Some of the hydrocarbon fuels (e.g. JP-4 and JP-8) have the endothermic effect that increases heat capacity by means of chemical heat absorption due to its thermal decomposition above some temperature. These fuels are called as the endothermic fuel (EF) and able to apply as the coolant for the regenerative cooling system of the hot parts in the propulsion system and the hypersonic flight vehicle. In the present paper, the heat absorption characteristics of methylcyclohexane (MCH) which is one of the EF and also one of the major component of hydrocarbon fuels (JP-4 and JP-8) are made experimentally clearly. Especially the decomposition temperature can be reduced experimentally with the platinum catalysts to the appropriate value for the regenerative cooling systems. These results are useful to giving the flexibility for setting the surface temperature of cooling parts as well as improving the cooling performance in the regenerative cooling systems with the EF.
The passenger amount of air transportation increased up to eight times during past 30 years. Due to the dramatically growth of aviation, CO2 emissions from aircraft engine doubled during this period. Rapid growth of aviation sector would cause climate change, local air pollution and noise problem. In order to mitigate these environmental impacts of aviation, optimal aircraft operation is necessary. The goal for the research is set to formulate optimization model which can consider these environmental impact and to evaluate the mitigation by applying the model to domestic lines of Japan. This paper describes the airline fleet assignment problem including externalities of environmental impacts. The model explores optimal aircraft type, which minimizes social cost that is the sum of total operating cost and external cost of CO2 and NOx emissions. The results show optimal fleet assignment can mitigate environmental impact in some degree. However, it might be almost impossible to achieve the reduction target only by optimal fleet assignment.
A novel two-dimensional grid generation method using binary data structure is developed in this study. Rectangular shape with 1:√2 is used as a grid element so that even after the grid is divided into two, the shape of the element is self-similar. The number of grid points required to describe the geometry is evaluated theoretically, and clearly shows that the geometry can be described by less number of grid points compared with quadtree structure which is often used in two-dimensional grid generation. A grid generator is developed and grid is generated around several different geometries. Finally, the way to extend current method to three-dimensional cases are shown.
The behavior of a laser-supported detonation wave and the power generation performance in a laser-driven MHD generator which can be one of the candidates of space-based laser-to-electrical power converters are examined by a time-dependent one-dimensional numerical simulation. The electric power is generated through two modes attributed to 1) the propagation of detonation wave itself in the MHD channel and 2) the high temperature and pressure gas flow caused enough after the propagation of detonation wave. The fluid and plasma properties just behind the detonation wave are varied markedly owing to the strong Lorentz force under the applied magnetic field. The generator performance is comparable or superior to that in the conventional seeded plasma MHD generator, although the laser-driven MHD generator is supposed to be operated repetitively.
It is reported that a control augmentation system (CAS) with a fuzzy neural network (FNN) controller for an aircraft is robust against various flight conditions. This paper describes analyses of the FNN controller's internal structure, and results of performance improvement, into the simulation. We have confirmed that the FNN controller which consists of a proportional gain and an offset, minor-feedback roll angular velocity of the aircraft, similar to a stability augmentation system (SAS), and the CAS with FNN can suppress variations of time constants and gains on the aircraft's lateral motion.