Investigation of the total pressure gain in rotating detonation combustors with dilution holes

Abstract

An investigation of the total pressure gain (TPG) in rotating detonation combustors (RDCs) with dilution holes is conducted by the experimental method in this study. The effects of pressure ratios (PR = 4.2–7.2) and equivalence ratios (ER = 0.5–1.5) on the total pressure gain are analyzed in four models, i.e., models A–D, of different throat areas A3.1 and dilution hole area A3.5. When the PR is small, the lowest ER causes the highest TPG, and when the PR is high, the highest ER leads to the highest TPG in Model A. While in models B–D, as ER increases, the TPG increases gradually in all the cases. Comparing the level of TPG between the four models, it is found that the increment of A3.1 and A3.5 results in the enhancement of the TPG. The present study's TPG shows superiority when compared with that of traditional RDC, which indicates that the RDC with dilution holes is more promising for achieving positive TPG in specific configurations. An empirical model considering the throat area A3.1, dilution hole area A3.5, outlet area A8, and heat (released by the fuel combustion) release rate Qv is proposed to better predict the performance of different RDC configurations. Positive total pressure gain is inferred to be promisingly attained at a high A3.1/A8, low A8/A3.5, and a high Qv. Total pressure measured by total pressure rake is verified by comparing with the data calculated by Mach-corrected-static-pressure and mass flow function methods, with relative errors in ±4% and ±15%, respectively.