Using the Design Environment for Low-amplitude Thermoacoustic Energy Conversion in the Classroom.

Abstract

The Design Environment for Low-amplitude Thermoacoustics Energy Conversion (DeltaEC) is a free software package that is capable of modeling quasi-one-dimensional, multi-domain acoustical networks and includes a 300-page users' guide. The program is a versatile differential equation solver that analyzes a series of "segments" representing ducts, compliances, speakers, etc., that are specified using MKS units. DeltaEC can be a useful pedagogical tool for an introductory course on acoustics in fluids. Examples of its instructional applications include illustration of effective length and quality factor for a Helmholtz resonator and the modes of coupled Helmholtz resonators, as well as standing waves within a resonator of variable cross section and within a catenoidal horn driven by an electrodynamic loudspeaker. Segments representing electrodynamic loudspeakers, radiation loading, and flow resistance in porous media will be used to demonstrate the coupled-oscillatory behavior of a bass-reflex enclosure's complex electrical impedance versus frequency. DeltaEC's plotting features allow immediate visualization of the pressure and velocity fields as well as the power flow or temperature distribution through a network or within a resonator, horn, or waveguide. The "thermo-physical property" feature provides fluid and solid properties at the students' choice of pressure, temperature, and frequency, making it useful as a "handbook" for other assignments.