Investigation On Cavitation Inside Micro Channel

Cavitation in hydraulic machine causes a range of hazards:noise, corrosion, reduction of efficiency, etc. Over the past century, the macro hydraulic machinery cavitation has been fully investigated, in order to improve the design of regular hydraulic machine. With the development of micro electro mechanical systems (MEMS) technology, more and more micro fluidic devices with different functions and diverse structures have been used in actual applications, including micro valves, micro pumps, computer ink-jet printing systems, lab-on-chip systems for biological and chemical analysis, and even micro rocket fuel systems. However, many problems (e.g. cavitation) also occurs in the design and use of such micro fluidic systems. Li discussed the scale effect relationship between the macro and micro fluid theoretically, and pointed out that under the micro scale conditions, the surface viscous force and surface tension will have a significant impact on the flow rather than the inertial force. On the other hand, there are few researches on the phenomenon of micro scaled cavitation in the past. Therefore, this paper tries to make some preliminary exploration on the characteristics of micro cavitation through a set of devices used for the occurrence and observation of micro cavitation.In chapter 1, the background and significance of the research was introduced, macro-and micro-cavitation research situation was analyzed, and the main research objectives and research content of this project was described.In chapter 2, the design and processing of microfluidic chips was introduced, experiments were done with silicon and glass as the substrates, and related parameters of sputtering, etching, and packaging were accumulated.In chapter 3, simulation and analysis was conducted under different boundary conditions according to the theory of cavitation, and a series of useful conclusions were given to help design the experimental platform.In chapter 4, a micro-cavitation observation test platform was built according to the cavitation theory and simulation results, microfluidic chips of different sizes were designed and fabricated, and the phenomenon and characteristics of micro-cavitaion was explored.In chapter 5, the work has been done was summarized, and the prospects for the next step was made.