摘要
针对某电厂350 MW机组电除尘器出口至引风机入口段烟道全压损失过大的问题,利用数值模拟软件Fluent,采用标准k-ε模型,对该段烟道烟气流场进行了数值模拟。模拟结果表明,该段烟道主要的全压损失主要源自汇流部位、弯管和变径管等部位。依此,本着先易后难的原则,采用逐步优化的方法,渐次设计了3套改造方案:方案一摒弃了原烟道采用较多急转弯头的设计,采用单个135°弯头平滑过渡烟道;方案二改变了其中一个烟气入口方向,使两股烟气提前汇流,增大了烟道截面积,降低了烟气流速;方案三在改造方案二的基础上,在烟气汇流处和交汇处倒圆角,在弯头处添加导流板,以降低全压损失。比较3套方案的减阻效果和改造费用表明,方案三可使烟道两侧平均全压损失由原烟道的217.73 Pa降至49.02 Pa,减阻率达77.4%,降低全压损失的效果显著。
Aiming at the problem that the total pressure loss of the flue which is from outlet of electric precipitator to inlet of the draft fan of 350 MW unit in a certain power plant is too much,the numerical simulation software Fluent is used to simulate the flue gas flow field of the flue with the standard k-ε model. The simulation results show that the main total pressure loss of the flue is mainly from the confluence part,the elbow and the reducer. Based on it,in accordance with the principle of "Easy to Difficult"and using the method of gradual optimization,gradually designed three reconstruction plans: Plan Ⅰ abandons the design that the original flue adopts multiple sharp bend elbows,and adopts a single 135° bend smooth transition flue. Plan Ⅱ changes the inlet direction of one of the flue gas,so that two flue gas confluence in advance,increase the flue section area,reduce the flue gas velocity. PlanⅢ is on the basis of reconstruction of plan Ⅱ,the reconstruction plan has rounded corners at the flue gas confluence and the intersection,and the guide plate is added at the elbow to reduce the total pressure loss. After comparing the resistance reduction effect and reconstruction costs in three plans,the results indicate that Plan Ⅲ can reduce the average total pressure loss from 217. 73 Pa to 49. 02 Pa on both sides of the flue,with a resistance reduction of 77. 4%,and reduce the effect of total pressure loss.
出处
《热能动力工程》
CAS
CSCD
北大核心
2017年第12期66-72,共7页
Journal of Engineering for Thermal Energy and Power
关键词
尾部烟道
数值模拟
全压损失
矩形截面改造
Tail Flue
Numerical Simulation
Total Pessure Loss
Flue Reconstruction
