| OCR Text |
Show Numer,i cal studies on drop traJ' e c t on'e s were aI so performed. In a TEA confiauratl' on smaller drops are carned outward by flow field h'l I C'. I ' C) , , W 1 e on y lew arger drops feed the mternal zone. These findmgs were confirmed by the results of the at 't' C' ' " , , , , . omlza Ion tests lor the evaluatIOn of drop size dlstnbutlon and fuel . ddls tnbtu' tlotnh pAroTdOucMe d by the Y- jet atomizer of TEA bu rner (F'I g, 6) . At oml.z atl.o n tests were carn,e ou. 1n e Ola. nd ISA Cla'. CI' l'lti'e s, deS'l gne dloCr ru'n.n'm g full scale expen,m ents, Malvern Particle Sizers and Aerometncs PDP A diagnostic devices were used. ~r---------------~I ------------~ z·o • AiOMli:::R A C[); 0 . 5 • 95 j.Jm) • A TOM I i:::R a C[); 0.5 • : 00 j.J en) ~ 11)0 \ :t , 160 ST[AM-AlP ... It) • I fa ~ o 11O 100 fa -100 -1)0 -1)0 -fO -1O 1O fO "C 00 r.enm DROP ~ I Z[ MAP Figure 6 : Drop size and COllcentration maps produced by the Y -jet atomizer, CFD modelling, coupled with the above mentioned experiments in cold conditions, suggested different reactor schemes, involving CSTR and plug flow reactors with different volumes, input and output streams, Figure 7 shows the scheme that gives the best performance in terms of ratio between accuracy in the prediction of NOx and simplicity. There is the internal reaction zone (IRZ) which is mainly fed by recirculation gases from the ECZ (external combustion zone), A small amount of air (essentially atomization air) penetrates the IRZ, while high momentum, larger drops carry part of the fuel into this zone. The ECZ is fed by the small evaporating drops that are entrained by the flow field, and by secondary air. Tertiary air reaches the post combustion zone (PCZ) where most of the ECZ products flow in. Detailed nitrogen chemistry has been implemented by considering the Miller and Bowman kinetic scheme based on thermal, prompt and fuel NOx formation reactions. 6 |
