As a fundamental study of the mixture formation process of the impinging diffusion direct injection diesel engine, characteristics of the unsteady gas jet impinging onto a projection on a wall was numerically studied. Numerical analysis was carried out on a 2-dimensional incompressible unsteady flow with two different gases of different density. The program code used was based on the SOLA scheme, which was expanded so that the density change caused by the mixing of the two different density of gases can be treated. Numerical results are able to describes the nature of the mixture formation process of the unsteady gas jet impinging onto a projection on a wall, which had been obtained through the authors' previous experimentation.
A liquid-phase methanol synthesis and decomposition process was proposed to recover wasted or unused discharged heat from industrial sources for the thermal energy demands of residential and commercial areas by chemical reactions. This paper summarized five fundamental researches and their results of the development of liquid phase reactor (heat exchanger accompanying chemical reaction), which are important to the methanol system. The five researches are as follows. (1) To evaluate the effect of transport process in the whole reaction process, the transport process of carbon monoxide (CO) and hydrogen (H2) gases in liquid phase methanol and methyl formate were studied. The fundamental data of transport process, such as solubility and diffusion coefficient, were obtained. (2) Solution and diffusion processes of single CO bubbles in liquid phase methanol were theoretically and experimentally studied under various pressures and temperatures. (3) The chemical reaction rate of methanol synthesis by hydrogenolysis of methyl formate was measured using a plate-type of Raney copper catalyst. The effect of thickness of Raney copper catalyst on the liquid-phase chemical reaction rate were investigated by varying the development time of the catalyst. (4) Investigation results of the catalyst such as surface area, pore radius, lattice size, and photographs of scanning electron microscope (SEM) were also obtained. (5) Furthermore, the liquid film distillation column accompanying chemical reaction was analyzed numerically to clarify the effect of gas flow velocity and liquid thickness on the catalytic reaction process.
This study purposes the development of the simulator system which evaluates the effect of the reduction measure of PM emitted from ships. As a case study, the Tokyo Bay that has six ports in the area was selected. The area has been modeled on a 1km × 1km grid scale. Calculations were based on the off-shore and coastal dispersion (OCD) model, which is popular as one of simulation models to predict the dilution at sea. This paper also arranged estimate technique of the emissions from ships. It is important that the PM emission is accurately estimated, when environmental policy is considered. So detailed inventories of ship emissions in the area were developed and mapped onto shipping routes and ports, based on 1999's record. The total emissions of PM from ships in the area amount to some 437tons per year. The distribution of the PM concentration was calculated by the numerical simulation. The results indicate that the contribution of PM emissions from ships to the air quality on land should not be disregarded.
In order to estimate the combustion process from the rate of heat release in two-stroke slow-speed diesel engines with side fuel injection type for marine use, it is necessary to grasp characteristics of the rate of heat release data under various engine conditions. Systematic measurements were carried out on assignment of the experiment design method with four parameters using a test engine. As a result, the characteristics of the three important values in the rate of heat release: combustion period, peak height, and period up to the peak could be obtained, depending upon mean effective pressure, engine speed and the four control parameters of engine performance. In particular, it was found that the peak in height does not change with increasing mean effective pressure over a certain level and double peaks can be seen under some fuel injecting conditions.