Investigation of the Jet Characteristics and Pulse Mechanism of Self-Excited Oscillating Pulsed Jet Nozzle

Abstract

Self-excited oscillation pulse jet technology is widely used to clean sediment from oil storage tanks. Its successful application is dependent on jet performance. As the cleaning requirements of the oil industry increase, it is necessary to optimise the structure of self-excited oscillation pulsed jet nozzles (SOPJNs) to optimise cleaning and energy efficiencies. In this study, the jet performance of a SOPJN is modelled and analysed based on computational fluid dynamics with consideration of a large eddy simulation and homogeneous cavitation. The modelling results are highly consistent with experimental results. The effects of the SOPJN’s inlet diameter, cavity diameter, cavity length, wall reflection angle, and inlet pressure on the jet’s peak velocity, oscillation frequency, and cavitation number were analysed. The results show that the oscillation frequency decreases with the increase of the inlet diameter d1, cavity diameter D, cavity length L and reflection angle of wall α. Optimisation of the SOPJN inlet diameter, cavity length, and wall reflection angle produced a jet with a high peak velocity and strong cavitation. The optimal nozzle cavity diameter strengthens cavitation, while the peak velocity fluctuates as the cavity diameter increases. The peak velocity increases with the inlet pressure, while the increasing rate of the peak velocity decreases. The results of this study can be used in the design and optimisation of similar nozzle structures for improved pulse jet cleaning.

Research Status and Development Trend of High-Pressure Water Jet Nozzle

“…It enhances the effectiveness of the jet by utilizing the strong impact force generated when a bubble ruptures, and solves engineering problems by utilizing the "cavitation effect" caused by bubble collapse. Practice has proved that cavitation jet has better cleaning and cutting effects than ordinary pure water jet under the premise of consistent flow rate and pumping pressure, and has been applied to deep water cutting, nuclear reactor cleaning and aerospace fields [16]. Cavitation nozzles are divided into shear type and oscillating type.…”

Special Issue on “Processing and Conversion of Oil and Gas: Modeling, Control, Simulation and Optimization”

“…Optimizing cleaning performance of reactors seems to be as important as process optimization. Therefore, Zhang et al [9] studied the structure of self-excited oscillation pulsed jet nozzles (SOPJNs) to optimize cleaning and energy efficacies. The jet performance of a SOPJN was investigated and modeled based on computational fluid dynamics considering a large eddy simulation and homogeneous cavitation.…”

Piezoelectric ring-stack actuator design for high-frequency valve

“…The treatment of transient oscillatory choked flow through a nozzle in the literature focuses primarily on rocket propulsion nozzle improvements. 6,7 Literature focuses on low frequencies, while this research will address the gap for transient behavior of high-frequency oscillatory flow. This investigation focuses on determining and controlling oscillatory air flow properties through area variation and examination of a selected fluid's contribution to the choked flow equation.…”

“…In self-excited oscillation pulse jet nozzles, Zhang found a relationship between the increase of the inlet and cavity diameters and increased cavity length resulting in a decrease in oscillation frequency. 6 The study by Bulat also focuses on a self-oscillating process in low-frequency ranges. 7 Speakers are a non-contact method of actuation and researchers applied them as a method of active control for avoiding flutter in fan blades, but the focus here is on a valve application that modulates mass flow.…”