S a g e and D e l t a E for thermoacoustic modeling

Abstract

Two of the most extensively used modeling tools in the thermoacoustics community are Sage and DeltaE. These codes are fundamentally different from each other, with Sage using finite differencing and DeltaE using integration of the wave equation. Generally, there is very good agreement between the two codes, with the exceptions being conventional thermoacoustics stacks, where Sage loses accuracy, and low temperatures, where DeltaE does not include real gas properties. The difference between these codes from the user’s perspective comes down to physical viewpoint and features. DeltaE presents an acoustic picture of the system displaying first-order pressure amplitudes and volume flows, whereas Sage presents physical components, mass flows, and pressures. Both codes model mechanical components such as transducers, mass, and springs. Sage has a click-and-drag graphical user interface, which is advantageous in presenting a picture of the system. DeltaE uses a DOS-based interface, which can be cumbersome to a casual user. A particularly powerful feature of Sage is the optimizer, which does a multivariable search to optimize a user-selected parameter. Both codes converge very rapidly.