Effect of ambient pressure oscillation on the primary breakup of cylindrical liquid jet spray

Abstract

The present simulation study investigates the effects of ambient pressure oscillation on cylindrical liquid jet sprays, using the volume of fluid method. The research is motivated by combustion instability in combustion engines, where strong harmonic pressure oscillation can damage internal structures. Oscillating pressure modulates not only the fuel mass flow rate but also the ambient gas density and liquid surface tension, and in liquid sprays, the ambient fluid density and surface tension can have substantial effects on spray breakup. In order to investigate the multiple property changes with ambient pressure oscillation, therefore, a new solver in OpenFOAM is developed. In the solver, liquid mass flow rate, ambient gas density, and liquid surface tension change simultaneously as a result of pressure oscillation. Simulations were conducted at a Reynolds number of 2000 and Weber number over 2000, conditions that are conducive to primary breakup in laminar flows. The simulations show that oscillations in ambient pressure significantly strengthen the surface instability of the liquid ligament, which depends on the surface tension–pressure coefficient, the mean pressure, and the amplitude of oscillation.

Effect of High-speed Solenoid Valve Dynamic Characteristics on Downstream Transient Spray Atomization of Bipropellant Thruster

“…(2) Physical model, boundary condition, and fluid properties assumptions In this simulation study, the focus is on comparisons of jet breakup and spray development. Therefore, 2D simulation cases are conducted to describe the macroscopic shape and stabilization of the entire spray field, comparing spray visualization and dimensionless total surface area ratio in different cases [9] . There are two kinds of axial-symmetric domain used for valve-switch flow and injector-spray simulations, respectively as shown in Figure 2 and Figure 3.…”

Effect of Upstream Valve Opening Process on Dynamic Spray Atomization of Bipropellant Thruster Injector

“…Therefore, 2D simulation cases are conducted to describe the macroscopic shape and stabilization process of the entire spray field, comparing spray visualization and dimensionless total surface area ratio in different cases. The wedge mesh has been proven to be capable of expressing radial dimensional properties [16], as shown in Figure 1.…”

“…Therefore, 2D simulation cases are conducted to describe the macroscopic shape and stabilization process of the entire spray field, comparing spray visualization and dimensionless total surface area ratio in different cases. The wedge mesh has been proven to be capable of expressing radial dimensional properties [16], as shown in Figure 1. There are two kinds of axial-symmetric domain used for valve-opening flow at upstream and injector-spray simulations at downstream, respectively, as shown in Figures 2 and 3.…”

Numerical simulation of jet break‐up using the local front reconstruction method

“…Moallemi et al 22 investigated the response of a water jet under different disturbances using a 3D VOF model in combination with the Adaptive Mesh Refinement. Zhang and hyuk Shin 23 studied the effect of an ambient pressure oscillation on cylindrical liquid jet break‐up using a 2D VOF formulation which showed a relevant impact of the pressure changes in the formation of ligaments and droplets.…”