A New Combustion Method in a Burner with Three Separate Jets

Oxy-flames from burners with separated jets present attractive perspectives because the separation of reactants generates a better thermal efficiency and reduction of pollutant emissions. The principal idea is to confine the fuel jet by oxygen jets to favor the mixing in order to improve the flame stability. This chapter concerns the effect of equivalence ratio on characteristics of a non-premixed oxy-methane flame from a burner with separated jets. The burner of 25 kW power is composed with three aligned jets, one central methane jet surrounded by two oxygen jets. The numerical simulation is carried out using Reynolds Average Navier-Stokes (RANS) technique with k-ε as a turbulence closure model. The eddy dissipation model is applied to take into account the turbulence-reaction interactions. The study is performed with different global equivalence ratios (0.7, 0.8 and 1). The validation of the numerical tools is done by comparison with experimental data of the stoichiometric regime (Ф = 1). The two lean regimes of Ф = 0.7 and 0.8 are investigated only by calculations. The velocity fields with different equivalence ratio are presented. It yields to increase of longitudinal and transverse velocity, promotes the fluctuation in interaction zone between fuel and oxygen also a better mixing quality and a decrease of the size of the recirculation zone.

Investigation of the Gasoline Engine Performance and Emissions Working on Methanol-Gasoline Blends Using Engine Simulation

The aim of this study is to develop the one-dimensional model of a four-cylinder, four-stroke, multi-point injection system SI engine and a direct injection system SI engine for predicting the effect of various fuel types on engine performances, specific fuel consumption, and emissions. Commercial software AVL BOOST was used to examine the engine characteristics for different blends of methanol and gasoline (by volume: 5% methanol [M5], 10% methanol [M10], 20% methanol [M20], 30% methanol [M30], and 50% methanol [M50]). The methanol-gasoline fuel blend results were compared to those of net gasoline fuel. The obtained results show that when methanol-gasoline fuel blends were used, engine performance such as power and torque increases and the brake-specific fuel consumption increases with increasing methanol percentage in the blended fuel.

Numerical Investigation of the Shock Train in a Scramjet with the Effects of Back-Pressure and Divergent Angles

Numerical simulations are carried out to study the effect of divergence angle and adverse pressure gradient on the movement of shock wave train in a scramjet isolator. The commercial software tool ANSYS Fluent 16 was used to simplify two dimensional Reynolds averaged Navier Stokes equation with compressible fluid flow by considering the density-based solver with standard K-ε turbulence model. The species transport model with single step volumetric reaction mechanism is employed. Initially, the simulated results are validated with experimental results available in open literature. The obtained results show that the variation of the divergence angle and back pressure on the scramjet isolator has greater significance on the flow field. Also, with an increase in the back pressure, due to the intense turbulent combustion, the shock wave train developed should expand along the length and also moves towards the leading edge of the isolator leading to rapid rise in the pressure so that the pressure at the entrance of the isolator can match the enhanced back pressures.

Effects of Biodiesel Blends Varied by Cetane Numbers and Oxygen Contents on Stationary Diesel Engine Performance and Exhaust Emissions

This work investigated waste plastic pyrolysis oil (WPPO), 2-ethyl hexyl nitrate (EHN), and ethanol as sources of renewable energy, blending conventional diesel (CD), WPPO, and ethanol with EHN was to improve the combustion and performance characteristics of the WPPO blends. EHN has the potential to reduce emissions of CO, CO2, UHC, NOX, and PM. Ethanol improves viscosity, miscibility, and the oxygen content of WPPO. Mixing ratios were 50/WPPO25/E25, 60/WPPO20/E20, 70/WPPO15/E15, 80/WPPO10/E10, and 90/WPPO5/E5 for CD, waste plastic pyrolysis oil, and ethanol, respectively. The mixing ratio of EHN (0.01%) was based on the total quantity of blended fuel. Performance and emission characteristics of a stationary 4-cylinder water-cooled diesel Iveco power generator were evaluated with ASTM standards. At 1000 rpm, the BSFC was 0.043 kg/kWh compared to CD at 0.04 kg/kWh. Blend 90/WPPO5/E5 had the highest value of 14% for BTE, while the NOX emissions for 90/WPPO5/E5, 80/WPPO10/E10, and 70/WPPO15/E15 were 384, 395, and 414 ppm, respectively, compared to CD fuel at 424 ppm. This is due to their densities of 792 kg/m3, 825 kg/m3 which are close to CD fuel at 845 kg/m3 and the additive EHN. These results show blends of WPPO, ethanol and EHN reduce emissions, and improve engine performance, mimicking CD fuel.

Stability Analysis of Long Combination Vehicles Using Davies Method

The cargo transportation in the world is mostly dominated by road transport, using long combination vehicles (LCV’s). These vehicles offer more load capacity, which reduces transport costs and thus increases the efficiency and competitiveness of companies and the country. But the tradeoff of LCV’s is their low lateral stability and propensity to roll over, which has been the focus of many studies. Most vehicle stability models do not consider the longitudinal aspects of the vehicle and the road, such as the stiffness of the chassis, the gravity center location, and the longitudinal slope angle of the road. But, the use of three-dimensional models of vehicles allows a more rigorous analysis of vehicle stability. In this context, this study aims to develop a three-dimensional mechanism model representing the last trailer unit of an LCV under an increasing lateral load until it reaches the rollover threshold. The proposed model considers the gravity center movement of the trailer, which is affected by the suspension, tires, fifth-wheel, and the chassis. Davies method has proved to be an important tool in the kinetostatic analysis of mechanisms, and therefore it is employed for the kinetostatic analysis of the three-dimensional mechanism of the trailer.

Application of Variable Compression Ratio VCR Technology in Heavy-Duty Diesel Engine

The chapter presents the application of variable compression ratio VCR technology for an internal combustion engine. The engine’s overall construction has been designed as the deep reconfiguration of liquid-cooled, heavy-duty diesel engine of type IFA 4 VD 14,5/12-1 SRW. An eccentric shaft-based sliding mechanism has been used for changing position of engine cylinder head assembly. By ensuring a high stiffness of the engine layout together with additional sliding mechanism, the combustion chamber volume of the engine can be changed precisely without changing the displacement of the cylinders. In result, the engine compression ratio can be continuously varied during normal engine operation from the value of 19:1 down to 9:1.

Knock Suppression of a Spark-Ignition Aviation Piston Engine Fuelled with Kerosene

Spark-ignition (SI) engine has a high power density, making it suitable for unmanned aerial vehicles. Normally, gasoline fuel with a high octane number (ON) is used for a spark-ignition engine. However, gasoline fuel is easy to be evaporated and has a low flash point which is unsafe for aviation engines. Kerosene with a high flash point is safer than gasoline. In this chapter, the combustion characteristics of kerosene for a spark-ignition aviation piston engine are analyzed. A three-dimensional (3D) model is setup, and the combustion process of the engine fuelled with kerosene is simulated. Later, the knock limit extension by water injection is evaluated experimentally. The results indicate that water injection can suppress the knock of SI engine with kerosene in some extent and the output power can be improved significantly.