High-temperature supersonic combustion testing with optical diagnostics

Abstract

The development of supersonic combustion ramjet (SCRAMJET) engines requires testing using new, nonintrusive, instrumentation methods in high-speed, high-enthalpy flow facilities. The stagnation temperatures for very high flight speeds (in excess of 3000 K) make the production of these flows impossible using conventional methods such as resistance heaters or vitiated flows. Similarly, measurements of properties in these flows is difficult since the measurement must be nonintrusive in nature. This article describes a test series using a shock tunnel to produce Mach 3.0 flows with stagnation temperatures in excess of 3000 K and an optical diagnostic set specifically tailored for measurements in supersonic high temperature systems. The test facility includes a hydrogen injection capability which makes combustion tests possible for these flows. This article describes the shock tunnel and its capabilities, provides an overview of the optical diagnostics used in the testing, and discusses the results of both combusting and noncombusting tests.