CDB含水率计产生非一致性响应的原因及改进

郭海敏.CDB 含水率计产生非一致性响应的原因及改进.测井技术,1993;17(2):154～160用微波传输线理论,简化 CDB 含水率计为集总参数电路。导出了这种含水率计的响应方程,给出了油气水混合电导率与持水率的非线性关系式,在此基础上认为这种含水率计的响应曲线呈 S型。导致响应出现非一致性现象的主要因素有:工作频率低,不能有效地消除地层水矿化度的影响;仪器外壁侧孔使信号向外辐射造成损耗;仪器与其它仪器相连,此时含水率计呈非纯容性。我们认为这些因素的影响使得 CDB 含水率计与传统的电容法含水率计在实质上没有明显差别。要消除非一致性现象,应从以上几点进行改进。     

Liquid holdup measurement in horizontal oil–water two-phase flow by using concave capacitance sensor

Due to the complex flow structures of horizontal oil–water flows, the liquid holdup measurement is still a challenging problem. In this paper, we using the finite element analysis build a two-dimensional model of the concave capacitance sensor and investigate the effect of sensor geometry on the distribution of the sensitivity field. Through calculating the sensor static response for different horizontal oil–water flow patterns, we figure out the optimum geometry of the concave capacitance sensor. In addition, we conduct experiment to obtain the measured response of the concave capacitance sensor and achieve the oil-holdup by using quick closing valve. The results indicate that the optimized concave capacitance sensor shows good performance for liquid holdup measurement of horizontal oil–water two-phase flow.     

气-液-固三相逆流化床动力学研究

在内径0.152 m,高2.5 m的气-液-固三相逆流化床中系统研究了动力学特性。获得了气体和液体速度及聚乙烯和聚丙烯颗粒密度对各相含率和最小液体流化速度的影响规律。研究发现随着气体速度的增加,液体最小流化速度降低;随着气体或液体速度增加,气体、液体和固体含率均增加。     

Development of a CFD Model of Bubble Column Bioreactors: Part One – A Detailed Experimental Study

The holdup and bubble size distribution (BSD) in bubble columns using both air/water and an industrially relevant air/fermentation media system are investigated. It was found that the BSD in the air/fermentation media system was quite narrow and did not change with height. In contrast, the BSD in the air/water system varied considerably with height depending on the sparger design used. Holdup measurements were also performed for different superficial velocities. The holdup in the air/fermentation media system was greater than that for the air/water system, a result attributed to the presence of surface‐active compounds in the fermentation media.     

Absorption characteristics of ammonia-water system in the cylindrical tube absorber

Experimental analysis was performed in a cylindrical tube absorber which is considered to be suitable for the bubble mode. Characteristics such as concentration, temperature, and pressure were measured and they reflected the condition of absorber well. The variation of characteristics was conspicuous near the inlet region of the ammonia gas. The ammonia gas and the solution flowed cocurrently and countercurrently and the results were compared. Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001) dedicated to Prof. H. S. Chun on the occasion of his retirement from Korea University.     

HEAT-TRANSFER AND GAS-HOLDUP STUDIES IN A BUBBLE COLUMN: AIR-WATER-GLASS BEAD SYSTEM

Air-holdup and heat-transfer coefficient values are measured in a 0.305 m diameter bubble column equipped with a seven-tube bundle for the air-water and air-water-glass bead system. The dependence of these two properties on air velocity (up to 0.28 m/s), temperature (297-343 K), glass bead powder average size (50-143.3 μm), solids concentration in the slurry (up to 20 weight percent) and bubble column diameter (0.108 and 0.305 m), is experimentally investigated. The effect of internals, as simulated by a single probe and a seven-tube bundle, in the two bubble columns is also examined. The models and correlations commonly employed to estimate these properties are assessed on the basis of generated data.     

湿天然气管路持液率计算方法研究

持液率计算在多相流工艺计算中占有重要的地位,各种相关式都是依赖于实验或现场数据得出的经验或半以验相关式。文中叙述了10种持液率相关式,利用实验数据和现场数据进行了评价。结论是Minami-Brill Ⅰ式、Minami-Brill Ⅱ式、Lockhart-Martinelli式的计算结果与实际误差较小,推荐采用这3个公式作为湿天然气管路持液率计算公式。     

Hydrodynamic characteristics of a horizontal flow ejector in a rectangular chamber

The effects of the volumetric flow rate of primary motive water, water height, and the geometric parameters of the hydrodynamiccharacteristics of the gas suction rate and gas phase holdup were investigated in a rectangular chamber (0.22×0.26×1.2 m-high) with a horizontal flow ejector. Gas suction rate increased with increasing volumetric flow rate of the primary motive water, mixing tube length and diffuser length, but it decreased with increasing water height and nozzle diameter. The gas phase holdup was directly proportional to gas suction rate, indicating its corresponding increase with the volumetric flow rate of the primary motive water. Conversely, it decreased with increasing water height and nozzle diameter. However, the mixing tube length affected the gas phase holdup minimally compared to other operating parameters. Both the gas suction rate and gas phase holdup correlated with the dimensionless equations of operating parameters.     

Hydrodynamics and mass transfer behavior in multiple draft tube airlift contactors

The draft tube configuration significantly affected the performance of an airlift contactor. The multiple draft tube configuration was demonstrated to give a better gas-liquid mass transfer when compared with a conventional one-draft-tube system. The airlift with a larger number of draft tubes allowed a higher level of bubble entrainment, which rendered a high downcomer gas holdup. This resulted in a higher overall gas holdup in the contactor. Liquid velocity was also enhanced by increasing the number of draft tubes. The ratio between downcomer and riser cross sectional areas, A _d /A _r , had a great effect on the system performance, where a larger A _d /A _r led to a lower downcomer liquid velocity and smaller quantity of gas bubbles being dragged into the downcomer. This resulted in low gas holdup, and consequently, low gas-liquid interfacial mass transfer area, which led to a reduction in the overall volumetric mass transfer coefficient. The presence of salinity in the system drastically reduced the bubble size and subsequently led to an enhancement of gas entrainment within the system. As a result, higher gas holdups and gas-liquid interfacial area were observed, and hence, a higher rate of gas-liquid mass transfer was obtained.