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„Supercavitation“ A new Aeration Technology Prof. Dr.-Ing. Schmid A. 8 th International Symposium on Cavitation - CAV2012 Singapore. Cavitation induced by hydrodynamic processes. Pressure distribution inside a cavitation-nozzle. Flow direction. Cavitation induction inside a nozzle. - PowerPoint PPT Presentation
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„Supercavitation“
A new Aeration Technology
Prof. Dr.-Ing. Schmid A.
8th International Symposium on Cavitation - CAV2012 Singapore
Cavitation induced by hydrodynamic processes
Flow direction
Pressure distributioninside a
cavitation-nozzle
Cavitation induction inside a nozzle
Low energy input High energy input
Pumpcharacteristic
Pressure P
Flow
-rate
Q
Pulsed cavitation
Supercavitation
Mixed cavitation
Startingcavitation
Bernoulli-limitof cavitation
Flow region without cavitation
0 barabsolute pressure
Limit ofpressure loss
Characteristics of cavitation nozzle
Demonstration of „Supercavitation“
„Supercavitation“-bubble development
Source: University of Minnesota – Twin Cities - USSt. Anthony Falls Laboratory - http://cav.safl.umn.edu/gallery.htm
„Supercavitation“ - sheath
Air-injection pipe
Cavitation nozzle
"Supercavitation"
Air
Aerator principle
Mechanical Aerator – Cav-Jet
1
2 3
4
ROTOX 1
ROTOX 2Cav-Jet
Inlet
Outlet
Experimental setup at WWTP Regnitzlosau
Operational data from WWTP Regnitzlosau
0
500
1000
1500
2000
2500
0
100
200
300
400
500
Pure oxygen consumption [m 3̂/d] Electricity consumption [kWh/d]
20.0
8.20
01
05.0
3.20
02
Pure oxygen consumption [m^3/d]
Ele
ctri
city
con
sum
ptio
n [k
Wh/
d]
ContinuousTesting
Test start
0
500
1000
1500
2000
2500
Oxygen consumption [m^3/d]01.1
0.20
02
20.0
4.20
03
Oxygen consumption [m^3/d]
Test phase of Cav-Jet
Icing problems
Operational data from WWTP Regnitzlosau
Oxygen input at treatment plant
Time
Diss
olve
d ox
ygen
conc
entra
tion
Rotox-Aerator
Cavitation-Aerator
Two-film theory of oxygen transfer – diffusion controlled
Water associates at low temperature
D1
D2
Supercavitation by tangential flow
Thank you very much for your attention
Literature
Schmid A.: New Jet-Aeration System using "Supercavitation" Environmental Science & Pollution Research, 17, 3, 582 - 585, 2010.
Schmid A., Geier W.: Vorrichtung und Verfahren zum Einbringen von gasförmigem und/oder flüssigem Medium in Flüssigmedium. Deutsche Patentschrift DE 103 20 840, 2003.
Schmid A.: Vorrichtung und Verfahren zum Einbringen von gasförmigem und/oder flüssigem Medium in Flüssigmedium. Deutsche Patentschrift DE 10 2004 027 398, 2004.
Flow characteristics
