Numerical Simulation Study Of Transverse Jet Primary Atomization Under Low Liquid To Gas Density Ratio

In this paper,based on the turbulence-induced primary atomization mechanism in the hybrid Euler-Lagrange framework,the transverse jet primary atomization process,which is affected by both liquid turbulence and aerodynamics,is split into two processes:the turbulence-induced primary atomization process and the aerodynamic correction process,and the newly developed primary atomization model is implanted into the OpenFOAM computational fluid dynamics platform to study low liquid-to-gas density ratio transverse jet atomization and transverse jet atomization under high-frequency sinusoidal pulse excitation.The specific works are as follows:(1)The simulation of transverse jet atomization with liquid-to-gas density ratio of 312 is carried out,where the primary atomization is affected by liquid turbulence and aerodynamics at the same time.The droplet diameter and velocity distribution predicted by the new model are generally in agreement with the experimental results.And the maximum average error of D32 and D10 at 20 mm downstream of the nozzle predicted by the model is 10.3%.Three different k-0mega SST based turbulence model is used in the simulation.The result shows that the DES and VLES turbulence models are able to capture the transient small-scale vortex structure of the flow field compared to the RANS model.In general,the VLES turbulence model outperforms the DES turbulence model in respect of droplet velocity distribution and droplet size distribution prediction.(2)Simulations are performed for different atomization breaking point height coefficients Cb.Simulation found that for a nozzle with length to diameter ratio of 10,Cb of 3.3 is the most reasonable choice.In addition,the influence of KH-RT,Reitz-Diwakar and TAB secondary fragmentation models on the atomization results is studied,and it is found that when there is no clear secondary atomization phenomenon in the computational domain,the secondary atomization model should not be used.(3)The simulation of transverse jet atomization under high-frequency pulsation of the jet is carried out.The results showed that under high-frequency sinusoidal pulsation,with the rise of the jet pulsation amplitude,the jet penetration depth enhanced,the main drop velocity gradually raised and the drop diameter reduced.The Sr number increases from 0.25 to 1.0 with the rise of pulsation frequency,when the Sr number is less than or equal to 0.75,the jet penetration depth gradually enhanced,the main droplet velocity decreases and the droplet diameter becomes smaller,and when the Sr number is greater than 0.75,the jet penetration depth decreases,the main droplet velocity increases and the droplet diameter becomes larger.