A numerical study of a standing-wave thermoacoustic engine is presented. The aim of this work is to study the effect of increasing the heat exchangers length on the acoustic power. The analysis of the flow and the pre...A numerical study of a standing-wave thermoacoustic engine is presented. The aim of this work is to study the effect of increasing the heat exchangers length on the acoustic power. The analysis of the flow and the prediction of the heat transfer are performed by solving the non linear unsteady Navier-Stocks equations using the finite volume method implemented in -ANSYS CFX- CFD code. The results show an increase in the limit cycle acoustic pressure and power as well as the specific work per cycle with the increase of heat exchangers length.展开更多
A numerical study based on direct thermal to electric energy conversion was performed in a reciprocal flow porous media burner embedded with two layers of thermoelements. The burner lean combustibility limit was sough...A numerical study based on direct thermal to electric energy conversion was performed in a reciprocal flow porous media burner embedded with two layers of thermoelements. The burner lean combustibility limit was sought in order to maximize global efficiency of thermal to electrical energy conversion by minimizing fuel consumption. Once the pairs of operational variables, composition and filtrational velocity of gas inlet mixture were found, the optimal length and placement of thermoelectric elements within the reactor high thermal gradients were sought to maximize the electric current, thermoelements and system overall efficiency. A two temperature-resistance model for finite time thermodynamics was developed for the thermoelectric elements energy fluxes. Results indicate a distribution of current and efficiencies that presents a maximum at different themoelements length. Maximum values for current and system efficiency obtained were 44.3 m A and 2.5%, respectively.展开更多
文摘A numerical study of a standing-wave thermoacoustic engine is presented. The aim of this work is to study the effect of increasing the heat exchangers length on the acoustic power. The analysis of the flow and the prediction of the heat transfer are performed by solving the non linear unsteady Navier-Stocks equations using the finite volume method implemented in -ANSYS CFX- CFD code. The results show an increase in the limit cycle acoustic pressure and power as well as the specific work per cycle with the increase of heat exchangers length.
文摘A numerical study based on direct thermal to electric energy conversion was performed in a reciprocal flow porous media burner embedded with two layers of thermoelements. The burner lean combustibility limit was sought in order to maximize global efficiency of thermal to electrical energy conversion by minimizing fuel consumption. Once the pairs of operational variables, composition and filtrational velocity of gas inlet mixture were found, the optimal length and placement of thermoelectric elements within the reactor high thermal gradients were sought to maximize the electric current, thermoelements and system overall efficiency. A two temperature-resistance model for finite time thermodynamics was developed for the thermoelectric elements energy fluxes. Results indicate a distribution of current and efficiencies that presents a maximum at different themoelements length. Maximum values for current and system efficiency obtained were 44.3 m A and 2.5%, respectively.
