Experiments on and development of a flow oscillator for ventilation systems

Abstract

Air conditioning systems have contributed to global warming. To reduce the consumption of fossil fuel and carbon emission, a flow oscillator is suggested to replace air conditioning vanes to facilitate flow mixing in a room. Replacing the active control of air conditioning vanes with a passive control of a flow oscillator will reduce the reliance on mechanics in terms of the movements of the vanes. This report studies the feasibility of implementing the flow oscillator into ventilation systems such as air conditioning systems to improve the mixing efficiency and the possibility of replacing the vanes. By further studying the flow oscillator, parameters that affects the flow oscillator are determined. Non-dimensional analysis is implemented to find the dominant parameters that influence the oscillation frequency. To verify the dimensionless equations obtained from the non-dimensional analysis, numerical simulation is used. The results indicated that for the oscillation in the study, the oscillation frequency increased linearly with the inlet mass flow rate and with differential inlet or outlet pressure. The mass flow rate also increases linearly with the differential pressure. The experiment results verified the numerical trends, but there were discrepancies of up to 40%. The non-dimensional study indicates that dimensionless equations, Strouhal number, and non-dimensional pressure were valid and can be used for geometrical changes in the dimensions. This study indicates that the flow oscillator can potentially be implemented for air conditioning systems in the future. Moving forward, this study can serve as a stepping stone toward the adoption of the flow oscillator into air conditioners to augment the mixing capacity and reduce the energy consumption.