Analysis Of Part Flow Evaporative Gas Turbines

Part flow evaporative gas turbine(PEvGT) cycles are the innovation and development of humid air turbine(HAT) cycles,which combines the characteristics of high power efficiency of HAT cycles and flexibly process steam provided for heating or cooling of steam-injected gas-turbine(STIG) cycles'.PEvGT cycles has the application potential in middle and small scale combined cooling,heating and power(CCHP) system.Since being put forward,PEvGT cycles have been studied by lots of researchers and experts,and their advantages in techno-economic have been theoretically improved.To further explore PEvGT cycles,this thesis focused on investigating the influences of cycles' flow structures on their performances.Based on the main components models of PEvGT cycles established,parameters optimization and performance analysis under design condition are carried out,and off-design performance analysis is performed.Furthermore,the thesis presents the preliminary study of the feasibility of PEvGT cycles applied in CCHP systems. Main research contents of this thesis are as follows:Firstly,according to different mixing positions of un-humidified and humidified air, two kinds of PEvGT cycles are built.For PEvGT-1 cycle,the un-humidified air and humidified air are mixed after recuperator,while for PEvGT-2 cycle,which are mixed before the recuperator.On the basis of parameter optimization,thermodynamic performance of the two PEvGT cycles under design condition are analyzed and compared with a STIG cycle and a HAT cycle.The results show that the mixing position of the two air steams has significant influences on the thermodynamic performance of PEvGT cycles. The highest power efficiency will obtained when the humidified ratio(the flow rate ratio of the air to be humidified to the air into compressor) is below 20%.Under design conditions, for the two PEvGT cycles,turbine inlet temperatures have significant influences on their efficiencies,specific powers and optimal pressure ratios,and the humidified air ratio has more obvious effects on the PEvGT-1 cycle than that of the PEvGT-2 cycle.Secondly,off-design performances of the two PEvGT cycles,which have higher efficiency than others on design point,are analyzed and compared with the STIG cycle and HAT cycle.The influences of ambient temperature,ambient pressure,turbine inlet temperature,load adjustment and the flow rate proportion of process steam to whole steam generated in the cycle are investigated.The results indicate that the PEvGT-2 cycle reveals better off-design performance than the others,and is relatively less influenced by the changes of environment parameters and part-load operation.Finally,the two PEvGT cycles are applied to CCHP systems.The characteristics and economic performances of the two PEvGT cycles based CCHP systems,which are applied in hotel and office respectively,are analyzed,and also compared with the HAT cycle and STIG cycle based CCHP systems.The results show that the PEvGT-2 cycle based CCHP system has better flexibility and economic performance.