摘要
为探究循环水养殖水处理系统中紫外发光二极管(Ultraviolet C Light Emitting Diode, UVC-LED)光反应器的合理结构,基于计算流体力学(Computational Fluid Dynamics, CFD)的方法建立了UVC-LED光反应器消毒计算模型,并对该反应器进行了验证与优化。结果表明:该计算模型可以很好的预测反应器的消毒效果,模拟与试验得到的微生物对数灭活率误差在8%以内。通过对整流区圆柱流道的优化可以提升反应器的消毒效果,当反应器具有10个圆柱形流道时,等效还原辐射剂量较之于原反应器提升了19.6%;内壁反射系数的增加对辐射强度的提升具有显著的影响,在高透光率的水环境中表现更为明显。构建了两种不同内壁材料的反应器模型,在紫外光穿透率(Ultraviolet Transmission, UVT)80%、UVT85%和UVT90%透光率下,高反射率模型比低反射率模型的等效生物验证剂量(equivalent Reduction Dose, RED)分别提高了47.74%、55.02%和66.87%。本研究用CFD建模对UVC-LED光反应器进行表征、优化和消毒性能分析,为循环水养殖水处理系统中新型紫外消毒光反应系统设计提供理论参考。
High fish stocking density has posed a huge hidden risk of diseases on sustainable aquaculture with environmentally friendly practices. The ultraviolet(UV) radiation has been widely used to disinfect the surfaces, water body, and air for the water treatment in an ever-increasing Recirculating Aquaculture System(RAS). The current UV light source is commonly applied to a low-pressure mercury lamp with a wavelength of 254 nm, particularly in the disinfection of aquaculture water body during industrialized production. However, the ultraviolet light light-emitting diode(UVC-LED) has been expected to replace the mercury lamp with high energy consumption and easy pollution in recent years. In this study, a disinfection model of UVC-LED photo-reactor was established to optimize the reasonable structure suitable for the circulating water aquaculture system using the computational fluid dynamics(CFD) simulation. The flow field of the reactor was evaluated using the momentum and mass conservation, and the light field distribution in the reactor was obtained using the radiation transfer equation by P1 approximation. Microorganisms were assumed as small particles during water treatment, of which movement in the independence of the flow field. A discrete phase model(DPM) was selected to simulate the flow of microorganisms in water. The residence time of microorganisms in the flow field was first calculated to integrate the radiation intensity within the duration, where the radiation dose was obtained by microorganisms through the reactor. Then, the effective radiation dose of the reactor was optimized using the microbial disinfection response curve from a parallel light test. E. coli was cultured. A microbial killing experiment was carried out in a UVC-LED photoreactor at the flow rates of 2 and 2.5 L/min. The experimental killing rate of the reactor was collected to compare with the calculation. The results show that the calculation model performed well to predict the disinfection effect of the reactor, where the error of logarithmic inactivation rate between simulation and experiment was less than 8%. The rectifying zone was significantly determined the flow field in the reactor.Furthermore, the structure of the rectifying zone was greatly contributed to tailor tailoring the water flow in the reactor for the better disinfection while the high flow of the system. The equivalent reducing radiation dose increased by 19.6% in the reactor with 10 cylindrical flow channels, compared with the original. The emissivity of the opaque surface was adjusted to calculate the radiation under the different inner wall reflection coefficients, both of which followed the Kirchhoff’s law. The inner wall reflection coefficient presented a significant effect on the high radiation intensity, especially in the water environment with a high light transmittance. Two models of the reactor with different inner wall materials were constructed under the ultraviolet Transmission(UVT) 80%, UVT 85%, and UVT 90% transmittance, where the red of high reflectivity model increased by 47.74%, 55.02%, and 66.87% respectively, compared with low reflectivity model. Consequently, the CFD modeling can be expected to characterize and optimize the disinfection performance of the UVC-LED photoreactor. This finding can provide a theoretical reference to design a new UV disinfection photoreaction system in an aquaculture water treatment system.
作者
田晔
肖润国
裴洛伟
叶章颖
朱松明
刘鹰
郭建林
王朔
Tian Ye;Xiao Runguo;Pei Luowei;Ye Zhangying;Zhu Songming;Liu Ying;Guo Jianlin;Wang Shuo(College of Biosystems Engineering and Food Science,Zhejiang University,Hangzhou 310058,China;Zhejiang Institute of Freshwater Fisheries,Huzhou 313001,China)
出处
《农业工程学报》
EI
CAS
CSCD
北大核心
2022年第1期258-265,共8页
Transactions of the Chinese Society of Agricultural Engineering
基金
农业农村部淡水渔业健康养殖重点实验室
浙江省淡水水产遗传育种重点实验室:浙江省淡水水产研究所,开放课题(ZJK202116)
国家重点研发计划项目(2019YFD0900500)
浙江省重点研发计划项目(2021C02024)。
关键词
水产养殖
LED
循环水养殖
消毒反应器
内壁反射系数
CFD
aquaculture
LED
recirculating aquaculture
disinfection reactor
reflection coefficient of inner wall
CFD
作者简介
田晔,研究方向为工程化水产养殖工程及计算流体力学。Email:tianyee163@163.com;通信作者:王朔,博士,助理研究员,研究方向为设施水产养殖水处理技术与装备。Email:sywshuo@zju.edu.cn。
