Wykorzystanie tarczowych mieszadeł dyspergujących do mieszania zawiesin

W pracy przedstawiono wyniki badań mocy mieszania w mieszalniku bez przegród układów dwufazowych ciecz-ciało stałe, tarczowymi mieszadłami dyspergującymi. Badania prowadzono w odniesieniu do zawiesin o różnym stężeniu cząstek stałych, wykorzystując różniące się wymiarami mieszadła. Na podstawie uzyskanych danych opracowano równania wyrażające krytyczną liczbę Reynoldsa i liczbę Eulera dla mieszania jednorodnych zawiesin.

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In the paper the mixing power measurements of suspensions for dispersing disc agitators are presented. The experiments were carried out in a flat-bottomed vessel with a diameter of 150 mm without baffles. The agitators were equipped with slanting blades on their periphery. The blade's angle of inclination was positive or negative depending on the way in which the agitator on the pin of the driving system was mounted. The measurements were carried out in a glycerine suspension of spherical glass particle with diameter ranging from 600 to 800 ?m and solid phase mass concentration in the range from 0 to 50%. The physical properties of the produced suspensions were calculated according to relations (1) and (2). The influence of the agitator's geometry on mixing power and the conditions regarding formation of suspension in the mixer were examined. The results of the experiments were presented on graphs as power characteristics showing the influence of the Reynolds number and solid concentration of suspensions on the Euler number. It was stated that the agitator's geometry has an influence on the mixing power. The mixing power of the suspensions using an agitator with a negative angle of blade inclination decreases compared to blades with positive inclination angle. On the basis of experimental data the way of determination of critical (minimum) agitator speed was worked out which is shown on Fig. 8. Taking into account the parameters having the influence on the conditions of suspension production the critical Reynolds number was determined which is described by relation (12). On the basis of the general equation (14) detailed form of Euler number was determined which is described by relation (17).