Oscillatory flow in jet pumps: Nonlinear effects and minor losses

Abstract

A nonresonant, lumped-element technique is used to investigate the behavior of tapered cylindrical flow constrictions (jet pumps) in the nonlinear oscillatory flow regime. The array of samples studied spans a wide range of inlet curvature radii and taper angles. By measuring the rectified steady pressure component developed across a jet pump as well as the acoustic impedance, the minor loss coefficients for flow into and out of the narrow end of the jet pump are determined. These coefficients are found to be relatively insensitive to all but the smallest curvature radii (i.e., sharp edges). For fixed radius of curvature, the inflow minor loss coefficient increases with increasing taper angle while the outflow coefficient remains relatively constant. For all of the samples, the steady flow minor loss coefficients are also measured and compared to their oscillatory flow counterparts. The agreement is good, confirming the so-called Iguchi hypothesis.

Acoustic coupling between the loudspeaker and the resonator in a standing-wave thermoacoustic device

“…Smith and Swift [16] have studied the effect of the channel curvature effect on the minor losses. Petculescu and Wilen [17] have studied the value of K for jet pumps with different taper angles and curvature radius. More recently Doller [18] has studied the energy losses through a change in a resonator cross-section.…”

“…The acoustic field in the system is given by the solution of acoustic equations (7)- (17), related through the joining conditions (18)-(23), and the electromechanical equation of the loudspeaker (24). The solution consists of finding R C , R B , R A , Z ac , U 0 , A, B, and C in that order, each coefficient depending on the previous one.…”

2-D PIV measurements of oscillatory flow around parallel plates

“…Oscillatory flow through a rapid expansion was also studied by Smith and King (2007), and Smith et al (2005). This is a similar geometry as a jet pump, which was studied by Petculescu and Wilen (2003).…”

The influence of Reynolds numbers on resistance properties of jet pumps

“…Gedeon streaming [3] is the chief component of mass streaming and the minor loss caused by Gedeon streaming can be restricted by the use of elastic membranes or the installment of structural asymmetric device which is normally called a jet pump. Nowadays, lots of research on acoustic streaming has been done [4][5][6][7][8] and minor loss of pressure can be described as [9]:…”