DESIGN AND BUILDING OF A SETUP FOR THE EXPERIMENTAL RESEARCH OF FINE BUBBLE GENERATORS Nicolae BĂRAN, Alexandru Sorin PĂTULEA, Ionela Mihaela CĂLUŞARU POLITEHNICA UNIVERSITY OF BUCHAREST, FACULTY OF MECHANICAL AND MECHATRONICS ENGINEERING, Bucharest, Romania
Abstract. The paper presents two types of fine bubble generators with the same number of nozzles, but differently placed. These two types of generators will be used in order to experimentally research the efficiency of the water oxygenation process; an experimental setup was designed and built; the setup is endowed with modern instruments: oxygen meter, manometer, thermometer, all of them having digital display. The results of the experimental measurements will indicate the most favorable generator architecture from the point of view of the increase of concentration of oxygen dissolved in water. Keywords: oxygen meter, fine bubble generator, oxygen dissolved in water Rezumat. În lucrare se prezintă două tipuri de generatoare de bule fine care au acelaşi număr de orificii dar amplasate în mod diferit. Cu ajutorul acestora se va cerceta experimental eficienţa procesului de oxigenare a apei; s-a conceput şi construit un ştand experimental prevăzut cu aparate moderne: oxigenometru, manometru, termometru, toate cu afişare digitală. Rezultatele măsurărilor experimentale vor indica care dintre cele două generatoare are o arhitectură mai favorabilă, privind creşterea concentraţiei de oxigen dizolvat în apă. Cuvinte cheie: oxigenometru, generator de bule fine, oxigen dizolvat în apă.
1. INTRODUCTION Oxygenation, named in also aeration in specialty literature  , constitutes the main operation that assures a proper quality of water in water treatment and purification processes. Water oxygenation is a process of mass transfer (O2 → H2O) largely applied in the following areas: – water treatment processes; – biological purification of wastewater; – separation and catchment of greases from wastewater. In hydrodynamics of gas-liquid biphase systems, the dispersed phase is represented by air bubbles (21% O2, 71% N2) generated by aeration systems and the continuous phase is represented by the liquid (clean water or wastewater). The oxygenation machines are based on the dispersion of a phase into the other one (gas → liquid), an energy consuming process. Nowadays there are numerous aeration technologies using bubble generators which can be classified as follows with respect to the constructive solution : 1) Pneumatic oxygenation equipment with porous diffusers; 84
2) Surface, medium or high depth mechanical equipment with rotor and brush; 3) Mixed oxygenation equipment. The diffusion of oxygen in water is the most important factor to be considered in the conception and design stage of water oxygenation machines. These machines must assure the transfer of oxygen towards water with a minimum energy consumption. With this object, porous diffusers made form ceramic materials, plastic etc. are actually used. The modern machines that assure the dispersion of air in tanks or basins are called fine bubble generators. Fine bubble generators (FBG) have to assure a uniform spreading of air in the whole mass of water. The finer and more uniform spread air bubbles, the more efficient the mass transfer from gas to liquid  . According to the dimension of air bubbles that intrude in the water mass, the bubble generators are divided in : 1) Fine bubble generators with the bubble diameter less than 1 mm; 2) Fine bubble generators with the bubble diameter in the range of 1 3 mm; 3) Fine bubble generators with the bubble diameter superior to 3 120 mm. TERMOTEHNICA 2/2011
DESIGN AND BUILDING OF A SETUP FOR THE EXPERIMENTAL RESEARCH
Compared to the porous diffusers manufactured from syntherised glass or other materials, the new type of fine bubble generator presented in this paper assures a uniform and accurate spreading of air bubbles, that leads to the increase of the...
References:  Robescu D. a.o., Reliability of processes and plants for water treatment and purification (in Romanian), Technical Publishing House, Bucharest, 2002.  OprinaG., Pincovschi I., Băran Gh., Hydro-gas-dynamics of aeration systems equipped with fine bubble generators (in Romanian), Politehnica Press, Bucharest, 2009.  Băran Gh, Băran N., Hydrodynamics of bubbles generated by porous diffusers (in Romanian), Romanian Review of Chemistry, vol. 54 , no.5 , pp.436-440, 2003.  Mateescu G., Băran N., Besnea D., Use of non-conventional technologies for the manufacturing of some water oxygenation devices, JOURNAL OF ENGINEERING STUDIES AND RESEARCH, Volume 16, No.3, pp.65-70, ISSN 2068-7559, 2010.  Donţu O., Manufacturing technologies and systems used in mechatronics (in Romanian), Printech Publishing House, Bucharest, 2003.  Mateescu G, Hydro-gas-dynamics of fine bubble generators (in Romanian), PhD Thesis, POLITEHNICA University of Bucharest, Faculty of Mechanical Engineering and Mechatronics, 2011.  Băran N., Băran Gh., Mateescu G., Research Regarding a New Type of Fine Bubble Generator, Romanian Review of Chemistry, vol. 61, no. 2, pp.196-199, ISSN 0034-7752, 2010.  Oprina G., Contributions of the hydro-gas-dynamics of porous diffusers (in Romanian), PhD Thesis, POLITEHNICA University of Bucharest, 2007.  Băran N., Pătulea Al., Băran Gh., Experimental researches regarding the obtaining of curtains of fine air bubbles, Proceedings of the 6th Conference of Hydro Energy Specialists of Romania, 27-28 May, pp. 23-32, Bucharest, 2010.  Băran N., Zaid A., Pătulea Al., Researches regarding the increase of the dissolved oxygen concentration in function of the duration of the water oxygenation process, TERMOTEHNICA, No.2, pp. 15-18, ISSN 1222-4057, 2010.  Băran N., Besnea D., Duminică D., Avarvarei I., Pătulea Al., Mechanism for the displacement of an oxygen meter probe in stationary waters, Procedings 3dr International Conference on Electronics Computer Technology (ICECT 2011), Kanyakumari, India, April 8-10 2011.
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