As part of a study to build a marine fuel cell system with reformer, a series of performance tests of a Polymer Electrolyte Fuel Cell (PEFC) which generates 1 kilowatt of electricity was carried out. Effects of fuel cell temperature, cell stack inclination and back pressure on power output were investigated. Followability of cell output to load variation was also examined. Prior to the performance tests, a reformer function verification test was conducted. It was confirmed that the reformer worked normally and that the concentration of carbon monoxide in the reformed gas was lower than the allowable value. As for the fuel cell stack, the following results were obtained: (1) Within a temperature range of 60 to 75 degrees Celsius, the temperature level of the cell stack did not affect its power output. (2) At a cell stack inclination of 22.5 degrees to the lamination direction of the cell, the power output was almost the same as that at upright attitude. (3) When back pressure was increased, the electromotive force of the cell stack increased to a value larger than that which can be derived from the Nernst equation. (4) The cell stack can follow rapid temporal and stepwise variations in electrical current.
In maritime transportation, one of the ways to comply with regulations on sulfur content requirements is to use sulfur-free gas or low flashpoint fuels. For this reason, the ME-GI that uses LNG as the main fuel was developed, and then its commercial success led to the development of the ME-LGI that can use methanol as well. The core technology of the ME-LGI, developed by MAN Diesel & Turbo, is a booster injection valve which allows methanol to be compressed inside the valve. Another key element for the ME-LGI was how to develop an overall safety concept of the engine, and in this regard, elaborate joint work has been done by the ship owner of Mitsui O.S.K. Lines, Minaminippon Shipbuilding, the engine manufacturer of Mitsui Engineering & Shipbuilding and the coordinator of Nippon Kaiji Kyokai (ClassNK). After going through this process, the ME-LGI has been produced, tested at a workshop and installed on ships.
Machine components such as bearings and gears are required to operate under severe tribological conditions such as elastohydrodynamic lubrication (EHL). There have been recent advances in techniques to improve sliding performance using coated films possessing superior tribological properties to reduce machine component failures. These techniques are often used under severe conditions such as elastohydrodynamic lubrication. In this paper, for coated film with interlayer and substrate used under elastohydrodynamic lubrication, distributions of oil film pressure, oil film thickness and stress distributions therein were numerically investigated in detail in consideration of traction acting on lubricated surface of coated film generated by lubricating oil flow. Also, the effects of lubricant properties on distributions of oil film pressure, oil film thickness and stress distributions were discussed. The typical results showed that maximum oil film pressure pmax, minimum oil film thickness hmin and maximum stress σmax of materials including coated film and interlayer when a paraffinic mineral oil is used are larger than those when a polyglycol synthetic oil is used.
This study experimentally investigates the condensation heat transfer and pressure drop characteristics inside a horizontal smooth tube containing R245fa, which is used as a working refrigerant for a high-temperature heat pump and binary generator. The test section is a 4m-long counter flow-type double pipe heat exchanger. In this section, the refrigerant flows through the inner test smooth tube, which is an 8.32mm inner diameter copper tube, and the heat source water flows in the annulus surrounding the inner tube. The annulus is divided into five subsections, each 557mm long. The condensation experiment is conducted under a mass velocity range of 50 to 300kg/(m2s) and saturation temperature range of 40°C and 60°C. The measured condensation heat transfer and frictional pressure drop characteristics of R245fa are clarified for the effects of mass velocity, vapor quality and saturation temperature. Furthermore, experimental results of condensation heat transfer coefficient and frictional pressure drop are compared with several previous correlations. The condensation heat transfer coefficient decreases with increasing saturation temperature, which is highly dependent on the flow patterns. Also the frictional pressure drop decreases with increasing saturation temperature, but it is less dependent on the flow patterns. In comparison with previous correlations for the condensation heat transfer coefficient, predicted results of Haraguchi et al., Cavallini et al. and Dobson - Chato are expected to be slightly smaller in conditions highly affected by forced convection. The experimentally determined frictional pressure drops are ±30% consistent with the predicted results of Haraguchi et al. and Miyara et al.
This paper discusses the configuration of battery system which is main power source of the battery propulsion ship conforming to CHAdeMO rapid charging protocol. A power consumption simulation on navigation and mooring of the battery ship ware developed to investigate a change of available energy in the battery. Based on the calculations, it was shown that SOC of the battery can be largely recovered while moored by designing the battery system voltage high. As a result, it is possible to operate the ship with sufficient leeway in SOC even with the same installed battery capacity. On the other hand, an efficiency of inverter get worse several % because of utilizing IGBT device with high rated voltage. This paper also mention the fact that a slight power dissipation increase at the inverter.