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

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1423
Author(s):  
Si Zhang ◽  
Biwei Fu ◽  
Lin Sun
Keyword(s):  
Oscillation Frequency ◽  
Cavity Length ◽  
Peak Velocity ◽  
Inlet Pressure ◽  
Pulsed Jet ◽  
Oil Storage ◽  
Reflection Angle ◽  
Excited Oscillation ◽  
Jet Characteristics ◽  
Pulse Jet

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.

Erosion Experiment of Self-Excited Oscillation Pulsed Jet

2014 ◽  
Vol 937 ◽  
pp. 614-619
Author(s):  
Chuan Lin Tang ◽  
Jie Pei ◽  
Dong Hu ◽  
Xiao Ting He
Keyword(s):  
Significant Influence ◽  
Cavity Length ◽  
Experimental Studies ◽  
The Self ◽  
Erosion Depth ◽  
Pulsed Jet ◽  
Excited Oscillation ◽  
Erosion Effect ◽  
Erosion Volume ◽  
Peak Value

In order to improve the erosion effect of jet under submergence condition, experimental studies of erosion generated from the self-excited pulsed jet was carried out by using developed self-excited oscillation nozzle. The erosion volume and depth of pulsed jet were measured and taking mortar block as an erosion part. The results were that the standoff has significant influence on erosion effect. The erosion volume firstly decreases with increases in cavity length and then increases to a peak value. Erosion volume of pulsed jet is significantly higher than that of continuous jet, the erosion depth of two jet has slight difference.

Experimental Study on Dynamic Characteristics of Self-Excited Oscillation Pulsed Jet

2014 ◽  
Vol 937 ◽  
pp. 624-631 ◽  
Author(s):  
Chuan Lin Tang ◽  
Jie Pei ◽  
Dong Hu
Keyword(s):  
Dynamic Characteristics ◽  
Cavity Length ◽  
Variable Cross Section ◽  
Variable Cross ◽  
Pulsed Jet ◽  
Jet Impact ◽  
Result Show ◽  
Excited Oscillation ◽  
Pump Pressure ◽  
Submerged Conditions

The dynamic characteristics of the self-excited oscillation pulsed jet is tested by using pulsed jet impact variable cross-section beam in submerged conditions and make comparison with continuous jet, analyzing the effects of operating parameters and nozzle structure parameters on the dynamic characteristics of the pulsed jet. The result show that the oscillating frequency of jet decreases with the increase of cavity length while increases with the increase of the pump pressure. The energy of pulsed jet has obvious change with different cavity length.

Study on the Frequency Characteristic of Self-Excited Oscillation Pulsed Water Jet

2011 ◽  
Vol 317-319 ◽  
pp. 1456-1461 ◽  
Author(s):  
Chuan Lin Tang ◽  
Dong Hu ◽  
Feng Hua Zhang
Keyword(s):  
Oscillation Frequency ◽  
Oil And Gas ◽  
Cavity Length ◽  
Water Jet ◽  
Experimental Result ◽  
Pressure Amplitude ◽  
Excited Oscillation ◽  
Pump Pressure ◽  
Pulsed Water Jet ◽  
Peak Value

The self-excited oscillation pulsed water jet (SEOP Jet ) has been used extensively in oil and gas well drilling, mineral mining, cutting and industrial cleaning. In order to improve the valid stand-off distance of water jet pressure and its range of action, the model of oscillation frequency of jet was given on the basis of hydroacoustics and fluid dynamics for better understanding the principle of increasing jet pressure amplitude. The SD150test system was used to analyze the effects of dynamic parameters on the frequency, the effects of pump pressure and the cavity length on the frequency were studied in detail. The test results showed that the peak value of the SEOP Jet is larger by about 20% than that of continuous jet. The oscillation frequency increased while increasing pump pressure and decreased while increasing cavity length. There was an optimum cavity length corresponding to the pressure peak value of the SEOP Jet. Experimental result is in good agreement with that of theoretical analysis.

scholarly journals Research on Resonance Mechanism and Collaborative Optimization of Double-cavity Self-Excited Oscillating Pulse Cavitation Jet Nozzle

2021 ◽  
Author(s):  
xiaoming yuan ◽  
Li Wang ◽  
Weidong Wang ◽  
Lijie Zhang ◽  
Yong Zhu
Keyword(s):  
Flow Field ◽  
Cavity Length ◽  
Nozzle Diameter ◽  
Collaborative Optimization ◽  
The Self ◽  
Inlet Pressure ◽  
Excited Oscillation ◽  
Jet Nozzle ◽  
Oscillation Pulse ◽  
Peak Value

Abstract The peak value and pulsation amplitude of the self-excited oscillating pulse cavitation jet nozzle are important indexes to evaluate the jet performance. It is of great significance in theory and engineering practice to predict the peak value of the self-excited oscillating pulse cavitation jet nozzle accurately. In order to investigate the evolution mechanism of the inner and outer flow field of a double-cavity self-excited oscillation pulse cavitation jet nozzle, a simulation model of the jet impact test of the nozzle was established. Before entrance rounded corners, former cavity cavity diameter, cavity cavity length, before the cavity under the nozzle diameter, cavity, the cavity cavity after entry the rounded, lumen diameter, cavity length and cavity after cavity under the nozzle diameter as design variables, and strike force to combat force peak pulse amplitude as the target variable, the orthogonal experiment method, back propagation neural network combined with non dominated sorting genetic algorithm, The collaborative optimization design method of self-excited oscillating pulse cavitation jet nozzle was determined. Based on the collaborative optimization results, the 3D printing technology was used to manufacture the visualization test model of the flow field of the self-excited oscillating pulse cavitation jet nozzle, and the experimental verification was carried out. The results show that when the inlet pressure is 2MPa, the main and secondary order of the influences of various factors on the jet performance of the nozzle is the nozzle diameter under the front cavity, the diameter of the back cavity, the diameter of the front cavity, the length of the front cavity, the nozzle diameter under the back cavity, the cavity distance, the fillet of the back cavity, the fillet of the front cavity and the length of the back cavity. Compared with the optimal result of orthogonal test, the amplitude of impact pulsation and the peak value of impact force are increased by 14.61% and 2.42% respectively. The optimal structure of the nozzle determined by collaborative optimization can produce obvious pulse cavitation jet, and the cavitation region of the nozzle cavity contracts periodically with time. The higher the inlet pressure, the higher the cavitation intensity and the higher the content of hollow bubble. This study can promote the development of jet performance calculation of self-excited oscillation pulse cavitation jet nozzles, and provide support for the design of self-excited oscillation pulse cavitation jet nozzles.

Simulation and experiment study of the self-excited oscillating mixer with abrasive jet used for the descaling of rusty steel

2019 ◽  
Vol 233 (5) ◽  
pp. 1109-1127 ◽  
Author(s):  
Hui Ji ◽  
Xiurong Cao ◽  
Songlin Nie ◽  
Fanglong Yin
Keyword(s):  
Simulation Experiment ◽  
Inlet Pressure ◽  
Abrasive Water Jet ◽  
Strip Steel ◽  
Chamber Length ◽  
Mixing Chamber ◽  
Excited Oscillation ◽  
Simulation And Experiment ◽  
Jet Characteristics ◽  
Chamber Diameter

A novel self-excited oscillating mixer is developed for the descaling of strip steel, which synthesizes the post-mixed abrasive water jet and self-excited oscillation. The realizable k-ɛ model is selected to investigate the effects of different abrasive entrance, inlet pressure, mixing chamber diameter, and length on the jet characteristics. Meanwhile, the effects of different inlet pressure and target distance on the outlet velocities for two kinds of mixers (including the developed mixer and conventional post-mixing mixer) with or without abrasive jet are investigated through simulation. Experiment as well as simulation results exhibited: (1) The oblique abrasive entrance can accelerate the mixture of water and abrasive due to its larger turbulent kinetic energy, and its outlet velocity is larger than that of radial and axial abrasive entrances. (2) For the developed mixer, the outlet velocity is preferable when the mixing chamber diameter is about 40–50 mm and the mixing chamber length is 20 mm. (3) The descaling efficiency of the developed mixer is superior to that of conventional post-mixing mixer. The research will lay foundation to optimize the structure of self-excited oscillating mixer for the descaling of rusty steel.

scholarly journals Dynamic simulation of the oscillation characteristics of supercritical carbon dioxide impacting jets

2018 ◽  
Vol 25 (1) ◽  
pp. 61-71 ◽  
Author(s):  
Xinwei Zhang ◽  
Yiyu Lu ◽  
Jiren Tang ◽  
Zhe Zhou ◽  
Qian Li
Keyword(s):  
Carbon Dioxide ◽  
Numerical Model ◽  
Supercritical Carbon Dioxide ◽  
Oscillation Frequency ◽  
High Speed ◽  
Rock Breaking ◽  
Target Distance ◽  
Inlet Pressure ◽  
Oscillation Characteristics ◽  
Supercritical Carbon

A numerical model was established to investigate the dynamic oscillation characteristics of supercritical carbon dioxide (sc-CO2) impacting jets. The jet hydrodynamics, heat transfer, and physical properties of sc-CO2 fluid were incorporated into the model. The coupling of multiple fields with large velocity and pressure gradients was achieved using a modified SIMPLE segmentation algorithm. Laboratory experiments validated the reliability of the numerical model by detecting dynamic changes in the pressure on the centerline of the sc-CO2 impacting jet. Analysis of the flow field showed single or double high-speed sc-CO2 mass structures for the sc-CO2 impacting jet, revealing the generation mechanism of the impacting oscillation frequency and the mechanism of improved rock-breaking efficiency by sc-CO2 jet. The oscillation frequency equation was obtained through a quantitative treatment of the velocity and motion area of the sc-CO2 mass. Finally, the equation and simulation results were used to analyze the influences of the target distance, inlet pressure and temperature on the sc-CO2 jet oscillation characteristics. The results showed that the oscillation frequency and amplitude first increased and then decreased with increases in the target distance. The oscillation frequency and amplitude both increased with increasing inlet pressure; the oscillation frequency increased slowly with increasing temperature.

Numerical modelling of percussion water jets driven by multiple collisions

2014 ◽  
Vol 229 (5) ◽  
pp. 976-984
Author(s):  
Zhaohui Lu ◽  
Zongyi Qin ◽  
Michael Hood ◽  
Yiyu Lu ◽  
Dihon Tadic
Keyword(s):  
Numerical Model ◽  
Model Comparison ◽  
Water Jet ◽  
Pulsed Jet ◽  
Water Jets ◽  
Proposed Model ◽  
Comparison Results ◽  
Multiple Collisions ◽  
Pulse Water ◽  
Pulse Jet

A numerical model is proposed in this research to analyse the behaviour of the pulse jet driven by percussion hammer. The mass of the hammer is usually larger than that of the piston and the resistance of compressed water can low down the piston, thus multiple collisions occur each time when the hammer strikes the piston. The proposed model has the merit to consider various striking possibilities to simulate the process of pulse water jet generated by multiple hammer collisions. In addition, a hammer-driven percussion pulse jet is developed and the corresponding experiments are carried out for verifying the reliability of the numerical model. Comparison results show that the predicted pressure and velocity values match well with the experimental data. The simulation of the generation of pulsed jet reveals the collisions and motions of the hammer and the piston and provides understanding of the mechanism of the pulse jet generation. The design of the hammer-driven pulse water jet device can be optimised through modelling different combinations of the parameters of the chamber, hammer, piston and nozzle for a specific purpose of rock fragmentation.

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