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The present study shows a performance of pulsed flame jet igniter in a two-stroke engine of small motorcycle where the high maximum rate of pressure rise and the high maximum combustion pressure are achieved. At the present stage, however, slight decreases in IMEP and thermal efficiency are recognized due to a large heat loss. An improvement in the execution of the exothermic process of combustion should enhance the performance characteristics of engines equipped with pulsed flame jet igniters.

The effects of fuel injection timing on fuel-air mixture formation, combustion and emissions for a PREmixed lean DIesel Combustion (PREDIC) engine has been studied numerically by the KIVA II modeling package. The software was modified with an improved autoignition and combustion submodel, which describes the formation of combustible or ignitable fuel-air mixtures by turbulent mixing, and describes four chemical reactions, including low-temperature oxidation. The results indicate that the present computational model reproduces major features of two-stage autoignition and experimentally observed trends in NO and unburned fuel emissions. The relationships among in-cylinder distributions of fuel sprays, fuel-air equivalence ratio, temperature and mass fractions of NO and unburned fuel were demonstrated by graphically imaged results. A method of fuel-air mixture characterization has been introduced and used to analyze the numerical results.

A transversely injected jet into a hypersonic flow is simulated numerically in order to study the flow field of the injection jet in the hypersonic atmosphere, its heat flux on the body surface and the moments working on the body. The flowfields is governed by the two-dimentional Reynolds averaged full Navier-Stokes equations with an algebraic eddy viscosity model developed by Baldwin-Lomax. The governing equations are solved using the Harten-Yee type TVD and central difference schemes to the convex and viscous terms, respectively. The real gas effect is considered in the numerical analysis. The jets injected across the main flows of Mach 10 and 15 are compared.

An impingement of axisymmetric supersonic jet on the ground is simulated numerically to evaluate the jet flow configuration on the ground, which inclines from 0 to 45 degrees, with a real gas assumption for two-dimensional simulations and with an ideal gas assumption for three-dimensional simulations. A solid particle-suspended two-phase jet impinging on the ground is also solved using the Euler equations for the solid particle-phase with a real gas assumption. An explicit TVD-Upwind scheme is used for the gas-phase and an explicit Flux Vector Splitting Upwind scheme for the solid-phase. Numerical results of a vertically impinging jet to the ground show that a plate shock forms just above the ground for the cases of the single-phase and two-phase jet. Then the jet flow is curved along the ground after hitting the ground to form the so-called wall jet, which is expanded and recompressed alternately along the ground. The solid particles hit and stay on the ground in the present system.