Reducing Ambient NOx with Environmental Artificial Tree (EAT)*

Ambient nitrogen oxides (NOx) are one of the main ingredients involved in the formation of the ground-level ozone (smog) which causes respiratory illnesses, especially in children and older adults and people with lung diseases, and contributes to global warming and the formation of particulates in the atmosphere. Investigations on the addition of titanium dioxide nanoparticles to the paint (enviro paint)and its potential in reducing ambient NOx concentration have provided opportunities for research and development of methods for passive control and filtration of the ambient NOx

We performed numerical optimization to identify an optimized leaf geometry for the development of an environmental artificial tree (EAT) with enviro paint for a significant reduction in ambient NOx. Optimization was focused on the half-cylinder step sheet. Metamodel of Optimal Prognosis (MOP) feature in ANSYS optiSLang was used to optimize the geometry. Optimization parameters such as the bump length, height, cavity length, and depth were used to generate a geometry with high residency time. The assumption was made that increasing streamwise circulation increases the residence time.  Numerical simulations of the final results at a freestream mean velocity of 1 m/sec. indicated more than 50% increase in recirculation and thus higher residence time as compared with a corresponding result for a flat surface. Details of the optimized parameters along with experimental verifications of the NOx reduction capacity will be provided during the presentation.