煤炭地下气化高温井筒温度场研究

基于井筒与地层的传热情况,根据能量守恒及井筒传热原理,考虑物性参数随温度和压力变化,建立了生产井井筒的温度场预测模型,形成了求解算法和数学仿真模型,研究了温度场的影响因素。结果表明:产出气各物性沿井深分布差异较大,在分析时有必要耦合考虑;随着日产量和井底温度增加,井筒各段的温度均上升,其中日产量在30×10⁴ m³/d时,井口的产出气温度最高(686℃),井底温度在1000℃时,井口温度为588℃;井底压力对温度场影响很小,在工程应用中可忽略不计;随着井深增加,井口温度下降。     

晶须长径比对复合材料力学行为影响的模拟

在单向晶须增强树脂基复合材料的轴对称模型和已有研究成果基础上,利用有限元分析方法,研究该类复合材料中晶须长径比的变化对材料整体力学行为的影响.结果表明:1)晶须长径比对晶须应力作用明显大于对基体的影响;2)晶须的长径比h/r≤30时,随着晶须长径比的增大,发生在晶须端部处的集中应力急剧增加;但当长径比h/r≥30时,长径比的进一步增加对集中应力影响不大;3)随着晶须长径比的增大,界面剪切应力减小,分布曲线下移;但当长径比h/r≥30时,长径比的进一步增加对剪切应力影响不大;4)随着晶须长径比的增加,复合材料的拉伸强度逐渐增大.     

The service of the hearths of arc furnaces for melting stainless steels with the use of oxygen

Conclusions During the operation of arc furnaces specializing in the melting of stainless steels, chemical and phase changes occur in the magnesite hearths which lead to the formation of a single type structure in the monolith of rammed layer and upper courses of the structure.Petrographic studies showed that the monolith was formed as a result of phase inversions of the minerals of the hearth under the influence of the silicate constituents of the slag being produced, which partly settles to the bottom after discharge of the melt. These inversions greatly affect the physicochemical properties of the hearth and especially the refractoriness. The inversions which increase the refractoriness include the process of recrystallization of the periclase and chrome-spinel with the formation of strong and dense periclase-spinel growths in the upper layers of the hearth.The reduction in the refractoriness occurs owing to the formation of montichellite under the influence of calcium slag constituents and the gradual replacement of the forsterite by this silicate, and also the partial solution of periclase in the silicate melt.The thermal resistance of the hearth is favorably affected by the fact that the new silicate formations are distributed irregularly over the height of the hearth, and the nature of the distribution depends on their fluidity and temperature gradient in the hearth. In view of this consistency, the most refractory silicates, such as forsterite and mervenite, are localized in the upper strata of the hearth, and the montichellite, being the most fusible silicate, migrates to the lower layers.The result of all the processes and phase inversions taking place in the hearth is that the refractoriness of the most important layers of hearth (upper and middle) remains high during service. The reduction in refractoriness in the lower layer cannot greatly affect the life of the hearth since this layer is quite far away from the working region of the furnace and is in the low-temperature region.Large amounts of metals are detected only in the part of the hearth located in direct contact with the furnace bath; metal does not take a large part in the processes occurring in the hearth.The positive influence of the additions of chromite on the life of the hearth of electric furnaces determined during operation, can be explained by the fact that the chromite is essential for the formation of refractory chromespinel phases [2], contributes to the formation of periclase-spinel growths in the upper parts of the hearth, and accelerates the process of removing the less refractory silicates from the upper layers of the hearth to the lower [3].     

直缝式燃烧器W火焰锅炉新型二次风箱特性研究

为解决直流缝隙式燃烧器W火焰锅炉原设计的全通二次风大风箱由于锅炉炉膛宽度宽、风箱截面尺寸大等原因产生的炉膛中部缺风问题,华能上安电厂将4号锅炉原风箱改造为分隔型新型二次风箱。新型二次风箱改造完成后对其特性的试验研究表明,常规冷态通风时拱上、拱下各喷口及各风道区域之间风速偏差较小。单侧送风机运行且联络门关闭时,送风机停运侧各喷口风速明显低于送风机工作一侧,但通过拱上、拱下二次风门的调整,能有效缓解由于单侧送风机运行带来的喷口风速偏差。单侧送风机运行联络门开启的情况下,3个风道区域平均风速的偏差与正常双送风机运行时差别不大。与改造前相反,锅炉运行炉膛出口氧量已呈现中间高两头低的趋势,适当调整二次风箱风门开度后炉膛出口氧量分布趋于均衡,说明改造后的二次风箱风门能有效调节炉内二次风配风进而改变炉膛出口氧量分布。通过二次风箱风门开度的适当调整,能有效降低SCR入口NOx浓度,保证锅炉经济环保运行。     

Effect of preparation conditions on the properties of microspheres prepared using an emulsion-solvent extraction process

Methylaluminoxane microspheres were prepared using a hydrocarbon-in-perfluorocarbon-emulsion solvent extraction process. The effect of the preparation conditions on the size of the microspheres was investigated. As expected, the size of the microspheres decreased with increasing stirring speed. At low surfactant concentrations the size of the microspheres was independent of the surfactant concentration. However, the size of the microspheres decreased as the surfactant concentration was further increased. The size of the microspheres was not only affected by the surfactant concentration but also by the volume ratio of the dispersed phase to the continuous phase. At a low volume ratio of the phases the effect of the surfactant on the size of the microspheres was larger than the effect of the increased volume ratio of the phases. At high volume ratios of the phases the effect of the volume ratio of phases on the size of the microspheres became more significant than the effect of the surfactant. A slow solidification increased the formation of non-spherical microspheres.     

The role of the symmetry and the flexibility of the anion on the characteristics of the nanostructures and the viscosities of ionic liquids☆

The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion.     

纳米填料/橡胶体系在贮存中的结构形态变化Ⅱ.结构变化的影响因素及其对性能的影响

综述了纳米填料／橡胶复合体系在熔融态或高弹态贮存停放过程中,影响其结构形态变化的因素,以及贮存停放对复合体系流变性能、物理机械性能和导电性能的影响,并评述了相关的理论模型。纳米填料／橡胶复合体系在熔融贮存过程中的结构变化主要受橡胶的黏度、填料特性及其用量、填料与橡胶之间的相互作用以及加工性能的影响。填料网络结构的絮凝程度强化使复合体系流变性能、动态力学性能降低,但导电性能提高。相关的填料聚集动力学和填料絮凝模型大部分是唯象模型。     

复合材料风扇叶片榫头铺层设计及加工制造

碳纤维复合材料风扇叶片榫头段是铺层数量最多、递减铺层最集中的部位,榫头的铺层质量影响叶片的低周疲劳强度。为完成叶片榫头段的铺层设计,基于铺层设计准则,建立了一种适用于航空发动机复合材料风扇叶片榫头段铺层设计的方法。根据铺层高度大小将铺层分为结构层和插入层,在结构层铺层设计中考虑了高度递减层的角度与铺放位置。在插入层铺层设计中,考虑了单组插入层铺层数量、单组插入层内部铺层顺序及铺层角度、单组插入层形成的坡度、相邻插入层之间的错开距离等五个方面的因素,确定了单组插入层的结构及其在榫头的分布。根据设计方案对榫头进行加工制造,成型的榫头试样件厚度检测质量良好,证实了该铺层设计方法的可行性。     

转炉一次除尘新OG系统高效喷淋塔喷嘴布置方式对喷淋特性的影响

采用离散相模型对新OG系统高效喷淋塔入口段及主体段喷嘴的布置方式进行数值模拟,考察了喷嘴喷射方向和喷淋层数对雾化场气流分布和降温效果的影响。结果表明,喷嘴的喷射方向和塔内的喷淋层数对雾化场的气流分布和降温效果影响较大;喷淋塔入口段采用逆流喷射时,出口截面的速度分布最均匀且降温效果最好;高效喷淋塔的主体段的喷淋层数为5时,塔内烟气的速度流场较均匀,且中心区域的气流速度为2~4 m/s,有助于延长气体与液滴的作用时间;随喷淋层数增加,塔内温度梯度变化增大,水蒸气质量分数分布与温度分布对应,塔内的平均湍动能逐渐增高。     

聚丙烯气相反应器工艺参数的计算和控制

以液相本低聚合和气相聚合组合式聚丙烯（PP）装置生产多相共聚PP产品为例，推导出了多相共聚PP生产中气相反应器工艺参数之间的关系式，并讨论了工艺参数对产品性能的影响，通过控制气相反应器的乙烯进料量与气相比，改变产品的抗冲击性能，乙烯含量越高，产品的抗冲击性能越好，刚性越差，无定形二聚物的含量越高，产品的抗冲击性能越好，但刚性相对降低。     

催化糠醛抽提液液平衡组成计算程序开发

用润滑油糠醛精制抽出液对催化裂化回炼油进行抽提,当回炼油组成变化或对裂化产品的质量要求发生变化时,为了确定适宜的抽提操作条件并减少实验工作量,有必要对抽提过程进行热力学模拟,通过计算来预测液液平衡组成。确定了液液平衡组成计算方法,采用UNIFAC模型计算组分活度系数,并用VB语言编制了计算程序,应用牛顿-拉斐森方法解非线性方程组。该方法具有收敛速度快、精度高等优点。分别用文献中的数据验证了其中计算活度系数的子程序和整个计算程序的可靠性。子程序的计算相对偏差为0．04％,应用程序计算来预测文献体系液液平衡组成的最大绝对偏差不超过0．02,程序的计算性能可靠,考察了以纯糠醛为溶剂液液平衡组成预测,效果很好。     

新型热解炉燃烧室流热固耦合仿真与结构优化

针对新型热解炉燃烧室结构,采用ANSYS Workbench流热固耦合方法,研究不同结构参数下燃烧室的温度场与变形场,获得了最优的燃烧室结构。结果表明,燃烧室内设挡板的结构性能优于无挡板的结构性能,燃烧室内设挡板的温度场变异系数的变化幅度比无挡板的变化幅度减小0.06,温度场分布更均匀;燃烧室的最大变形出现在燃烧室与热解室之间的隔板上,有挡板的燃烧室最大变形量较无挡板的燃烧室减少80%,且最大变形量均随着挡板位置距中心的距离或挡板长度增加呈先减小后增大的趋势,而挡板厚度对变形场的影响最小;在挡板位置为150 mm,挡板长度为800 mm,挡板厚度为14 mm时,新型热解炉燃烧室的结构最优。     

闭式热源塔运行参数对热泵系统性能的影响

热源塔风机和防冻溶液循环泵是热源塔热泵系统中除压缩机外的主要耗电设备。通过改变热源塔风机和防冻溶液循环泵的工作频率,实验研究了冬季制热工况下闭式热源塔运行参数对热源塔吸热量和热泵系统性能的影响,研究结果表明,热源塔风机频率降低导致热源塔吸热量、系统制热量和热泵机组COP下降,但使系统能效比增大;热源塔吸热量随循环泵频率的增加先升高后降低并在25 Hz时达最大值,系统制热量同样随循环泵频率的增加先升高后降低,且随着风机频率的增大,制热量最大值对应的循环泵频率由35 Hz变为25 Hz;同时循环泵频率增加使热泵机组COP增加,但系统能效比减小;循环泵和风机频率均在15 Hz时,压缩机压缩比增大,压缩机效率低;系统制热量最高超过14.30 kW,热泵机组平均COP最高为3.31,系统平均能效比最高可达2.37。     

基于ABAQUS的降雨对群桩加固斜坡软弱土路堤的影响分析

降雨入渗是斜坡软弱地基路堤强度降低甚至失稳的一个重要因素,因此降雨条件下斜坡路堤的加固变得极其重要。本文基于ABAQUS有限元软件,结合具体工程实例,进行了一系列降雨方案下斜坡软弱地基路堤变形和稳定性分析,重点研究降雨强度和降雨时间对斜坡路堤坡面水平位移及桩体水平位移的影响,并研究了降雨强度为0.02m/h、降雨时间为18h时桩体弹性模量和桩间距对路堤顶部变形和安全系数的影响。研究结果表明:路堤坡面水平位移及桩体水平位移与降雨强度和降雨时间成正比关系;桩体弹性模量增加路堤顶部位移随之减小而安全系数变大;桩间距越小对路堤顶部沉降减小作用越明显,但可以提高路堤的安全系数。综合考虑路堤稳定性、桩体变形和经济性提出了研究工况下最佳加固方案,可供相似工程参考。     

升温速率对复合材料修补片固化过程热应力的影响

采用有限元法数值模拟了3234/T300B热固性树脂基复合材料修补片的热补仪加热固化过程,分析了工程应用范围内不同升温速率下的复合材料修补片固化历程中的温度、热应力分布和变化特征,并研究了升温速率对补片在不同时间点的残余热应力值的影响规律。研究结果表明:升温阶段热应力主要集中在补片表面中心区域及其与母板接触的区域,降温阶段复合材料修补片内部热应力高于表面热应力;升温速率越快,固化越迅速,在升温阶段修补片内部热应力及峰值热应力越大;在保温和降温阶段,修补片内热应力分布和大小不受升温速率的影响;对于较低升温速率,热应力最大值出现在升温结束时刻;对于较高的升温速率,热应力最大值出现在接近升温末期的时刻。研究结果为合理选择升温速率从而减小升温阶段的内部热应力并控制补片分层等缺陷提供了参数依据。     

生物柴油浸没喷吹的雾化特性

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。     

聚丙烯细粉产生的原因及影响

结合CS－2型高效催化剂在液相本体法聚丙烯装置应用的实际，分析了细粉含量增加的主要原因有：催化剂本身粒径的分布，催化剂钛含量，铝／钛（摩尔比，下同）控制情况，预聚效果以及聚合反应条件的影响。通过对细粉增加原因的分析，提出了3条改进措施：改进催化剂制备，选择粒径分布好，强度高的催化剂载体，控制好制备的各个环节；调整预聚操作条件，保证预聚效果，减少催化剂破损；根据催化剂特性，控制好催化剂的铝／钛，充分利用催化剂活性是减少细粉生成的有效措施。     

The theory of the practice of steam deodorization of saponifiable oils

Summary The pressure of steam entering the deodorizer is approximately half the pressure of the steam supply. The relative dimension of the apparatus and form of the outlet may be calculated from the equation given in the paper. To shorten the time of deodorization the most important factors are low pressure in the deodorizer and high temperature of the oil. In the application of the counter current principle which amounts to the same thing as continuous deodorization the apparatus used is a tower in which the air is admitted at the top and the steam at the bottom. The whole apparatus is maintained under reduced pressure and the oil is withdrawn from the apparatus in a finished condition, while the odoriferous matter is carried over with the steam into a condenser at the top of the apparatus. The advantages which may be claimed are short time of contact with the steam and economy in the use of steam.     

Special Features Of Stabilization Of The Growth Process In Plasma-arc Growth Of Single Crystals Of Refractory Compounds From SHS Products

Problems of the stability of the growth process in growing single crystals of refractory compounds (carbides and bondes of transition metals) by the method of plasma-arc remelting are considered. The main reasons behind the loss of stability of the spatial configuration of the melt (a shift of the anode lock-on of the arc from the center of the molten pool, disturbance of the symmetry of the plasma jet, superheating of the melt) are considered. The effect of cyclic perturbations in the crystallization system that appear upon replenishment on the fluctuation of the energy characteristics of the arc, the temperature of the melt, and the displacements of the crystallization surface is described. It is established that the crystallization rate and the process of coarsening of the crystallites in the formation of a columnar structure in the ingot depend on the frequency of feeding new portions and on their mass.     

新建地方本科院校生物化工专业实习体系的构建

新建地方本科院校生物化工专业实习体系中存在着目标体系和管理体系不完善、实习内容单调、实习条件薄弱、缺乏科研项目支撑等问题,必须通过对实习的目标体系、内容体系、条件体系和管理体系的科学构建来完善,并通过实践,证明其体系的科学性和可操作性。