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In recent years, entirely combined CFD-Multi-Zone chemistry combustion models have been developed fashionably in investigating the HCCI engine combustion. In this work, an enhanced Multi-zone chemistry model is recommended for the HCCI engine combustion and emission simulation. There are four sorts of zones enclosing the crevice zone; boundary layer zone, external zones and center zone of the engine cylinder have been applied. The volume of each zone is steady and depends on the engine geometry. The boundary layer zone is the closest zone to the engine cylinder wall. In this study, the reduced chemical kinetic oxidation mechanism of diesel/biodiesel-ethanol has been numerically investigated in homogenous charge compression ignition (HCCI) engine. The oxidation mechanism of the diesel oil-biodiesel-ethanol at different blends was developed and coupled with Multi-Zone chemical kinetics model.

The capabilities of various numerical models to accurately account for the onset and development of cavitation in diesel injector nozzles is assessed and evaluated. The numerical predictions of the models are computed, and are compared to measured experimental data and observations. The numerical predictions for actual diesel nozzle geometry have been validated with experimental measurements of the total vapor mass flow rate. This vapor flow is found to be developed along the nozzle length due to the nucleation of the cavitation bubbles inside the diesel injector. The cavitation inception criteria that is used for the quantitative cavitation calculations included vapor quality, voidage, cavitation kinetic energy and cavitation energy. The results indicate that the cavitation simulation model predicts a diffused and gradual vapor distribution inside the nozzle in agreement with the experimental data.

This work seeks to confirm the possibility of using Dimethyl ether (DME) as an additive to the blend of pure Natural gas or Natural Gas/Hydrogen blend to improve performance, efficiency, and emissions of a homogeneous charge compression ignition (HCCI) engine. In the proposed technique, Hydrogen could help to extend the operating range of CNG fuel in HCCI engine and decrease the regulated emissions significantly, while DME will play a major role in controlling the auto-ignition timing of the HCCI engine combustion especially at low intake charge temperature. This task has been achieved herein theoretically and numerically with farther validation by the experimental work. The main goal was to find the optimal operating conditions of CNG HCCI engine with the minimum number of laboratory engine tests.

The interaction of natural gas fuel manifold injection with the in-cylinder flow field, and the combustion behavior of an HCCI engine is numerically investigated by using numerous capabilities of multi-dimensional computational fluid dynamic (KIVA-3VR2) code coupled with detailed chemical kinetics. A validating oxidation reaction mechanism that mainly consisted from 314 elementary reactions among 52 species is employed to simulate the whole engine physicochemical process including the intake flow interaction with natural gas port fuel injection, the homogeneity of the gas fuel and the air during suction and compression strokes, autoignition and combustion process. The simulation problem of the gaseous fuel injection by using the original KIVA spray sub-model is solved by implementing a new modification into the original KIVA sub-routines to enable multiple inlet conditions through the use of regions.