Wave Structure of Heterogeneous Detonations in Rotating Detonation Rocket Engines
Abstract
A strong motivation exists to better understand the wave structure of heterogeneous detonations, as rotating detonation rocket engines (RDREs) are best-suited for engine cycles employing gas/liquid propellants. Experimental studies to examine the wave structure of heterogeneous detonations have only been conducted in detonation tubes at base pressures of 1 atmosphere or less, with all of these studies dating back several decades. In this manuscript, we identify key factors that influence the wave dynamics of heterogeneous detonations, and have constructed a simple model to inform the behavior of a droplet in a heterogeneous detonation flowfield. The purpose of this model is do discern trends in the time and length of the reaction zone as droplet size, base pressures, and mixtures are varied. The analysis focuses on the behavior of the droplet, and utilizes an analysis to estimate the rate of mass shed off the droplet based on viscous boundary layer instabilities at the free surface of the gas/liquid interface. The trajectory of the droplet is computed by assuming that it travels through gas medium that matches a ZND profile. It is found that the droplet size and the dynamic pressure induced onto the droplet by the leading shock front are the two most important factors that affect the droplet breakup process. It is found that smaller droplet diameters, higher base pressures, and reactants with lower sound speeds are desired for close coupling of the leading shock front to the heat-release zone. The model results are applied to a gox/kerosene RDRE test with known injector sizing and wavespeed, and it is found that there may be short bursts of discrete, intense heat release followed by substantial periods of little heat release in between adjacent injector elements. The implications of this detonation wave structure are discussed.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 03, 2022
- Accession Number
- AD1208951
Entities
People
- Ariana Martinez
- Stephen D. Heister
Organizations
- Purdue University