The woody biomass becomes more important fuel in the plants which utilise solid fuel such as coal and pet coke, because the woody biomass can be used as renewable energy. This trend is same for both power boilers and industrial boilers. There are some of boilers which have already utilised the woody biomass for co-firing with coal. However its co-firing ratio is limited to a few percent due to pulveriser's capacity margin. The difficulty of pulverising woody biomass affects the pulveriser performance directly. Therefore the grinding phenomenon have been analysed by using the laboratory scale experimental equipment. It became clear that the roller type pulveriser is most effective among three grinding types which are ball mill, vibration mill and roller type.
The author introduces a typical trend of bunker fuel (fuel for marine engines) quality in the world. Recent troublemaking fuels have rather low-viscosity and low-sulfur percentage originated in much cutter stocks blending. In this paper, the counter effects of high-aromatic cutter stocks like LCO (“light cycle oil” or “cracked gas oil”) on bunker fuel combustion are examined applying a visual test engine. Furthermore an approach to model bunker fuel (heavy residual portion as base stocks plus light portion as cutter stocks) combustion by CFD is introduced. The author reasons that the rise of cylinder liner temperature due to longer burn-up flame length could be an origin of recent lubricating troubles. The extended flame would be caused by such a malfunction that the high-aromatic light portion would not complete its role to help the combustion of the heavy residual portion.
Maruti Suzuki developed CNG /LPG Bifuel vehicle that has cost effective, good performance, high reliability system with sophisticate multi-point gas injection technologies. Optimized engine setting show comparable engine power in CNG and LPG operation compared with petrol operation. Using with same emission system with base petrol vehicle, BS4 emission standard was achieved in each fuel operation by adjusting dedicated ECU software.
Recently, engine control becomes more and more complicated for the low emission and low fuel consumption. The number of controller parameters is increasing and minute control is necessary. Therefore, it is important to optimize controller parameters depending on operating conditions and to optimize device operations in consideration of delay and interaction. However, it requires huge resources. Thus, we established MBC (Model Based Calibration) technology, which can optimize the controller parameters in short time with high accuracy, through the development of the measurement technique for the DISI (Direct Injection Spark Ignition) and the DISI turbo. In addition, we established HILS (Hardware in the Loop Simulation) and MILS (Model in the Loop Simulation) technologies, which could examine the motion of devices on the desk, with the developed MBC.
Because of an accidental event of sodium spillage, occurred in a nuclear facility, Japan, sodium combustion has attracted special attention since 1995. In this lecture, relevant to the sodium combustion, the spontaneous ignition for a droplet and/or a pool has been discussed with putting focus on the ignition delay and ignitability which have been elucidated through coorparative works after the accident. For elucidating ignition phenomea of sodium, a theoretical work has been conducted, under consideration that the surface reaction can mainly exert influences. Through conducting the asymptotics, it has been found that the governing equation for the energy has the same form as that used in 1930s for constructing “Thermal Explosion Theory”, and that both the ignition delay time and the limit of ignitability are closely related to the oxygen concentration and the representative size of droplet and/or pool, as well as the initial sodium temperature. It has also been derived a set of comprehensive parameters for the ignition delay time and the limit of ignitability, by which it has succeeded in fairly correlating dominant parameters that can exert influences on the ignition. In addition, a fair degree of agreement between the experimental and analytical results has been demonstrated, as far as the trend and approximate magnitude are concerned. Because of the simple forms of the comprehensive parameters, they are expected to be useful in evaluating ignition delay and ignitability. Related subjects are also explained although they are on the way.
The effect of the Lewis number of a mixture on characteristics of the edge flame established in a counterflow field was experimentally investigated. The edge flame was established in a counterflow field with a stretch rate gradient between the inclined counterflow slot-jet burners. A flame edge was generated in the high stretch region where the distance between two burners was small, and twin counterflow flames were stabilized in the low stretch side where the distance between burners was large. The flame shape strongly depended on the Lewis number irrespective of fuel. The local stretch rate at the flame edge of CH4 mixtures that the Lewis number was nearly unity was influenced by the Lewis number. On the other hand, the local stretch rate at the flame edge of C3H8 mixtures that the Lewis number was much larger than unity showed no dependence on the Lewis number. Such a characteristic well agreed with numerical results of extinction behavior of twin counterflow planar flames. A difference between the edge flame and twin counterflow flames appeared in the threshold mole fraction of He in the mixture when the local stretch rate at the flame edge or the extinction stretch rate of twin counterflow flames changed from decreasing trend to increasing trend.