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| 1.
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小林, 佳弘 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Nano meter size particulate matter (PM) and polycyclic aromatic hydrocarbons (PAHs) have harmful effects for human health. Investigations of the fundamental characteristic of PAHs behavior in
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combustion process were required for the establishment of the reduction technologies for nano-PM emission. In this paper, PAHs characteristics in diffusion flames of propane gas were investigated using laser diagnostic and gas sampling methods. A laser induced fluorescence (LIF) method was used to obtain the spatial distributions of PAHs. Spatial distributions of soot were also measured by a laser induced incandescence (LII) method. A transition region from PAHs to soot was defined from the results of LIF and LII. Further, PAH concentrations in the test flames were measured using a gas chromatography (GC), and the profiles of PAHs concentrations in the test flames were investigated. As the results, heavier molecules PAHs such as fluorene and pyrene were confirmed as precursors of soot.
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| 2.
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倉持, 大輔 ; 川口, 知宏 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinged on an extrude
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d wall, which was a top of cylindrical column, were experimentally investigated. Appearance positions of OH and C_2 radical luminosities and luminous flame kernel were stereoscopically observed using a two-way fiber optical system. The extruded column was fixed in a high temperature and high pressure combustion chamber. A diesel spray was impinged vertically to the extruded wall. Effects of cylindrical column diameter (D=5,10,15mm, ∞(flat wall)) on ignition and combustion characteristics were investigated. As the result, appearance position of OH luminosity was observed near the spray tip except for D=∞ (flat wall). The maximum volume of luminous flame impinged on the extruded wall was strongly influenced by the diameter of the column. In a condition of low-ambient temperature, the maximum volume of blue flame on the extruded column of 10 mm diameter was larger than those on other columns.
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| 3.
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世取山, 幸作 ; 天野, 俊輔 ; 藤原, 秀智 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />A new low NO_x combustor for kerosene fueled micro gasturbine was proposed, and the combustion characteristics of prototype combustor were investigated. In order to enhance the recirculation in
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a primary combustion zone, a swirler was set between the primary and secondary combustion zones. Combustion air was introduced through the swirler and forced to flow upward to the combustor bottom, from where the fuel spray was supplied through a nozzle. To achieve high combustion stability and low emission in wide fuel air ratio, the optimum configuration of the primary combustion zone were investigated. The optimum one was found out by measuring the fundamental combustion characteristics such as lean combustion limit, flame luminosity, exhaust gas composition and combustion gas temperature.
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| 4.
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小林, 佳弘 ; 斉藤, 孝充 ; 天谷, 賢児 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Since the engine combustion is affected by a variety of parameter such as well as fuel characteristics, it is very difficult to find out the clear effect of fuel property. In order to
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clarify the change of emission characteristic caused by fuel change, we propose a fundamental flame research method using a small pool-wick flame system. By using this system, PAHs (polycyclic aromatic hydrocarbons) formation mechanism in a flame was investigated as a fundamental study of diesel combustion. Characteristics of PAHs formation in a laminar diffusion flame were measured by a laser induced fluorescence (LIF) method. It was compared with PM charactersistics measured by a laser induced incandescence (LII) method. The effect of the lubricating oil contamination on the PAHs distributions in the flame was discussed. As the result, it was found that the PAHs concentration in the flame increased with increasing the lubricating oil contamination and it caused the increase of PM formation in the flame.
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| 5.
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天野, 俊輔 ; 新井, 雅隆
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application/pdf<br />Journal Article<br />A new concept of combustion liquid fuel suitable for Gas Turbine combustor was
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investigated. Combustion in high temperature and low oxgen concentration by Burnt Gas Recirculation (BGR/FGR/EGR) is an important technology for low NO_χ combustion of liquid fuel. Upward swirl was focused to produce forced recirculation flow of burnt gas. A combined method of analytical approach (Computational Fluid Dynamics: CFD) and experimental approach was used. Flow pattern produced by the upward swirl introduced into combustion zone from the direction of combustion zone exit was investigated. CFD showed that a kind of guide vanes to produce flow to inside of radial direction at the top of combustion zone had important role for the upward swirl to recirculate fully to the top of combustion zone. A prototype combustor with the design based on results of CFD with and without combustion was made and tested. Non-luminous flame was observed at lean combustion condition. These results showed that this new concept of the primary zone had a high potential as a low NO_χ combustion technology of liquid fuel.
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| 6.
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川口, 知宏 ; 長瀧, 翼 ; 天谷, 賢児 ; 古畑, 朋彦 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Ignition and combustion characteristics of diesel spray impinging on a wall were experimentally investigated. Ignition position and appearance position of the luminous flame
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kernel were stereoscopically observed using a two-way fiber optical system. Flat
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| 7.
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HAYASHIDA, Kazuhiro ; AMAGAI, Kenji ; SATOH, Keiji ; ARAI, Masataka
概要:
application/pdf<br />Journal Article<br />Spontaneous Raman spectroscopy with KrF excimer laser was applied to obtain a fuel concentration distribution in a sooting flame. In the case of sooting flame, fluorescence from polycyclic
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aromatic hydrocarbons (PAH) and laser-induced incandescence (LII) from soot particles appeared with Raman scattering. These background emissions overlapped on the Raman scattering. In order to separate the Raman scattering and the background emissions, polarization property of laser-induced emissions was utilized. Since the background emissions were depolarized whereas the Raman scattering was highly polarized, it is possible to subtract the background emissions from the overlapping signal of the Raman scattering and the background emissions. Subtracting the emission signals for the electric vector of the laser light perpendicular and parallel to the direction of observation allows to extract the precise Raman signals. By using this technique, detailed fuel concentration distribution in sooting flames could be obtained based on Raman scattering.
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| 8.
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石井, 哲人 ; 佐藤, 博之 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />The effects of gravity on the fluctuation characteristics of turbulent diffusion flames were experimentally investigated. Super gravity fields were formed using a spin tester. The gravity
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level G was changed from 1 to 20, where G was defined as the value of super gravity per normal gravity. Flame states such as laminar, flickering and turbulent flames were observed under the various conditions of gravity level, G and Reynolds number, Re. The transition from laminar to turbulent and blow out limit were summarized on a G-Re map. Characteristics of turbulent fluctuation were measured by a laser light reflection method. Power spectra and auto-correlations were derived from the signal of laser intensity. As the result, it was found that the turbulent flame was begun to periodic oscillation with increasing the gravity level. Time scale of turbulent fluctuation in the super gravity became long than that in the normal gravity. Spectrum component in power spectrum shifted to the low frequency side when the gravity level became high. And the full width at half-maximum of autocorrelation peak became wider in the super gravity conditions.
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| 9.
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林田, 和宏 ; 天谷, 賢児 ; 佐藤, 桂司 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Raman scattering technique with KrF excimer laser was applied to obtain a fuel concentration distribution in a sooting flame. In the case of sooting flame, fluorescence from polycyclic
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aromatic hydrocarbons (PAH) and laser-induced incandescence (LII) from soot particles appeared with Raman scattering. These background emissions overlappped on the Raman scattering. In order to separate the Raman scattering and the background emissions, polarization property of laser-induced emissions was utilized. Since the background emissions were depolarized whereas the Raman scattering was highly polarized, it is possible to subtract the background emissions from the overlapping signal of the Raman scattering and the background emissions. Subtracting the emission signals for the electric vector of the laser light perpendicular and parallel to the direction of observation allows to extract the precise Raman signals. By using this technique, detailed fuel concentration distribution in sooting flames could be obtained based on Raman scattering.
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| 10.
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新井, 雅隆 ; 天野, 俊輔 ; 藤原, 秀智
概要:
application/pdf<br />Journal Article<br />The combustion characteristics of a prototype micro-gasturbine combustor fueled by kerosene were investigated. In order to enhance the recirculation in a primary combustion zone, a swirler was
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set between the primary and secondary combustion zones. Primary combustion air was introduced through the swirler and forced to flow upward to the combustor bottom, from where the fuel spray was supplied through a nozzle. The fundamental combustion characteristics such as lean combustion limit, flame luminosity etc. showed that this prototype combustor had a high potential for lean combustion and wide flame holding. Since a strong forced recirculation flow was induced by the upward swirl, lean and non-luminous flame was maintained in the primary combustion zone. Further, burned gas recirculation and highly turbulent shear flow in the primary combustion zone, both of which were caused by the upward swirl, resulted the low NO_x emission characteristics.
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| 11.
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HUANG, Zuohua ; SHIGA, Seiichi ; UEDA, Takamasa ; JINGU, Nobuhisa ; NAKAMURA, Hisao ; ISHIMA, Tsuneaki ; OBOKATA, Tomio ; TSUE, Mitsuhiro ; KONO, Michikata
概要:
application/pdf<br />Journal Article<br />A basic characteristics of compressed natural gas direct-injection (CNG DI) co
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mbustion was studied by using a rapid compression machine. Results show that comparing with homogeneous mixture, CNG DI has short combustion duration, high pressure rise due to combustion, and high rate of heat release, which are considered to come from the charge stratification and the gas flow generated by .the fuel injection. CNG DI can realize extremely lean combustion which reaches 0.03 equivalence ratio, φ. Combustion duration, maximum pressure rise due to combustion and combustion efficiency are found to be insensitive to the injection modes. Unburned methane showed almost the same level as that of homogeneous mixture combustion. CO increased steeply with the increase in φ when φ was greater than 0.8 due to the excessive stratification, and NO_x peak value shifted to the region of lower φ. Combustion inefficiency maintains less than 0.08 in the range of φ from 0.1 to 0.9 and increases at very low φ due to bulk quenching and at higher φ due to excessive stratification. The combustion efficiency estimated from combustion products shows good agreement with that of heat release analysis.
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| 12.
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坂下, 直己 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Fuel droplet and vapor distributions in a spray flame formed in the hot air stream were measured by an exciplex fluorescence method. Kerosene was used as a test fuel. Kerosene was miscible
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with a small quantity of exciplex-forming dopants, TMPD (N, N, N', N'-tetramethyl-1,4-phenylene diamine) and naphthalene. A Nd : YAG laser (355nm) was used for excitation of the fuel. The fuel spray was injected from a swirl atomizer into an air stream. Air temperature was changed from room temperature to 1000k which was higher than the self-ignition temperature of a kerosene spray. Distributions of the fuel droplets and vapor were strongly affected by the air temperature. Furthermore it was confirmed that the fuel vapor was transported into recirculating flow area formed on the flame holder.
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| 13.
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岩崎, 浩二 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Combustion characteristics and engine performances of a swirl-chamber type IDI diesel engine using two-stage injection were experimentally investigated. The injection timing and fuel allocation ratio
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between first and second injections were widely varied. Heat release rate was analyzed to evaluate the combustion phenomena in the engine. As the result, ignition delay period for two-stage injection became longer than that for single-stage injection when the amount of fuel in the first stage injection was small. However, when the amount of fuel in the first injection was large, there was no difference of ignition delay period between two-stage injection and single-stage injection. NO and Smoke emissions and fuel consumption were improved by two-stage injection when ingition delay period became long.
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| 14.
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斉藤, 正浩 ; 天谷, 賢児 ; 萩原, 五郎 ; 新井, 雅隆
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application/pdf<br />Journal Article<br />To clarify the effect of water content on combustion characteristics of watery
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materials, combustion test of a high water-permeable balsa wood was performed using a thermogravimetric furnace. The furnace temperature is between 650℃ and 1000℃, and water contents in the small balsa pieces (0.3g) were varied up 70 wt%. Mass reduction during pre-heating, volatile matter combustion and char combustion were measured with a microbalance. Also, the variations of flame temperature and center temperature of the test piece during combustion process were measured. On the combustion of high water-contained balsa, it was found that ignition started before the water was evaporated completely. It means that two proceses, devolatilization of volatiles and vaporization of remaining water, are proceeding simultaneously during the volatile matter combustion. Ignition delay and retention time of volatile matter combustion increased with increasing the water content. The increases of flame temperature and center temperature of the test piece were prevented by the latent heat of water vaporization. The combustion rate of volatile matter was drastically reduced in proportion to the water content. Also, it was confirmed that a part of char burned during the latter stage of volatile matter combustion. The effect of water content on char combustion rate was small. From this study, it was concluded that the water content over 50 wt% affected remarkably to the volatile matter combustion.
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| 15.
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茂木, 俊夫 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Fundamental characteristics of the catalytic combustion of vaporized kerosene
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spray were studied experimentally. Palladium catalyst supported on the cordierite honeycomb monolith was used. Inlet temperature was elevated up to 700 K to evaporate the kerosene spray. Premixed gas of air and kerosene vapor was introduced into the catalyst. The catalytic combustion and gas phase reaction after catalyst were observed in this combustion system. The lean limit of the catalytic combustion was not affected by the space velocity and equivalence ratio of the mixture, but it was greatly affected by the inlet temperature. The parabolic shape blue flame that was supported on the catalyst was formed when the supplied mixture was not completely burned in the monolith. To clarify a reaction process in an combustive gas between the monolith and the blue flame, CO, HC(C_1～C_7) and NO were analyzed. When the blue flame was observed after the catalyst, the HC and CO were formed from the unburned composition of fuel and they were burned as the blue flame. The NO emission level of the catalytic combustion was very low compared with the gas phase reaction of lean mixture.
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| 16.
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OKAI, Keiichi ; ONO, Yutaka ; MORIUE, Osamu ; SHIBA, Seiji ; ARAKI, Mikiya ; NOMURA, Hiroshi ; SHIGA, Seiichi ; TSUE, Mitsuhiro ; KONO, Michikata
概要:
application/pdf<br />Journal Article<br />Experimental investigation was conducted on two droplet-array combustion of methanol and methanol/dodecanol mixture fuels in microgravity. For methanol, effects of ambient pressure and
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droplet spacing were examined. Results show that the droplet lifetime decreases with increasing spacing at relatively low pressure and the droplet lifetime becomes independent of spacing at higher-subcritical and supercritical pressures. For methanol/dodecanol mixture, effects of pressure, fuel composition were investigated in terms of occurrence of disruption. Disruption of droplet during combustion was demonstrated both for single droplet and droplet pairs.
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| 17.
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岩崎, 浩二 ; 荻原, 五郎 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Combustion characteristics and engine performances of a two-stage injection DI diesel engine were experimentally investigated. Two-stage injection was achieved by using two injection pumps.
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Injection timing and fuel allocation ratio between first and second injection were widely controlled. Engine performance of a two-stage injection diesel engine was compared with that of a single injection diesel engine with early timing injection. The heat release rate was analyzed to understand the combustion phenomena in a two-stage injection diesel engine. As a result, NO emission of two-stage injeciton diesel engine was improved when the first injection timing is early. The various pattern of heat release rate appeared with the change of a fuel allocation ratio. It was greatly affected by the first injection spray impinged on the cylinder wall or the piston top. The trade-off tendency between NO and smoke was influenced by the fuel allocation ratio of sub-injection pump was high.
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| 18.
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岡井, 敬一 ; 小野, 豊 ; 森上, 修 ; 芝, 世弐 ; 荒木, 幹也 ; 野村, 浩司 ; 志賀, 聖一 ; 津江, 光洋 ; 河野, 通方
概要:
application/pdf<br />Journal Article<br />Experimental investigation was conducted on two droplet-array combustion of methanol and methanol/dodecanol mixture fuels in microgravity. For methanol, effects of ambient pressure and
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droplet spacing were examined. Results show that the droplet lifetime decreases with increasing spacing at relatively low pressure and the droplet lifetime becomes independent of spacing at higher-subcritical and supercritical pressures. For methanol/dodecanol mixture, effects of pressure, fuel composition were investigated in terms of occurence of disruption. Disruption of droplet during combustion was demonstrated both for single droplet and droplet pairs.
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| 19.
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長谷川, 和之 ; 茂木, 俊夫 ; 天谷, 賢児 ; 新井, 雅隆
概要:
application/pdf<br />Journal Article<br />Behavior of a spray combustion in a hot air was studied experimentally. A kerosene spray was injected from swirl atomizer into a hot air stream. The air temperature was controlled from room
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temperature to 1 100 K which was higher than the self-ignition temperature of a kerosene spray. Flame shape and temperature distribution were measured to characterize the spray combustion appeared in the hot air stream. Flow state around the spray was visualized by a Schlieren method to analyze the behavior of the air entrainment into the flame. Furthermore, Mie scattering from the spray droplets by irradiation of the laser beam was observed to visualize the spray concentration in a flame. As the result, ignition point was shifted to the upstream side with an increase of air temperature. When the air temperature became higher than 800 K, the blue flame appeared at the bottom portion of the flame. Penetration of the spray became shorter with an increase of air temperature. Spatial distribution of the spray which were not vaporized in a flame was strongly affected by the air temperature.
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| 20.
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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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| 21.
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松江, 孝博 ; 新井, 雅隆 ; 廣安, 博之
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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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| 22.
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志賀, 聖一 ; 八木, 静夫 ; 盛田, 宗宏 ; 松本, 隆 ; 柄沢, 隆夫 ; 中村, 寿雄
概要:
application/pdf<br />Journal Article<br />In this paper we present the first stage of a study on the effect of early-closing of intake-valve on the engine performance in a spark-ignition engine. A four-valve single-cylinder engine was
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used with several values of expansion ratio and a half early-closing intake cam. The half early closing leads to almost a half of the volumetric efficiency and the BMEP for all cases of the expansion ratio. It can realize an improvement of about 7% in thermal efficiency under WOT,and about 4% under partial load of BMEP=0.2 MPa. These beneficial results are considered to be mainly caused by the effect of the more-expansion. The ratio of expansion to compression ratios was estimated to be around. 1.4 on the basis of motoring pressure analyses. Under the early-closing condition, an increase in the residual gas fraction was suggested and verified by a heat release analysis using a two-zone combustion model.
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| 23.
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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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| 24.
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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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| 25.
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小保方, 富夫 ; 橋本, 徹 ; 五十木, 慎一 ; 柄沢, 隆夫 ; 志賀, 聖一 ; 倉林, 俊雄
概要:
application/pdf<br />Journal Article<br />The swirl and axial components of gas velocity in the disk-type combustion cha
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mber of a firing engine were measured by an LDA. The engine was operated under the conditions of a speed of 1500rpm, η_υ=0.5, φ=1.4 and ignition timing of 30°BTDC. The gas velocities at 9 points on a diameter at midheight of the combustion chamber were analyzed by the cycle-resolved method. The bulk (mean) velocity was determined by the frequency discrimination method with the cut-off frequency of 667Hz. The flame propagation pattern was detected by ionization probes set at 17 points on the piston. It has been observed that, in the case of fired operation, the turbulence intensity is higher, the integral length and micro length scales are longer and the swirl flow is weaker and is eccentrically shifted compared with the case of motored operation. These results show that it should be noted that there are remarkable differences in the gas flow between motored operation and fired opeation.
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| 26.
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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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| 27.
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ARAI, Masataka ; HIROYASU, Hiroyuki ; NAKAMORI, Kaoru ; NAKASO, Shinji
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 kerosene 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 spray, which was achieved by high-speed air jets. The combustion characteristics such as combustion stability, temperature distribution and exhaust emissions were compared with a conventional swirler-type combustor. NO and THC emissions exhausted from nonluminous kerosene flame were at lower levels than those exhausted from the swirler-type combustor.
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| 28.
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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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| 29.
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松江, 孝博 ; 新井, 雅隆 ; 廣安, 博之
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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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| 30.
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志賀, 聖一 ; 江原, 秀治 ; 柄沢, 隆夫 ; 倉林, 俊雄
概要:
application/pdf<br />Journal Article<br />This paper presents one of the studies which aim to reveal the capability of controlling diesel combustion by exhaust gas recirculation (EGR). In a previous paper, the effect of EGR on soot emission
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was examined, and it was shown that soot emission is suppressed under the condition that the mass fraction burned by spontaneous (pre-mixed) combustion is increased. In a present paper, diesel knock intensity is defined as a sound pressure distributed over 1-1.5kHz, and the effect of EGR on the diesel knock intensity is examined. The diesel knock intensity is remarkably reduced by EGR under the same operating condition as soot emission is reduced by EGR. By calculating the heat release rate based on the indicated pressure diagram, it was suggested that a reduction of knock intensity originates from the reduced reaction rate in the spontaneous ignition. The quantitative relationship between the diesel knock intensity and the maximum rate of pressure rise is also presented.
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| 31.
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志賀, 聖一 ; 江原, 秀治 ; 柄沢, 隆夫 ; 倉林, 俊雄
概要:
application/pdf<br />Journal Article<br />By using a direct injection diesel engine, the effect of exhaust gas recirculation (EGR) on soot emission was investigated. It was revealed that EGR had both effects of soot promotion and
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suppression. Soot emission was suppressed when the premixed (initial rapid) combustion fraction of the two combustion patterns was increased, which was accomplished by throttling the intake valve equipped the engine or advancing the injection timing. It was also suggested that the effect of EGR on soot emission should not ascribe only the physical or thermal properties of the inert gases within the exhaust gas, but some chemical properties of CO_2. Because it was shown that only CO_2 had the effect of soot suppression under some conditions.
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| 32.
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柄沢, 隆夫 ; 志賀, 聖一 ; 倉林, 俊雄
概要:
application/pdf<br />Journal Article<br />This paper presents the experimental study on the phenomena of evaporation and
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ignition of the fuel-droplet impinged upon a hot surface. The experiment was made on the seven kinds of fuel. It was revealed that cool flame is generated in η-Heptane and diethyl-Ether at a surface temperature range which is 300-400 K below that of hot flame generation. The surface temperatures at which the cool and hot flames were generated were measured by applying a statistic method. Their delay times were also measured and then divided into physical and chemical delays by applying the statistic technique which was presented by S.Kumagai et al. Based upon these investigations, the natures of both the cool and hot flames were clarified and the difference between the surface temperature of hot flame generation and the ignition temperatures measured by using the crucible method was discussed.
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| 33.
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中山, 満茂 ; 荻原, 五郎
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application/pdf<br />Journal Article<br />In order to develop the low NO_x combustion system and high performance steam
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generator, several tests had been made. The first, to reduce NO_χ emissions , a new type swirl nozzle has been developed. The feature of this nozzle. The second, the combustion tests with package type boiler have been made. From the experimental investigations, NO_χ emission levels emitted from this combustion chamber the grooved swirl nozzle were 30-40 percent less than that of the conventional hollow-cone type swirl nozzle.
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| 34.
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鈴木, 富雄 ; 中山, 満茂
概要:
application/pdf<br />Journal Article<br />各種燃料の燃焼形態は大別して輝炎, 不輝炎である. 単一燃焼器でこれら火炎が任意に得られる旋回流形式による噴霧燃焼器の試作を示す. 燃焼に関与する諸条件(燃
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料量, 噴霧特性, 空気量など)を同一としたままで, 旋回流の流れ場と噴霧主流との相対位置を選択することによって燃焼を制御, それぞれの燃焼形態での燃焼特性を明らかにした. これらデータは噴霧燃焼のモデリング, あるいは数値計算による予測に利用が期待される.
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