This work discusses the combination of two thermodynamic cycles seeking to improve the overall chemical energy conversion rate into mechanical energy. Here one engine operates according a Rankine cycle in order to use...This work discusses the combination of two thermodynamic cycles seeking to improve the overall chemical energy conversion rate into mechanical energy. Here one engine operates according a Rankine cycle in order to use part of the thermal energy released to the boundary, i.e., the neighboring atmosphere. The analysis of this combined cycle shows that it might, under proper condition, represent a gain of 1.2% in the overall delivered engine power.展开更多
The analysis and the design of turbojet engines are of great importance to the improvement of the system performance.Many researchers focus on these topics,and many important and interesting results have been obtained...The analysis and the design of turbojet engines are of great importance to the improvement of the system performance.Many researchers focus on these topics,and many important and interesting results have been obtained.In this paper,the thermodynamic cycle in a turbojet engine is analyzed with the entransy theory and the T-Q diagram.The ideal thermodynamic cycle in which there is no inner irreversibility is analyzed,as well as the influences from some inner irreversible factors,such as the heat transfer process,the change of the component of the working fluid and the viscosity of the working fluid.For the discussed cases,it is shown that larger entransy loss rate always results in larger output power,while smaller entropy generation rate does not always.The corresponding T-Q diagrams are also presented,with which the change tendencies of the entransy loss rate and the output power can be shown very intuitively.It is shown that the entransy theory is applicable for analyzing the inner irreversible thermodynamic cycles discussed in this paper.Compared with the concept of entropy generation,the concept of entransy loss and the corresponding T-Q diagram are more suitable for describing the change of the output power of the analyzed turbojet engine no matter if the inner irreversible factors are considered.展开更多
文摘This work discusses the combination of two thermodynamic cycles seeking to improve the overall chemical energy conversion rate into mechanical energy. Here one engine operates according a Rankine cycle in order to use part of the thermal energy released to the boundary, i.e., the neighboring atmosphere. The analysis of this combined cycle shows that it might, under proper condition, represent a gain of 1.2% in the overall delivered engine power.
基金supported by the National Natural Science Foundation of China(Grant Nos.51376101&51356001)
文摘The analysis and the design of turbojet engines are of great importance to the improvement of the system performance.Many researchers focus on these topics,and many important and interesting results have been obtained.In this paper,the thermodynamic cycle in a turbojet engine is analyzed with the entransy theory and the T-Q diagram.The ideal thermodynamic cycle in which there is no inner irreversibility is analyzed,as well as the influences from some inner irreversible factors,such as the heat transfer process,the change of the component of the working fluid and the viscosity of the working fluid.For the discussed cases,it is shown that larger entransy loss rate always results in larger output power,while smaller entropy generation rate does not always.The corresponding T-Q diagrams are also presented,with which the change tendencies of the entransy loss rate and the output power can be shown very intuitively.It is shown that the entransy theory is applicable for analyzing the inner irreversible thermodynamic cycles discussed in this paper.Compared with the concept of entropy generation,the concept of entransy loss and the corresponding T-Q diagram are more suitable for describing the change of the output power of the analyzed turbojet engine no matter if the inner irreversible factors are considered.
