Cavitation field analysis for improving the substrate pre-treatment by ultrasound
Pre-treatment of sludge by ultrasonic systems intends to disintegrate particles for the subsequent anaerobic digestion in a way that an increased biodegradability and consequently,an increased gas production can be obtained.For achieving a positive energy balance of the process,those types of ultrasonic configurations have to be determined,which provide the highest sonication efficiency for sludges of different viscosities,due to an optimal reactor shape and power density.To accomplish this,the formation and propagation of cavitation fields in highly viscous media was investigated and compared with the behaviour of cavitation fields in water.The experiments were carried out with a novel acoustic measuring method for determining the cavitation noise figure.The results indicate that the cavitation intensity is generally lower in highly viscous substrates,but remains at a rather constant level independent of the distance to the transducer plate within the tested ranges (0-200 mm).The limitation of the reaction space to 80 and 43 mm by use of passive reflector plates resulted in a concentration of the ultrasound energy and led to an intense cavitation field even in highly viscous substrates.The cavitation noise figure could thus be increased from 5 to 25 decibels in the used model substrate xanthan.
Anaerobic digestion ultrasound pre-treatment cavitation measurement submersible transducer
Jochen Bandelin Jorg E.Drewes Konrad Koch
Chair of Urban Water Systems Engineering, Technical University of Munich, Am Coulombwall 3, 85748 Garching, Germany
国际会议
The 15th IWA World Conference on Anaerobic Digestion( 第15届IWA世界厌氧大会)
北京
英文
736-739
2017-10-17（万方平台首次上网日期，不代表论文的发表时间）