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关键词： 凝析气藏   注气吞吐   油环   衰竭式开采   采收率   采出流体   组分变化  

摘要： 凝析气藏注气吞吐可提高采收率,但凝析气藏注气吞吐实验一般多研究注气量、注气速度及采收率的变化,而缺乏对注气后采出流体组分变化规律的研究。在建立带油环凝析气藏多次注气吞吐室内物理模拟评价方法的基础上,开展了带油环凝析气藏衰竭式开采后注气吞吐开采实验。结果表明:凝析气注气吞吐开采过程中,随注气吞吐次数增多,产出流体N_(2)+C_(1)含量降低,C_(2)—C_(4)和C_(5)^(+)含量升高;随着注气吞吐次数增加,采出流体组成变化越来越小,至第4次注气吞吐后流体组成基本不变。油环油注气吞吐过程中,产出流体N_(2)+C_(1)含量高,而C_(2)—C_(6)和C_(7)^(+)含量低;随着注气吞吐次数增加,采出流体N_(2)+C_(1)在初始几次注气吞吐中升高较明显,C_(2)—C_(6)和C_(7)^(+)含量明显降低,注气吞吐达到9次时,采出流体组成趋于稳定。

关键词： 核心素养   教学目标   液体的表面张力  

摘要： 以鲁科版高中物理选修3-3(2017版)"液体的表面张力"教学为例,依托于教材和学情,以物理核心素养为导向来指引物理教学目标的设计,进而暴露出当前物理教学中存在的问题,从而来还原物理学科的本质属性,并以学生为主体,来改善物理"淡化情境""忽视教学对象"的问题。

关键词： 跨声速静叶叶栅   附面层端壁抽吸   流动损失   角区分离  

摘要： 为探究附面层抽吸对跨声速扇形扩压叶栅分离流动控制、气动性能和流场结构的影响,本文基于CFX数值模拟方法对扇形扩压叶栅进行端壁孔抽吸方案研究,并分析叶栅抽吸效果随抽吸流量的变化规律。抽吸位置分布在上下端壁近吸力面端壁处,将弦长四等分为四个不同方案。对比原型及各抽吸孔方案可以得到,当抽吸流量为原型叶栅进口质量流量的0.7%时,最优方案为分离点下游附近的抽吸方案,下端壁单侧抽吸时扇形叶栅总压损失较原型叶栅降低7.83%,静压较原型提高7.86%。同时随着抽吸流量的增加,叶栅流动损失逐渐降低,扩压能力提升。

关键词： 支链醇醚磺酸盐   复配   相互作用参数   表面张力   界面张力  

摘要： 目的以支链醇醚TEO、1,3-丙烷磺酸内酯为原料合成了支链醇醚磺酸盐TEOS,测定了支链醇醚TEO、TEOS及两性Gemini表面活性剂GCS12在蒸馏水中的临界胶束浓度(cmc)及临界胶束浓度下的表面张力(γ_(cmc)),进行支链醇醚磺酸盐与两性Gemini表面活性剂的溶液性质研究。方法评价了醇醚磺酸盐TEOS与GCS12复配体系的表面活性,并对两者之间的相互作用进行研究,同时也研究了二元复配体系与长庆原油的界面活性。结果合成的醇醚磺酸盐质量分数达96.5%,耐盐性好;TEO、TEOS、GCS12在蒸馏水中cmc分别为0.05 mmol/L、0.40 mmol/L和0.05 mmol/L,γ_(cmc)分别为26.02 mN/m、34.58 mN/m和25.27 mN/m;溶液热力学理论研究表明TEOS与GCS12具有明显降低混合溶液临界胶束浓度的中等相互作用;60℃下,用模拟地层水配制的混合溶液在n(TEOS)︰n(GCS12)=3︰1时达到最低的界面张力,加盐200 g/L时,界面张力为0.021 mN/m。结论支链醇醚磺酸盐与两性Gemini表面活性剂的混合体系具有较好的耐温耐盐能力和较高的界面活性,为驱油表面活性剂的开发提供了技术支持。

关键词： Circulating Fluidized Bed   Particle Circulation Device   Seal Valve   Evaporator   LOOP-SEAL   HEAT-EXCHANGER   PRESSURE-DROP   SOLIDS FLOW   FLUCTUATIONS   PERFORMANCE   GAS  

摘要： In order to solve the particle circulation problem of external circulation fluidized bed evaporator, a new particle circulation device was developed, and a cold experiment device was set up for reference to the principle of gassolid circulating fluidized bed U-loop seal valve. The adjustment characteristics of the particle circulation device were studied experimentally. The effects of different flow combinations on pressure drop, particle circulation rate and particle volume fraction of heat exchange tube were investigated when the main flow and any auxiliary flow of the sealing valve were combined. It was found that when the main flow rate is constant, the pressure drop of the heat exchange tube increases with the increase of the auxiliary flow rate, and the pressure drop trend is stable when the main flow and loose flow are combined. The flow rate of particle circulation can be adjusted by adjusting the flow rate of any auxiliary flow alone, and fluidized flow has the strongest ability to regulate the particle circulation rate. The amplitude of the power spectral density of the pressure differential fluctuation signal is related to the particle circulation rate and volume fraction, so the flow state in the pipe can be studied by this method.

关键词： Sewage sludge   Supercritical water gasification   Fluidized bed reactor   Mechanism   HYDROGEN-PRODUCTION   BIOMASS GASIFICATION   CELLULOSE   LIGNIN   CONVERSION   PYROLYSIS   MECHANISM   GLUCOSE   DEPOLYMERIZATION   DISSOLUTION  

摘要： Sewage sludge supercritical water gasification in fluidized bed reactor was studied in this work. Effect of temperature on the distribution of products and gas compositions were researched. In order to improve the gasification process more effectively, the effect of temperature on reaction process development and gas products generation was also studied. A variety of analytical methods were used to study the detailed characteristics of products generated at different reaction conditions. The variation of product yield distribution and products properties showed that organic matter in sewage sludge was completely dissolved and hydrolyzed at 480 degrees C. Multiple reactions happened in these dissolved and hydrolyzed products and then gas products were formed when temperature increased from 480 to 540 degrees C further. At the same time, dehydrogenation and polymerization also took place in the solution and hydrolyzed products, and it could be explained by the Diels-Alder reaction mechanism well. (c) 2021 Elsevier Ltd. All rights reserved.

关键词： Micro fluidized beds (MFBs)   Flow regime   Hydrodynamics   Kinetics   Scaling up   PHOTOCATALYTIC HYDROGEN-PRODUCTION   GAS-SOLID REACTION   SCALE-UP   MICROFLUIDIZED-BED   STEAM GASIFICATION   BUBBLE BEHAVIOR   BIOMASS GASIFICATION   PYROLYSIS KINETICS   CATALYTIC CRACKING   CHAR GASIFICATION  

摘要： Fluidized beds (FBs) are commonly employed by many practical applications, and continuous optimization of FBs is necessary to improve their application performance. However, it is uneconomical and impractical to conduct the parametric investigation and kinetic studies based on a large-scale FB. Accordingly, the micro fluidized beds (MFBs), with excellent mass/heat transfer and sufficient mixing between phases, serve as the suitable platform for understanding the reaction behaviors and extracting kinetics on a laboratory scale. In this review, a global view of the properties of the whole MFBs family (including gas-solid, liquid-solid and gas-liquid-solid MFBs) are comprehensively presented. The differences and correlations of hydrodynamics (e.g. enhanced wall effect) between MFBs and full-scale FBs are discussed, and modified correlations for predicting the minimum fluidization velocity (u(mf)) and hydrodynamic features (e.g. flow regimes and residence time) of MFBs are summarized. Additionally, the application of MFBs in the areas of kinetic studies, rapid reactions and pharmaceutical engineering are also discussed. Finally, the parameter correlation between MFBs and full-scale FBs is discussed critically, and scaling up/scaling out strategies for guiding the design of industrial FBs are proposed. The conclusions of this review serve the purpose of a bridge to link the findings from lab-scale MFBs with the design and optimization of industrial FB reactors.

关键词： 双材料   微滴喷射   黏度   表面张力   喷射速度  

摘要： 针对银墨水/树脂双材料微滴喷射一体化成形精度调控需求,建立基于气液两相流耦合的VOF流体体积函数模型以及微滴沉积模型,研究材料黏度、表面张力以及喷射速度等参数对微滴成形效果的影响,并进行了微滴喷射对比实验。结果表明,黏度影响微滴成形距离及微滴体积,黏度增大会增加成形时间,并增大微滴体积;表面张力影响微滴断裂距离及底板铺展面积,表面张力越大则成形距离越短,在底板上的铺展面积越小;喷射速度影响微滴成形距离及成形形态,其中断裂距离和卫星滴数量与喷射速度成近线性关系。实验结果证明,当喷嘴直径为60μm时,树脂材料在3.58 m/s的喷射速度下可以产生直径为70μm的微滴,验证了微滴喷射仿真结果的有效性。

关键词： 早强剂   防冻剂   引气剂   泡沫高度   混凝土含气量   表面张力  

摘要： 为了提高严寒环境下混凝土早期强度和抗冻性,常将引气剂与早强剂和防冻剂复合使用,而复合使用时的起泡、稳泡性能及机理尚不明确。本文选取了3种引气剂十二烷基苯磺酸钠(SDBS)、三甲基十六烷基溴化铵(CTAB)以及脂肪醇聚氧乙烯醚(AEO-9),系统比较了早强剂(Na_(2)SO_(4)、NaNO_(2))和防冻剂(乙二醇)对不同引气剂溶液的表面活性、泡沫性能以及引气混凝土含气量的影响。结果表明:Na_(2)SO_(4)、NaNO_(2)的加入都会降低引气剂溶液临界胶束浓度(c_(m)),乙二醇增大了CTAB的c_(m),而对SDBS和AEO-9的c_(m)影响不大;引气剂溶液泡沫高度变化符合指数衰减模型,Na_(2)SO_(4)、NaNO_(2)和乙二醇降低了SDBS和CTAB泡沫稳定性,却不同程度地提高了AEO-9泡沫的稳定性;混凝土含气量结果与引气剂溶液泡沫性能具有一定相关性,也存在明显的差异性。

关键词： Mini-fluidized bed   VOF-DEM   Phase holdup   Bubble wake   Gas-liquid-solid fluidized bed   VOF-DPM SIMULATIONS   SLURRY TAYLOR FLOW   CFD-DEM   3-DIMENSIONAL VOLUME   NUMERICAL-SIMULATION   BEHAVIOR   MODEL   DYNAMICS   PARTICLES   EXPANSION  

摘要： Previous simulations of three-phase fluidization systems based on the Euler-Lagrange approach have made progress in the studies of bubble and suspension dynamics. However, for guiding the operation and design of reactors, it is obviously more practical to obtain the phase holdup characteristics under the steady state. In this study, the hydrodynamic simulations on the gas-liquid-solid mini-fluidized beds (GLS-mFBs) were performed from the initial introduction of bubbling flow to the steady three-phase fluidization using the coupling model of volume of fluid (VOF) and discrete element method (DEM). After the initial process of bubbling flow accompanied by redistribution of phase holdups, i.e., the contraction of fluidized bed, the steady state of the GLS-mFB was achieved and maintained by the interactions between bubbles and fluidized bed. The axial and radial profiles of phase holdups in the steady GLS-mFBs, which is difficult to measure through experiments, are obtained and discussed. It is found that the suspension resistance against the rising bubbles is strengthened by the wall confining effect arising from the shrinkage of bubble-wall gap under smaller column diameter, and the phase holdup characteristics and bubble dynamics are investigated and explained by this effect. The bubble wake, which plays an important role in the momentum exchange between bubbles and suspension, is analyzed in terms of formation mechanism and size changes. It is proved that the VOF-DEM simulation is an effective method to predict the phase holdups of the GLS-mFBs and explain the underlying hydrodynamic mechanism.