Simulation Study On Structure Model Of Edible Bacteria Dryer

As an important means for edible fungus, the process of drying has to consume huge energy. Drying’s thermal efficiency is generally low, only 25%-50%. The structure of dry device is closely related to energy consumption. Meanwhile, hot air velocity is crucial to the quality of edible fungus.Therefore, this research focuses on the structure of drying device. Different hot supply structures causing various velocity field distribution and various cross-section angles has been reached in this paper. Then the approved model is tested, which can provide some advices about how to modify the uniformity of the velocity field distribution in the drying device, improve the quality of dried products and energy efficiency.Based on the characteristics of velocity distribution of drying device, a variable-section and parallel air supply drying device with two square-hole baffles that are uses for air supply and return is designed and modeled by using CFD. The interior space of the drying device is divided into three areas for variable-section and parallel air supply, heat exchanging, and parallel air return, respectively. An adjustable variable cross-section set inside the parallel air supply, which can increase hot air circulation on the upper surface and improve velocity distribution of the drying device.In this paper, three phases were carried out. Firstly, different structure forms drying device were simulated and the results show that the variable-section and parallel air supply drying device has the best velocity distribution; the average air velocity is about 0.6 m/s when the inlet air velocity is 1.5 m/s in the heat exchange part,0.3-0.5 m/s on the upper surface. Compared with the drying device that no variable cross-section, the area of small air velocity decreases 33%.The second phase is to research effect of the variable cross-section angle on the velocity field after determining the construction of the drying device. I found when θ=arctan(1/10), the drying device has the best velocity distribution. The third phase is to study inlet air velocity under the optimal structure. The results show that when the hot air inlet velocity is around 2.5 m/s, the velocity distribution at all directions of the drying device is more homogeneous, and air flow velocity is suitable for edible fungi.The experimental verification of the drying device designed and optimized in modeling has been carried based on the numerical analysis. Numerical relationship is analyzed between the simulated values and experimental values at the selected measurement points. The results indicate the presented model, in general, achieve a gradual balance of velocity. This novel drying device also provides a reference for designing interior baffle configurations in drying device of the similar application.