| In China,grain drying industry is facing enormous challenges because of the grain output is large, the grain drying machine is difficult to meet the actual needs, the drying efficiency is low and the pollution is serious. The radiation and convection heating dryer has the advantages of high efficiency, energy saving, low pollution, and the existing drying method which can solve the traditional drying methods is very important to improve the efficiency of grain drying. In this paper, the experiment of radiation and convection combined heating test system is carried out. The main contents are as follows:First of all, the paper focuses on the radiation and convection combined heating and drying system designed by Beijing University of Posts and Telecommunications. It is mainly introduced from the mechanical structure and the control system. Based on the analysis of the mechanical structure of the drying system, the principle and technological process of grain drying were analyzed. In the control system, the control system and the hardware and software of the system are introduced.Secondly, on the base of theory of porous media, the grain is assumed to be a virtual continuum, and the parameters are determined. At the same time, the existence of water and heat transfer in grain were analyzed.Thirdly, with com as the object of study and applying local non-equilibrium theory, the control equations of corn temperature, corn moisture content, gas phase humidity, gas phase temperature, gas phase continuity equation and Darcy's law were established on the base of the virtual continuum assumption, and the control equation for radiation heat radiator is established.Finally, a series of dry pilot experiments were carried out in Harbin Dongyu Agricultural Machinery Engineering Limited company by using convection radiation dryer as experimental platform. The superiority of the radiation and convection combined heating and drying system is proved by analyzing the performance of the dryer. |
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