GT2010- ONE AND THREE-DIMENSIONAL ANALYSIS OF CENTRIFUGAL COMPRESSOR FOR 600 KW SIMPLE CYCLE GAS TURBINE ENGINE

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1 Poceeding of ASME Tubo Expo 0: Powe fo Land, Sea and Ai GT0 June 14-18, 0, Glagow, UK GT0- ONE AND THREE-DIMENSIONAL ANALYSIS OF CENTRIFUGAL COMPRESSOR FOR 600 KW SIMPLE CYCLE GAS TURBINE ENGINE Elkin I. Gutiéez Veláquez Maco A. R. Nacimento Ruben A. Mianda Caillo Univeidade Fedeal de Itajubá UNIFEI Itajubá, MG, Bazil Newton R. Moua Petoba Reeach and Development Cente Rio de Janeio, RJ, Bazil ABSTRACT Cuently, indutial countie geneate mot of thei electicity in lage centalized plant. Thee plant have excellent economie of cale, howeve, they uually tanmit electicity though long ditance and can affect the envionment. Ditibuted geneation i anothe appoach that educe the amount of lot enegy duing tanmiion a the electicity i geneated cloely to whee it i ued, thi way educing the ize and numbe of powe line to be contucted. The cuent technologie in DG include mall ga tubine engine, intenal combution ecipocating engine, photovoltaic panel, fuel cell, ola themal conveion and Stiling engine uing foil fuel and bio-fuel. Among them, mall ga tubine engine ae a pomiing technology fo the implementation of ditibuted geneation ytem in the nea futue. Thi wok peent the eult of the peliminay compeo deign of a imple cycle ga tubine engine, obtained with the ue of a taightfowad one-dimenional FORTRAN code, which enable to calculate the main chaacteitic of a centifugal compeo by mean of the application of non-dimenional paamete, with a vat eduction of computational time. The eult obtained wee compaed with a CFD analyi and with expeimental eult taken fom pecialized liteatue; theefoe a eaonable ageement wa eached. The main contibution of thi pape i to demontate that by the ue of a imple code it i feaible to obtain faily cloe eult in compaion with thoe which can be obtained by laboiou iteative pocee uch a thoe developed though the analyi uing CFD technique. INTRODUCTION The implementation of new type of electic geneation mut conide eveal iue uch a geogaphic ditibution of electic enegy poduction, eliability and flexibility of opeation, availability and fuel pice, tem of intallation and contuction, financing condition and envionmental licening, among othe. Electicity geneation mut theefoe be adapted to the need of the enegy maket, while taking featue of the electical ytem into account, intoducing efficiency, eliability and flexibility, while eeking to meet the challenge of eve inceaing efficiency ue of enegy eouce and, at the ame time, minimizing envionmental impact of thi poce. In thi context, DG aie a a viable altenative, offeing a ange of benefit to the electicity ecto uch a: fat epone to iing demand, inceaed eliability by the ue of a ouce not ubject to tanmiion failue, eduction of tanmiion loe, deceae of envionmental impact by the ue of cleane fuel and the open up of moe maket oppotunitie. Ga tubine peent ome advantage ove othe DG technologie, uch a eaonable capital cot, a wide ange of powe ( kw) [1], opeation poibility with diffeent fuel at eaonable efficiency (30-33% with egeneato) and low level of emiion []. In the development of tubo-machine analytical method fo pedicting pefomance, by mean of paametic tudie, ae ued to demontate the influence of geomety change on pefomance unde deign and off-deign condition. 3- dimenional Computational Fluid Dynamic (CFD) code ae ued a eliable deign tool fo centifugal compeo avoiding expenive expeimental development. The impelle i one of the key component of the indutial centifugal 1 Copyight 0 by ASME

2 compeo and tubochage. The impelle deign i citical to the ucce of a compeo tage deign. Baic izing infomation to etablih the initial paamete can ave development time fo the indutial centifugal compeo. The diffue alo play an impotant ole in the compeo opeating ange once a pooly deigned diffue educe the compeo opeating ange and tage efficiency. At peent, the Enegy Conveion Technologie Reeach Goup - GETEC, fom the Fedeal Univeity of Itajubá, i paticipating in the development of poject oiented to the manufactuing of ga tubine engine fo divee application enabling the ue of diffeent type of fuel (bioma ga, biodieel, alcohol, etc.), thu olving the need fo enegy in emote aea. Theefoe, a a fit tep in the manufactue of ga tubine engine, the goup i woking on the development of tool a a uppot fo the deign poce. Thi wok peent the eult of the peliminay compeo deign of a imple cycle ga tubine engine obtained with the ue of a one-dimenional FORTRAN code [3]. Thi pemit the calculation of the main chaacteitic of a centifugal compeo by mean of the application of nondimenional paamete, with a vat eduction of computational cot. Compaion ae made with full thee-dimenional CFD analyi and expeimental meauement data to validate the eult of the developed code. The pupoe of thi tudy i to demontate that the ue of a imple code can poduce fat and eliable eult without equiing ophiticated compute equipment. NOMENCLATURE a Speed of ound [m/] A Aea [m] b Blade height [mm] C Abolute velocity [m/] CFD Computational Fluid Dynamic D Diamete [m] DG Ditibuted geneation GCS Gate Cycle Softwae k Specific heat atio M Mach numbe m Ma flow ate [kg/] n Specific peed p Peue [kpa] P Powe [kw] PR Peue atio R Ga contant [J/(kg k)] Radiu [mm] T Tempeatue [K] TPR Total Peue Ratio TTR Total Tempeatue Ratio U Tangential velocity [m/] V Relative velocity [m/] FVM W. ND Finite Volume Element Powe coefficient Geek α Flow angle β Blade angle φ Flow coefficient η Efficiency λ Incidence facto μ Slip facto θ Ma flow paamete ρ Denity υ Hub/Shoud Radiu Ratio ψ Blade loading coefficient Subcipt 0 Stagnation 1 Impelle inlet Impelle dichage 5 Diffue inlet 6 Diffue exit h Hub i Impelle, input m Meidian component Shoud, tage THERMAL PERFORMANCE CYCLE SIMULATION The GE Gate Cycle Ente oftwae 5.51 [4] wa ued to pedict the teady tate condition deign pefomance of a imple cycle ga tubine. The aim of thi imulation wa to obtain the ai condition at the compeo entance. The imulation model ued in the imple cycle i hown in Figue 1. Figue 1. Simple ga tubine cycle cheme ued fo the themal imulation The input deign paamete ued in the imulation made in GCS ae hown in Table 1. Thee data ae baed on cuent technologie fo adial tubo-machine. The tubine inlet tempeatue of 113K wa choen a thi i the maximum tempeatue put up by the mateial fo the manufactue of adial tubine, maintaining the mechanical eitance and the ueful life without blade cooling [5]. Copyight 0 by ASME

3 Table 1. Deign point input paamete Paamete Value Unit Ambient tempeatue 88 K Ambient peue 1,3 kpa Tubine inlet tempeatue 113 K Fuel tempeatue 88 K Peue atio 4 -- Compeo adiabatic efficiency 80 % Combution adiabatic efficiency 99 % Tubine efficiency 85 % Mechanical efficiency 98 % Ai humidity 60 % Ga tubine powe output 600 kw ENGINE DESIGN POINT SELECTION The deign of a compeo tat with the etablihment of the deign point obtained by a peliminay imulation of the themal cycle. The output eult of the themal imulation ae hown in Table. Table. Themal imulation eult Steam Tempeatue [K] Peue Flow [kpa] [kg/] S1 88,0 1,3 4,8 S 461,4 405,84 4,8 S3 88, ,07 S4 113,0 397,17 4,35 S5 846, 1,3 4,35 COMPRESSOR DESIGN The objective of the developed code i to find out the baic geomety of a centifugal compeo fom ome input data. Thi infomation define the expected pefomance of the deigned compeo. The impelle geomety main element and a co ection of the entance aea ae hown in Figue. Figue. Radial tubo-machine impelle geomety Thi wok i pat of the deign of a 600kW imple cycle ga tubine, with annula combution chambe, o the deigned compeo doe not have a volute. A vaned diffue model with fixed blade in the hape of a cicle ac wa elected. The mathematical model applied fo the calculation wa developed by Japike [6], which allow detemining the ecovey peue that can be attained, and the ideal length of the blade, the numbe and adiu of the cuvatue theeof. ONE- DIMENSIONAL CALCULATION In the development of any calculation code that intend to conceive a tubo-machine one mut take into account a ange of featue and/o limitation impoed by the aeodynamic condition, a well a the mateial ued fo uch contuction. Fit, it i neceay to etablih the peue atio a the deign paamete. Thi and othe impotant input paamete fo the one-dimenional code ae hown in Table 3. The lip facto of 0,85 i popoed by Dixon [7] a a uual value fo centifugal compeo. Table 3. One-dimenional code input data Paamete Value Unit Peue atio (PR) 4,0 -- Ma flow ate ( m ) 4,8 kg/ Inlet tagnation peue (P ) 1,3 kpa Inlet tagnation tempeatue (T ) 88 K Slip facto (μ) 0,85 -- Impelle efficiency (η i ) 84% -- Stage efficiency (η ) 80% -- Inlet blade angle (β 1 ) -60 deg Dichage blade angle (β ) -5 deg Inlet abolute flow angle (α 1 ) 0 deg Dichage ab. flow angle (α ) 65 deg Hub/houd adiu atio (υ) 0,8 -- Impelle adiu atio ( 1 / ) 0,5 -- Diffue diamete atio (D 5 /D 6 ) 1,35 -- Exit diffue mach numbe (M 6 ) 0,33 -- Fom thee vaiable, the code detemine the velocity tiangle a a function of the inlet Mach numbe, and the themodynamic elation to the enty, afte that it detemine the velocity tiangle in the dichage, and then et the elative Mach numbe in the dichage. Once the velocity tiangle at the inlet and output ae detemined, the pefomance dimenionle paamete calculation i initiated. The pogam compute the nondimenional paamete lited in Table 4. Finally the baic dimenion of the compeo ae computed, ome of which ae hown in Table 5. In ode to validate the eult obtained wee made compaion with expeimental meauement. The diffeence obtained between the computed and the meauement data ae hown in Table 6. The meauement wee made by Kain [8] and the eult calculated wee detemined by the onedimenional code. Thi Table how that thee diffeence ae eaonably mall. The geatet diffeence how deviation 3 Copyight 0 by ASME

4 below 4%. No infomation elated to othe paamete i peented once the autho doe not epot any additional infomation. Table 4. Non-dimenional paamete [13] Paamete Equation Incidence facto μ λ 1 tan β / tanα (1) Impelle Speed Flow Coefficient Ma Flow Paamete Blade Loading Coefficient Specific Speed Powe Coefficient U a k 1 1/ k ( PR) 1 = ηλ ( k 1) () ρ 1 1 C1 a ϕ= (1 υ ) ρ a U (3) U θ = ϕ a (4) ψ = (5) N λη ( πϕ ) 1 = ψ 3 4 (6). U W ND = ψθ (7) a Table 6. Deign impelle compeo validation eult Paamete Expeimental [8] Code Dev[%] Inlet Hub Radiu 35,4 35,5 0,8 Inlet Shoud Radiu 91,7 9,0 0,36 Exit Radiu 00,0 00,9 0,44 Rotation [pm] ,14 Exit Abolute Mach 0,96 0,9 3,89 Tangential Velocity 468,3 480,5,60 CFD SIMULATION In ode to compae the data fom the one-dimenional code, a numeical CFD modeling wa pefomed. In the imulation ANSYS CFX thee-dimenional code [9] wa ued, thi applie the Finite Volume Method (FVM) technique to olve the Navie-Stoke equation. The CFD modeling of the configuation wa pefomed baed on the value peented in Table 1. Fo the mehing poce hexahedon element wee ued and the chaacteitic of the meh geneated fo both the impelle and the diffue ae hown in Table 7. The dimenion ued fo the geneation of the meh equied fo the CFD imulation, wee obtained fom the data poduced by the onedimenional code. Figue 3 peent the meidional view of the impelle blade and the diffue vane upplied fo the imulation. Figue 4 how the configuation of the geomety achieved fo both the impelle and the diffue. A compaion between the eult obtained by the one-dimenional code and the CFD imulation i hown in Table 8. Table 5. Baic impelle geomety [13] Vaiable Equation Impelle Dichage Aea Impelle Dichage Radiu A. m θρ a = (8) 1 A = π (9) Blade Height θ b = ρ C ρ a 1 m (10) Shoud Radiu = (11) Hub Radiu 1 1 h 1 = υ (1) Figue 3. Meidional view of the flow paage and blade 4 Copyight 0 by ASME

5 Figue 4. CFD aemble impelle-diffue Table 7. Meh chaacteitic Domain Node Element Impelle Diffue All Domain Table 8. One-dimenional and CFD compaion eult Stage Pefomance Impelle Diffue Inlet Outlet Inlet Outlet Paamete CFD Code Dev [%] Ma Flow 4,11 4,8 4,1 Input Powe 780,4 75, 3,61 TPR 4,08 4,3 3,69 TTR 1,69 1,61 4,7 η i 74,58 80,00 7,7 Static Peue 89,84 89,84 0,00 Total Peue 1,3 1,3 0,00 Static Tempeatue 78,3 78,3 0,00 Total Tempeatue 88,1 88,0 0,03 Abolute Mach 0,41 0,4 0,93 Tangential Velocity 8,6 50,9 9,75 Abolute Velocity 138,5 144,8 4,58 Static Peue 80,0 3,4 17,0 Total Peue 51,4 49,0 16,3 Static Tempeatue 40,7 388,6 3,50 Total Tempeatue 486,6 463,0 4,87 Abolute Mach 0,93 0,98 4,69 Relative Mach 0,58 0,56,83 Abolute Velocity 377, 386,5,48 Abolute Velocity 380,6 349,5 8,18 Abolute Mach 0,94 0,88 6,3 Flow Angle 6,36 4,3 8,37 Abolute Velocity 144,7 14,3 1,67 Abolute Mach 0,33 0,33 1,1 Flow Angle 33,78 35,19 4, Static Peue 375,8 375,8 0,00 Total Peue 413,6 405,3,07 Static Tempeatue 467,3 453,1 3,13 Total Tempeatue 486,1 463,0 4,99 The imulation wa pefomed uing a otational domain with an angula velocity of 5149 pm and a tationay domain fo both the impelle and the diffue epectively. A efeence peue of 1,3 kpa wa ued. The option fo the heat tanfe wa Total Enegy, which include the high-peed enegy effect. The tubulence model ued wa the k- baed Shea-Ste-Tanpot (SST) model, whoe upeio pefomance ha been demontated in eveal validation tudie [10]-[1]. The oto-tato inteface wa connected by a geneal connection inteface uing the Stage Fame Change Model. The combination of the bounday condition ued wa total peue at an inlet and tatic peue at an outlet. Thi combination wa choen in ode to detemine the ytem ma flow a pat of the olution. Both bounday condition at inlet and outlet wee configued with ubonic flow egime. The elative peue at inlet wa et up in 0 kpa. The inlet total tempeatue wa 88 K. The elative peue at outlet wa et up in 74,5 kpa. Figue 5 how the compeo pefomance cuve to the deign peed achieved by CFD analyi; additionally the deign point fo the pojected one-dimenional code i plotted. Peue Ratio Ma Flow [kg/] 100% Speed Deign Point Figue 5. Simulated pefomance centifugal compeo cuve at the deign velocity ASSESSMENT OF RESULTS Accoding to the eult peented, the one-dimenional code developed pemit the calculation of the baic dimenion, the velocity tiangle at the inlet and outlet, and the opeating condition of the two component, the impelle and the diffue. The et of eult obtained by thi code wa compaed with both expeimental meauement and CFD imulation. Reult how that the dicepancie obtained ae ignificantly lowe, being thoe lee than 4% when compaed with expeimental data, and lee than 5%, in mot paamete evaluated fo compaion with the eult obtained by CFD imulation. In the latte cae, the geatet diffeence ae found in the output impelle peue, which diffe aound 17%. Thee 5 Copyight 0 by ASME

6 dicepancie ae peented pecifically in the aea nea at the inteface impelle-diffue, which i a highly untable aea. The eult in thi aea how conideable diffeence baically fo two eaon: fit becaue the one dimenional code doe not conide the loe peent thoughout the paage (which i the ubject of futue wok), and econd becaue the code developed ignoe the effect of impelle-diffue inteface. The computational cot epeent a ignificant diffeence becaue the computational time equied fo the onedimenional code i lee than two econd and the computational time pent fo each imulation of the whole impelle-diffue domain i about 10 hou. CONCLUSIONS The application of non-dimenional paamete, applied to the deign of centifugal compeo, facilitate the deign tak, geneating eliable eult in ignificantly le computation time. The developed one-dimenional code contitute a pactical and eliable peliminay deign tool fo detemining the baic configuation of centifugal compeo. The code wa validated by mean of value obtained though expeimental meauement and though imulation baed on CFD technique and the eult have hown good appoximation. The pogam developed povide good eult, howeve it equie futhe development to impove the computed eult. ACKNOWLEDGMENTS The autho wih to thank the Petoba Reeach and Development Cente (CENPES), the Coodination of Impovement of Highe Education (CAPES), the National Council of Technological and Scientific Development (CNPq), and the Foundation fo Reeach Suppot of Mina Geai (FAPEMIG) fo thei collaboation and uppot in the development of thi wok. egeneative ga tubine engine. Poceeding of ASME Tubo Expo 009: Powe fo Land, Sea and Ai [6] Japike D, Baine N. Diffue Deign Technology. Concept ETI Inc, Vemont, USA [7] Dixon SL. Fluid Mechanic and themodynamic of tubomachiney. Elevie 003. [8] Kain H. Tet Cae : Centifugal Impelle, DLR. In: Goup ETS, edito. Semina and Wokhop on 3D Tubomachiney Pediction II. Val d Ièe, Fance; [9] Any Inc. ANSYS CFX [10] Badina JE, Huang PG, Coakley TJ. Tubulence Modeling Validation Teting and Development. NASA Technical Memoandum [11] Badina JE, Huang PG, Coakley TJ. Tubulence Modeling Validation. AIAA Pape [1] Alenca HS, Nacimento MAR, Villanova H. Etudo Numéico temo-aeodinâmico paa Câmaa de Combutão paa Tubina a Gá: Aplicação ao Cao da Mico tubina. Itajubá - Bail: Univeidade Fedeal de Itajubá. [Numeical tudy fo themal aeodynamic Combution Chambe fo Ga Tubine: Application to the Cae of Mico tubine. Itajubá - Bazil: Fedeal Univeity of Itajubá] - UNIFEI; 007. [13] Whitfield A, Baine NC. Deign of adial tubomachine. Longman Scientific & technical; REFERENCES [1] Nacimento MAR, Ventuini OJ, Loa ES, Siea GA, Rodigue LO, Cavalho HM, Moua NR. Cycle election and compeo deign of 600kw imple cycle ga tubine engine. ASME Tubo Expo [] Silva Loa E, Nacimento MAR. Geação Temelética: Planejamento, Pojeto e Opeação. [Themoelectic Powe Geneation: Deign, Poject and Opeation]. 004; pp [3] Compaq Compute Copoation. Compaq Viual FORTRAN [4] Enegy Sevice. GATE CYCLE [5] Oliveia LM, Nacimento MAR, Menon GJ. The themal impact of uing ynga a fuel in the egeneato of 6 Copyight 0 by ASME