Foam breakdown in centrifugal field

The centrifugal technique is extensively used for the destruction of emulsions and for the study of the rate of emulsion separation to disperse phase and disperse medium. 

A detailed study of emulsion behaviour in centrifugal field up to 56000 rpm has been performed by Rehfeld [74], Void and Groot [75-77] and Mittal and Void [78]. It has been shown that emulsions become rapidly polyhedral and their further destruction (the rate of separation of the dispersion medium and coalescence) depends on the concentration and type of both emulsifier and electrolyte, as well as on the acceleration of the centrifugal field. However, the technique applied in [74-78] has certain disadvantages it provides information 

A new experimental technique has been introduced by Kruglyakov et al. [82] and Vilkova and Kruglyakov [83] for the kinetic study of the foam expansion ratio increase and foam column destruction in centrifugal field. It involves increase in the excess pressure in the foam liquid phase and reduction of the time needed to reach high excess pressures. 

2 - lid 3 - inner electrode 4 - conductometer or high resistant voltmeter is the longest distance from the rotation axis l is the distance from the rotation axis to the foam layer surface let is the distance between rotation axis to electrode end. 

By means of sliding contacts the electrodes were connected to high resistance voltmeter V7-16 (4) or to a conductometer. The speed of rotation could be changed from 250 to 5000 rpm. The average experimental foam expansion ratio n0 was calculated from Eq. (4.32). 

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