8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Thu 811:10-14:00P7.113Motion and oscillation of interphase meniscus inside anorifice during bubble formationPetr Stanovsky 1 and Marek Ruzicka 11 Institute of Chemical Process Fundamentals ASCR, Rozvojova 135, 16502,Prague 6 - Suchdol, Czech RepublicThe bubble formation at the orifices above a large gas plenum is widely encountered at spargers inthe chemical industry. Despite of a large research in this field there is not a decisive guideline fordesigning these spargers. It’s believed that large scatter of the bubble size produced during normaloperation is due to liquid flow in the vicinity of the sparger [1]. However, recent studies have shownthat subtle phenomenon, what is a motion of interphase meniscus inside the orifice, is responsiblefor the above mentioned scatter [2]. The meniscus motion inside the orifice can be modelled as adamped pendulum which elgibility is clearly shown on the experimentally measured oscillationsof the meniscus position by high-speed camera. The influence of operational parameters (as thechamber volume under plate with the orifice, liquid viscosity, liquid height and orifice length) willbe highlighted in a present study. Other details about experimental setup can be found in previousstudy [2]. The increase of the chamber volume results in the emergence of zones with multiplestates for the bubble size. This corresponds to the multiple states of bubbling period. The increaseof the liquid viscosity, a liquid height and an orifice length is more complex. The surface propertiesof the orifice and the ratio of the orifice diameter to the capillary length have to be considered inexplanation of observed behaviors. The support of Grant Agency of Academy of Sciences ofCR (under grant No. KJB200720901) and also Grant Agency of the Czech Republic (grant No.104/07/1110) is gratefully acknowledged.[1] Kulkarni and Joshi, Ind. Eng. Chem. Res. 44, 5873 (2005).[2] Ruzicka et al. , Chem. Eng. Res. Des. 87, 1349 (2009).113