Numerical Model of Heat Transfer through an Ultraviolet Lamp in a Wastewater Disinfection Reactor

摘要

A computational model has been developed to calculate the rate of heat transfer through an ultraviolet lamp in a wastewater disinfection reactor. The boundary conditions on the lamp surface were accurately applied in the model using a Hermitian method. Non-linear instabilities were controlled by the subgrid scale viscosity using a Smagorinsky model with C{sub}s = 0.10. The computations were conducted using a nonuniform grid to keep the subgrid-scale viscosity on the lamp surface small compared with the molecular viscosity. Boundary layer separation, vortex shedding frequency, and heat transfer rate were in exact agreement with experimental observations using relatively coarse grids of 120×240 and 240×480 for Reynolds numbers Re = 1000 and 4000, respectively.