Relationship of Lagrangian microscopic energy efficiency of a gas parcel in a thermoacoustic engine to macroscopic one

As suggested by much smaller microscopic Carnot efficiency of a transversely oscillating gas-parcel in a thermoacoustic engine than macroscopic Carnot efficiency of the whole stack, the Lagrangian microscopic energy efficiency of a gas parcel is different from the macroscopic energy efficiency of the whole stack. The relationship of the former to the latter is theoretically discussed. Furthermore, it is numerically shown that the microscopic energy efficiency in a wet stack is considerably lower than that in a dry stack due to both heat loss by latent heat of water evaporation and more heat influx associated with evaporation.

Automated summary

The microscopic energy efficiency of a gas parcel in a thermoacoustic engine is different from the macroscopic energy efficiency of the whole stack, and the efficiency is considerably lower in a wet stack compared to a dry stack due to heat loss by water evaporation and increased heat influx.