摘要
针对内燃机排气碳烟沉积、导致换热器的换热性能大幅降低的问题,本文建立了包含碳烟颗粒沉积与移除机制的数值模型,基于管排换热器沉积分布特性,研究了换热管形状及布置方式对碳烟沉积特性以及换热压降性能的影响规律。结果表明:沉积层达到动态平衡的时间随椭圆管轴长比增大而增大,与圆管结构相比,合适的椭圆管结构能够抑制碳烟沉积引起的换热性能下降;在无碳烟沉积时叉排结构换热压降性能优于顺排结构,但碳烟沉积对叉排换热器性能影响极大,考虑沉积后叉排圆管性能恶化82.53%,其性能反而远差于顺排结构;在考虑碳烟沉积的情况下,顺排轴长比为0.8的椭圆管结构的平均换热压降性能与顺排圆管和叉排圆管相比分别提高了51.63%和223.31%。
For the problem of soot particles deposition in internal combustion engine exhaust,which will cause the heat transfer performance of the heat exchanger to be greatly reduced,a numerical model of soot particle deposition and removal is developed in this paper.Based on the deposition and distribution characteristics of soot particles of tube heat exchanger,we explored the effects of different heat exchange tube shapes and tube row arrangements on their deposition performance,heat transfer performance and pressure drop performance.The results show that:The time of the deposition to reach dynamic equilibrium increases with the increase of the axial length ratio of elliptical tubes.Compared with round tubes,the elliptical tube structure can reduce the deterioration of heat performance due to soot deposition.Without soot particles deposition,the heat transfer and pressure drop performance of staggered arrangement is better than in-line arrangement.But its performance decreases significantly considering soot particles deposition.After deposition,the performance of staggered round tube structure decreases by 82.53%,so it is worse than in-line arrangement.Compared with in-line round tubes and staggered round tubes,considering soot particles deposition,the average performance of the elliptical tube structure with the axial length ratio of 0.8 in the in-line increases by 51.63% and 223.31%respectively.
作者
张钊
田华
丁占铭
张岩
王振彪
ZHANG Zhao;TIAN Hua;DING Zhanming;ZHANG Yan;WANG Zhenbiao(Science and Technology on Diesel Engine Turbocharging Laboratory,China North Engine Research Institute,Tianjin 300400,China;State Key Laboratory of Engines,Tianjin University,Tianjin 300072,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2023年第3期769-780,共12页
Journal of Engineering Thermophysics
基金
基础加强计划重点基础研究项目(No.2019-JCJQ-ZD-341-00-4)。
关键词
烟气换热器
碳烟颗粒
沉积模型
管排结构
exhaust heat exchanger
soot particle
deposition model
tube structure
