Ultrasound-Based Diagnostics of Local Regression Rates of Solid Fuel in Ramjet Combustors

This study evaluates the local regression behavior of solid fuel in a ramjet combustor by using an ultrasonic technique.Multiple ultrasonic transducers were employed to measure the regression rate at various axial locations.Combustion experiments were performed in a direct-connect, two-dimensional solid-fuel ramjet combustor with vitiated air supplied by a preheater.The effects of inlet air mass flow rate and temperature on the regression rate were examined.Results indicated that the average regression rate increased with both the air flow rate and temperature.The addition of oxidizer to the solid fuel further enhanced the average regression rate and introduced distinct variations in its spatial distribution.The ultrasonic technique developed in this study will be applied in future work to quantitatively measure the regression rate of three-dimensional annular solid fuels. . . 2 - . . , . . 3 .