Study Of Annulus Cavitation Device On Process Enhancement

Cavitation is a process that vapor or gas vacuoles appearing in the liquid or on the liquid-solid surface form, develop and collapse when the partial pressure within the liquid is lower than the saturated vapor pressure of the liquid. Bubble collapse will produce instantaneous high temperature, high pressure, strong shock wave and high-speed micro-jet and other extreme physical conditions, which can make water molecules bond cleave and produce free radicals. Because free radicals have a very high activity, cavitation can enhance chemical processes. In the cavity flow field there are high jet. shock and severe turbulence and other mechanical effects, which can enhance physical processes.Traditional hydraulic cavitation devices are orifice plates or Venturi tubes where pores are in the middle. This paper aims at the research of a kind of annulus hydraulic cavitation device where pore is on the periphery. This device will greatly increase the cavitation area, and increase the opportunity that vacuoles and side wall contact, so that enhance the intensity of bubble collapse. In addition, the structure that pore is on the periphery of the annulus hydraulic cavitation device determines that it will have wider application space comparing with traditional devices. In order to study the cavitation intensity, strengthening effect of chemical processes and physical processes of this annulus hydraulic cavitation device, this paper has done the following research work.(1)Design several groups of different types, different size series of annulus hydraulic cavitation device for experimental use.(2)Select the best structure type and structure size of cavitation devices through experiments. Seperately change the operating parameters(such as inlet pressure, temperature, etc.) and structure parameters of the annulus cavitation device, study the influence of each parameter on cavitation intensity, and select the best structure type and structure size of the annulus cavitation device under the conditions of this experiment.(3)Study the application of the annulus hydraulic cavitation device in specific chemical process through experiments. Choose two areas of application. The first one is the degradation of organic matter. This paper has studied the degradation of the pesticide omethoate using the annulus cavitation device, and studied the influence of operating parameters and device structural parameters on omethoate degradation rate. The second one is removing the scale on pipe inner wall. This paper has selected a type of pipe where the inner wall scale is asphalt, and done scale removal experiments using the annulus cavitation device. Seperately change operating parameters and device structural parameters, and study the hydraulic cavitation conditions suitable for removing this type of scale.(4)Make theoretical research on the annulus cavitation device. Use the theory of fluid mechanics, cavitation dynamics and computational fluid dynamics and choose the applicable theoretical model and calculation method to take nemerical simulation on the flow field of the annulus cavitation device. Study the cavitation effect of the annulus cavitation device theoretically.