ThermodynamicsAnalysisofSemi‐ClosedGasTurbine Cycle HadeelRaheem

ThermodynamicsAnalysisofSemi‐ClosedGasTurbine Cycle HadeelRaheemJasim1 | EmanShakerHussein2 |AmeerAbdulkadhimOudahAl‐Shamkhee3 |MujtabaA.Flayyih4 | WisamAl‐Obaidi2 |AbdellatifM.Sadeq5 1DepartmentofMaterialsEngineering,AlQadisiyahUniversity,AlQadisiyah, Iraq | 2DepartmentofMechanicalEngineering,AlQadisiyahUniversity,Al Qadisiyah, Iraq | 3Technical InstituteAL,Al‐FuratAl‐AwsatTechnicalUniversity,Diwaniyah, Iraq | 4BiomedicalEngineeringDepartment,Collegeof EngineeringandTechnologies,Al‐MustaqbalUniversity,Hillah, Iraq | 5MechanicalandIndustrialEngineeringDepartment,CollegeofEngineering,Qatar University,Doha,Qatar Correspondence:AbdellatifM.Sadeq(as1004958@qu.edu.qa) Received:19April2025 | Revised:16July2025 | Accepted:21July2025 Funding:ThisworkwassupportedbyQatarNationalLibrary. Keywords: fuelconsumption|gascycles|gasturbinemodification|heatingefficiency|powerplant|pressureratio|regenerating ABSTRACT Thepropertiesofasemi‐closedcombinedcyclepowersystemmakeitabetteroptionforthisstudythananopensystem,sinceit turnsanopen‐cyclegasturbineintoapollutant‐freepowersystem.Alsointheselectedcycle,theexhaustischanneledtowarda dividerratherthanbeingreleasedintotheatmosphere,andtheexhaust isdividedintoaseparationductandareturnductby thedivider.Partoftheexhaustisdirectedbacktowardthecompressorviathereturnduct.Thisstudyinvestigatestheeffectof thermodynamic parameters analysis (turbine inlet temperature, ambient air temperature, pressure ratio, and regenerator effectiveness)onthermalefficiencyandspecificfuelconsumption(S.F.C.)forasemi‐closedsystem.Thepropertiesofasemiclosedcombinedcyclepowersystemmakeitabetteroptionforthisstudythananopensystem,sincetheyturnanopen‐cycle gasturbineintoapollutant‐freepowersystem.Alsointheselectedcycle,theexhaustischanneledtowardadividerratherthan beingreleasedintotheatmosphere.Theexhaustisdividedintoaseparationductandareturnductbythedivider.Partofthe exhaust isdirectedback toward the compressor via the returnduct. This study investigates theeffect of thermodynamic parameters analysis (turbine inlet temperature, ambient air temperature, pressure ratio, andregenerator effectiveness) on thermal efficiencyandS.F.C. for a semi‐closedgas turbine cycle. Theoperatingconditions are taken intoaccountwhen determiningtheanalytical formulasforassessingthermalefficiencyandS.F.C.,whicharecalculatedbyusingthermodynamic equations.ThemodelisconstructedusingMATLAB®.Theresultsshowthatthethermalefficiencyisincreasedduetoincreased turbine inlet temperature, increased regenerator effectiveness, anddecreasedambient air temperature. Conversely, S.F.C. decreases.Itwasalsofoundthatwhenthepressureratiowasroughly2, thethermalefficiencyrose,whiletheS.F.C.startedto decrease.Afterthisvalue,thethermalefficiencybegantodeclinegradually,andtheS.F.C. increased.Also,astheregenerator’s effectivenessincreasedtoroughly0.95,thedataindicatethatthethermalefficiencyachieveditsmaximumvalueof0.60.andat aturbineinlet temperatureofabout1600K,whiletheS.F.Crecordedaminimumvalueof0.1394