title: Numerical study of the effects of surface roughness on water disinfection UV reactor.
abstract: UV reactors are an emerging choice as a big barrier against the pathogens present in drinking water. However, the precise role of reactor's wall roughness for cross flow ultraviolet (CF-UV) and axial flow ultraviolet (AF-UV) water disinfection reactors are unknown. In this paper, the influences of reactor's wall roughness were investigated with a view to identify their role on the performance factors namely dose distribution and reduction equivalent dose (RED). Herein, the relative effects of reactor's wall roughness on the performance of CF-UV and AF-UV reactors were also highlighted. This numerical study is a first step towards the comprehensive analysis of the effects of reactor's wall roughness for UV reactor. A numerical analysis was performed using ANSYS Fluent 15 academic version. The reactor's wall roughness has a significant effect on the RED. We found that the increase in RED is Reynolds number dependent (at lower value of turbulent Reynolds number the effects are remarkable). The effects of reactor's roughness were more pronounced for AF-UV reactor. The simulation results suggest that the study of reactor's wall roughness provides valuable insight to fully understand the effects of reactor's wall roughness and its impact on the flow behavior and other features of CF-UV and AF-UV water disinfection reactors.
authors.affiliation: School of Mechanical Engineering, Hanyang University, Haengdang-dong, Sungdong-gu, Seoul 133-791, Republic of Korea.
authors.forename: Tipu
authors.initials: T
authors.lastname: Sultan
authors.affiliation: Institute for Applied Materials, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany.
authors.forename: Sarfraz
authors.initials: S
authors.lastname: Ahmad
authors.affiliation: School of Mechanical Engineering, Hanyang University, Haengdang-dong, Sungdong-gu, Seoul 133-791, Republic of Korea. Electronic address: jscho@hanyang.ac.kr.
authors.forename: Jinsoo
authors.initials: J
authors.lastname: Cho
mesh_terms: D019149:Bioreactors; D003252:Construction Materials; D004203:Disinfection / Q000379:methods*; D057446:Hydrodynamics; D008962:Models, Theoretical; D013499:Surface Properties; D014466:Ultraviolet Rays; D014873:Water Pollutants / Q000302:isolation & purification; D018508:Water Purification / Q000379:methods*
chemical_list: D014873:Water Pollutants
keywords: Fluence rate; Relative roughness; Reynolds number; UV lamps; UV reactor; Water disinfection