Numerical Simulation And Optimization Of Fan Forced Convective Heat Transfer Of Fu-brick Tea Drying Room

Fu brick tea, as a drink loved by more and more consumers,it’s production quality and efficiency has become the focus of attention. The parameter control during the Fu brick tea "blossom",directly affects the quality of the final product. At present the drying room used for blossom has many problems, design and use of the drying room mainly based on experience, lack of theoretical guidance, such problems like temperature variations exist during the production, lead to the uneven quality of Fu brick tea products. Analyse and optimization to drying room temperature distribution has a great significance on conserve energy, improve the product quality. This paper based on a typical Fu brick tea drying room of a company,use FLUENT software, using numerical simulation method, establish Fu tea drying room "blossom" mathematical model, analysis features of velocity field and temperature field distribution in a drying room. On this basis, using fan forced convection methods of improvement and optimization of drying room temperature distribution. The main content and conclusion of this paper includes:(1) Experimental study on thermal physical parameters of the fu tea. using line heat source method to get the fu tea thermal conductivity coefficient is between0.04587～0.07198W/m·K,when the moisture content is25%, it’s specific heat capacity is2.125kJ/kg-K.(2) Steady three dimensional model was established for typical Fu tea drying room in bolssem period. Using standard k-ε two-equation model and SIMPLE algorithm to numerical simulation of drying room, and using experimental data to verify the reliability of simulation model. The result shows:air natural convection velocity is slow, and there are flow blocking zones, temperature stratification in the drying room is clear, temperature distribution is very uneven, maximum temperature difference nearly5℃.(3) Preserve existing heating mode, change the cement barrier to mesh barrier of the drying room, design different fan scheme.The result shows:Forced convection causes the generation after the installation of the air fan, air velocity increased significantly, the temperature distribution in the room is uniform. Particularly two fans method gives best temperature uniformity. Install the fan on both sides of the wall to flow field and temperature field uniformity improvement effect is not ideal(4) For two fan scheme, under certain wind conditions, changes the temperature of the heat source, analyze the variation of the temperature field in the drying room. The result shows:to achieve Fu Tea "blossom" process requirements, heat source temperature controlled within the range of80℃-90℃is the most reasonable.