OPTIMIZATION OF RANKINE CYCLE WITH TWO PUMPS AND TWO-STAGE TURBINE IN COMBINED BRAYTON-RANKINE CYCLE

U ovom radu je prikazana termodinamička analiza kombiniranog Brayton-Rankineovog ciklusa. Opisane su teorijske osnove Braytonovog i Rankineovog ciklusa, svakog zasebno, te kombiniranog Brayton-Rankineovog ciklusa. Izvršena je optimizacija kombiniranog ciklusa s ciljem postizanja maksimalnog stupnja djelovanja. Optimizacija je provedena variranjem tlaka do vrijednosti 24 bara, variranjem maksimalne temperature do 1500°C, izentropskih stupnjeva djelovanja turbina i kompresora te međutlaka kompresora u plinskom ciklusu. Dobiveni podaci i njihov utjecaj na svojstva ciklusa su opisani i grafički prikazani s naglaskom na stupanj djelovanja. Prilikom rada korišten je programski paket Engineering Equation Solver (EES) koji olakšava proračun i omogućava grafički prikaz rezultata.This paper presents the thermodynamic analysis of a combined Brayton-Rankine cycle. Theoretical basis of Brayton and Rankine cycles are described separately and combined together creating a combined gas-steam cycle. The analysis was carried out with the aim of optimizing the process while achieving the maximum thermal efficiency. The optimization was carried out by varying parameters such as the maximum pressure up to 24 bars, the maximum temperature up to 1500°C, the isentropic efficiency of the turbine and compressor, and the pressure between the degrees of compressor in gas cycle, whose impacts on the properties of the cycle are described and graphically depicted, predominantly the influence on the thermal efficiency. During the work, the Engineering Equation Solver (EES) software package was used which facilitates calculations and enables graphical display of the results