Experimental Investigations on a Standing-Wave Thermoacoustic Engine

Mahmoud Emam
2013 Figshare  
Thermoacoustic engine is one of the emerging technologies in the field of energy conversion. Thermoacoustic engines convert thermal energy, possibly at relatively low temperatures to mechanical energy in the form of acoustic oscillations of high amplitudes that can drive a thermoacoustic refrigerator or can be converted to electrical energy using a linear alternator. In this work, a prototype of a thermoacoustic engine was built, operated and tested. Sustainable operation of the engine is
more » ... le due to the relatively efficient hot and cold heat exchangers that were able to sustain the temperature gradient across the stack. Both the transient and steady-state performance of the thermoacoustic engine are investigated using variable gas mixtures and using square-cell stacks of variable porosities. The engine performance is studied during full runs consisting of start-up, steady operation, and shutting-down. The steady-state engine performance and wave characteristics are investigated at different heat input values, different gas mixtures, and different stack porosities. Inserts with different patterns and open areas are used inside the resonator to investigate their effect on suppressing the high harmonics of the produced acoustic wave. A numerical model of the current prototype is built using the free simulation software DELTAEC. The model is validated using the experimental data and is then used to obtain more information about the engine performance. Results show that the used gas mixture, the pressure ratio, and the stack cell dimensions significantly affect the engine power output, the wave dynamic pressure amplitude, and the harmonic content of the wave. Experimental data agrees with DELTAEC calculations in trend, but the values of acoustic power and dynamic pressure are significantly lower than the numerical model calculations. The values of the frequency are within 3% of the measured values. The transient analysis shows that the dynamic pressure amplitude of the gas reaches a peak after on [...]
doi:10.6084/m9.figshare.765445 fatcat:dlxmpjstcvgknf2xh3aho4dhsy