NUMERICAL MODELLING OF THERMOACOUSTIC HEAT PUMPS AND PRIME MOVERS WITH NO STACKS AND INTERMITTENT STACKS
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Thermoacoustic systems with no stacks or intermittent stacks represent a promising alternative to conventional stack-based systems. There is theoretical and experimental evidence that such systems can perform more efficiently and produce more acoustic power than thermoacoustic systems with an array of flat plates or regular pores. As opposed to conventional thermoacoustic systems, no-stack setups do not include porous material as a medium for storing and transferring heat. In such systems, heat is transported by gas parcels directly between heat exchangers. A simplified Lagrangian model has been developed in this work to approximately analyze no-stack standing-wave thermoacoustic configurations. More accurate simulations of favorable configurations are investigated with the help of computational fluid dynamics (CFD). Using CFD code FLUENT, more efficient setups were found with the second law efficiency up to 55%. The dependence of system performance is reported for a range of system parameters. A good agreement between the simplified model and CFD results was achieved in most cases. Heat exchangers with finite-thickness plates were additionally investigated in high-performance setups. For porosities below 25%, the thickness effect appeared to be insignificant.In the other part of this study, a reduced-order model was applied for examining a transverse-pin array stack thermoacoustic system. This configuration can be more efficient than conventional stack systems by reducing the heat loss through conduction in the direction of acoustic oscillations and by increasing the contact surface between the working fluid and the solid material. Also, finite heat capacity of the pins was accounted for in this model. Effects of different thermal and geometrical parameters on the performance of the setup were investigated. The numerical model can be used as a tool to optimize such systems.
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Hill, Otto J. (Otto Julius), 1900-1999; Spielman, Arless Asman, 1916-; Wolberg, F. B. (Floyd Byron), 1904- (Pullman, Washington : State College of Washington. Extension Service., 1943-05)
Hodgson, R. E. (Ralph Edward), 1906- (Ralph Edward), 1906-; Knott, J. C. (Joseph Carlton), 1893-; Hill, Otto J. (Otto Julius), 1900-1999 (Pullman, Washington : State College of Washington. Extension Service., 1937-07)
Huber, M. G.; Ewalt, H. P. (Pullman, Washington : State College of Washington. Extension Service., 1953-04)