Design and Development of Micro-Turbine Coupled Compressor for Air-Conditioning System in Automobiles

Transcription

1 Journal of Emerging Trend in Engineering and Applied Science (JETEAS) (): 59-6 Scolarlink Reearc Intitute Journal, 0 (ISSN: -706) jetea.colarlinkreearc.org Journal of Emerging Trend in Engineering and Applied Science (JETEAS) ():59-6 (ISSN: -706) Deign and Development of Micro-Turbine oupled ompreor for Air-onditioning Sytem in Automobile K.T. Ajayi and A. E. Ojakovo Department of Mecanical Engineering, Faculty of Engineering, Univerity of Lago, Nigeria orreponding Autor: K.T. Ajayi Abtract Te ue of te ig kinetic energy in te exaut ga from te engine to power a micro-turbine coupled to te compreor of an automobile (conceptualized) i poible a revealed by te deign, contruction and tet of ti preent invetigation. Te termodynamic analyi of te engine coupled to te air conditioner reveal a gain of 7 % in te effectivene of compreion ignition (I) engine on te conceptual mode of powering te compreor at any given combution temperature a againt tat of te conventional, were te engine directly power te compreor. For park ignition (SI) engine te gain in effectivene decreae wit increaing combution temperature attaining a value of % at combution temperature of 00K. Ti tecnology bring to a trong exigency of new ytem for automobile pace cooling wit te poibility to obtain a primary energy diverification reulting in fuel economy and better lifepan of te engine. Keyword: micro-turbine, exaut ga, i and ci engine, air-conditioning ytem. INTRODUTION Te ability of air conditioning ytem in an automobile to cool te paenger compartment troug direct coupling of te compreor to te engine (conventional) a been etablied but concern remain for te eavy load requirement on te engine and te increae in fuel conumption. Depite te effort made in recent time to improve on te performance of air-conditioning ytem in veicle troug latet tecnologie uc a te eat ventilation ytem, te matrix infrared enor ytem, te pollen removal mode, te oxygen generator, te ejector ytem, te internal eat excanger ytem, te main engine direct driven bu air-conditioning ytem, and te package air-conditioning ytem a reported by (Kataoka, Takano and Taniguci, 00, Anderen, Atkinen, Baker, Ouloojian and illp, 007, Lorentzen and etteren, 99, Brown, Yana- Motta and Domanki, 00, Huang, Tzerg and Jeng, 006, Kiatiriroat and Euakit, 997) and on te performance of te engine troug variou invetigation, uc a, on engine cycle and fuel (Agarwal, Filipi, Aani and Baker, 998, Bayraktar and Durgun, 00, Georgio, 005, Gulder, 98, Gallo and Milanez, 99, Kopac and Kokturk, 005, Kota, 995, Rezac and Metgalci, 00, Sezer, 008), flame propagation and combution (Bilgin, 00, Tabaczynki, Trinker and Sannon, 980, Keck, 98, Agarwal, Filipi, Aani and Baker, 998, Blizard and Keck, 97, Dai, Newman and Davi, 996, Tabaczynki, Ferguon and Radakrinan, 977, Tallio, 998) and many oter a reported by (Ajayi, 009a, Ajayi, 009b), te 59 power demand on te engine to run te airconditioner in veicle till remain relatively ig. Te need to free ti energy for oter ue and till maintain relative comfort in te paenger compartment by optimally upplying te required energy alternatively, i eldom reported in te literature. Terefore, tere i te need for a creative deign and innovation involving compreenive utilization of te energy of te exaut ga of te engine to power te air conditioner, ence ti tudy. METHODOLOGY Experimental Metod Te material ued for te experimental invetigation include, a car, intelligent teter, Temperature enor, Gray at Iron, Mild Steel, Nickel Alloy and Steel. Te ability of cat iron to aborb and dampen vibration make it an excellent material for te turbine ouing and inlet, wile mild teel being te commonet material for fabrication and contruction purpoe wit mot of te deirable propertie find ue in exaut pipe, coupling and compreor pulley. Te turbine blade, being a very important component for te converion of te kinetic and eat energy in te exaut ga at ig temperature to aft work needed to turn te compreor, wa contructed from nickel alloy, wile te turbine aft wa fabricated from teel for it tougne and ardne propertie. Deign Expreion Te overall ientropic entalpy drop i given a, o(ien)

2 Journal of Emerging Trend in Engineering and Applied Science (JETEAS) ():59-6 (ISSN: -706) o( ien ) g ( T0 T0 ) g T0 g of te roduct (0, H O, N ) can be obtained at any pecified temperature uing te JANAF table (Dorofeeva, Iori, Novikov and Neumann, 00). Te power output ( w ) i given a, m m m W w g in out g actual g out ombution of premium motor pirit, 8 H 8, H β + a (0 +.7N ) n O +n H O+n N Were, n, n, n. 76a a, are all contant. w Required turbine flow, m g were A i te actual entalpy drop. Te prouting velocity, o i computed a follow: o o ien For pecific (N) peed and pecific diameter (D), 5 N Q D H N and D 5 Q H ND wic implie tat, ND = 6 H Te blade velocity at inlet i, N D U N r 7 Terefore, U 0.707, U o o opt Te velocity diagram for te flow entering radially and leaving axially i given below: Figure : Blade velocity diagram for radial-inflow turbine A f tan, f n0. 9 U were = nozzle lo coefficient, wic i n 0.06 n 0.5 for 90 0 inward flow turbine. For a Radial macine, te Reaction R i given a, R 0 were i te temperature drop (blade loading) coefficient, given a, W = S. U Te turbine flow area, mg Af f Te Tip diameter of te Turbine at Inlet can be obtained from D N U U D N At turbine exit, D 0.65 and U = D N D Since te flow velocity f i contant, f f For a zero Exit wirl, t = 0 and f 5 From te exit velocity diagram, f f tan tan 6 U U and f r. 7 Sin T T0, 0 T 0 0 and T RT0 According to (Glaman, 976) te required number of blade (n b ) to prevent turbine reveral i given a, n = 0.07 (0 - tan ) tan, b Rotor inlet blade widt b i given a, m b g r D 0 Lengt of Hub (L ),

3 Journal of Emerging Trend in Engineering and Applied Science (JETEAS) ():59-6 (ISSN: -706) D L. 5 D. Te flow coefficient ( ) i given a, f = U According to (Kafkey and Nubaun, 97), r = 0.5 r = 0.5 r t r t Fig : Hub To Tip Radiu Ratio For te turbine ouing, d i Ra R D but R cl, were cl i te clearance. Te torque tranmitted by te aft i, NT T 5 N Te Torque,T i related to te diameter of te aft a, d T 6 6 were i te permiible ear tre for te aft material. Terefore, d = 6T S = 80 N Termodynamical Analyi Applying firt and econd law of termodynamic in te evaluation of park ignition(si) and compreion ignition (I) engine a reported by (Ajayi, 009a, Ajayi, 009b) yield te overall efficiencie of te engine a follow: For SI engine coupled to te car air-conditioner conventionally, 7 o γ γ T R T R γ T T R W 8 For uing te exaut ga from SI engine to run a micro-turbine coupled to te car air-conditioner, conceptually, wa / T R T o T TR 9 For I engine coupled to te car air-conditioner conventionally, T T WA/ R R T o T T R 0 For uing te exaut ga from I engine to run a micro-turbine coupled to te car air-conditioner, conceptually, o T T T were T e i given a, T R T e R R T R A W T A / Te coefficient of performance (.O.) and energy efficient ratio(eer) of air-conditioning ytem for any vapor compreion ytem, aving te four baic component, namely, compreor, condener, expanion valve and evaporator are repectively given a, Re frigeratio n effect. O.. Heat of compreio n Ueful cooling capacity EER ower input RESULTS AND DISUSSION Applying te initial data and condition of table to te deign expreion of ection, yielded te deigned value of te required number of turbine blade and te oter neceary parameter of te micro-turbine and aft a lited in table, wile toe of te turbine ouing are given in table and te correponding ketc in figure. Te neceary component of te fabricated micro-turbine togeter wit oter tandard acceorie are ow in figure wit te correponding lit in table. A cematic flow diagram of te vapor compreion ytem owing neceary component i preented in figure 5. Irrepective of te type of working fluid and te mode of work done on te compreor, te traditional ytem remain te ame coniting of te condener, e 6

4 Journal of Emerging Trend in Engineering and Applied Science (JETEAS) ():59-6 (ISSN: -706) flow control ytem, evaporator and compreor. In te conventional mode, work i done on te ytem by mecanically coupling te compreor to te engine. But in ti invetigation, te aembled deigned component of figure coupled to te compreor via clutc wa driven by te energy in te exaut ga from te engine. Te conceptual power upplied to te compreor operated te cycle in figure 5, wile te coefficient of performance (.O.) and te energy efficient ratio (E.E.R.) i under furter invetigation. From te termodynamic analyi, te relief on te engine by extracting te required work, W t from te kinetic and eat energy of te exaut ga i clearly repreented in figure 6. A own, tere i ignificant power uage by te mecanical compreor of an automobile traditionally coupled to te engine for bot park and compreion ignition engine. For te range of te invetigation, te effectivene of te SI engine increae from 0.7% at combution temperature of 70K to an aymptotic value of 9.8% at combution temperature of 00K and remain contant tereafter for an engine conventionally coupled to te compreor a compared to te drop in effectivene from.7% to 5.5% wen te energy in te exaut ga i ued to run te compreor for te ame temperature range. But for I engine, te effectivene drop gradually from 5.% to 5.5% and from 7.8% to 70.% for te ame temperature range for conventional and conceptual mode of te car air conditioner repectively. A better repreentation of te data wit power fitting a own in figure 7 preent a contant gain of about 7% of te conceptual over te conventional for I engine, but varying value (from 0 % to %) of te conceptual over te conventional for SI engine for te invetigated temperature range of te combution camber. Table : Available Deign Data DESRITION ompreor ower Engine Inlet Manifold reure Stagnation Temperature at Turbine Inlet Engine Manifold reure ratio(r) GIEN INFORMATION 5.5H (. kw) Fuel Ued remium Motor Spirit ( 8H 8) Turbine Deign For wit Zero Exit Swirl, o ( ien) 0.8, r 0 Total-to-tatic efficiency, TS 80% OMMENT (Mean of information) Manufacturer 0 ka Obtained wit intelligent Teter 00 o Obtained wit temperature enor.5 SAE, International Journal of Engine ol.() N = 0.8, D =.5 For 80 % ientropic efficiency, from turbine performance Map From Balje diagram Table : Te deigned value Decription d ( ( ( D (mm) D (mm) b (mm) r t (mm) r (mm) L (mm) n (mm) o ) o ) o ) Deigned value Table : Deign value for turbine ouing N/S ( o ) Ra (mm) Figure : Turbine caing 6 Figure : Micro-turbine wit neceary acceorie

5 Journal of Emerging Trend in Engineering and Applied Science (JETEAS) ():59-6 (ISSN: -706) Table : omponent decription of micro-turbine and te acceorie S/N DESRITION MATERIALS REMARKS QTY Exaut ipe Mild Steel Standard Turbine Houing at Iron Fabricated Turbine Blade Nikel Alloy Fabricated oupling Mild Steel Fabricated 5 Turbine Saft Steel Fabricated 6 Turbine Inlet at Iron Fabricated 7 ompreor ulley Mild Steel Standard 8 ompreor Steel Standard 9 Screw Bolt Mild Steel Standard 6 % Gain in Effetivene SI_Engine I_Engine 0 ompreor lutc Mild Steel Standard ombution Temperature (K) Figure 7: % Gain in Effectivene of onceptual Over onventional of Work Input to te ompreor Efficiency (%) Figure 5: Scematic vapor compreion cycle (70, 7.8) (70,.7) (70, 5.) (70, 0.7) (800, 7.) (800, 57.8) (800, 5.) (800,.) (000, 70.) (000, 5.9) (000, 5.5) (000, 8.) (00, 70.) (00, 5.) (00, 9.8) (00, 5.6) ombution Temperature (K) SI_ SI_ I_ I_ (00, 5.8) (00, 70.) (00, 5.5) (00, 9.8) Figure 6: Effective Relief on Automobile Engine by Uing Exaut Ga Driven ompreor ONLUSION From te experimental tudy, te energy in te exaut ga from te engine operated te microturbine coupled compreor of an automobile. Te invetigation furter reveal tat air conditioning ytem being a ingle larget auxiliary load on te veicle reduce te effectivene of te engine by 7 % for compreion ignition engine for a combution temperature range of 70K to 00 K, but varying reduction in effectivene from 0% at combution temperature of 70K to % at combution temperature of 00K. Effective utilization of te available kinetic energy in te exaut ga in operating te compreor in te car air conditioning ytem cycle i ubject to furter invetigation. REFERENES Agarwal, A., Filipi, Z.S., Aani, D.N. and Baker, D.M., (998): Aement of ingle- and two-zone turbulence formulation for quai-dimenional modeling of park-ignition engine combution, ombut. Sci. Tecnol. 6, 9. Ajayi, K. T., (009a): Optimization of Exaut Ga and Micro-turbine to power air conditioning ytem in compreion ignition automobile, Global Journal of Engineering and Tecnology, () pp Ajayi, K. T., (009b): Modeling a micro-turbine to power air conditioning ytem in park ignition automobile, International Journal of Engineering, () pp

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