Influence of fuel properties on internal nozzle flow development in a multi-hole diesel injector

Journal Article · 30 May 2017 · Fuel

DOI: https://doi.org/10.1016/j.fuel.2017.04.123 · OSTI ID:1413755

Torelli, Roberto  ^[1]; Som, Sibendu ^[1]; Pei, Yuanjiang ^[2]; Zhang, Yu ^[2]; Traver, Michael ^[2]

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1. Argonne National Lab. (ANL), Lemont, IL (United States)
2. Aramco Services Co., Novi, MI (United States)

Fuel phys­i­cal prop­er­ties are known to in­flu­ence in-noz­zle flow be­hav­ior, in turn af­fect­ing spray for­ma­tion in in­ter­nal com­bus­tion en­gines. A se­ries of 3D sim­u­la­tions was per­formed to model the in­ter­nal noz­zle flow in a five-hole mini-sac diesel in­jec­tor. The goal of the study was to eval­u­ate the be­hav­ior of two gaso­line-like fu­els (full-range naph­tha and light naph­tha) and com­pare them against n-Do­de­cane, se­lected from a palette used as a diesel sur­ro­gate. Sim­u­la­tions were car­ried out us­ing a multi-phase flow rep­re­sen­ta­tion based on the mix­ture model as­sump­tion with the Vol­ume of Fluid (VOF) method, and in­clud­ing cav­i­ta­tion ef­fects by means of the Ho­mo­ge­neous Re­lax­ation Model (HRM). Val­i­dated method­olo­gies from our pre­vi­ous stud­ies were em­ployed to ac­count for full nee­dle mo­tion. De­tailed sim­u­la­tions re­vealed the in­flu­ence of the fuel prop­er­ties on in­jec­tor per­for­mance, in­jected fuel en­ergy and propen­sity to cav­i­ta­tion. The three fu­els were com­pared with re­spect to global pa­ra­me­ters such as mass flow rate and area con­trac­tion co­ef­fi­cients, and lo­cal pa­ra­me­ters such as pres­sure and ve­loc­ity dis­tri­b­u­tion in­side the sac and ori­fices. Para­met­ric in­ves­ti­ga­tions were also per­formed to un­der­stand the fuel re­sponse to changes in the fuel in­jec­tion tem­per­a­ture, in­jec­tion pres­sure, and geom­e­try de­tails. Cav­i­ta­tion mag­ni­tude was ob­served to be strongly as­so­ci­ated with the val­ues of sat­u­ra­tion pres­sure. Ow­ing to their higher volatil­ity, the two gaso­line-like fu­els were ob­served to cav­i­tate more than n-Do­de­cane across all the in­ves­ti­gated con­di­tions. While at full nee­dle lift cav­i­ta­tion was re­duced for all fu­els, dur­ing the in­jec­tion tran­sients the gaso­line-like fu­els showed more propen­sity to cav­i­tate in­side the ori­fice and seat re­gions. This is ex­pected to have a pro­found in­flu­ence on noz­zle ero­sion. Al­though full-range and light naph­tha have lower den­si­ties com­pared to n-Do­de­cane, ow­ing to their lower vis­cos­ity, the mass flow rate dif­fer­ences be­tween the naph­tha fu­els and n-Do­de­cane were small. In conclusion, the analy­sis of fuel en­ergy con­tent showed that the higher lower heat­ing value (LHV) of light naph­tha helped com­pen­sate for the slightly lower to­tal de­liv­ered mass.

• Research Organization: Argonne National Lab. (ANL), Argonne, IL (United States)
• Sponsoring Organization: Aramco Services Company; USDOE
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1413755
• Alternate ID(s): OSTI ID: 1415657
• Journal Information: Fuel, Journal Name: Fuel Journal Issue: C Vol. 204; ISSN 0016-2361
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English