Experimental Determination of Thermal Loads on a Supersonic Exhaust Diffuser

We present the results of an experimental investigation into heat transfer within the flow duct of a gas-dynamic tunnel during tests with solid-fuel combustion products containing a minor fraction of condensed particles. Static pressure and heat flux density distributions along the duct are measured using an array of 29 heat flux sensors and 25 pressure transducers. The design of the heat flux sensors and key aspects of their implementation are described. Suitable scaling parameters for nondimensionalizing the experimental data are proposed. Based on the processed and compiled heat flux and pressure distributions, a conceptual model is developed to describe the flow processes inside the supersonic diffuser channel. The primary factors governing the thermal loads on the diffuser structure are identified.