CONTROL OF SOOT EMISSION FROM DIESEL ENGINES

Transcription

1 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran ONTROL OF SOOT EMISSION FROM DIESEL ENGINES Rae Al-ASANAT, rhasanat@hotmail.com Ministry of Eucation an igher Eucation, ebron, Palestine Moh QAWASMI, qawasmim@ppu.eu Department of Mechanical Engineering, Palestinian Polytechnic University, ebron, Palestine ABSTRAT Soot emission is a problem in major cities in the worl. The number of iesel cars raise a lot in last years in Palestine, were 57,3% of the new cars in 010 were equippe with iesel engines[9]. This evolution was motivate by iesel engine excellent fuel economy an urability. This paper iscusses soot combustion funamental processes in term of the in-cyliner combustion an emission. The new research requeste both simulation an experimental researches to stuy funamental process involve in iesel engines in orer to ecrease the soot emissions of iesel engines an to contribute to the global emission reuction. This project of soot moeling is evelope to integrate to the conception cycle the ability of preicting the soot particle concentration from combustion in iesel engines. The goal is to evelop a moel that can be applie uring the concept phase of the engines, this moel has for vocation to preict the soot concentration uring the combustion cycle. eywors: harm emission reuction an soot combustion process. 1. INTRODUTION Diesel is also responsible of emission, in particulate iesel particulate matter which inclues soot particulates. These very fine particulates are consiere as responsible for amaging health effects as cariac, pulmonary an cancer effects. The effect of the particulates was also unerline; soot warms arctic in two primary ways.' When it is in the atmosphere, soot absorbs incoming solar raiation an warms the atmosphere while possibly ecreasing clouiness. On the groun, it blackens snow an ice, making it less reflective so that absorbs more warning raiation'[]. In orer to regulate the soot emissions ifferent norms were create incluing soot, the Euro norms shown in table(1).

2 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran Soot particles are commonly believe to be forme by coagulation of PA species, the resulting small particles essentially grow by heterogeneous surface reactions with acetylene being the most important growth species. These reactions are commonly moele by the reaction mechanism. The combustion of soot particles occurs mainly by heterogeneous reactions with O raicals an molecular oxygen[3,,5]. Table(1) exhaust emission norms for iesel heavy-uty, automobiles an buses Norms Years Exhaust emission stanar, g/kw.h NO X Smoke Soli particles O EURO ,0 0,8 0,100,1 EURO ,5 0,5 0,0 1,5 EURO-5 008,0 0,5 0,0 1,5 EURO ,13-0,01 1,5 In the present stuy numerical simulation of soot particles formation in iesel cyliner are presente, the kinetic moel use to escribe physical chemistry interactions, the formation an combustion of soot particles is escribe by etaile kinetically base soot moel, In orer to evelop this moel, all the formation an oxiation steps shown in fig(1) have to be escribe in the moel from the gas phase to the soli interactions: - The gas phase - The formation of the first particles from the gas phase by collision of two pyrenes (molecules with four aromatic rings), this step is calle nucleation or inception - The conensation of the PAs on the surface of the first particles - The coagulation which accounts for the collisions of the particles between them to form bigger ones - The surface growth an oxiation base on the yrogen Abstraction arbon Aition mechanism[1,7]. Fig(1) soot formation steps

3 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran In the present stuy of soot particles formation in iesel cyliner are presente the chemical kinetics use to escribe physical chemistry interactions, the formation an combustion of soot particles escribe kinetically, ifferent assumptions for soot particles concentration are applie an the results are iscusse in a comparison with experimental ata provie. -MATEMATIAL MODEL OF SOOT FORMATION A preictive moel of soot formation in flames is being evelope by using elementary reaction to escribe the basic flame chemistry, soot particles growth an combustion in the case of application fuel aitives. Sectional equations for soot formation, growth an oxiation are expresse in a form suitable for concurrent soot moeling an etaile gas-phase kinetic moeling[,7]. By using aitives, which contain Ba,, a an other metals, an by conserve general moel construction, provie only summary about metal's character. The primary carbonyl fraction with appearance particular soot Ċ, growing an burning their surface, consiere in the following form: X Y 3 (1) 3 () (3) () (5) 5 5 Me(O) ( 5 5 ) MeO 3 (5a) ( 5 5 ) Me Me 5 5 (5b) () m (n) sur. (7) (n) sur. ( n ) sur. (8) (n) sur. ( n ) sur. (9) O Me O (10) O Me O (11) O Me O (1) O Me O (13) O O (1) Me O MeO (1a) In presente system, equation(1) escribes the primary fraction of fuel to iniviual hyrocarbons, equations(-5) escribe high-temperature of fraction iniviual hyrocarbons to acetylene, equation(5a) illustrates isolate carbonyl groups then joining raicals, equation (5b)shows isolation metal by carbon, equation() escribes the ecomposition of acetylene with generation embryonic

4 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran charge soot particles, equation(7) process carbonation an appearance physical embryonic acetylene, equations(8-9) self-accelerate growth the surface of soot particles, equation (10-1)show burning of soot particles, equation(1a) restores metal oxie by oxies of carbon[3,,7]. Provie system kinetic equations in the form of ifferential equations to escribe in-cyliner processes, omputer simulation gives possibility to solve the equations with high accuracy to efine the instantaneous rational amount of soot relative to crank angle position (φ o ), presente simulation escribes in-cyliner processes soot generation an the combustion in iesel engine. A part stuy escribe by the moel was performe for -soot which correctly preicte experimental soot mass concentration, the stuy inclue cases in which only ae to the soot. Mathematical moel (Inex ) consiers the change of soot particles concentration with crank angle position in egrees (φ o ) an so when exhaust valve opens estimate the quantity of soot particles with exhaust gases[3,7]. 3. RESULTS The high-quality of computing results inicate in comparison with experimental ata. In fig.(3) presente experimental an computing rational amount of soot formation in iesel cyliner as a function of crank angle position in egrees (φ o ). Graphics show goo agreement for soot particles concentration in iesel cyliner, so it confirm our assumption of chemical kinetics[3,]. Fig(3) Soot emission with exhaust gases (rational amount of soot). Pe=3bar.

5 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran In fig() presente experimental results of soot concentration (rational amount of soot) in iesel cyliner as a function of φ o. An 8-cyliner iesel engine stuy of water-in-iesel emulsion was conucte to investigate the effect of water emulsification on soot emission with exhaust gases. Emulsifie iesel fuel 17% water/iesel ratio by volume, were use irect injection iesel engine, operating at 1700 r.p.m. an molti-loas (Pe=1,1,85). Graphics inicate that the aition of water in the form of emulsion ecreases soot emission with exhaust gases to 0% [7,8,10]. In the result of ripping emulsifie fuel increases mixture quality. Decreasing temperature on account of water Dissociation an sharply ecelerate chemical reactions of soot formation. The system saturates with hyrogen s raicals which assist to suppress formation of chains at the stage of sootier raical formation so the burning spee of soot particles increases on account of increasing of carbon gasification[8,10]. Fig() the effect of water emulsification on soot emission with exhaust gases(rational amount of soot). 1-Pe=1,1bar -Pe=, bar 3-Pe=3, bar -Pe=,85 bar, iesel fuel, ---- Emulsifie iesel fuel, 1700r.p.m.

6 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran The results of numerical simulation show soot particles concentration (rational amount of soot) in iesel cyliner as a function of crank angle positioning in egrees (φ o ). In fig() presente computing results of soot formation in iesel cyliner. A single cyliner iesel engine stuy of metallo-organic compoun fuel aitives for iesel was conucte to investigate the effect of antismoking aitives on soot emission with exhaust gases. Moifie iesel fuel 0,5% aitive/iesel ratio by mass, were use irect injection iesel engine, operating at multi-loas (Pe=bar, Pe=5bar, an Pe=7bar) an 10 r.p.m. Graphics inicate that the aition of antismoking aitives (SLD) ecreases soot emission with exhaust gases to 0% [7]. Fig() the effect of antismoking aitives on soot emission with exhaust gases(rational amount of soot). 1-Pe=bar -Pe=5 bar 3-Pe=7 bar, iesel fuel, ---- moifie iesel fuel, 10r.p.m.

7 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran The soot particles reucing effects of many aitives are well-known, but little is unerstoo about the etails of soot particles suppression mechanism, a laminar iffusion flame burning was seee with a metallo-organic aitive, by evaporating the aitive from a crucible place in the heate fuel gas flow, foun that aitives suppress the formation of PA an accelerate the burning process[7,8,10]. -OLUSION: The test for computer matrix simulations was evelope, an parametric test results were obtaine by using stanar fuel an fuel with metallo-organic compoun fuel aitives. Simulation results inicate the following: Antismoking aitives is effective in reucing soot. In perio of time, metallo-organic compoun fuel aitives checke process heat generate, but in perio iffusion flame accelerate burning process, this reuce P.M. in exhaust gases at least 0%. Achieve a funamental unerstaning of the formation an escription in iesel particulate matters. The presente work confirme effective of moifications on processes of soot formation in iesel cyliner, an permit to make conclusion about mechanism their effect on the actual processes of soot formation in iesel engine, an by using ripping emulsifie fuel, ecrease harm emission with exhaust gases in atmosphere. A mechanism for the catalysis is propose. We hope that this paper stimulates interest in pursuing further solutions of environmental problems. 5. ANOWLEDGEMENT: The authors offer their sincere thanks. All cooperate with the aim of proviing accurate an complete information that woul be useful in the training of eat Engines technicians. Special thanks are owe to the following organizations for information: Palestinian Ministry of Transport, Palestinian Ministry of Eucation an igher Eucation, Palestinian Polytechnic University an Altai State Technical University.. REFERENES: 1.. Bockorn, (199), "Soot Formation in ombustion", Springer Series in hemical Physics, Vol.59., Springer, Berlin.. och D., J. ansen (005), "Distant origins of Arctic black carbon", A Goar Institute for Space Stuies Moel Experiment. J. Geophys. Res., 110, D00, oi:10.109/00jd Novosolov A.L., (1980), Application of Antismoking Aitives in Diesel Fuel, Engine's Structure11, 10-11, Russia.. Pisch., Riesmier E., Peter N., (00), Unsteay Flamlete Moeling of Soot particles Formation in Turbulent Diffusion flames, works of eielberg University, Germany.

8 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran 5. Agafonov G.L. Nulmeier M., (00), Detaile inetic Moeling of PA Growth an Soot particles Formation in Shock Tube Pyrolysis of Benzene an Ethylene, works of eielberg University, Germany.. Mateevsky D.D. Antonov P.A., (197), Effects of antismoking aitives actual performance an the smoking of iesel engine, Works of Altai State Technical University, Barnaul. 7. Rae A.F. asanat, (001), Experimental omputing Research in the Effect of Metalcontaining Antismoking Aitives on the Actual Performance an Soot particles Emission with Exhaust Gases of Diesel Engine, Ph.D. thesis, Russia Siegman. B. Xue 199: Laboratory for ombustion Aerosol an Suspene Particles, hina. 9. Ministry Of Transport// elivere post No.908/ Baturin S.A. Makarov B.B., (197), Physic-chemical Mechanism an Methos of alculating Amount of Soot particles in Diesel engine, Works of SNUTA19, 8-93, Russia. Inex (1): List of Symbols: sur. surface T m Average temperature in the center of flame. F Specific surface of soot particles, M /kg n Engine angular spee, min -1 N comb. Soot particles combustion N form. Soot particles formation rank angle position α Theoretical air fuel ratio α comb Actual air fuel ratio σ Equivalence ratio X Specific heat generation (ombustion efficiency) N n Initial value of soot particles concentration in iesel cyliner at firing instant R 5 Reaction spee of soot particles growth P Pressure of gases in iesel cyliner r 5 Acetylene volumetric concentration G air yclic entere air for 1kg fuel, m 3 G D Soot particles concentration with exhaust gases kg/m 3 Me Metal PM Particulate Matter Ċ Particular Soot Rational amount of soot particles 113/1 One yliner AMAZ Engine, yliner Diameter 13cm, Length of Stroke 1 cm. SLD Antismoking Aitive, which contains Barium. r.p.m. Revolution per minute Pe Effective Pressure TD Top Dea enter

9 The 7 th Joranian International Mechanical Engineering onference (JIME 7) 7-9 September 010, Amman Joran Inex (): mathematical moel of soot formation 1- ( ), 3,5 5, п = Σ - 3- ( ( ) ), 1 0,5 3 3 п = Σ - 5- ( ), 0,5 1, n о М М = Σ Σ - ( ), 0,5 1, n = Σ Σ 7- ( ), 0,5 8 7 п D = 8-, = i= i