Dynamic Bihavior of a Directly Combined Binary Turbine System Using a Mixture (R 134 a/R 123) as a Secondary Medium.

Abstract

Dynamic behavior of a directory combined binary turbine system using a mixture of R 134 a and R 123 is investigated experimentally and theoretically. Our previous binary turbine system, which employs steam as the primary working fluid, used R 11 as the secondary working fluid because R 11 has good characteristics as a working fluid in power plants. However, substitute LBMs (Low Boiling temperature Medium) are being developed because of the ozone layer depletion by CFCs (Chloro Fluoro-Carbons). We investigated the system using R 123 in the second stage. Because R 123 is also controlled, in this paper, the steady state characteristics and dynamic behavior of the system using a mixture of R 134 a and R 123 are investigated taking into account the mole fraction of the mixture. In addition to the investigation using the experimental system, the following are clarified using our model : In the steady-state characteristics, there are remarkable differences in pressure based on the thermodynamic properties and in the load allotment of the two turbines. However, in the dynamic characteristics, the effect of the mole fraction could hardly be observed on the response characteristics of the rotating components to the load change.