排序方式: 共有27条查询结果,搜索用时 19 毫秒
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环状出口气泡雾化喷嘴研究 总被引:3,自引:0,他引:3
本文对环状出口气泡雾化喷嘴出口下游液膜的破碎过程进行了研究,发现气体的介入是促使液膜破碎的主要原因。利用DUALPDA对其下游流场的速度分布、颗粒直径分布以及通量分布进行了实验测量。发现喷嘴出口附近主流区域存在大量具有负向速度的颗粒,并且此处的颗粒平均直径显著减小,为气泡雾化机理提供了佐证;在喷嘴出口下游轴心处液雾呈现逆向流动趋势,证明此处存在负压回流;沿轴向的速度分布曲线与颗粒直径分布曲线的变化趋势说明气泡"爆炸"发生在出口下游5-15 mm距离内。 相似文献
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Ligang Chen 《Talanta》2010,82(4):1186-1192
A green and simple method was developed for determination of sulfonamides (SAs) in soil samples. The procedure was based on the microwave-assisted extraction (MAE) of SAs from soil using non-ionic surfactant Triton X-114 as the extraction medium. Then sodium chloride was added into the MAE extract and the mixture was equilibrated for some time at high temperature. The analytes in the surfactant-rich phase were concentrated with the help of centrifugation and directly analyzed by high performance liquid chromatography with UV detection. None of potentially hazardous organic solvents was used in the whole sample preparation procedure. The significant variables for the performance of extraction and concentration were studied. The limits of detection of SAs obtained are in the range of 3.2-5.7 ng g−1. The relative standard deviations of intra- and inter-day tests ranging from 3.5% to 7.7% and from 4.6% to 9.5% are obtained, respectively. This method was applied to the determination of SAs in some soil samples with different characteristics. The SAs recoveries obtained at fortified level of 100 ng g−1 for these samples are in the range of 81.2-93.7%. The effect of ageing time of spiked soil samples on the SAs recoveries was examined by the proposed method and a method reported in the literature. The recoveries of SAs decreased when the ageing time changed from 1 day to 4 weeks. 相似文献
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Experimental and numerical analysis of spray-atomization characteristics of biodiesel fuel in various fuel and ambient temperatures conditions 总被引:2,自引:0,他引:2
Su Han Park Hyung Jun Kim Hyun Kyu Suh Chang Sik Lee 《International Journal of Heat and Fluid Flow》2009,30(5):960-970
The purpose of this work is to reveal the effects of fuel temperatures and ambient gas conditions on the spray-atomization behavior of soybean oil methyl ester (SME) fuel. The spray-atomization behavior was analyzed through spray parameters such as the axial distance from the nozzle tip, local and overall Sauter mean diameter (SMD). These parameters were obtained from a spray visualization system and a droplet measuring system. In addition, the experimental results were compared with the numerical results calculated by the KIVA-3V code. It was revealed that the increase of the fuel temperature (from 300 K to 360 K) little affects the spray liquid tip penetration. The increase of the ambient gas temperature (from 300 K to 450 K) caused a increase in the spray liquid tip penetration. Also, biodiesel fuel evaporation actively occurred due to the increase in the fuel temperature and the ambient gas temperature. Of special significance was that the highest vapor fuel mass concentration was observed at the center region of the spray axis. In the results of the microscopic characteristics, the detected local droplet size at the axial direction and overall droplet size at the axial and radial direction in a control volume increased when the fuel temperature increased. This is believed to be due to an increase in the number of small droplets that quickly evaporated. In addition, the increased fuel temperature caused the decrease of the number of droplets and the increase of the vapor fuel mass. The mean axial velocity of droplets decreased with increasing fuel temperature. 相似文献
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采用密度泛函理论研究CO2在脂肪胺水溶液热力学参数.研究的脂肪胺包括烷基胺、链烷醇胺、二胺以及氨基酰胺.在B3LYP/6-311+ G(d,p)水平计算脂肪胺在CO2气相中的振动频率.通过连续介质模型在HF/6-31G(d)水平计算了溶剂几何优化的标准自由能,评价了CO2吸收到脂肪胺水溶液过程有关的两个重要参数:酸解离常数和标准焓变二者之间大致呈线性关系.随着胺碱度的提高,CO2吸收过程释放的热量增加,则胺再生所需的能量增加. 相似文献
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