Simulation And Optimization Design Of The Drying System In A Sterilizer

In order to decrease ozone leakage after using a sterilizer and accelerate dishes drying speed, this paper focuses on an optimization target of enhancing the uniformity of temperature field and flow field in the intracavity. A CFD simulation model for the drying system of a sterilizer is established based on the theory of hydromechanics, heat transfer and finite element analysis. The flow field and temperature field are analyzed and verified by theoretic formula of heat transfer and temperature test. The simulation result is in good consistency with the experimental situation and the error is less than 8%. The result indicates that high temperature region concentrates on the upper part, therefore, there exists large temperature gradient and flow streamline locates in the middle of the intracavity, temperature and flow field are not uniform.After analyzing the influence of heater position and surface area on temperature field, it can be found that acting as the heat source of the drying system, the light wave tube will cause air around it flows upward quickly, which will result in large temperature gradient. Lateral movement of light wave tube cannot change the situation. Based on this principle, it is found that a larger area of heat source can slow down flow velocity and improve the uniformity of temperature distribution significantly. Therefore, optimization plan for inner circulation of the drying system is established. After analyzing the influence of arrangement of centrifugal fan and pipe on flow field, it can be found that the exhaust inlet of centrifugal fan influences flow field remarkably. Putting air duct into the intracavity and reducing bending area as much as possible can reduce airflow loss. Therefore, optimization plan for outer circulation of the drying system is established.The overall optimization plan can be obtained from the integration of inner and outer circulation. It is further optimized that the direction of the outlet of air duct can be set parallel with the axial direction of heater to make more heat transferred into the intracavity. The simulation result indicates that the uniformity of temperature and flow field distribution are improved notably. The nonuniformity coefficient of temperature decreases 19.6% and 6.2% respectively for inner and outer circulation. Temperature concentration disappears and flow velocity increases a little. The optimization target is well achieved and that can be a reference for the research and development of the drying system for a sterilizer.