Some aspects of production of gas-liquid bubble systems with very smal
l bubbles (microbubble medium) are discussed. Using photographic measu
rements and dispersed analysis, parameters of a microbubble medium are
determined (bubble mean diameter approximate to 40 mu m). Results of
simple hydrodynamic experiments with this medium are described. Measur
ements of the drag coefficient of a solid ball in the microbubble medi
um were performed at Reynolds number from 0.1 up to 2.2 x 10(4) and wi
th gas void fraction less than 2.5%. Flow of the microbubble medium in
horizontal tubes was investigated under conditions in which the air f
raction and the Reynolds number were between 0.0% and 0.7%, and betwee
n 10(3) and 2.5 x 10(4), respectively.