气流干燥器加速段的计算

加速段是气流干燥器质热传递最有效的部份，其长度在总管长中所占的比例，直接影响干燥器的效率。阻力系数，饱和水蒸汽压，湿球温度的计算以及微分方程组的建立是加速段设计中的关键问题。本文提出了阻力系数，饱和水蒸汽压计算的经验式，计算湿球温度的高位试差法，建立了气流干燥器加速段质热传递的微分方程组，并利用龙格库法得到了比较精确的值数解。

Calculation for Acceleration Section in Pnumatic Dryer

The most efficient part for heat and mass transsfer in a pneumatic dryer is the acceleration section,proportion of its length to the total tube length has an effect directly on the efficiency of dryer. The key problems in design of the acceleration section are the calculations of drag coefficent and saturated steam pressure,of the wet-bulb temperature,and the creation of the differential equations. In this paper the empirical eqrations of saturated steam pressure, of drag coefficients for sphere, and the high bit-trial-error method for calculation of the wet-bulb temperature are presented,the differential equations (9-18)for heat and mass transfer of the acceleration section are created,its numerical solution is more accurately obtained using Runge-Kutta method.