It is very obvious that drastic improvement of technology for reduction of CO2 emmsion from ocealice going vessels will be required world widely. 400m long towing tank and ice model basin of NMRI are laegest tanks in Japan for each technology area. 400m long towiung tank is testing facility of every kind of vessels from huge oil tanker (VLCC) to 50knots high speed boat. The maximum speed of towing carriage is 15m/sec.. Ice model basin is a model testing facility of ships and offshore structures to be used in ice-covered waters. The basin at NMRI is 35m in length, 6m in width and 1.8m in depth. Recently the basin is used for various research problems including oil spilling in ice and ice loading on ship hulls.
The Deep Sea Basin at the National Maritime Research Institute of Japan was constructed in 2002 because of the increasing demand for R&D on deep sea technology; such as the riser technology for deep water oil and gas production, drilling and deep water utilization. In this paper, we described the main characteristics of the Deep Sea Basin. It consists of two parts, the circular basin with a depth of 5m and with 14m in diameter. The deep pit is 30m in depth and 6m in diameter. It has the maximum depth of 35m. It is one of the deepest model basins in the world. 128 absorbing-type wave generators surround the circumference of the circular basin. For simulation of ocean currents we have one main current generator for the circular basin and six compact current generators for the deep pit. For measuring the dynamic behavior of underwater objects we have 3-D measurement equipment. This consists of 20 sets of two high resolution CCD cameras and one underwater light. Finally, we described the results of model tests on the behaviour of the riser pipe, of the Ocean Nutrient Enhancer“TAKUMI.”This is one example of the utilization of the Deep Sea Basin.
The High Pressure Tank in the National Maritime Research Institute (NMRI) is an experimental facility for research and development of deep-sea technology, where deep-sea conditions, such as pressure and temperature, can be conveniently simulated. The tank has a size of 1.1m at the inner diameter and 3.0m depth. The maximum pressure is 60MPa. Sensors are installed to measure the pressure, temperature and pH of the water in the tank, and six monitoring cameras have been installed in the tank. Subsidiary units belonging to the tank control its pressure, temperature and pH in the tank. Using the tank the NMRI has carried out various experiments of deep-sea technologies, such as a pressure test of the pressure vessel for a submersible vehicle, the corrosion test of ship materials in a deep-sea environment, and simulation experiments of ocean storage of Carbon Dioxide (CO2) .
This article is an overview of the Simulation Tank for Oil Recovery in Marine Situations (STORMS) which the Port and Airport Research Institute (PARI) operate; and related research activities conducted in the STORMS. Oil spills may still cause severe environmental and economic damage. Research works into responding to such incidents are important to prevent or minimize damage. STORMS is a seawater test tank specially designed for oil spill response and was built in 2004. The tank is as large so as to test full scale oil skimmers and can simulate various situations in which any oil recovery mission may actually encounter at sea; this includes wave, current, temperature, as well as wind. Over the last 4-years of operation, the facility has played an important role in oil spill research and response engineering in Japan. This article also present an example of developments carried out in STORMS, such as the high oil concentration weir skimmer.
A Simulation Tank for Control Systems was built between 2004 and 2006 and funded by the Ministry of Land, Infrastructure, Transport and Tourism-Japan. It has been in use since April 2006. The objective of the tank is to simulate operations of various surveys, measuring and scoping about various structures at port and airport's facilities. We can obtain the specific data from the tank tests, and it will be helpful to consider the important functions of the operation, both more simply and accurately than with the tested data collected at sea where is complex situations. The tank is the only one in its design concept in Japan. The scale of free basin with a wave generator is relatively-large in simulation tanks for research in Japan. In this paper, I introduce the facility and show some outputs from the tank tests over the last 2-years.
The regulation of air pollutant from fossil fuel combustion process has been tightened up gradually. The increase of crude oil price is concerned with serious problems of national management. These both subjects should be cleared with any improvement of the marine engines. The regulation Annex VI for diesel exhaust gas has been discussed, and it has been enforced since May 2005. NOx, SOx, COx and PM (particulate matter) are well known as main components of air pollutants that emitted from diesel engines. The engines have high heat efficiency with CO2 emission rate, and SOx is possible to reduce by after treatment process in exhaust gas. Therefore, it is important to clear NOx and PM of marine engine. An emulsion fuel oil, mixed HFO and water with an additive, was applied to combustion tests by Optic Combustion Analyzer, 2/4 stroke diesel engines and test boiler. The emulsion fuel is not separated in any condition of heating up to 120°C with keeping emulsion state. The fuel property for combustion is maintained. It leads to decrease of NOx and PM with low cost.
Exhaust gas economizers have been installed on a wide range of ships, for better fuel oil economy; since the oil crises of the 1970's. After the turn of the century, the pressure improve the fuel economy further, as well as to protect the environment markedly increased. The authors propose a concept for a power generation system, for domestic ships, to substantially improve fuel oil economy. Also, reduce SOx emissions by utilizing the rejected heat of exhaust gases from marine diesel engines. As a heat exchanging device, a circulating fluidized bed, here a mixture of the exhaust gas and fine, desulphurization solid particles circulate. This for reason of higher overall heat transfer coefficients and the quality to reduce sulphur-oxides emissions through a dry desulphurization process, in the fluidized bed. As an electric power plant, a radial steam turbine was integrated with a high speed dynamo, this selected because of a higher energy conversion rate. This technology is based on the micro gas turbine. A preliminary estimate indicates that an electric power of 80 to 100 kW will be recovered from the exhaust gases, and at the loading factor of 75 % for 1500kW-class marine diesel engines.
A reamer bolt is widely used in the marine engineering field, bolted joints being subjected to large shear forces. The most important application is in the joint couplings, composing the propeller shaft system. The diameter of a reamer bolt is basically equal to that of the bolt-hole. When installed into the joint a reamer bolt is cooled in order to temporarily reduce its diameter for easy insertion. Dry ice or liquefied nitrogen is commonly used to lower the bolt temperature. In actual practice it's customary that a tightening torque is applied to the reamer bolt when its temperature is below that of the ambient one. Accordingly, the reamer bolt elongates with the temperature increase, during the tightening operation. In the final state, the axial bolt force is reduced to some extent. In this paper, an equation that estimates the amount of bolt force reduction due to the temperature increase is proposed. For joints with sufficient strength, the proposed equation is both practical and useful. It will determine the amount of excess torque that compensates for the bolt force reduction. The validity of the equation is demonstrated by experimentation. Based on the proposed equation and the experimental results, a guideline is shown for securely tightening the reamer bolt using a cooled fitting.
Nowadays, low-speed two-stroke cycle diesel engines are used for marine transportation because of their high thermal efficiency, thus utilizing cheap fuel, of course good from the economical viewpoint. However, some marine diesel engines have been damaged when low grade bunker oil is used. Here, ignitability and combustibility of 107 samples of bunker fuel oil was evaluated. Visualization via a high-speed color video camera was conducted with signals of photo-sensors, rate of heat release and analysis of fuel properties. It was found that ignition delay and after-burning do differ, fuel to fuel. By changing the gas temperature at injection time, the degree of ignitability for the sample fuel could be clearly judged. Short or long after-burning was shown in spite of the same ignition delay. In some fuel oils, the combustion was promoted after ignition, even if the ignition delay was long. Some fuel oils, those with low sulfur content of less than 1.0%, and a higher nitrogen content with a CCAI value between 840 and 860, presented both worse ignitability and worse combustibility. However, on the other hand, some fuel oils showed good combustibility, even in these properties. Therefore, this equipment will be a strong tool to judge the fuel quality of combustion before bunkering fuel oil.
In order to improve the accuracy of practical numerical analysis of high-pressure injection fuel sprays under high-pressure and high-temperature ambient gas conditions using relatively coarse computational grids, we introduced the following our original models into authors'GTT code for fuel injection engine combustion analysis: 1) Gas parcel method. 2) Two-stage modified wave break-up model, and its parameter functions. 3) Model of relative velocity between each droplet and the ambient gas. Using these models, the three-dimensional numerical analysis of the combustion in a direct-injection diesel engine could be performed under various conditions. The calculated results were compared with the experimental data. As a result, we could confirm that the original models are effective in improving the accuracy of engine combustion analysis.
The combustion characteristic of FIFO (Heavy Fuel Oil) was clarified so as to reduce and avoid problems in combustion. A constant volume type fuel ignition analyzer (FIA) and exhaust gas analyzer for NO and CO were used. Not only was ignition delay and combustion period data obtained by FIA; but also NO and CO concentrations in the FIA test vessel, these were found useful for aptitude test of HFO. It can be concluded that a more reliable threshold to avoid combustion troubles was obtained when we coupled analyses of the FIA original data and the exhaust gas compositions.
This study examines a corrosion control technique for corrosion-resistant materials or of stainless steel. This employs an effect of Radiation Induced Surface Activation (RISA) . The experimental results revealed: (1) The mechanism behind the corrosion control proposed by the previous report was confirmed to be appropriate. This via tests that measured the amount of dissolved oxygen and iron ions, in the solution. (2) The corrosion control technique was confirmed to be useful for stainless steel with any kind of metal oxide film coating on the surface. (3) It was also shown to be useful even in actual seawater, due to biological effects, which is a far more severe environment for corrosion control than simple salt water. The corrosion control technique for corrosion-resistant material using RISA in seawater has therefore been shown to offer a significant potential for practical applications in naval architecture and marine structures.