title: On the performance and flow characteristics of jet pumps with multiple orifices.
abstract: The design of compact thermoacoustic devices requires compact jet pump geometries, which can be realized by employing jet pumps with multiple orifices. The oscillatory flow through the orifice(s) of a jet pump generates asymmetric hydrodynamic end effects, which result in a time-averaged pressure drop that can counteract Gedeon streaming in traveling wave thermoacoustic devices. In this study, the performance of jet pumps having 1-16 orifices is characterized experimentally in terms of the time-averaged pressure drop and acoustic power dissipation. Upon increasing the number of orifices, a significant decay in the jet pump performance is observed. Further analysis shows a relation between this performance decay and the diameter of the individual holes. Possible causes of this phenomenon are discussed. Flow visualization is used to study the differences in vortex ring interaction from adjacent jet pump orifices. The mutual orifice spacing is varied and the corresponding jet pump performance is measured. The orifice spacing is shown to have less effect on the jet pump performance compared to increasing the number of orifices.
authors.affiliation: Department of Thermal Engineering, University of Twente, Enschede, The Netherlands.
authors.forename: Joris P
authors.initials: JP
authors.lastname: Oosterhuis
authors.affiliation: Department of Thermal Engineering, University of Twente, Enschede, The Netherlands.
authors.forename: Michael A G
authors.initials: MA
authors.lastname: Timmer
authors.affiliation: Department of Thermal Engineering, University of Twente, Enschede, The Netherlands.
authors.forename: Simon
authors.initials: S
authors.lastname: Bühler
authors.affiliation: Department of Thermal Engineering, University of Twente, Enschede, The Netherlands.
authors.forename: Theo H
authors.initials: TH
authors.lastname: van der Meer
authors.affiliation: Chart Inc., Troy, New York 12180, USA.
authors.forename: Douglas
authors.initials: D
authors.lastname: Wilcox