)CoMPared with the design requirements,the iMPact force of the model nozzle is less than 0.1N,the pulse frequency is more than 90 Hz,and the cleaning rate is less than 90% at 40 s,which needs further optimization.3.Uing CFX software to analysis the influence of single factor structural parameters on the flow field and pressure fluctuation of the nozzle.The results show that:(1)Compared with the nozzle without suction condition,the velocity at the nozzle outlet under suction condition is increased by 41%.(2)The nozzle structure parameters have an important influence on the gas-liquid mixing ratio in the chamber,and the appropriate gas-liquid mixing ratio in the chamber can help to improve the velocity of the jet water and slow down the attenuation of the jet water velocity.(3)The size of the cavity has great influence on the time-frequency characteristics of pressure fluctuation and jet pressure fluctuation,but has little influence on the stability of pressure fluctuation;The size of the cavity has little influence on the time-frequency characteristics of pressure fluctuation,jet pressure fluctuation and the stability of the fluctuation;The diameter of the lower nozzle has great influence on the pressure fluctuation,jet pressure fluctuation frequency and the stability of the fluctuation.4.Basing on response surface methodology,the coupling effects of structural parameters of self-suction pulse sprinkler on sprinkler performance were studied by taking the cavity length,cavity height and inlet diameter of the lower nozzle as independent variables,and the iMPact force F,pulse frequency f,pulsation value F and cleanliness rate S as response variables.The results show that:(1)The iMPact force,cleanliness rate and pulsation value of the sprinkler are affected by a single structural parameter and the order of influence is: cavity length,inlet diameter of upper nozzle and cavity height;The order of influence of single structure parameter on impulse frequency of nozzle iMPact force is inlet diameter,cavity length and cavity height of upper nozzle.(2)The optimum range of structural parameters obtained by synthesizing the performance of the nozzle is 1.3-1.4 mm in diameter,16-17 mm in length and 5.3-5.5 mm in height.The optimum structural parameters are 1.4 mm in diameter,17 mm in length and 5.5 mm in height.5.The performances of the optimized model nozzle were tested,including jet flow characteristics,iMPact force and cleanliness test.The test results show that:(1),the optimized nozzle jets show obvious droplet aggregation,forming obvious catch-up jets.(2)The average strike force is 0.13 N,which is 42.9% higher than that before optimization;The pulse dispersion is 28% higher;The pulse frequency is between 80 and 90 Hz;And the cleaning rate is 96% at 40 seconds,which all meet the design requirements.