稀薄气体流动的粒子图像测速实验研究

建立了一套可对真空度进行调节的实验装置,从大气压开始逐渐降低系统压力,进行系列稀薄气体流动的PIV流场实验.系统压力从101kPa、90kPa逐次降至10kPa,使用所选粒子在不同系统压力下分别进行PIV实验获得测量区域流场分布情况.运用计算流体力学的方法模拟大气压条件下实验区域的内部流动,对比结果发现该种条件下数值模...     

木素脱氢聚合物-葡萄糖复合体形成机理的研究

为阐明植物纤维细胞壁中木素与聚葡萄糖化学键的连接,本研究探讨了在(6-13C)葡萄糖和纤维二糖的存在下,松柏醇葡萄糖苷的过氧化物酶催化脱氢聚合过程中与碳水化合物之间化学键的形成。研究发现,木素脱氢聚合物(DHP)能与(6-13C)葡萄糖形成DHP-(6-13C)葡萄糖的聚合物,核磁共振碳谱(13C NMR)分析结果表明,葡萄糖C6位上的碳与木素结构单元以苯甲醚键连接。此外,研究还发现,木素前驱物与纤维二糖之间发生了共聚,得到了DHP-纤维二糖的复合体,13C NMR分析结果表明,纤维二糖与DHP之间可能存在苯甲醚键、苯甲酯键和α-缩醛键等化学键的连接。     

井间示踪测试中示踪剂用量计算方法

在参考国外井间示踪测试中示踪剂用量设计方法的报导及大庆油田井间示踪实践的基础上．以Brigham—Smith提出的水驱五点井网有效示踪物质用量计算方法为基础,提出了多层条件下的井网外的稀释修正,井网类型的修正、放射性示踪剂的衰变修正,并充分考虑环保因素和技术要求的示踪剂用量计算方法。同时也提出了商品纯度及有效示踪物质含量的示踪化学剂用量的计算方法。     

综放工作面风量及采空区漏风定量检测

通过对中煤塔山煤矿30509综放工作面采空区漏风及有害气体分析的研究,总结了通过定量连续释放SF₆示踪气体,来检测工作面风量与采空区漏风的方法,测定了沿工作面采空区的漏风分布及漏风流线的深度。采用定时测量法,确定了30509工作面随工作面不断推进,与对应地表发生了导通现象;采用定量测量法,确定了内部漏风量和外部漏风量较大,对综采工作面采空区自然发火存在较大风险,同时提出了防范措施,为减少综放工作面采空区漏风、防止自然发火的发生提供了参考。     

示踪法测量气体流量的试验研究

以空气作为被测流体,以CO作为示踪气体,在直径为0.300m的90°弯曲管道内对示踪法测量气体流量进行了试验研究。结果表明,多点释放/多点取样比单点释放/单点取样时,取样点处示踪气体的浓度测量偏差小。释放点位于弯头上游7D～13D(D为管道直径)、取样点位于弯头下游10D～14D处,流量计算值(示踪法)与测量值(涡轮流量计)的相对误差在-2.15%～1.69%的范围内,释放点与取样点的位置越远,示踪法测量流量的相对误差越小。示踪气体的释放量需要与管道输送气体流量相匹配。对于含有脏污介质的大口径管道工业气体输送过程中的流量计,采用示踪法进行在线校准,是一种简单有效的校准方法。     

Emulation of gas‐liquid flow in packed beds for offshore floating applications using a swell simulation hexapod

A laboratory‐scale packed column was positioned on a six degree of freedom swell simulation hexapod to emulate the hydrodynamics of packed bed scrubbers/reactors onboard offshore floating systems. The bed was instrumented with wire mesh capacitance sensors to measure liquid saturation and velocity fields, flow regime transition, liquid maldistribution, and tracer radial and axial dispersion patterns while robot was subject to sinusoidal translation (sway, heave) and rotation (roll, roll + pitch, yaw) motions at different frequencies. Three metrics were defined to analyze the deviations induced by the various column motions, namely, coefficient of variation and degree of uniformity for liquid saturation fluctuating fields, and effective Péclet number. Nontilting oscillations led to frequency‐independent maldistribution while tilting motions induced swirl/zigzag secondary circulation and prompted nonuniform maldistribution oscillations that deteriorated with decreasing frequencies. Regardless of excited degree of freedom, a qualitative loss of plug‐flow character was observed compared with static vertical beds which worsened as frequencies decreased. © 2015 American Institute of Chemical Engineers AIChE J, 61: 2354–2367, 2015     

二维双支腿流化床内气体混合特性

Experiments of gas mixing between two half-beds were performed in a dual-leg circulating fluidized bed(DL-CFB)240 mm in width,40 mm in depth and 2000 mm in height by using glass beads with diameter of 0.25-0.28 mm as bed material.SO₂ and CO as the gas tracers entering the left and right distributors separately were used to simulate the gas mixing between the two legs.MSD(mean square displacement)model was adopted to calculate the gas dispersion coefficient(D_w)which was used to investigate the effect of fluidization velocity and bed material inventory on gas mixing in the DL-CFB.The experimental results showed that D_w was about 50-300 cm²穝^-1 at different fluidization velocities and bed material inventories.A higher fluidization velocity benefited particles exchange between two half-beds,which intensified the gas-solids interactions at the region with higher solids volume fraction.The gas mixing in the lower region of the DL-CFB was stronger than that in the upper region of the bed.A higher bed inventory was helpful to gas mixing at a lower fluidization velocity,while a higher fluidization velocity weakened gas mixing because of higher solids concentration in the center of the bed that prevented gas mixing.     

用示踪气体方法研究通风房间的空气龄

应用示踪气体测量得到了8种强制通风工况下实验小室各各测点处的浓度衰减曲线,并计算出各测点的空气龄,实验结果表明,示踪气体用于强制通风研究时实验可重复性较好,实验结果正确合理,测得的空气龄反映了房间各点空气的新鲜程度,也揭示了室内空气的流动形态。     

堵塞对复合垂直流湿地水力特征的影响

复合垂直流人工湿地系统(IVCW)堵塞后其水力特征会发生变化，通过示踪剂对小试和中试系统堵塞前后的水力特征进行了研究。结果表明，堵塞后IVCW出水流量减小，小试系统实际停留时间由堵塞前21．3h延长至32．5h，中试系统实际停留时间从19.4h延长至26．8h。IVCW堵塞后容易造成下行池表面积水，既恶化了卫生条件又降低了系统的处理能力。     

韧致辐射法同时测量90Sr和90Y

本工作提出了用韧致辐射法同时测量样品中~(90)Sr和~(90)Y的设想.采用二(2-乙基已基)磷酸萃取制备无~(90)Y的~(90)Sr溶液,应用阱型NaI(Tl)探测器进行跟踪测量,得到~(90)Sr与~(90)Y探测效率比k.根据k值,跟踪测量未知样品,可以得到样品中~(90)Sr和~(90)Y的量.因此可以直接用~(90)Sr-~(90)Y作为Y的示踪剂.