High-voltage Pulsed Electric Field Modeling And Application For Food Sterilization

Now the problems of food safety had been paid more attention, especially safety and quality of liquid food, for example juice, wine and so on which is directly related to whether effective sterilization. Conventional thermal sterilization has significant shortcomings not only in color, flavor, structures, physical and chemical properties of food but also nutritional value, and even produce toxic substances. So high-voltage pulsed electric field(Pulsed electric field, PEF) sterilization method is one of the non-thermal sterilization technologies which is researched by the scholars in the food processing industry, and it has advantages of no pollution, low temperature, less energy consumption and better bactericidal effect, So, the study about PEF sterilization for liquid food processing industry has far-reaching significance.PEF sterilization system consists high voltage pulse generator and process chamber. But the sterilization effectiveness influenced by pulse waveform produced by pulse generator and multi-physical fields(electric field and flow field, temperature field) distribution characteristics. This topic from the two main influence factors to build pulse generator and processing chamber model, and use COMSOL Multiphysics to simulate the chamber was carried out on the processing chamber, higher performance requirements which can provide theoretical basis for the pilot-scale and industrialization of PEF sterilization system.Study the general process of PEF sterilization processing; summarize the key problems of the PEF sterilization processing. By reading literature, summarized the advantages and disadvantages of high-voltage pulsed electric field sterilization technology, simply introduces the development and status of PEF sterilization at home and abroad and the research foundation of the numerical simulation method.PEF sterilization mechanism and the main influence factors of the sterilization effectiveness were studied which provides the theoretical basis for the design of pulse generator and treatment chamber, finally validate the feasibility of numerical simulation method was applied to study of PEF sterilization technology.In order to optimize the structure of the processing chamber, this topic designed different insulation structure of co-liner chamber and use COMSOL Multiphysics software to simulate and analysis its inner multi-physics coupling characteristics. Parametric modeling was used to study the distance and radius of the insulation of the modified treatment chamber which influences the internal multi-physical distribution characteristics, on the basis of the homogeneous degree of the electric field and temperature field, it is concluded the optimal processing chamber insulator geometry parameters. At last, the laboratory tests have been done based on foundation of this theoretical analysis so as to verify the correct of the theoretical analysis and lay basement on practical application.