Study On The Internal Flow Field And Structural Optimization Of Vending Machines Based On CFD

The distribution of temperature inside the vending machine not only is of much concern to the storage of goods, but consumption. Especially, increasing living standard make people demand more and better the quality of food. Therefore, how to meet user demand and to reduce energy consumption is the main significance of this article. But, the main factors which influence the temperature distribution is the uniformity of air flow. Uniform airflow can effectively reduce the heat of the storage items, but also to ensure the uniformity of the temperature inside the vending machine.Based on the combination of theoretic calculations analysis and numerical calculation, the article investigate airflow field of the vending machine. Firstly, according to the theory of computational fluid dynamics, a stable three-dimension governing equation is established, then the governing equations of the differential form is discretizated by the second-order upwind scheme and finite volume method. Finally, based on Realizable k-ε two equation turbulence model using SIMPLE algorithm calculate the discrete equations. According to the theory, a mathematical model of automat is established.Based on the mathematical model, the commercial CFD software Fluent is used to simulate the internal airflow field. Through the analysis and discussion of the original program model simulation results identifies the impact of uneven airflow distribution:The fixed motor baffle impede the entry of the flow field behind each shelf; At the same time, due to the limited space inside the vending machine, the airflow easily form attached jet with the box, affecting the diffusion of the flow field. Considering the vending machine internal airflow factors, according to the uniform air distribution scheme commonly used in engineering, three improvement projects are presented:the slot air supply, perforated plate air supply, louver air supply program.Using the simulation method for three kinds of the improved model has carried on the feasibility analysis of the vending machine. Firstly, outlet and duct are designed by theoretical calculations for each program, and then the three programs that applied to the e vending machine are simulated by the numerical calculation. Results shows that guarantee absolute uniformity of air supply is impossible, no matter what kind of solution only ensure relatively uniform. The improved the slot air supply of three kinds of schemes can better meet the requirements of uniformity of the blower.