Heat transfers in heat exchangers in steady and oscillating flows

Heat exchangers are a key constitutive element in thermoacoustic machines. Although they are required to operate with oscillating gas, their design is mostly guided by direct extrapolation of the knowledge applicable to steady flow heat exchangers, due to the lack of objective criteria for the design of oscillating flow heat exchangers. Most of the works in the literature present theoretical or numerical results, but very few experimental data are available to confirm (or refute) the strong hypothesis leading to the extrapolation. This study presents the comparative measurements of the heat transfers capabilities of triangular louvered fin heat exchangers in steady and oscillating flows under otherwise similar conditions.