摘要
灰分广泛存在于锅炉尾部烟气和各类干燥乏气中,在烟气/乏气余热回收环节是不可忽视的因素。本文以含灰分烟气/乏气的余热和水回收问题为研究背景,采用含灰分湿空气模拟烟气/乏气,对含灰分湿空气的换热特性展开实验研究,获得了换热系数随时间的变化规律并观察了积灰形态。实验研究发现:在含灰分的情况下,湿空气对流冷凝换热系数随时间的增加先减小后维持稳定,呈现指数规律变化。相比较于干空气,湿空气换热系数达到稳定状态所需时间较长、降低幅度较大,积灰严重且主要集中于上部管束。
Ash particles widely exist in flue gas and all kinds of dryer exhaust, which could not be neglected in the process of waste heat recovery from flue gas or exhausted gas. In this paper, for the purposed of recovering waste heat and water, wet air with ash particles was used to simulate flue gas or exhausted gas. Experiments were taken to study heat transfer characteristics for wet air containing ash particles. Heat transfer coefficients against time were obtained. Ash deposition pattern was presented. It was found that when the mainstream contained ash particles, heat transfer coefficients of wet air decreased against time and then reached stable values, presenting an index attenuation law with time. Compared to dry air, the time to reach steady of wet air was longer, the decreasing range of heat transfer coefficients was larger, and the ash deposition was more serious and mainly concentrated in the upper tubes.
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2017年第11期2382-2386,共5页
Journal of Engineering Thermophysics
基金
国家重点基础研究发展项目计划(No.2015CB251504)
国家自然科学基金(No.51406152
51436006)
关键词
灰分
冷凝
换热器
换热特性
ash particles
condensation
heat exchanger
heat transfer characteristics
