ANALYSIS OF TEMPERATURE DISTRIBUTIONS IN A GERMICIDAL CHAMBER SUPPORTED BY LIGHT-ILLUMINATED GOLD NANORODS USING CFD-EQUATIONS AND A THERMAL CAMERA

Since the COVID-19 pandemic, protection against pathogenic germs and surface disinfection have become critical issues. Most effective bacteria/virus inactivation methods are either power-consuming or require using caustic chemical substances. Herein, thermal inactivation appears to be an affordable and effective technique as long as high temperatures are reached quickly and long-termly maintained. Therefore, the preparation of a chamber that accomplishes this purpose has been envisioned, designed and manufactured, allowing significant germ inactivation and offering an effective tool for water purification stations. In this regard, this work proposes applying 16-16-65-nm laser-illuminated gold nanorods (AuNRs) as a non-standard heat source, which can produce the generated heat inside a considered volume. Consequently, the locations of AuNRs deposited on glass platforms, stuck on the internal or external chamber's walls, from two sides, were investigated to intensify the heat transfer processes upon the entire chamber. To verify the efficiency of the energy conversion from light to heat, spectroscopy techniques and laser power meters were used. Similarly, temperature fields at the illuminated platforms were solved using the Computational Fluid Dynamics (CFD) equations and two different theoretical models which adopt the Rayleigh approximation and consider the delivered heat flux with a fixed efficiency, respectively. The considered Models were verified using a calibrated and highly-resolved thermal camera. Upon 900-mW 808-nm laser illumination for 50 min, the temperature of the platforms increased by ΔT ≈ 57.1°C and ΔT ≈ 388.3°C for an unfocused and focused beam, respectively. However, the quickest heat diffusion process is visible when the AuNR platform is situated in the internal position of the chamber, offering ΔT ≈ 39.4°C after 50 min of illumination.