Jet penetration and particle dispersion behaviors of supersonic gas–solid oxygen jet under high ambient temperature

Abstract

Supersonic gas-powder mixing jets are widely utilized across various industrial processes such as fluidized bed, drug delivery, and steelmaking. In the current study, the impact of high-temperature environment on flow pattern and heat transfer behaviors of supersonic gas-powder flow in the convergent-divergent nozzle are numerically studied via Euler-Lagrangian method. Following validation through experiments, simulations are conducted across diverse conditions, involving four distinct ambient temperatures and powder feeding rates. The results reveal the following insights: (i) Increasing the ambient temperature from 500 K to 1000 K enhances the gas penetration depth and slows down the decay of particle velocity; (ii) The low-temperature gas within the jet core can obtain more energy from external environment via convection and thus expands more sufficiently; (iii) Once the powder mass flow rate surpasses a specific threshold of 8 kg/s, it fundamentally disrupts the supersonic flow structure and causes a large subsonic region downstream of the nozzle exit, substantially diminishing the capacity to accelerate particles; (iv) Increasing the particle feeding rate to 4 kg/s markedly amplifies particle radial dispersion; (v) Increasing the velocity difference between phases enhances both momentum and energy transfer. These findings offer significant insights into the behavior of supersonic gas-powder jets within high-temperature environments, contributing to the understanding of their dynamics and potential applications.