Use of vortex rings for mixing

Experiments on the use of vortex ring transport for the mixing and de-stratification of liquids are described. The experiments were conducted using tube (chimney) type vortex ring mixers in rectangular and cylindrical mixing tanks having capacities of 1,110 L and 2,000 L respectively. The mixing experiments are primarily concerned with the mixing destratification of hot/cold water systems. Also the results of computer modelling of the transport of vortex rings through a stratification layer with Reynolds number of 1352, 4465 and 13520 and Richardson numbers of 0.0093 and 0.091 for a Prandtl number of 7.00 are reported. It is apparent that the penetration of a vortex ring an therefore the mixing or destratification of a liquid system are primarily dependent on the Richardson number and virtually independent of the Reynolds number. Furthermore, mixing energies of the order of 1.0 to 2.0 J/L for complete mixing or energy consumption rates of 0.001 to 0.026 W/L depending on the frequency of operation of the mixer.