Design of an Additively Manufactured Chamber for Combustion Health Monitoring in Air-Breathing Rotating Detonation Flows

Additively manufactured, water-cooled test hardware was designed for combustion health monitoring, thermochemical performance assessment, and passive calorimetry analysis in an air-breathing rotating detonation engine architecture. The water-cooled chamber hardware was designed for extended-length hot-fire testing and additive-manufacture from stainless steel 316L at The University of Texas at San Antonio (UTSA). The hardware was developed with the specific aim of enabling discrete optical access locations for quantitative thermochemical measurements via mid-wave infrared (mid-IR) laser absorption spectroscopy (LAS) and other emission-based methods. The large-port, steady-state access also facilitates gas sampling probe installation in addition to standard RDE evaluation instrumentation, such as capillary tube attenuated pressure (CTAP) and infinite tube pressure (ITP) measurements. The design leverages additive manufacturing to enable coolant channels to "snake" around sensor ports while minimizing exposed hot-gas wall surface area, which enables heavy instrumentation of the monolithic, axially cooled chamber without compromising coolant flow for traditional subtractive manufacturability. Conjugate heat transfer analyses (CHT) were performed to predict the temperatures within the combustor wall at worst-case 3 MW/m^2 steady-state heat flux conditions—for a given coolant flow rate—to assess the impact of each type of coolant snake on the hot wall and overall hardware survivability. The chamber developed in this work will enable new quantitative insights into extended-length detonative processes, which offers access to uniquely explore how transient trends, mode-switching/mode-locked behavior, and thermochemistry coalesce toward heat transfer model development.