共查询到18条相似文献,搜索用时 187 毫秒
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利用离散相模型对转炉一次除尘新OG系统高效喷淋塔内喷嘴的雾化特性进行模拟,分析了喷射角度、喷射压力、喷射流量及喷嘴水平间距等因素对雾化场索太尔平均直径(SMD)和蒸发效率的影响. 结果表明,在一定范围内随喷射角度增加,液滴在雾化场中的覆盖面增大,液滴驻留时间变长,蒸发效率增加,雾化场SMD减小,喷射角度大于60o时,SMD值减小缓慢. 随喷射压力增大,液滴蒸发效率增加,雾化场SMD减小,压力大于1.0 MPa时对SMD的影响较小. 随喷射流量增加,液滴蒸发效率减小,雾化场SMD增加,流量小于0.15 kg/s时,SMD增加幅度偏小. 两喷嘴水平间距越大,液滴分布面积越大,但对雾化场SMD影响较小. 在一定条件下,喷嘴间距约为800 mm时,截面速度分布较均匀. 相似文献
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通过对气化炉运行参数比较,研究了水煤浆气化有效气含量的影响因素,分析了原料煤质量、水煤浆浓度、气化氧煤比以及烧嘴雾化效果对水煤浆气化有效气含量的影响。结果表明:高质量原料煤、高浓度水煤浆、合适的氧煤比以及较佳雾化效果的烧嘴均能提高有效气含量。同时,操作条件调控还受到生产安全条件制约。因此,需要综合考虑多方面因素的影响,尽可能在安全的前提下提高水煤浆气化有效气含量,提高经济效益。 相似文献
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以清水和空气为实验介质,对同轴双通道气流式喷嘴雾化特性进行了实验研究,分析了喷淋量对雾化角及径向流通量分布的影响,分别考察了气速和喷嘴轴向位置对液滴索特平均直径(SMD)的影响。研究结果表明,喷嘴径向流通量分布随着雾化气量的升高而趋于集中,当气体流量高于1500 L/min时,雾化角随着气量升高而降低;喷口处气速与喷嘴轴向位置均是影响液滴SMD与粒径分布的重要因素,液滴SMD随着气速增大逐渐减小,当气速超过150 m/s时其下降趋势变缓,粒径分布均匀度显著提高;随着喷嘴轴向距离增大液滴SMD逐渐减小,当距离大于300 mm时其变化不再显著,但粒径分布均匀度显著提高。 相似文献
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喷雾冷冻液滴的冻结过程决定着干燥产品的微结构。本文以单个雾化液滴为研究对象,利用数值模拟的方法研究了液滴大小、气体流速和环境温度3个参数对其冻结过程的影响。结果发现,液滴越大冻结时所需的形核时间和完全固化时间越长,而且冻结过程随着气体流速的增大和环境温度的降低而缩短。通过方差分析发现,液滴大小较气体流速和环境温度对液滴完全固化时间的影响有较显著差异。液滴冷冻过程中,其质量损失率随着液滴大小的增大而略有减小,随着气体流速的增加及环境温度的降低而减小,其中环境温度对液滴质量损失率的影响最大。 相似文献
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Kangwook Kim Hakduck Kim Changyeon Kim Juhun Song 《Korean Journal of Chemical Engineering》2016,33(5):1612-1619
Liquid carbon dioxide (LCO2) could potentially be utilized in coal gasification plants for effectively transporting coal particles, replacing conventional carriers such as water (H2O), particularly in wet-fed gasifiers. However, it is essential to understand the atomization behavior of LCO2 leaving an injector nozzle under both coal-free and coalfed conditions. We examined the atomization behavior of a coal-LCO2 slurry during the throttling process. The injector nozzle was mounted downstream of a high-pressure spray system. The effect of upstream pressure on flash atomization and devolatilization behavior was presented. Compared with the coal-LCO2 mixture, the spray pattern of the coal-water mixture was significantly different, since it evidenced a Rayleigh-type breakup mode. This difference indicates that the coal-water slurry did not transport the coal as effectively as the coal-LCO2 slurry. 相似文献
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For the design and optimization of a tubular gas–liquid atomization mixer,the atomization and mixing characteristics of liquid jet breakup in the limited tube space is a key problem.In this study,the primary breakup process of liquid jet column was analyzed by high-speed camera,then the droplet size and velocity distribution of atomized droplets were measured by Phase-Doppler anemometry (PDA).The hydrodynamic characteristics of gas flow in tubular gas–liquid atomization mixer were analyzed by computational fluid dynamics (CFD) numerical simulation.The results indicate that the liquid flow rate has little effect on the atomization droplet size and atomization pressure drop,and the gas flow rate is the main influence parameter.Under all experimental gas flow conditions,the liquid jet column undergoes a primary breakup process,forming larger liquid blocks and droplets.When the gas flow rate (Q_g) is less than 127 m~3·h~(-1),the secondary breakup of large liquid blocks and droplets does not occur in venturi throat region.The Sauter mean diameter (SMD) of droplets measured at the outlet is more than 140μm,and the distribution is uneven.When Q_g127 m~3·h~(-1),the large liquid blocks and droplets have secondary breakup process at the throat region.The SMD of droplets measured at the outlet is less than 140μm,and the distribution is uniform.When 127Q_g162 m~3·h~(-1),the secondary breakup mode of droplets is bag breakup or pouch breakup.When 181Q_g216 m~3·h~(-1),the secondary breakup mode of droplets is shear breakup or catastrophic breakup.In order to ensure efficient atomization and mixing,the throat gas velocity of the tubular atomization mixer should be designed to be about 51 m·s~(-1)under the lowest operating flow rate.The pressure drop of the tubular atomization mixer increases linearly with the square of gas velocity,and the resistance coefficient is about 2.55 in single-phase flow condition and 2.73 in gas–liquid atomization condition. 相似文献
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以生物柴油替代柴油进行浸没喷吹熔池熔炼是发展低碳铜冶炼的重要途径。针对该过程建立生物柴油浸没喷吹雾化流动过程计算模型,本文模拟计算了喷枪在水模型中浸没深度为20mm时不同油气比条件下生物柴油雾化颗粒的雾化特性,并实验验证了计算模型。研究结果表明:油滴颗粒的贯穿距随着空气流速的增加而增大;在气泡内油滴颗粒以一定的雾化半角向前扩散;当油滴颗粒到达气泡底部时,油滴颗粒以气泡底部平面为中心向整个空间扩散;气泡内距离喷枪轴向越远的观察面内大颗粒数目越多;油滴颗粒的索特平均直径(SMD)沿喷枪轴向先增大后减小;气泡内距喷枪口越远油滴颗粒SMD越大,进入水区域的油滴颗粒SMD逐渐减小;雾化空气流速越大,油滴颗粒SMD最大值的位置距喷口越远。 相似文献
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The direct‐ignition technology of an entrained‐flow coal‐water slurry gasifier with hot‐oxygen burner (HOB) is presented. Experimental tests were carried out using diesel oil and coal‐water slurry in a bench‐scale entrained‐flow opposed multi‐burner (OMB) gasifier. Using a CCD camera equipped with high‐temperature endoscope, flame images inside the gasifier were recorded and subsequently processed. The results show that the HOB diesel flame is more stable than the normal two‐channel burner flame typically used. Entrained‐flow coal‐water slurry gasifiers can start up using the HOB directly without a higher preheated wall temperature. An HOB can potentially save gasifier preheating time and operation costs and enables a wide range of future applications. 相似文献
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压力、煤浆浓度、氧煤比对水煤浆气化的影响 总被引:2,自引:0,他引:2
研究了水煤浆气化技术操作参数的优化途径;分析了气化压力、煤浆浓度、氧煤比(氧碳比、氧浆比)对碳转化率、产气率、冷煤气效率、合成气有效组分含量等水煤浆气化参数的影响;对各参数之间的最佳搭配进行了优化;确定了各个量的最佳操作值,为气化装置低能耗、高效益运行提供依据。 相似文献