Relations between stagnation and in-flight phases are derived both analytically and numerically, for hydrodynamic variables relevant to direct-drive inertial confinement fusion implosions. Scaling laws are derived for the stagnation values of the shell density and areal density; also the hot spot pressure, temperature and areal density. Simple formulas are derived for the thermonuclear energy g...

LLE Review, Volume 90 49 Introduction The base-line direct-drive ignition target design for the National Ignition Facility (NIF)1 is a thick cryogenic DT-ice layer enclosed in a thin CH shell.2,3 In direct-drive inertial confinement fusion (ICF)4 a spherical target is illuminated by a large number of laser beams to provide a spherically symmetric implosion. Target implosions with cryogenic DT f...

Homogeneous Charge Compression Ignition (HCCI) is an advanced combustion strategy that able to reduce nitric oxides (NOx) emissions and increase fuel efficiency simultaneously. This study investigated the effects of premixed kerosene fuel on the auto-ignition characteristics in a light-duty compression ignition engine. A partial HCCI engine was modified from a single cylinder, four-stroke, dire...

The influence of corners on the ignition of a solid exposed to a surface energy flux is analyzed with large activation energy asymptotics. We begin with the analysis of the ignition of semi-infinite wedges by a constant heat flux. Two stages and two spatial zones, reactive and inert, are found. The ignition stage can be described by a slowly convergent asymptotic expansion for the increment in ...

To characterize the ignition process in homogeneous charge compression ignition engines, high fidelity simulations are performed to study the effects of different initial temperature distributions on the autoignition of a turbulent homogeneous mixture at high pressure. The effects of the initial temperature distribution on the ignition and subsequent heat release are studied by comparison of si...

Ignition processes in the hydrogen-oxygen system were simulated by solving the corresponding conservation equations (i.e., conservation of mass, energy, momentum, and species mass) for one-dimensional geometries using a detailed reaction mechanism and a mUltispecies transport model. An additional source term in the energy conservation allowed the treatment of induced ignition, and a realistic m...

In order to understand better the auto-ignition process in an HCCI engine, the influence of some important parameters on the auto-ignition is investigated. The inlet temperature, the equivalence ratio and the compression ratio were varied and their influence on the pressure, the heat release and the ignition delays were measured. The inlet temperature was changed from 25 to 70 °C and the equiva...

This paper presents a comprehensive approach to improve the analysis and design process of automotive ignition coils. The delivered voltage and energy of the coil to the spark plug load are the two essential requirements placed on a coil design. The prediction of these two quantities, derived from the simulated transient secondary current and voltage, is fundamental to the design process and al...

Catalytic partial oxidation (CPO) of methane to syngas has received considerably interest recently as a way to utilize remote natural gas resources. Despite this interest, the mechanism of methane CPO is not completely understood. For example, there is disagreement in the literature if syngas is formed directly from oxidation or whether an indirect mechanism is responsible. Investigation of the...