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前置碱雾发生器内气液固多相流动的测量研究 总被引:2,自引:0,他引:2
根据两相流相似模化原理建立了前置碱雾发生器烟气脱硫颗粒图像测速技术多相流动实验台,运用颗粒图像测速(PIV)技术对前置碱雾发生器内气液固三相流动进行测量,得到不同工况条件下喷雾射流与固体颗粒的流动结构和流场信息.结果表明:由于雾化液滴射流的卷吸作用,大部分固体颗粒被卷吸进雾化锥内,在喷嘴出口一定区域固体颗粒与雾化液滴具有较大的速度差,在雾化锥内固体颗粒与雾化液滴发生剧烈的碰撞形成浆液,此为形成碱雾的主要区域.合理设计边壁风量有利于抑制甚至防止雾化液滴以及碰撞形成的浆滴可能的粘壁现象. 相似文献
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《汽轮机技术》2016,(1)
在欧拉-欧拉两相流模型的基础上,加载群体平衡模型,采用分组法对汽轮机喷嘴内部盐析两相流场进行数值模拟,得到了沿介质流动方向不同物质盐沉积颗粒平均粒径的分布特性,预测了汽轮机喷嘴内汽固两相流不同物质盐沉积颗粒的分布规律。计算结果表明:在喷嘴的流道内,沿介质的流动方向,不同盐沉积颗粒的平均粒径均呈现逐渐增大趋势,主流区盐沉积颗粒平均粒径较小,近壁面处盐沉积颗粒平均粒径较大。此外,受相间传质及颗粒微观行为影响,沿介质的流动方向,小粒径颗粒的组分数分布逐渐减小,大粒径颗粒组分数分布逐渐增大。不同物质盐沉积颗粒平均粒径和颗粒组分数的分布,在喷嘴流场内变化是不同的。 相似文献
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对循环流化床中气田惯性分离过程进行了详细的数值研究。湍流模型采用雷诺应力模型,研究对象为U型分离器内的气一固两相流动。为了真实描述固体颗粒与分离器壁面之间的碰撞过程,固体颗粒模拟采用颗粒轨道模型,引入壁面粗糙度的影响,同时考虑了固体颗粒在湍流中的扩散作用和颗粒之间的相互碰撞。模拟计算了不同入口速度、分离器挡板数目对颗粒分离效率和流体压降的影响,计算结果不仅给出了分离器内的气-固两相流动结构特性,而且给出了分离器效率、压降与入口主流速度和分离器结构参数的关系。 相似文献
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柱状旋流分离器内液滴运动轨迹的数值模拟 总被引:1,自引:0,他引:1
在不考虑相间相互作用的条件下,气相采用RNGk-ε湍流模型,液相采用随机轨道模型,对热气机排气系统中的气液分离器两相流动进行了数值模拟,揭示了气液分离器内的流动分布和液滴的运动轨迹及分离机理。计算结果表明:分离器内的速度场分布不均匀,并且靠近进出口的气流速度较大,柱体中心的气体切向速度很小;另外不同粒径的液滴运动轨迹差别很大,粒径大的液滴较容易分离;液滴入射的初始位置不同,其分离速度的差别较大,运动轨迹也明显不同。 相似文献
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采用欧拉-拉格朗日方法,建立了湿法烟气脱硫系统折流板除雾器内气液两相流动模型。通过三维数值模拟,得到了不同进口气速和叶片间距下液滴的运动和捕集特性,分析了液滴间的碰撞作用、气流对液滴的破碎作用以及液滴与壁面间的相互作用对分离效率的影响规律。结果表明:进口气速和液滴粒径是影响分离效率的主要因素,小粒径液滴对气流的跟随性较强,大粒径液滴的运动主要由惯性主导;模拟中考虑液滴的碰撞作用时整体的除雾效率增大,气流对液滴的破碎作用对分离效率的影响甚微,考虑了液滴与壁面间相互作用的模型可更加准确地描述分离过程中出现的二次夹带现象。 相似文献
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湿法烟气脱流装置中水力旋流器分级试验表明,进口石灰石浆液的颗粒质量浓度为15%时,溢流口颗粒质量浓度达30%,溢流颗粒粒径则集中于30μm以下;随着颗粒粒径的增大,颗粒底流口回收率也在增大,当粒径达到30μm时,回收率已经接近100%。数值模拟表明,雷诺应力湍流模型、自由表面多相流动模型和斯托克斯拉格朗日模型能很好地描述水力旋流器内复杂三维运动的石灰石颗粒分级运动和规律。采用了初始边界条件不给出分流比、也不设定空气柱的模拟方法,模拟结果显示了空气柱的形成、流体的旋流流动。模拟得到的不同粒径颗粒的分级效率与高进口质量浓度条件下的试验结果吻合较好。 相似文献
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为了降低核电站严重事故中碎片床冷却性分析的不确定性,采用2个尺寸范围的砂石颗粒模拟构建碎片床,并进行了单相与两相流动实验。基于测量的单相流动阻力压降和Ergun方程计算出砂石颗粒的有效直径,在此基础上进行气-水两相流动实验,测量并获得了颗粒堆积床内的两相流动阻力压降,验证碎片床内两相流动阻力模型。结果表明:对于小尺寸砂石颗粒堆积床,其两相流动阻力压降随气相雷诺数的增大呈现上升趋势,在气相雷诺数较低时,Lipinski模型计算值与实验值吻合较好,随着气相雷诺数增大,实验值逐渐接近Reed模型计算值;对于大尺寸颗粒堆积床,相间摩擦力对两相流动阻力有重要影响,其两相流动阻力压降随气相雷诺数的增大呈先下降后上升的趋势。 相似文献
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《International Journal of Hydrogen Energy》2022,47(63):26789-26797
The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO2 and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized. 相似文献
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基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁(MgO),研究了该型MgO膨胀剂(MEA)细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析(TG DSC)分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。 相似文献
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General expressions for the heat of vaporization of mixtures at constant pressure; at constant temperature; and at constant pressure, temperature, and composition are proposed. The last one is related to the liquid-vapor interface where steady vaporization or condensation is taking place. Numerical examples by the proposed expressions are shown for binary mixtures of HCFC22(R22) and (HCFC123(R123) © 1997 Scripta Technica, Inc. Heat Trans Jpn Res, 25(1): 12–24, 1996 相似文献
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应用瞬态谱分析方法对燃烧流化床声波信号进行了频谱分析,发现气泡能量分布呈Gamma分布形式,在Argyrious和Yoshida等人提出的模型的基础上,发展了燃烧流化床气泡能量分布模型,并通过优化迭代对模型参数进行求解,在实验和理论的基础上得出了更加切合实际的燃烧流化床气泡能量分布模型 相似文献
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城镇生活污水处理装置是由农村户用沼气地发展演变而来,是一种小型、分散化处理污水的装置 ,是环境建设的需要。文章着重从我国环保政策及目标、生活污水造成的污染状况、急需整治的公共设施、生活污水净化装置的演变以及社会经济效益和环境效益等方面,阐述了其产业化的重要性。 相似文献
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The paper deals with second law thermodynamic analysis of a basic gas turbine based gas-steam combined cycle. The article investigates the effect of variation of cycle parameters on rational efficiency and component-wise non-dimensionalised exergy destruction of the plant. Component-wise inefficiencies of the combined cycle have been quantified with the objective to pin-point the major sources of exergy destruction. The parameter that affects cycle performance most is the TIT (turbine inlet temperature). TIT should be kept on the higher side, because at lower values, the exergy destruction is higher. The summation of total exergy destruction of all components in percentage terms is lower (44.88%) at TIT of 1800 K & rp,c = 23, as compared to that at TIT = 1700 K. The sum total of rational efficiency of gas turbine and steam turbine is found to be higher (54.91%) at TIT = 1800 K & rp,c = 23, as compared to that at TIT = 1700 K. Compressor pressure ratio also affects the exergy performance. The sum total of exergy destruction of all components of the combined cycle plant is lower (44.17%) at higher value of compressor pressure ratio (23)& TIT = 1700 K, as compared to that at compressor pressure ratio (16). Also exergy destruction is minimized with the adoption of multi-pressure-reheat steam generator configuration. 相似文献
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Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined. 相似文献