Study On Simulation Technique Of Temperature Field For Infrared Drying Oven Of Moisture Analyzer

Infrared drying oven used to dry the test samples is one of the most important parts of moisture analyzer. It can directly affect the measuring accuracy of the moisture analyzer and also is the key issue of the project. Infrared drying oven's structure is comparatively complicated where the temperature field with large temperature gradient is generated by several way of heat transfer. As one of the most important indicators of infrared drying oven, temperature determines the performance of infrared drying oven. However, occurred the phenomenon that partial sample was dried deficiently and carbonized when moisture analyzer was working. Therefore, it is necessary to research the change law of temperature when infrared drying oven is working. Since infrared drying oven's structure is relatively closed, it is difficult to measure the internal temperature. So temperature field simulation has become the more practical research method.This thesis studies the real-time characteristics of heat transfer and temperature distribution, analyses the 3D transient temperature field of infrared drying oven by simulation technique of temperature field of computational fluid dynamics, details are as follows:Firstly, aimed at heat transfer of infrared drying oven, it systematically introduces heat transfer theory, focuses on the infrared radiation heat transfer and infrared heating drying technology. Computational fluid dynamics technology is introduced in detail, the main methods are introduced and compared, especially the discretization method of finite volume method. The workflow and characteristics of FLUENT based on the finite volume method is analysed briefly.Secondly, analyses the key issues of numerical simulation of infrared drying oven. Simplified reasonably the model, proposes solving hypothesis and boundary conditions. Analysis the fluid-solid coupled heat transfer model, calculates the available thermal radiation of infrared tubes, analyses the change law of infrared tube based on fuzzy controller, and uses the User Defined Function to define the internal heat source that is same with realistic energy, as well as analysis the method of determining surface reflectivity of infrared radiation.Thirdly, the geometric model of infrared drying oven and the mesh of geometric model are built. Selects and confirms the infrared radiation model and boundary conditions of infrared drying oven, simulates the heating process by FLUENT from the beginning to the steady state, the time of simulation is 300s. Measure the temperature of infrared drying oven by the infrared thermal imager and thermocouple thermometer when the moisture analyzer is working. The temperature results show a satisfactory agreement with both experiment and simulation.By numerical simulation of temperature field, reveals the data about the regularity of temperature of infrared drying oven during its heating period, found that the temperature of sample is smaller than the temperature of sensor, and the decination is different in different stages of heating. The cause of errors is associated with the thermal characteristics of samples. The results of simulation can used to improve the design of moisture analyzer and related engineering applications.