Performance evaluation of a novel pilot-scale pinned disc rotating generator of hydrodynamic cavitation

Investigation into cavitational intensity and COD reduction performance of the pinned disc reactor with various rotor-stator arrangements

“…Several different cavitator designs have been successfully employed for advanced oxidation of dissolved organic compounds (a review provided in [1] , [6] , [7] ) and disinfection (a review provided in [2] , [8] ) of WW. These include orifice plates [9] , [10] , venturi tubes [10] , [11] , vortex cavitation [12] , and rotating devices [13] , [14] , [15] , [16] , [17] , [18] , [19] , [20] , [21] , [22] , [23] , [24] that will be hereinafter referred to as rotational generators of hydrodynamic cavitation (RGHC).…”

“…This, on the other hand, comes at the expense of a greater complexity of internal geometry and cavitation mechanism as opposed to fixed-geometry cavitators. Several different RGHC designs have been developed in the recent years, including dimpled rotors [14] , [15] , [18] , [19] , [21] , [23] vaned rotor–stator devices [20] , serrated discs [16] , [17] , [25] , [26] , [27] , and pinned discs [22] . Dimpled rotors have been proven effective in sludge solubilization [3] , [15] , destruction of cyanobacteria [18] and in esterification of vegetable oil [23] but are limited by relatively low liquid throughputs and somewhat modest COD removal performance.…”

“…Unlike the RGHC designs discussed above, serrated disc (SD) and pinned disc (PD) variants of rotary cavitating devices are easily scalable, allowing for high wastewater and sludge processing capacity [17] , [22] . The performance of SD RGHC has so far been studied on both lab-scale [25] , [26] , [28] , [29] and pilot-scale [16] , [17] , [27] , [30] with promising results regarding sludge solubilization, fibrillation of conifer fibers, wastewater disinfection and degradation of various dissolved organic compounds (i.e.…”

“…However, the most commonly used SD RGHC design with radial serrations requires a low and uniform rotor–stator clearance for optimal operation [27] and is thus prone to clogging or damage by larger solid particles. To overcome these limitations, Gostiša and co-workers [22] proposed a more robust, novel pinned disc design and evaluated its performance against a SD RGHC of the same rotor size. Results of the study suggest that at the same rotational speed and liquid flow rate, the pinned disc generates more intense cavitation than the serrated disc, while also consuming significantly less energy per liquid pass and per mass of COD removed [22] .…”

Challenges of numerical simulations of cavitation reactors for water treatment – An example of flow simulation inside a cavitating microchannel

“…Different types of cavitation reactors are being promoted by researchers, nowadays. We can generally divide them into i) pump&constriction [3] , [4] , ii) blow through [5] , [6] and iii) rotor–stator type of setups [7] , [8] , [9] . Most of the advanced lab-scale reactors are the pump&constriction type, where the contaminated water (containing bacteria, virus, algae, etc.)…”