Publications Scientifiques

Permanent URI for this communityhttps://dspace.univ-boumerdes.dz/handle/123456789/10

Browse

Author: search.filters.author.Loubar, KhaledSubject: search.filters.subject.Natural gas

Search Results

Now showing 1 - 6 of 6
  • No Thumbnail Available
    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, Mohand
    This 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.
  • No Thumbnail Available
    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, Mohand
    With 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.
  • No Thumbnail Available
    Item
    Numerical investigation on combustion characteristics of both diesel and dual fuel engine at part load conditions using converge cfd
    (2019) Benbellil, Messaoud Abdelalli; Lounici, Mohand Said; Loubar, Khaled; Ouchikh, Sarah
    Petroleum resources are nite and, therefore, search for their alternative non-petroleum fuels for internal combustion engines is continuing all over the world. Moreover, gases emitted by petroleum fuel-driven vehicles harm the environment and human health. Dual-fuel engine (diesel/NG) represents one of a possible solution to reduce emissions from a diesel engine. Therefore, this method has been given a lot of attention from many researchers to improve engine performance and reduce diesel consumption, particularly at full loads. However, it is necessary to study the dual-fuel (DF) combustion process with more details at part loads, due to the poor performance at these conditions. This study numerically investigated the e ect of DF (dual fuel) operating mode on combustion characteristics of an existing diesel engine using natural gas as primary fuel and neat diesel as pilot fuel at part loads by adopting a 3D-CFD simulation using the code CONVERGE. A series of numerical simulations were carried out, the purpose of which to gain a better understanding of the combustion behavior in dual-fuel engines. The results are rst validated using experimental data. A comparison with neat diesel fuel operation is achieved.
  • No Thumbnail Available
    Item
    Experimental investigation on NG dual fuel engine improvement by hydrogen enrichment
    (Elsevier, 2014) Lounici, Mohand Said; Boussadi, Asma; Loubar, Khaled; Tazerout, Mohand
  • No Thumbnail Available
    Item
    Towards improvement of natural gas-diesel dual fuel mode : an experimental investigation on performance and exhaust emissions
    (Elsevier, 2014) Lounici, Mohand Said; Loubar, Khaled; Tarabet, Lyes; Balistrou, Mourad; Niculescu, Dan-Catalin; Tazerout, Mohand
  • No Thumbnail Available
    Item
    Investigation on heat transfer evaluation for a more efficient two-zone combustion model in the case of natural gas SI engines
    (Elsevier, 2011) Lounici, Mohand Said; Loubar, Khaled; Balistrou, Mourad; Tazerout, Mohand
    Two-zone model is one of the most interesting engine simulation tools, especially for SI engines. However, the pertinence of the simulation depends on the accuracy of the heat transfer model. In fact, an important part of the fuel energy is transformed to heat loss from the chamber walls. Also, knock appearance is closely related to heat exchange. However, in the previous studies using two-zone models, many choices are made for heat transfer evaluation and no choice influence study has been carried out, in the literature. The current study aims to investigate the effect of the choice of both the heat transfer correlation and burned zone heat transfer area calculation method and provide an optimized choice for a more efficient two-zone thermodynamic model, in the case of natural gas SI engines. For this purpose, a computer simulation is developed. Experimental measurements are carried out for comparison and validation. The effect of correlation choice has been first studied. The most known correlations have been tested and compared. Our experimental pressure results, supported for more general and reliable conclusions, by a literature survey of many other studies, based on measured heat transfer rates for several SI engines, are used for correlation selection. It is found that Hohenberg’s correlation is the best choice. However, the influence of the burned zone heat transfer area calculation method is negligible