含灰湿空气外掠翅片管束积灰和阻力特性实验研究

Experimental Study on Ash Deposition and Resistance Characteristics of Wet Air with Ash Particles across Finned Tube Bundles

本文针对以褐煤预干燥乏气为代表的含灰含湿气体余热回收问题,采用含灰湿空气模拟真实干燥乏气/烟气,搭建了混合气体外掠圆形翅片管束对流冷凝实验系统,获得了灰分浓度、水蒸气质量分数、主流气体入口温度等因素对其积灰和阻力特性的影响规律。实验结果表明,阻力系数随着灰分浓度和气体入口温度的增加而增加,随水蒸气质量分数的增加而减小,其中灰分浓度影响重大,当其从1.5g·m3增加到12.8g·m-3时,平均阻力系数从0.07增长到0.46,增长幅度约为536%.积灰程度表现出与阻力系数相同的趋势,当灰分浓度大于7.7g·m3时即积灰严重,甚至会产生堵塞流道的现象,需要及时清理。

In this paper,aiming at the problem of waste heat recovery of the gas with water vapor and ash particles,represented by the lignite dryer exhaust,the mixture of air,water vapor and ash particles was used to Simulate the real gas,and an experimental system of the mixture vapors across finned tube bundle was built.The effects of the ash particle concentration,water vapor mass fraction and mainstream inlet temperature on ash deposition and resistance characteristics were obtained.The experimental results showed that,the resistance coefficient increased with the increase of the ash particle concentration and mainstream inlet temperature,and reduced with the increase of the water vapor mass fraction.Especially,the effect of the ash particle concentration was significant.When it increased from 1.5 g·m-3 to 12.8 g·m-3,the average resistance coefficient increased from 0.07 to 0.46,with an increase of about 536%.The ash deposition showed the same trend with the resistance coefficient.When the ash particle concentration was larger than 7.7 g·m-3,the ash deposition was severe,even blocked the flow channel,and should be cleaned in time.