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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2019, Vol. 40 ›› Issue (6): 122783-122783.doi: 10.7527/S1000-6893.2019.22783

• Fluid Mechanics and Flight Mechanics • Previous Articles     Next Articles

Direct numerical simulation of impinging jet with non-Newtonian shear thinning properties at high ambient pressure

ZHU Chengxiang, ZHENG Haoming, YOU Yancheng   

  1. School of Aerospace Engineering, Xiamen University, Xiamen 361005, China
  • Received:2018-11-07 Revised:2018-12-06 Online:2019-06-15 Published:2019-02-26
  • Supported by:
    National Natural Science Foundation of China (51606161); Fundamental Research Funds for the Central Universities (20720170055); Natural Science Foundation of Fujian Province (2016J06011)

Abstract: Impinging liquid jets have been widely used in liquid rocket propulsion systems as a fuel atomization method. The breakup efficiency of impinging liquid jets directly determines the mixing and combustion efficiency of the fuel. The present work applies a Direct Numerical Simulation (DNS) tool to study the three-dimensional unsteady impinging jet breakup with non-Newtonian shear thinning properties at high ambient pressure 10 MPa, including the three-dimensional structure, breakup mechanism, and non-Newtonian feature of the liquid. The results indicate that the impinging jet breakup exhibits a radial circular flow structure and forms a Mushroom head and an Ω shape local protruding. The distribution of gas vorticity is split into two categories that include the regulated attached region and irregular blasting region. The breakup from liquid sheet to ligament is determined by the average air force and viscous force, whereas the breakup from ligament to droplet is determined by local flow parameters. The dimensionless liquid surface area increases with time and can be divided into five phases. Additionally, the non-dimensional viscosity of the liquid at the impinging jet head decreases to only 0.7 due to high local shear stresses.

Key words: impinging jets, non-Newtonian fluid, high pressure environment, direct numerical simulation (DNS), shear thinning

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