Creep of elastic support rubber used for main engine on actual ship was measured periodically between 8 years half. And the effects of the creep on property (rubber hardness, compression spring constant, tension intensity, elongation), vibration displacement, and vibrational acceleration were examined. Coefficient of thermal expansion by temperature change of rubber vibration isolator agrees almost even in the condition that the load was taken with theoretical value. Degradation of the property of the rubber as the distortion rate reached 15% was about average 20% and deterioration quantity as vibration isolator were 5 or 10dB in the average of each frequency.
In this paper, an expert system for deciding running condition and diagnosing faults of medium and large-sized diesel engines are presented. The system consists of three parts. First is the transient data acquiring part by which the necessary parameters of the engine can be acquired through the A/D transforming circuits, Second is the simulative calculation part by which we can able to calculate subsequent spatial and temporal history of most of the parameters, such as burning rate, local temperature, NO emission and soot etc, and according to this information, the best running condition for marine diesel engines can be decided. By com-paring the experimental with calculated values for the engines, it is revealed that the model predicts with good accuracy engine performance and with reasonable accuracy nitric oxide emissions. Third is the expert diagnostic part, which is still not completed because of lacking of the data.
Up to now pollutant emissions was not considered a problem in the field of marine engines. However, the International Maritime Organization (IMO) is agreed with the legislation that the NO emission of the marine engine produced from 2000 will be reduced to the present level of 70 percent. In this paper, the combustion simulation model, initially developed for high-speed, direct injection diesel engines, is used for studying the performance and emission characteristics of the 2-cycle, slow speed diesel engines are presented. In the simulative calculation by which we can able to calculate subsequent spatial and temporal history of most of the parameters, such as burning rate, local temperature, NO emission and soot etc, and according to this information, distribution of liquid fuel's temperature and burning area in the combustion chamber can be described three dimensionally using a 3-D volume rendering application.
The knowledge of subcooled film boiling heat transfer is important as the basis of understanding the reflood-ing phenomenon during the emergency cooling in a nuclear reactor under a loss of coolant accident. In this study, forced convection film boiling heat transfer from a vertical cylinder in Freon-113 flowing upwards along the cylinder was measured for the flow velocities ranging from 0 to 1.3 m/s, and liquid subcoolings ranging from 0 to 20 K at pressures near atmospheric. A platinum heater with a diameter of 3 mm was heated by electric current. The heat transfer coefficients obtained are almost independent of vertical positions on the cylin-der. The heat transfer coefficients are almost independent of velocity for the velocities lower than about 1 m/s and become higher for the velocities higher than 1 m/s. The heat transfer coefficients at each velocity are higher for higher liquid subcoolings. Improvement of film boiling heat transfer from the vertical cylinder with the increase in flow velocity is much less than that of horizontal cylinder in cross flow previously reported by the authors. This is mainly due to the difference of heat transfer enhancement mechanism; the former is the drug force on vapor flow acted by a liquid flow and the latter is the pressure gradient near the front stagnation point caused by external potential flow.