Numerical investigation on turbulent oscillatory flow through a jet pump

Area of Science:

• Fluid dynamics
• Acoustics
• Thermodynamics

Background:

• Gedeon streaming is a phenomenon in thermoacoustic engines that can reduce efficiency.
• Jet pumps offer a potential solution for flow control in oscillatory systems.

Purpose of the Study:

• Investigate the flow characteristics and pressure drop induced by an asymmetrical jet pump in turbulent oscillatory flow.
• Analyze the impact of Womersley number and acoustic Reynolds number on jet pump performance.
• Determine the hydrodynamic mechanism behind the jet pump's effect on oscillatory flow.

Main Methods:

• Numerical simulation of turbulent oscillatory flow through an asymmetrical jet pump.
• Analysis of dimensionless governing equations.
• Numerical measurement of steady and oscillatory flow resistance coefficients.

Main Results:

• The jet pump induces a time-averaged pressure drop, suppressing Gedeon streaming.
• Oscillatory flow resistance coefficients are largely insensitive to Womersley number below 46.
• Quasi-static assumption is validated for turbulent oscillatory flow.
• Increased Womersley number beyond 46 reduces the time-averaged pressure drop.

Conclusions:

• Asymmetrical jet pumps are effective in suppressing Gedeon streaming in thermoacoustic engines.
• The Womersley number is a critical parameter influencing jet pump performance in oscillatory flow.
• Numerical simulations provide insight into the hydrodynamic mechanisms governing jet pump behavior in oscillatory flow.