滚筒式牧草干燥机参数模拟与分析

为了分析滚筒干燥机内部的温度和气流分布,确定干燥条件对苜蓿含水率的影响。模拟滚筒干燥机内部的温度场和热风流量场分布,并在滚筒式牧草干燥机上进行苜蓿干燥试验。结果表明,在滚筒式牧草干燥机工作过程中,苜蓿与热空气间的90%热交换发生在干燥机滚筒的前半段,且适当增加滚筒长度可使热风气流呈现层流状态,有利于苜蓿段在滚筒内运动、换热和脱水。通过分析干燥参数对牧草最终含水率的影响规律,在苜蓿初始水分为78.5%时,得到合理苜蓿滚筒干燥参数组合:干燥温度为360℃,滚筒转速10r·min-1,热风速度1.8m·s-1,喂入率为25kg·min-1。研究结果为优化滚筒式牧草干燥机结构和确定合理工艺参数提供了依据。

Simulation and analysis of drying conditions for rotary dryer

In order to analyze the state of the temperature and flow of hot-air and effect of drying conditions on final moisture content of alfalfa forage. the Ansys software was employed to simulate the distribution of temperature and hot-air flow field in a rotary dryer for the alfalfa drying, drying experiments of alfalfa forage were performed at a self-manufactured rotary dryer. The results showed that 90% heat transfer between the alfalfa stems and hot-air happen at forward half section of rotary cylinder, and the laminar flow state within rotary cylinder was presented by extended the length of cylinder to 4 m, thus facilitating the process of movement, heat transfer and dehydration of alfalfa stems within the rotary dryer. Based on the effect of drying conditions on the final moisture content of alfalfa stems, at the initial moisture content of 78.5%, the optimum parameters was obtained as following: drying temperature of 360 ℃, rotary speed of 10 r·min-1, hot-air velocity of 1.8 m·s-1 and input rate of 25 kg·min-1. The results were very useful for optimized structure of rotary dryer and determined optimum parameters of drying technology.