A study on post impingement effects of urea-water solution spray on the heated wall of automotive SCR systems

2018 Asia Conference on Energy and Environment Engineering

能源学;生态环境科学

Shahariar, G.M.H.^1 ; Wardana, M.K.A.^1 ; Lim, O.T.^1

School of Mechanical Engineering, University of Ulsan, Ulsan

680-749, Korea, Republic of^1

关键词: Constant volume chamber;    Desired conditions;    Droplet evaporation;    Droplet size distributions;    Eulerian-Lagrangian approach;    Impingement effect;    Two-layer approach;    User-defined functions;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/133/1/012025/pdf
DOI  :  10.1088/1755-1315/133/1/012025

学科分类：环境科学（综合）

来源: IOP

【 摘 要 】

The post impingement effects of urea-water solution spray on the heated wall of automotive SCR systems was numerically investigated in a constant volume chamber using STAR CCM+ CFD code. The turbulence flow was modelled by realizable k- two-layer model together with standard wall function and all y+ treatment was applied along with two-layer approach. The Eulerian-Lagrangian approach was used for the modelling of multi phase flow. Urea water solution (UWS) was injected onto the heated wall for the wall temperature of 338, 413, 473, 503 & 573 K. Spray development after impinging on the heated wall was visualized and measured. Droplet size distribution and droplet evaporation rates were also measured, which are vital parameters for the system performance but still not well researched. Specially developed user defined functions (UDF) are implemented to simulate the desired conditions and parameters. The investigation reveals that wall temperature has a great impact on spray development after impingement, droplet size distribution and evaporation. Increasing the wall temperature leads to longer spray front projection length, smaller droplet size and faster droplet evaporation which are preconditions for urea crystallization reduction. The numerical model and parameters are validated comparing with experimental data.