The Ship & Ocean Foundation set up“a research and development committee for MHD ship propulsion”in 1985 and started an extensive R & D studies, and to construct an experimental ship to demonstrate that a ship can really be propelled by MHD thrusters with all the necessary machinery and equipments on board. The experimental ship, named the YAMATO 1, was completed in the fall of 1991 and was actually propelled successfully by MHD thrusters in the summer of 1992 in KOBE harbour. There are many complete different handlings & operational sequences required for the operation of Superconducting MHD thruster in comparison with usual one. This paper describes the manner & results of initial cooling down and exciting & demagnetization of the superconducting magnets, and compares measured data on the BOLLARD test with values calculated theoretically, and reports the agreement with them.
As a case study regarding the actual situation of air pollutant discharge from ships, the paper investigates the discharge amounts of nitrogen oxides NOx and sulfur oxides SOx from all ships sailing in Osaka Bay. Marine traffic in Osaka Bay is very intensified because it is surrounded by the highly industrialized Hanshin-Megalopolis and also Osaka Bay situates at the point connecting Pacific Ocean and Seto inland sea. This is the reason why Osaka Bay was selected here as a case study area. The investigation is carried out by three stages. The first is to investigate the trip table, that is, the OD-table of all ships sailing in Osaka Bay. The second is to study the dischage rate of each ship of various kinds at various operating conditions and the third is to estimate the dischage amount from all ships. The estimation results reveal that total discharge amount from ships is unexpectedly large, and NOx is comparable with the amount from land and SOx is larger than the land. As for the dischage intensity per area, the marine is also larger than the land especially in the port zone near the coast. Thus the report indicates that the discharge from ships could not be ignored and its effect on the coastal environment should be investigated in order to search the proper procedures against air pollution.
In this paper we compare NOx emission of low speed engine with that of high speed engine adopting original numerical simulation program of NOx emission. Further NOx emission of low speed engine, which was experimentally measured at the shop trial, was statistically treated with driving condition and weather condition. Measured engines are MAN-B&W type 2-stroke diesel engine. And JIS A oil as a fuel was used in the test. Consequently, we obtained conclusions as follows. (1) NOx genelation of low speed engine is not differant essentially from that of high speed engine. However, NOx emission of low speed engine is more dependent on staying time at higher gas temperature than high speed engine. (2) In case of higher scavenging air temperature, NOx emission is increased, however it is little influenced by the scavenging air pressure and exhaust gas temperature. (3) In case of increasing explosion ratio, NOx emission increase. (4) Increasing the load, NOx emission increase, and there is maximum value at near of the 90% load. (5) NOx emission is dependent on the fuel injection nozzle. (6) NOx emission of low speed engine is more insensible to the humidity than that of high speed engine.