氨燃料部分预裂解对预燃室射流点火氨发动机燃烧及温室气体排放的影响OA北大核心

Based on an ammonia engine system that utilizes exhaust gas waste heat to achieve partial fuel pre-decomposition,an ammonia decomposition reactor simulation model was established,and numerical simulation of a pre-chamber jet ignited large-bore marine gas engine was carried out on the basis of model-predicted ammonia conversion rate.The impact of fuel decomposition ratio on the combustion of pre-chamber ammonia engines and greenhouse gases(GHGs)emissions were investigated.Furthermore,oxygen enrichment measures were implemented in the low decomposition ratio case,characterized by poor engine performance yet stable ammonia conversion rates in the decomposition reactor,to investigate the impact of oxygen enrichment conditions on ammonia engine performance.It is found that the increase of both decomposition ratio and oxygen volume ratio contributes to the enhancement of fuel mixture combustion,with the indicated thermal efficiency of the engine reaching 48.98%and N2O emission reduced to 0.39 g/(kW·h)at 7.5%decomposition ratio,while similar engine performance can be achieved by increasing the oxygen volume ratio to 27%(2.5%decomposition ratio).However,the significant increase in NOx emissions may limit the ability to achieve better engine performance by further increasing the decomposition ratio and oxygen volume ratio.In addition,the maximum reduction in GHGs emissions in the 10.0%decomposition ratio case is estimated to be about 64.2%through full life cycle GHGs emissions.