Optimizacija kombiniranog Brayton-Rankineova ciklusa s obzirom na ukupni termički stupanj djelovanja

master's thesis

• Title (english): Optimization of combined Bryton-Rnakine cycle with respect to total thermal efficiency
• Author: Martina Rauch
• Mentor: Antun Galović (mentor)
• Mentor: Zdravko Virag (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2014-12-05, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U radu je matematički modeliran kombinirani Brayton – Rankineov ciklus koji se sastoji od sljedećih komponenata: kompresora, komore izgaranja, plinske turbine, generatora pare na otpadnu toplinu, parne turbine, kondenzatora te pumpe. Definiran je model kombiniranog ciklusa s 13 karakterističnih točaka na ulazima, odnosno izlazima iz komponenata sustava. Za svaku točku dane su pripadajuća temperatura, tlak, entalpija i entropija. Iz zakona očuvanja energije izračunati su izmjenjeni toplinski tokovi i neto dobivene snage u sustavu, te termodinamički (termički) stupnjevi djelovanja pojedinačno plinskog i parnog ciklusa te ukupni termodinamički stupanj djelovanja kombiniranog ciklusa. U programskom paketu Matlab razvijen je odgovarajući numerički postupak za određivanje maksimalnog termodinamičkog stupnja djelovanja kombiniranog ciklusa uz zadana ograničenja: temperature dimnih plinova na ulazu u plinsku turbinu te temperature kondenzacije vodene pare u parnom dijelu ciklusa (kondenzatoru). Za svaki promatrani slučaj iznađene su radne točke kombiniranog procesa pri kojima se postiže taj traženi maksimalni termodinamički stupanj djelovanja. Zaključeno je da se kombiniranim ciklusom povećava ukupno dobivena snaga i ukupni termodinamički stupanj djelovanja procesa. Za temperaturu dimnih plinova na ulazu u plinsku turbinu od 1400 °C maksimalni termodinamički stupanj djelovanja kombiniranog procesa iznosi 61,5 %. Nadalje, u radu je dana i jednadžba pomoću koje se može preliminarno odrediti maksimalni termodinamički stupanj djelovanja za različite vrijednosti odabranih parametara ΔTpinch i izentropskog stupnja djelovanja kompresora te plinske i parne turbine.

Abstract (english)

In this paper combined Brayton–Rankine cycle is mathematically simulated. It consists of the following components: compressor, combustion chamber, gas turbine, heat recovery steam generator, steam turbine, condenser and pump. Model of combined cycle is defined by 13 characteristic points on system components entries in and exits. Every point is defined by its temperature, pressure, enthalpy and entropy. Exchanged heat flows and net power output in system as well as total thermal efficiency of combined cycle were calculated based on the laws of energy preservation. Adequate numerical procedure was developed in “Matlab” software package in order to determine maximum thermal efficiency with given limitations: temperature of exhaust gases on the gas turbine input and steam condensing temperature. Combined cycle working points, by which wanted maximum of thermal efficiency is achieved, were obtained for every observed situation. It is concluded that the total power output and total thermal efficiency of combined cycle were increased. Equation is also given, which allows preliminary definition of maximum thermodynamic power efficiency for various ΔTpinch settings and isentropic efficiencies of compressor, gas turbine and steam turbine.

• Keywords: kombinirani Brayton-Rankineov ciklus; maksimalni termodinamički stupanj djelovanja; optimizacija
• Keywords (english): combined Brayton–Rankine cycle; maximum thermal efficiency; optimization
• Language: croatian
• URN:NBN: urn:nbn:hr:235:239555
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Closed access
• Created on: 2019-05-22 12:05:00