Computational Investigation on the formation of liquid-fueled oblique detonation waves

TL;DR

This study uses computational simulations to explore how liquid-fueled oblique detonation waves form in high-altitude, high-speed conditions, revealing the importance of vapor content and structural features in their development.

Contribution

It demonstrates the effects of vapor proportion and on-wedge strips on ODW formation using advanced flow modeling, providing new insights into liquid-fueled detonation dynamics.

Findings

Higher vapor content promotes ODW formation.

On-wedge strips induce bow shocks that facilitate ODW.

Pure droplet conditions prevent ODW formation.

Abstract

Utilizing a two-phase supersonic chemically reacting flow solver with the Eulerian-Lagrangian method implemented in OpenFOAM, this study computationally investigates the formation of liquid-fueled oblique detonation waves (ODWs) within a pre-injection oblique detonation wave engine operating at an altitude of 30 km and a velocity of Mach 9. The inflow undergoes two-stage compression, followed by uniform mixing with randomly distributed n-heptane droplets before entering the combustor. The study examines the effects of droplet breakup models, gas-liquid ratios, and on-wedge strips on the ODW formation. Results indicate that under the pure-droplet condition, the ODW fails to form within the combustor, irrespective of the breakup models used. However, increasing the proportion of n-heptane vapor in the fuel/air mixture facilitates the ODW formation, because the n-heptane vapor rapidly participates in the gaseous reactions, producing heat and accelerating the transition from low- to intermediate-temperature chemistry. Additionally, the presence of on-wedge strips enhances ODW formation by inducing a bow shock wave within the combustor, which significantly increases the temperature, directly triggering intermediate-temperature chemistry and subsequent heat-release reactions, thereby facilitating the formation of ODW.