本文關(guān)鍵詞：基于KIVA的柴油機常規(guī)排放物變參數(shù)研究　出處：《河北工業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 柴油機 數(shù)值模擬 燃燒 排放

【摘要】：隨著環(huán)境污染日益嚴(yán)重,排放法規(guī)越來越嚴(yán)格,如何能進(jìn)一步降低柴油機排放成為現(xiàn)如今最重要的課題。柴油機以其高動力性和低燃油消耗率在動力裝置方面得到廣泛應(yīng)用,柴油機的主要常規(guī)排放物有NOX,HC,CO和SOOT。由于計算科學(xué)的不斷發(fā)展以及計算機運算能力的提高,數(shù)值模擬成為研究燃燒過程的重要手段。數(shù)值模擬耗時短,費用低,能獲取大量試驗無法得出的流場信息。本文以KIVA軟件為研究工具,應(yīng)用KIVA軟件中的前處理器對4102柴油機的燃燒室進(jìn)行了網(wǎng)格劃分,并確定了計算的初始參數(shù)和邊界條件,然后進(jìn)行了數(shù)值模擬計算,模擬結(jié)果和實驗結(jié)果較為吻合,說明建立的燃燒模型真實可行。計算分析了不同EGR對柴油機燃燒和排放性能的影響,為了確定CO2、H2O和N2這三種氣體對柴油機燃燒與排放的影響差別,分別用它們來彌補氧氣量的減少以維持進(jìn)氣量的總量不變,進(jìn)行了EGR率為3%,6%,9%三個工況的九組模擬計算。結(jié)果表明三種氣體對柴油機缸內(nèi)燃燒及HC、NOX、CO和SOOT污染物排放的影響大致相同:都是隨著EGR量增加,缸內(nèi)最大爆發(fā)壓力和最高燃燒溫度呈下降的趨勢,其峰值出現(xiàn)的位置越接近壓縮上止點,且高溫持續(xù)時間縮短,燃燒始點隨著EGR率的增大而后移;HC最終排放量也逐漸升高;NOX最終排放量顯著下降;CO最終排放量隨著EGR率的增大而減小;SOOT最終排放量隨著EGR率的增大而增大;但最終數(shù)值卻不盡相同,發(fā)現(xiàn)在廢氣再循環(huán)中起主要作用的還是它的稀釋效應(yīng),而化學(xué)效應(yīng)和熱效應(yīng)起的作用較小。計算分析了不同負(fù)荷對柴油機燃燒和排放性能的影響,發(fā)現(xiàn)隨負(fù)荷的增加,缸內(nèi)平均壓力和溫度會逐漸增大,其最大爆發(fā)壓力和最高燃燒溫度也隨之增大,曲線最大值所對應(yīng)的曲軸轉(zhuǎn)角向后推遲;最終的HC、NOX、CO和SOOT污染物排放量也是隨之增大。計算分析了不同噴油提前角對柴油機燃燒和排放性能的影響,發(fā)現(xiàn)缸內(nèi)最大爆發(fā)壓力和最高燃燒溫度隨著噴油提前角的增大而增大,且其峰值出現(xiàn)的位置越接近于壓縮上止點,燃燒始點隨著供油提前角的前移而提前,高溫持續(xù)時間增長;HC的最終排放量隨噴油提前角的增大而減小;NOX生成量也隨之增大;CO的最終排放量也隨噴油提前角的增大而增大;但SOOT的排放量則是減少的趨勢。
[Abstract]:With the increasingly serious environmental pollution, emission regulations are becoming more and more stringent. How to further reduce diesel engine emissions has become the most important issue nowadays. Diesel engine has been widely used in power plant because of its high power performance and low fuel consumption rate. The main conventional emissions of diesel engines are NOXCHCCO and SOOT.Because of the continuous development of computational science and the improvement of computer computing ability. Numerical simulation has become an important means to study combustion process. Numerical simulation takes short time, low cost, and can obtain a large amount of flow field information that can not be obtained by experiments. In this paper, KIVA software is used as a research tool. The combustion chamber of 4102 diesel engine was meshed with the preprocessor of KIVA software, and the initial parameters and boundary conditions were determined, and then the numerical simulation was carried out. The simulation results are in good agreement with the experimental results, which shows that the established combustion model is feasible. The effects of different EGR on the combustion and emission performance of diesel engine are calculated and analyzed in order to determine the CO2. The effect of H _ 2O and N _ 2 on combustion and emission of diesel engine is different. They are used to make up for the decrease of oxygen quantity to keep the total amount of air intake unchanged, and the EGR ratio is 3%. The results show that the effects of the three gases on the combustion in the cylinder and the emission of HCN NOXCO and SOOT pollutants in the diesel engine are approximately the same: both of them increase with the increase of the amount of EGR. The maximum burst pressure and the maximum combustion temperature in the cylinder showed a downward trend. The peak value was closer to the compression stop point, and the high temperature duration was shortened, and the combustion start point moved backward with the increase of EGR ratio. HC final emissions also increased gradually; The final emission of NOX decreased significantly; The final emission of CO decreases with the increase of EGR rate. The final emission of SOOT increases with the increase of EGR rate. But the final value is not the same, it is found that the main role in the exhaust gas recycling is its dilution effect. The influence of different load on combustion and emission performance of diesel engine is analyzed. It is found that the average pressure and temperature in cylinder will increase gradually with the increase of load. The maximum burst pressure and the maximum combustion temperature also increased, and the crankshaft rotation angle corresponding to the maximum curve was delayed. The final emissions of CO and SOOT also increased. The effect of different fuel injection advance angle on combustion and emission performance of diesel engine was calculated and analyzed. It is found that the maximum burst pressure and the maximum combustion temperature increase with the increase of the injection advance angle, and the position of the peak value is closer to the compression stop point, and the combustion start point advances with the advance angle of the fuel supply. The duration of high temperature increased; The final emission of HC decreases with the increase of fuel injection advance angle. The amount of NOX also increased. The final emission of CO also increases with the increase of fuel injection advance angle. But SOOT emissions are a decreasing trend.
【學(xué)位授予單位】：河北工業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TK421;X701

【參考文獻(xiàn)】

相關(guān)期刊論文 前2條

1 周華祥;龍華;胡佳英;任成高;王雪紅;;汽車尾氣污染的凈化處理技術(shù)[J];裝備制造技術(shù);2007年02期

2 孫俊;KIVA-Ⅱ程序計算網(wǎng)格生成方法的應(yīng)用研究[J];武漢理工大學(xué)學(xué)報(交通科學(xué)與工程版);2002年06期

，

本文編號：1431489