Publications Scientifiques
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Item Investigation of natural gas enrichment with high hydrogen participation in dual fuel diesel engine(Elsevier, 2021) Benbellil, Messaoud Abdelalli; Lounici, Mohand Said; Loubar, Khaled; Tazerout, MohandThis study explores the impact of natural gas (NG) enrichment with high H2 concentrations (20, 30, 40 and 50 by v %) on combustion characteristics, engine performance, exhaust emissions and knock in a compression ignition engine running in dual fuel (DF) mode. Results indicated that H2 addition to NG contributes to enhance gaseous fuel combustion that corresponds to an increased heat release rate (HRR) during the premixed phase of gaseous fuel that also causes an increase in the pressure peak, particularly at high loads. The maximum pressure peak and HRR correspond to 50% H2 addition. The combustion duration is shortened for all H2 mixtures. Regarding engine performance, an important benefit in terms of brake thermal efficiency is noted for all H2 blends; it increases with increasing enrichment rate and reaches approximately 16% increase for the 50% H2 mixture relative to pure NG case. Moreover, enriching NG with H2 is an effective solution for reducing unburned hydrocarbons and carbon monoxide at moderate to high engine loads. However, for NOx emissions, the addition of H2 to NG is only attractive at low and moderate loads. In addition, over 80% engine load, NG enrichment with H2 generates knock, which rapidly reaches high intensities.Item Investigation of natural gas enrichment with high hydrogen participation on knock in dual fuel diesel engine at high loads(2021) Benbellil, Messaoud Abdelalli; Lounici, Mohand Said; Loubar, Khaled; Tazrout, MohandWith growing worries about the safety of the environment and the lack of supplies of crude oil, a great deal of effort has been made to use alternative fuels in engines. For internal combustion engines, natural gas (NG) is one of the most attractive available fuels. The dual fuel (DF) concept is an effective way for its use. NG has a slow burning velocity and limited lean-burn ability. Enriching NG with hydrogen is an effective way to mitigate such demerits, since H2 is characterized by a rapid combustion speed, wider combustion limit and low ignition energy. For high engine loads operation, the engine risks to go through a hazardous knocking regime. This study explores experimentally the effect of NG enrichment with high H2 concentrations (20, 30, 40 and 50 by v %) in DF mode on knock at high engine loads of a compression ignition engine. Results indicated that enriching NG with high H2 concentrations in DF mode is an interesting technique for improving dual fuel engine up to 80% load without any knock. However, beyond this load (at 90% of full engine load) the knocking phenomenon appears with high intensities and occurs before achieving the maximum output power of the diesel engine (4.5 kW). In the case of pure NG, the engine reach the maximum output power (100% of full engine load) without knocking. An occurrence of knock with H2 addition might be due to a very low methane number of H2 that means hydrogen is highly prone to generate the knock than NG, which is mainly composed of methane. Knocking combustion causes major engine damage, reduces the efficiency and requires particular attention. Therefore, it is advisable to operate DF engine with H2 enrichment at the safe zone (from 20% to 80% engine load) to prevent knock.Item Experimental investigation on NG dual fuel engine improvement by hydrogen enrichment(Elsevier, 2014) Lounici, Mohand Said; Boussadi, Asma; Loubar, Khaled; Tazerout, Mohand