Operation And Structure Optimization Of Impulse Pneumatic Dryer By Simulation

Impulse dryer is a kind of high efficiency drying equipment and has more and more applications in industries. Since the fluid flow status is so complex that little effort has been attributed to the research of the mass and heat transfer in it. As it has more and more industrial applications, it is important to study effects of operating conditions and structure parameters to specific energy consumption and develop a comprehensive mathematic model for impulse drying process.Based on the mechanism of heat and mass transfer, a mathematic model of specific energy consumption for impulse dryer has been established. The model for impulse dryer includes eight different equations, namely velocity, moisture contents and temperature of particles, humidity and temperature of air, pressure drop, the variation of cross area of the stream in impulse drying, and specific energy consumption. According to the characteristics of the model equations, the four-order Runge-Kutta integration method was used to solve them. Compared to experimental data, the model were verified feasible.The mathematic model of operation optimization for impulse dryer with minimum specific energy consumption as objective function was established. A series of operation condition figure and optimal simulation parameters which included air preheating temperature, air-velocity and solid-gas ratio were obtained in the require range of moisture contents of particles.Set the height of accelerating section and decelerating section, ratio of pipe-diameter as alterable parameter, the mathematic model of structure optimization was established. A series of structure parameters and operation parameters were obtained, and the relations of structure sizes, operation conditions with objective function were found.Besides, different heights and different decelerators impulse dryers were simulated with structure optimization mathematic model and were compared with the same height pneumatic dryer, relations of dryer height, decelerator number and...