Modeling of thermoacoustic systems using the nonlinear frequency domain method

Area of Science:

• * Physics
• * Acoustics
• * Thermodynamics

Background:

• * Nonlinear effects like time-average mass flows and higher harmonics are crucial in high-amplitude thermoacoustic (TA) devices.
• * Existing models often rely on computationally expensive time integration of nonlinear governing equations.
• * Accurate modeling of TA devices is essential for understanding and optimizing their performance.

Purpose of the Study:

• * To present a novel, fast one-dimensional nonlinear model for thermoacoustic devices.
• * To eliminate the need for computationally intensive time integration by directly solving the periodic steady state.
• * To facilitate the analysis of nonlinear phenomena in TA devices with improved efficiency.

Main Methods:

• * Development of a frequency-domain nonlinear model for TA devices.
• * Direct solution of the periodic steady state, bypassing time-domain integration.
• * Implementation of phase delays for viscous resistance and thermoacoustic heat exchange.

Main Results:

• * The model accurately simulates an experimental standing wave thermoacoustic engine.
• * Results align with both experimental data and established nonlinear time-domain models.
• * Demonstrated significant reduction in computational cost compared to traditional methods.

Conclusions:

• * The developed frequency-domain nonlinear model offers a computationally efficient alternative for TA device analysis.
• * This reduced computational cost enables extensive nonlinear thermoacoustic optimization studies.
• * The model provides a valuable tool for advancing the design and understanding of TA devices.