Abstract:

Transient numerical simulations of multi-field coupling involving heat， fluid， solid， and acoustics of regenerative cooling channels in scramjet engines are conducted. The phenomenon of thermoacoustic waves propagating from the solid to the fluid domain， as a result of the rapid heating of combustion chamber walls during ignition of scramjet engines， is examined. The impact of thermoacoustic waves on the extreme values of structural stress and the variation of these waves as they pass through the fluid-structure interface is analyzed. Key parameters such as thermal conductivity， Young’s modulus， density， and thermal expansion coefficient of thermal structure are investigated in terms of their effects on the amplitude and frequency of thermoacoustic waves at the fluid-structure interface. The results show that changes in the Young’s modulus and density of the structure lead to variations in wave speed， affecting the energy propagation speed and significantly influencing the amplitude and frequency of stress and pressure fluctuations at the interface. Altering the thermal conductivity causes variation in the temperature field， thereby affecting the amplitude of stress waves； doubling the thermal conductivity increases the stress peak by 30%， but has almost no effect on the frequency of stress waves and thus has limited impact on the amplitude and frequency of pressure at the interface. Doubling the thermal expansion coefficient increases wall deformation， leading to a doubling of the stress and pressure peaks at the interface， with no significant effect on their frequencies.

Key words: fluid-structure interaction, interfacial wave, supercritical fluid, regenerative cooling, transient analysis