Effect of photocatalytic surface roughness on reactors effectiveness for indoor air cleaning

Photocatalysis is a promising technique for remediation of indoor air pollution. This study focuses on the enhancement of the effectiveness of the photocatalytic process by the introduction of artificial roughness on the interior reactor surface. Artificial roughness elements on the catalytic surface could enhance the turbulence intensity close to the catalytic surface. The enhanced turbulence intensity would translate to an increased in the mass transfer of airborne contaminants to the catalyst surface, improving the efficiency of photocatalysis. Air flow properties in a model photoreactor channel with transverse rib roughness on the wall are investigated by the “realizable k–epsilon (k–ε)” model. The investigation includes different shapes, sizes, and arrangements of the roughness elements for determining the maximum enhancement of turbulence intensity in the photoreactor channel. The optimum roughness has been determined to be an isosceles triangle shape with the bottom angle (α) equal to 75°, the relative height (e/h) equal to 0.05, and the pitch ratio (p/e) equal to 10. An experimental study was also carried out, which verified that the photocatalytic reactor performance for indoor air cleaning is significantly improved by a roughness pattern on catalyst surface compared to a reactor with a smooth catalyst surface.