Izvorni znanstveni članak
https://doi.org/10.21278/brod77415
Numerical investigation on EGR strategy and combustion-emission characteristics for a large two-stroke marine ammonia/diesel dual-fuel engine across the entire operating envelope
Xianfu Ma
; Marine Engineering College, Dalian Maritime University, Dalian 116026, China
Daoyi Lu
; Marine Engineering College, Dalian Maritime University, Dalian 116026, China
*
Juntian Liu
; Marine Engineering College, Dalian Maritime University, Dalian 116026, China
Huaiyu Wang
; College of Power and Energy Engineering, Harbin Engineering University, Harbin, 150001, China
Keying Cui
; Dalian Marine Diesel Co., Ltd, Dalian 116021, China
Huibing Gan
; Marine Engineering College, Dalian Maritime University, Dalian 116026, China
* Dopisni autor.
Sažetak
To balance NOX emissions and performance in ammonia-fueled marine engines, this study investigates exhaust gas recirculation (EGR) effects on combustion, performance, and emissions, and proposes a full-load EGR strategy. Based on a validated CFD model of a methanol/diesel dual-fuel engine and an ammonia spray model, an ammonia/diesel dual-fuel engine model was developed. Simulations at four typical loads were conducted with various EGR rates. Results show that higher EGR slows ammonia combustion, prolongs combustion duration, intensifies after-burning, and increases ammonia emissions. Heat release rate is load-dependent, with peaks regulated by EGR. Engine performance varies with load: the gross indicated mean effective pressure (IMEPg) increases with EGR at low-to-medium loads, but first rises then decreases at high loads. EGR effectively reduces NOX emissions at all loads, with maximum reduction ranging from 71.5 % to 90.2 %. Fuel NOX shows higher sensitivity to EGR than thermal NOX. However, EGR also increases ammonia and N2O emissions—marginal at low loads but significant at medium-to-high loads, with a distinct surge threshold. Recommended EGR rates are 50 %, 40 %, 30 %, and 10 % at 25 %, 50 %, 75 %, and 100 % loads, respectively. This strategy enables compliance with IMO Tier III NOX regulations, achieves low ammonia and N2O emissions, and improves IMEPg.
Ključne riječi
Ammonia/diesel engine; high-pressure direct injection; exhaust gas recirculation; entire operating envelope; NOX reduction
Hrčak ID:
351221
URI
Datum izdavanja:
1.10.2026.
Posjeta: 0 *