本文關(guān)鍵詞： 船舶中速柴油機 工作過程 數(shù)值仿真 排放 噴射參數(shù)　出處：《集美大學(xué)》2014年碩士論文　論文類型：學(xué)位論文

【摘要】：隨著能源危機的爆發(fā)和環(huán)境污染的日益嚴(yán)峻，人們對船用柴油機的經(jīng)濟性和排放性要求日益嚴(yán)格。本文研究的對象為4190ZLC型船舶中速柴油機，該機排放不滿足IMO Tier II的排放標(biāo)準(zhǔn)要求�；谏鲜鲈�，學(xué)校決定對柴油機的供油系統(tǒng)進(jìn)行改造，改善其經(jīng)濟性和排放性。 利用AVL FIRE軟件對4190ZLC柴油機的進(jìn)氣壓縮過程進(jìn)行了多維瞬態(tài)數(shù)值模擬，研究了氣門運動對氣道及氣缸內(nèi)流場分布的影響，分析流場的結(jié)構(gòu)，得到不同時刻進(jìn)氣道和缸內(nèi)的流場，研究發(fā)現(xiàn)：隨著進(jìn)氣門的開啟，缸內(nèi)瞬時進(jìn)氣流量迅速增加，缸內(nèi)氣體的速度分布均勻性比較差；氣門升程由大到小變化時，缸內(nèi)壓力場和速度場逐漸趨于均勻。在小氣門升程時，由于氣門盤的節(jié)流作用，導(dǎo)致進(jìn)氣喉口位置流速迅速變化，由于螺旋進(jìn)氣道的渦流作用，導(dǎo)致螺旋進(jìn)氣道下方渦團比切向進(jìn)氣道更靠近氣門座位置；隨著活塞的運動，缸內(nèi)壓力逐漸增大，湍動能由喉口位置向缸內(nèi)逐漸擴散，最后湍動能以及溫度在缸內(nèi)均勻的分布。 利用AVL FIRE軟件中的ESE-Diesel模塊建立4190ZLC柴油機的燃燒模型，仿真發(fā)現(xiàn)：噴孔錐角對柴油機的排放有顯著影響，直接影響油束與空氣的混合。采用140°的噴孔錐角時，可以得到最少的NOx排放，但碳煙排放較高；其它條件不變的情況下，減小噴孔直徑可以使噴霧細(xì)化，使燃油與空氣均勻的混合。0.26mm噴孔直徑的碳煙排放惡化，0.28mm噴孔直徑的NOx生成量最高；噴油提前角增大，導(dǎo)致NOx的排放惡化，但降低了碳煙顆粒的排放。
[Abstract]:With the outbreak of energy crisis and the increasingly serious environmental pollution, the requirements of economy and emission of marine diesel engines are becoming increasingly strict. The object of this paper is 4190ZLC medium speed diesel engine. The emission of the diesel engine does not meet the requirements of the IMO Tier II emission standard. For the above reasons, the school decided to improve the fuel supply system of the diesel engine to improve its economy and emissions. The multi-dimensional transient numerical simulation of intake compression process of 4190ZLC diesel engine was carried out by using AVL FIRE software. The effect of valve movement on the distribution of flow field in the air port and cylinder was studied. The structure of the flow field was analyzed and the flow field in the inlet port and cylinder at different times was obtained. It is found that with the opening of the inlet valve, the instantaneous intake flow in the cylinder increases rapidly, the velocity distribution of the gas in the cylinder is relatively poor, and when the valve lift varies from large to small, The pressure field and velocity field in the cylinder tend to be uniform gradually. In the small valve lift, the throttle action of the valve disk results in the rapid change of the inlet throttle velocity and the swirl effect of the spiral inlet. As a result, the vortex cluster below the spiral inlet is closer to the valve seat than the tangential inlet, and with the movement of the piston, the pressure in the cylinder increases gradually, the turbulent kinetic energy gradually diffuses from the throat position to the cylinder, and the final turbulent kinetic energy and temperature are uniformly distributed in the cylinder. The combustion model of 4190ZLC diesel engine is established by using the ESE-Diesel module of AVL FIRE. The simulation results show that the cone angle of the injection hole has a significant effect on the emission of the diesel engine, which directly affects the mixing of fuel beam and air. When the cone angle of the injection hole is 140 擄, the combustion model of the diesel engine is established. The minimum NOx emission can be obtained, but the soot emission is higher. If other conditions are not changed, the spray can be refined by reducing the diameter of the nozzle. The soot emission of 0.26mm injection hole diameter of the fuel and air mixture is aggravated. The NOx emission of 0.28mm injection hole diameter is the highest, and the fuel injection advance angle increases, which results in the deterioration of NOx emission, but decreases the soot particle emission.
【學(xué)位授予單位】：集美大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2014
【分類號】：U664.121

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