| Porous ceramic membranes have been widely used in seawater desalination,sewage treatment,chemical production and other fields because of their selective permeability and stable properties.However,with the increase of running time,porous ceramic membrane will reduce the efficiency of osmotic separation due to pollution.Ultrasonic cleaning and scale removal technology has been widely used in the field of industrial cleaning due to its advantages of high cleaning efficiency.Ultrasonic cleaning technology is mainly based on the cavitation effect generated by ultrasonic,so the exploration of ultrasonic cavitation mechanism and its influencing factors has become the key to explore the application of ultrasonic cleaning of porous ceramic membrane.Firstly,this paper introduces the mechanism of permeation and fouling of ceramic membrane from the theoretical point of view,discusses the different types of membrane,its permeation mechanism and application scenarios,and discusses the different modes,models and characterization methods of membrane fouling.Then,the factors affecting the ultrasonic cavitation effect were investigated from the experimental and simulation perspectives.In the experimental part,an experimental platform for ultrasonic cavitation intensity measurement was built.Two methods,noise method and metal film cavitation etching method were used.The noise method was used through acoustic sensor,and the LabVIEW software was used for filtering.The thin film cavitation erosion law measures the corrosion of metal film in the cavitation field,and carries out binarization treatment on the corrosion part through MATLAB software,so as to obtain the corrosion area to measure the strength of cavitation,and mainly explores the relationship between the liquid level height,power and other factors and the strength of cavitation.In the simulation part,the mainstream numerical simulation software ANSYS Fluent,based on the VOF model and the basic governing equation of fluid mechanics,explores the expansion and contraction process of a single bubble in the ultrasonic cavitation field,reflects the cavitation effect through the ratio of the maximum and minimum areas in the whole process,and changes the pressure inlet parameters through the UDF function.The influence of frequency,ultrasonic amplitude and other factors on the cavitation intensity is mainly explored,which provides a theoretical basis and reference for the experiment of ceramic membrane scale removal in the following chapter.Finally,this paper explores the ultrasonic cleaning effect of porous ceramic membrane,constructs the ceramic membrane fouling cleaning effect quality evaluation criterion,set the ultrasonic cleaning test bench,through to the power plant desulfurization wastewater pollution after the tubular ceramic membrane cleaning,showed that ultrasonic cleaning effect of mainly inorganic membrane pollution,ceramic membrane permeation flux recovery significantly.At the same time,the performance of the ceramic membrane and the change of its own structure before and after cleaning were also discussed.The experiment showed that when the liquid level height was 5cm and the position of the membrane tube was 5cm from the transducer,the ceramic membrane’s own structure was not damaged and its performance was not affected.The influence of various influencing factors on the cleaning effect was explored,and a certain rule was obtained,which provided a reference for further research and industrial application. |
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