Light intensity profiles in a perfectly mixed photoreactor

Abstract

The light intensity distribution in a perfectly mixed photoreactor has been studied experimentally and analytically. Experimental measurements of intensities within the reactor were made with a specially designed light probe. These data were then used to test the validity of a model which treats the ultraviolet lamp as a linear source radiating in all directions. I t was found that this model, which seems appropriate and allows reasonable computations, is somewhat in error owing to the neglect of the finite size of the lamp and the existence of reflection and refraction effects within the reactor. An empirical correction function was determined for use with the model which then yields predictions in close agreement with experimental data when the reactor is filled with a light absarbing liquid.

Light intensity models for annular UV disinfection reactors

“…The light intensity, I, at any point p in the reactor is related to the surface flux, I,, by a one-dimensional form of Lambert's law of absorption (Jacob and Dranoff, 1966) I d(rI) r dr --El where E is the monochromatic absorbance of water using logarithms to the base e. Integration of Q. 2 using the limit I = I, when r = r, gives Therefore, the average point intensity, 4 within an annular reactor is The integrated result is where m is defined as the intensity factor and represents the ratio of the average point intensity in the reactor to the surface flux a t the quartz tube.…”

Impact of reflection on the fluence rate distribution in a UV reactor with various inner walls as measured using a micro-fluorescent silica detector

“…In addition, a combination of an FR distribution model with a computational fluid dynamics model allows the optimization of the configuration of a UV reactor to achieve higher efficiencies (Sozzi and Taghipour, 2006;Elyasi and Taghipour, 2010a;Chen et al, 2011). Some numerical models have been developed for the determination of the FR distribution in UV reactors including the point source summation (PSS) (Jacob and Dranoff, 1970), line source integration (LSI) (Blatchley, 1997) and extense source with volumetric emission (ESVE) (Irazoqui et al, 1973(Irazoqui et al, , 2000 models. Bolton (2000) developed a model that considered some key factors, such as reflection and refraction of UV at the quartz sleeve and the absorbance of water.…”

Modeling of Gas-Phase Photodegradation of Chloroform and Carbon Tetrachloride

“…Many research groups have contributed to the development of light distribution models that describe the irradiation field inside the homogeneous reactors based on some theoretical assumptions; however, the most frequently used models are the line source spherical emission (LSSE), 8 the diffused line source emission (DLSE), 9,10 and the extense source with volumetric emission model (ESVE). 18,19 It was found in an earlier study that all three models predict quite accurately the irradiance along the radius and no model has apparent advantages over other models.…”

“…In the LSSE model originally proposed by Jacob and Dranoff, 8 it is assumed that the line source (lamp) is divided into infinitely small points, where each point in the line emits radiation in all directions and isotropically. Hence, the irradiance at an arbitrary point A (Figure 1) within the reactor caused by a point source at a distance x from the base of the lamp can be described mathematically by where 2 ϭ r 2 ϩ (z Ϫ x) 2 .…”