The Research On Flow Control Technology Of Wind Circulation In The Wood Drying Kiln

Wood drying is an important part in wood physical properties improvement, timber loss reduction, timber utilization and wood-product quality guarantees. China is a country with limit forest resources, we could protect it by making use of wood resources effectively. In the timber manufacturing process, wood drying is an indispensable step, and it affects the wood products quality and utilization directly. Therefore, the research on efficient energy-saving wood drying kiln system is an important method in improving the wood drying quality and saving timber resources which is significant to protect the forests and save the energy.The main way to improve timber utilization is to improve the wood drying efficiency, methods and techniques. Wind circulation system is the key part of wood drying in kiln. Therefore, how to improve the numerical control system of wind circulation becomes an important factor for wood drying quality improvement.The thesis includes the basic contents as follows:(1) Basic principles, drying technologies and modeling methods on the wood drying. Studies on the change of the moisture content in the timber drying process, optimization process of wood drying, mathematical modelling establishment and the energy saving method. (2) Studies on generating system, organization structure and numerical control system of wind circulation in the wood drying kiln, and establishment of the wind circulation system modelling combine with the aerodynamics theory. (3) The change of various parameters and mutual coupling, relations of wind circulation system in the wood drying kiln controls in the drying process. A series of parameters that effect wood drying was quantified, such as airflow velocity, temperature, pressure, humidity and so on. Further, the best combination of numerical was obtained through the experiments in order to control the wood drying process preferably.The former researching achievements in the thesis are (1) the negative effect of existing wind circulation numerical control system to the wood drying quality in the wood drying kiln has been studied, the formation reason was analyzed, several new wind circulation numerical control system was raised by combining with the computer technology and automatic control theory; furthermore, the simulation experiments were made. (2) The reason influence wood drying effect was analyzed through the simulation industrial environment of drying kiln wind circulation system, and some solutions were put forward to improve the utilization of wood, which offers the theory basis. (3) The airflow expands effects to wood drying quality caused by gaps of the single or multiple wood stacks were studied. Finally, the effective measures and theoretical basis on how to avoid or eliminate these disadvantages were founded.Those research achievements in this thesis are feasible and practical and have significance in establishing new wood drying system, saving energy, improving the timber utilization, reducing wood defects such as crack, warping and shrinks and so on, and shorting the drying time.