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廣安, 博之 ; 小田, 晴己 ; 西田, 恵哉 ; 鈴木, 護 ; 吉川, 滋 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />An experimental study on emission formation processes, such as particulate, nitric oxide and total hydrocarbon, in a small D. I. diesel engine was carried out by using a newly developed total
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in-cylinder sampling technique. The sampling method was composed of rapidly opening a blowdown valve attached to the bottom of the piston cavity, and quickly transferring most of the in-cylinder contents into a large sampling chamber below the piston. The sampling experiment gave a history of spatially averaged emission concentrations in the cylinder. The effects of several engine variables on the emission formation processes were investigated.
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松江, 孝博 ; 新井, 雅隆 ; 廣安, 博之
概要:
application/pdf<br />Journal Article<br />Combustion characteristics of a single CWM (Coal-Water-Mixture) droplet placed on a hot surface in a test furnace were investigated. The collapsing load of an ash grain which is formed by the
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combustion of the CWM droplet was also measured to clarify the relationship between the burning temperature and burn-out state of the droplet. Two stage combustion which is usually observed in pulverized coal combustion was observed in the burning sequence of the CWM droplet on the hot surface. The first stage of combustion was due to the burning of flammable gas from the volatile matter in the coal. The second stage was the char combustion of the coal. As the temperature on the hot surface increased, the collapsing load of the ash grain decreased. It reached a minimum load and then increased with an increase of the temperature of the hot surface. It was considered that the combination of the unburned coal at low temperatures and melted ash at high temperatures resulted in the hard grain of ash which had a high collapsing load.
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西田, 恵哉 ; 廣安, 博之 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />An experimental study was conducted on the evaporation and combustion phenomena of a single n-dodecane drop in ambient gas pressurized and heated beyond the critical point of fuel, that is,
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supercritical environments produced on a hot wall. The evaporation lifetime in air at the wall temperature below the ignition temperature was found to be shorter than that in nitrogen at the same wall temperature. The end of combustion time in air at ambient pressure below the critical pressure of the fuel was correlated with the evaporation lifetime, and it was maximum in the wall temperature range where the drop showed spheroidal evaporation. As the ambient pressure increased beyond the critical pressure of the fuel, the end of combustion time increased in the wall temperature range around the critical temperature of the fuel, and in other wall temperature ranges, it decreased.
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西田, 恵哉 ; 廣安, 博之 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />An experimental study was conducted on the evaporation and combustion phenomena of a single fuel drop in ambient gas pressurized and heated beyond the critical point of fuel, that is, supercritical
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environments on a hot wall. Several kinds of liquid paraffin such as n-heptane, n-decane, n-dodecane and n-tetradecane were used as the test fuel. The evaporation lifetime in air was found to be shorter than that in nitrogen at the same wall temperature. The difference in the evaporation lifetimes in air and nitrogen environments was greater under higher ambient pressure for the same fuel ; for the same ambient pressure, it was greater under a larger ratio of ambient pressure to critical pressure of the fuel. As ambient pressure increased from subcritical to supercritical pressure, the end of combustion time increased in the wall temperature range around the critical temperature of the fuel, whereas in a wall temperature range higher than the critical temperature of the fuel, it decreased.
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松江, 孝博 ; 新井, 雅隆 ; 廣安, 博之
概要:
application/pdf<br />Journal Article<br />A single CWM droplet was suspended in a hot air stream by a fine R-type thermocouple. The surface temperature of this evaporating and burning droplet was measured by a radiation thermometer. The
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emissivity of the CWM droplet surface was kept at around 0.98 until the char combustion of the droplet proceeded to its middle stage. In the later stage of the char combustion, the emissivity decreased gradually to 0.82. Several degrees of temperature difference between the center and the surface of the droplet remained at the dry-up time, even when the diameter of the droplet was reduced to 2mm. The surface temperature at the start of char combustion was 700K when the droplet was exposed in surroundings of less than 900K. However, the surface temperature at the start increased from 700K in surroundings where it's temperature exceeded 900K. When the surroundings were 650K, the surface temperature at the char combustion start was 700K and higher than the surroundings, and the center temperature of the droplet was higher than that of the surface, which suggested that slow exothermic reactions in the droplet were already initiated before the char combustion started.
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新井, 雅隆 ; 廣安, 博之 ; 中森, 薫 ; 中曽, 伸二
概要:
application/pdf<br />Journal Article<br />A new combustion system called a jet-mixing-type combustor was designed to obtain a nonluminous blue flame of a kerosine spray. A spray was injected by a conventional-type swirl atomizer into
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the combustor and combustion air was introduced through a baffle plate with 16 inlet holes. The principle of this combustion method was revealed as a prompt mixing of the air and the spray, which was achieved by a high-speed air jet. The combustion characteristics such as combustion stability, temperature distribution and exhaust emissions were compared with a conventional swirler-type combustor. NO and THC emission levels exhausted from nonluminous kerosine flame were lower than those exhausted from the swirler-type combustor.
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松江, 孝博 ; 新井, 雅隆 ; 廣安, 博之
概要:
application/pdf<br />Journal Article<br />The evaporation and combustion characteristics of a single coal-water slurry droplet were studied in an elevated temperature environment and in a hot air stream by measuring the
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temperature of a burning droplet and observing its behavior. When the droplet was suspended in an elevated temperature environment, the decomposing combustion, that is, the combustion of an inflammable gas included in the coal, started after the dry-up. The surface reaction, that is, the combustion at the coal surface, followed after that. Thereby, the surface reaction was slightly influenced by the decomposing combustion. When the droplet was suspended in a hot air stream, the decomposing combustion started during the surface reaction process and a blue wake flame was induced. In this case, the spread of the surface reaction region was prevented by a flame of the decomposing combustion.
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