• Journal of Navigation and Port Research
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• v.38 no.6
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• pp.695-700
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• 2014

This paper analyzed the peak stage of typhoons by using 10 years(2002~2011) data. The main purpose of this research is to provide the characteristic and tendency of peak stage of typhoons for navigators of ship. The research results show that typhoons of maximum wind speed 20~29m/ s and 40~49m/s account for 25% and 24% of whole typhoon, respectively. Ultra Typhoon of maximum wind speed 50m/ s and over accounts for 24% of whole typhoon. Peak stage mean arrival time from tropical depression and tropical storm are 3.6 days and 2.1 days, respectively. Duration time of peak stage is within 2 days and mean duration time of peak stage is 31hours. Latitudes and longitudes that mainly appears peak stage are at $15^{\circ}{\sim}25^{\circ}N$ and $120^{\circ}{\sim}140^{\circ}E$. This dangerous sea area has the oceanic environmental characteristic that Taiwan and Philippines are locate west side and a vast the North Pacific occupy east side. Navigators of ship in this dangerous sea area keep strict watch. Ultra Typhoons occur most frequently in September. Peak stage of Ultra Typhoon also appears at $15^{\circ}{\sim}25^{\circ}N$ and $120^{\circ}{\sim}140^{\circ}E$.

• Journal of ILASS-Korea
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• v.14 no.1
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• pp.8-14
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• 2009

This paper present the diesel fuel spray evolution and atomization performance in a multi-hole nozzle in terms of injection rate, spray evolutions, and mean diameter and velocity of droplets in a compression ignition engine. In order to study the effect of split injection on the diesel fuel spray and atomization characteristic in a multi-hole nozzle, the test nozzle that has two-row small orifice with 0.2 mm interval was used. The time based fuel injection rate characteristics was analyzed from the pressure variation generated in a measuring tube. The spray characteristics of a multi-hole nozzle were visualized and measured by spray visualization system and phase Doppler particle analyzer (PDPA) system. It was revealed that the total injected fuel quantities of split injection are smaller than those of single injection condition. In case of injection rate characteristics, the split injection is a little lower than single injection and the peak value of second injection rate is lower than single injection. The spray velocity of split injection is also lower because of short energizing duration and small injection mass. It can not observe the improvement of droplet atomization due to the split injection, however, it enhances the droplet distributions at the early stage of fuel injection.