污泥薄层干化热通量估算.docx

HEAT FLUX ESTIMATION IN THIN-LAYER DRYING
薄层干化热通量估算
ABSTRACT
A method is developed in order to determine the drying curves for sludge thin-layer drying. Since mass balance is very difficult to measure for thin-layer drying, these curves are obtained through energy balance. An experimental device is built up, in order both to provide and to estimate the heat flux density at the interface between a hot metallic plate and the drying sample. An analytical direct model is made using the quadripole formalism, and the system transfer function is calculated. The inverse problem is solved using the beck's sequential function specification method, and the corresponding drying curve is deduced by a simple energy balance. Real experiment results are presented.
摘要
开发了一种方法，以确定污泥薄层干燥的干燥曲线。由于薄层干燥的质量平衡很难测量， 所以这些曲线是通过能量平衡获得的。 建立了一个实验装置， 以便提供和估计热金属板和干
燥样品之间的界面处的热通量密度。 使用四极形式来进行分析直接模型， 并计算系统传递函
数。使用beck的顺序函数规范方法解决了逆问题， 并通过简单的能量平衡推导出相应的干燥
曲线。介绍了实验结果。
INTRODUCTION
绪论
Among contact drying technologies, drum drying is widely used in the food industry, to treat heat-sensitive products. It also presents a great interest for sludge drying. The product is sprinkled or coated on a hot rotating cylinder. The wall temperature is above boiling temperature. Absence of mixture and agitation constitutes an advantage for viscous products like sludge, enabling a good control of residence time, averaged water content and thermal efficiency. For contact dryer ' s design, ilt tio pnpoilditadrying rates, but this rate is limited by
internal conductive transfers. It is then necessary to find aaximum ideal reference, not driven by internal transfers, but by the intrinsic product ' s thin film boiling rate : this is the main scope of this paper. The present study
application is for sludge.
在接触干燥技术中，滚筒干燥广泛用于食品工业， 用于处理热敏产品。它也对污泥干燥有很大的兴趣。
将产品洒在或涂在热旋转圆筒上。壁温高于沸点温度。缺乏混合和搅拌是粘性产品如污泥的优点，可以很 好地控制停留时间，平均含水量和热效率。对于接触式干燥器的设计，重要的是预测干燥速率，但是这个 速率受到内部传导传递的限制。因此，需要找到一个最佳的理想参考值，而不是由内部转移驱动，而是通 过本征产物的薄膜沸腾速率：这是本文的主要