Impact of Multi-Component Surrogates on the Performances, Pollutants, and Exergy of IC Engines

Abstract

Even though there is a pressing interest in clean energy sources, compression ignition (CI) engines, also called diesel engines, will remain of great importance for transportation sectors as well as for power generation in stationary applications in the foreseeable future. In order to promote applications dealing with complex diesel alternative fuels by facilitating their integration in numerical simulation, this paper targets three objectives. First, generate novel diesel fuel surrogates with more than one component. Here, five surrogates are generated using an advanced chemistry solver and are compared against three mechanisms from the literature. Second, validate the suggested reaction mechanisms (RMs) with experimental data. For this purpose, an engine configuration, which features a reacting spray flow evolving in a direct-injection (DI), single-cylinder, and four-stroke motor, is used. The RNG k-Epsilon coupled to power-law combustion models is applied to describe the complex in-cylinder turbulent reacting flow, while the hybrid Eulerian-Lagrangian Kelvin Helmholtz-Rayleigh Taylor (KH-RT) spray model is employed to capture the spray breakup. Third, highlight the impact of these surrogate fuels on the combustion properties along with the exergy of the engine. The results include distribution of temperature, pressure, heat release rate (HRR), vapor penetration length, and exergy efficiency. The effect of the surrogates on pollutant formation (NOX, CO, CO2) is also highlighted. The fifth surrogate showed 47% exergy efficiency. The fourth surrogate agreed well with the maximum experimental pressure, which equaled 85 Mpa. The first, second, and third surrogates registered 400, 316, and 276 g/kg fuel, respectively, of the total CO mass fraction at the outlet. These quantities were relatively higher compared to the fourth and fifth RMs.

Utilization of renewable biodiesel blends with different proportions for the improvements of performance and emission characteristics of a diesel engine

“…The principle of energy conservation states that the sum of the heat entering the micro-element and the work done on the micro-element by body and surface forces is equal to the rate of energy increase within the micro-element. Equations are as follows [ 37 ]: where e is the specific internal energy in the cylinder, J/kg; h e is the specific enthalpy of the inflow gas, J/kg; h o is the specific enthalpy of the outflow gas, J/kg; Q j is the heat release of fuel, J; p i is the pressure in the cylinder, Pa; V is the working volume, cm 3 ; Q s is the heat loss, J; h u is the specific enthalpy of the leaking gas, J/kg; q o is the fuel latent heat of vaporization, J; f is the fraction by mass of vaporized fuel. Ideal gas equation of state …”

Entropy Generation Analysis in Turbulent Reacting Flows and Near Wall: A Review

“…In addition to the efforts made to investigate generic or canonical systems, numerical investigations on entropy generation in the RANS framework were also performed in practical systems, such as IC engines [ 118 , 119 , 120 , 121 , 122 ]. Most of the reported numerical studies related to IC engines extend to 3D the methodology referenced above in the experimental investigations [ 37 , 39 , 41 , 43 , 44 , 46 ] mentioned in the previous section dealing with simple exergy or energy balance.…”

“…Recently, Fathi et al [ 121 ] and Mondo et al [ 122 ] also applied the exergy balance within the RANS framework on an IC engine. The first investigation [ 121 ] revealed that the variation of the spray angle in a Reactivity Controlled Combustion Ignition (RCCI) dual fuel engine, fueled by n-heptane, affects the exergy efficiency, which found its maximum value for spray angle between 5° and 20°.…”

“…The first investigation [ 121 ] revealed that the variation of the spray angle in a Reactivity Controlled Combustion Ignition (RCCI) dual fuel engine, fueled by n-heptane, affects the exergy efficiency, which found its maximum value for spray angle between 5° and 20°. The second work [ 122 ] performed the investigation on direct-injection (DI), single-cylinder and four-stroke diesel engines to test different fuel reaction mechanisms, which are numerically generated and assess their predictability in comparison with available experimental data. The exergy efficiency was found to be different when using different reaction mechanisms and was observed to follow the behaviors of the pressure variations.…”