Event № 206
Thermoacoustics is a highly promising technology for the upcoming decades. Based on the heat transfer between a temperature gradient stack and an oscillating acoustic wave, it is expected to replace current heat pumps or heat engines, such as solar panels or air conditioners, due to its improved efficiency compared to conventional methods. However, it is yet a young research topic with many improvements and tests to come. One of the most recent improvements is the addition of a reactive component to the inert media as it creates a coating layer over the stack pore's walls and forms an additional concentration gradient as a result of its phase-exchange interaction with the active component, encouraging the oscillating amplitudes for a more desirable performance and efficiency. This thesis develops the mathematical non-dimensional approach established by the physical parameters of the system building it from the conservation of momentum, concentration and energy equations applying the required boundary conditions to solve for the velocity, concentration and temperature fluctuations, respectively. Then plugging the results into the continuity equation in order to arrive to the wave equation, which describes the pressure fluctuations along the stack. At this point, it is possible to find the acoustic work flux, which determines the efficiency of the system based on all the physical parameters involved. The results evaluation is focused on the analysis of limiting cases and approximations, such as the inviscid limit or the boundary layer approximation, and their theoretic impact on the performance. Finally, the required setup for a concentration and a temperature gradient onset is found independently in the pursuit of triggering an instable oscillation.