A newly-developed wide range molecular flow meter based on AAO leak element

An innovate constant volume flow meter (ICVFM) using AAO leak element was developed, and then applied to measure the pumping speed of dry vacuum pumps. The AAO leak element was calibrated with dynamic differential pressure decay method. The results imply that the conductance of AAO leak is inversely proportional to the square root of the molecular mass, and remains unchanged with pressure varying from vacuum to atmosphere. Then the pumping speed was measured by a simple test system. In the end, the uncertainties of calibrating AAO leak element and measuring pumping speed were considered to confirm the measurement capability. The newly developed flow meter enables flow measurements at pressures ranging from vacuum through atmospheric pressure, which has potential application in the semiconductor industry.     

Comparison of throttle devices to measure two-phase flowrates of wet gas with extremely-low liquid loading

The online measurement of wet gas with extremely-low liquid loading (Lockhart-Martinelli parameter lower than 0.02) remains a challenge. In this study, three types of throttle devices, Venturi, orifice plate and cone, are compared experimentally with air-water two-phase flow in a horizontal pipe of inner diameter of 50 mm. High-precision correlations are established to measure the gas and liquid flowrates via a single throttle device. Results show that the two-phase mass flow coefficient (K) of the three throttle devices all increase linearly with the liquid densiometric Froude number and the K correlations are established respectively to correct the gas mass flowrate deviation. The pressure loss ratio (δ) for Venturi is sensitive and monotonous to the liquid loading, which contributes to the high accuracy of liquid flowrate measurement. By incorporating the K correlations, both the gas and liquid mass flowrates can be predicted precisely. The relative error of the gas mass flowrate predicted by the Venturi is within ±2.0% at 95% confidence level, and that of the liquid mass flowrate is within ±15% at 90% confidence level.     

TLCD基础隔震框架结构的减振控制研究

为了避免和减轻由过大隔震层位移引起的损害,对基础隔震框架结构装设调频液柱阻尼器(tuned liquid column damper,简称TLCD)后混合系统的减振效果进行研究。建立了单层和多层混合控制系统在地震作用下的运动方程,采用TLCD-结构体系转化为调频质量阻尼器(tuned mass damper,简称TMD)-结构体系的等效方法,利用TMD参数优化公式,得到单个TLCD初始设计参数,并采用状态空间方程得到多个TLCD最优设计参数。通过对某8层基础隔震结构进行模拟,证明了该理论设计方法的合理性。该混合结构不仅可以减小隔震层位移和加速度,而且对上部结构位移和加速度反应都能更有效的控制。     

碳酸盐岩裂缝性储层常规测井评价方法

哈萨克斯坦K油田石炭系KT-Ⅱ段储层为开阔台地相中低孔、特低渗灰岩储层，裂缝对改善储层的渗流能力至关重要，前人研究的利用常规测井资料评价碳酸盐岩储层裂缝的方法由于受裂缝产状、饱和度、泥浆侵入深浅等多方面因素的影响，存在确定性差、容易误判的缺陷。基于研究区目的层段有限的取心和电成像测井资料，结合孔隙型储层和裂缝-孔隙型储层测井响应特征，提出了利用补偿中子确定基块岩石电阻率与基块声波时差，再比较二者与深侧向电阻率、声波时差的差异特征，进而综合识别储层不同产状裂缝发育段，最后建立了裂缝孔隙度、次生孔隙度、裂缝渗透率、总渗透率等储层参数的测井解释模型，实现了利用常规测井资料对碳酸盐岩油藏储层的裂缝识别及参数定量评价。该方法应用的测井综合评价成果与取心物性分析、生产动态情况能够更好地匹配，为该类油藏的合理高效开发提供了依据。     

长江经济带城市生态效率演变及驱动因素分析

城市生态文明建设依托于生态效率的改善，基于2005—2016年长江经济带107座城市面板数据，采用超效率SBM（slacks-based measure)模型测算生态效率，并结合探索性空间分析与空间马尔科夫链等探讨生态效率时空演化格局的内在规律， 实证分析生态效率驱动因素的影响效果。研究表明：2005—2016年经济带生态效率总体呈平稳态势，上、中、下游呈现“阶梯型”分布，下游依次优于中游和上游地区，部分地区生态效率呈“两级型”分化趋势；城市间生态效率发展存在空间联动效应，与生态效率高的城市为邻，其正向溢出作用促进城市状态向高水平跃迁，而与生态效率低的城市为邻，其负向作用拉动城市状态向低水平发展；人口规模与产业升级对经济带不同流域具有异质性作用，其提升下游生态效率而抑制中游和上游生态效率，产业升级与生态效率存在“U”型关联，意味着产业升级在短期内并不能使生态效率状态改善，而经济发展有利于促进生态效率向高水平状态演变。     

泵站压力管道振动特性分析及减振优化设计

为探究泵站压力管道的不同布置形式对管道振动的影响,选取宁夏盐环定泵站工程二泵站#1压力管道为研究对象,建立基于流固耦合的泵站压力管道水流ALGOR数值模型,并采用DASP振动测试系统获取振动信号对模拟结果进行验证,分析压力管道水流流态对管道振动的激励特征并提出优化设计方案。结果表明,压力管道进水管处、支管总管相接处及总出水管处均有强烈的振动,但进水管的振动较出水总管振动更为强烈;减振优化设计方案中,调整支管距离对降低水流对管道振动的激励效果微弱,增大管径及改变总管走向对其效果较好,其中总管走向在2°～5°之间较佳,不仅能降低管道振动,而且能减少泵站能耗损失。研究结果可为高扬程泵站压力管道的优化设计提供理论依据。     

The Impingement Heat Transfer Data of Inclined Jet in Cooling Applications: A Review

On the impingement heat transfer data,the experimental studies of air and liquid jets impingement to the flat surfaces were collected and critically reviewed.The oblique impingements of both single circular and planar slot jets were considered in particular.The review focused on the surface where the jet impingement cooling technique was utilized.The nozzle exit Reynolds numbers based on the hydraulic diameter varied in the range of 1,500–52,000.The oblique angles relative to the plane surface and the dimensionless jet-to-plate spacing vary in the range of 15°–90°and 2–12 respectively.The review suggested that the magnitude of maximum heat transfer shifted more for air jets compared with the liquid jets.The drop in the inclination angle and the jet-to-plate separation led to the increase in the asymmetry of heat transfer distribution.The displacement of maximum Nusselt number(heat transfer)locations was found to be sensitive to the inclination angle and the smaller jet-to-plate distance.Also,the Nusselt number correlations proposed by various researchers were discussed and compared with the results of the cited references.     

双层毛细芯对环路热管传热性能的实验分析

环路热管作为一种高效的相变传热装置,其性能与位于蒸发器和储液槽之间的毛细芯结构密切相关。为了更深入研究双层毛细芯对环路热管传热性能的影响,利用不同颗粒直径铜粉制备双层毛细芯,在毛细芯总厚度为5 mm的条件下,通过调整大粒径和小粒径层的相对厚度来改变毛细芯厚度比,对平板型蒸发器环路热管启动和变工况运行进行实验测试。实验结果表明:在同一工况下,不同厚度比的双层毛细芯启动特性存在显著差异,启动过程中出现小粒径层蒸发效率低引起的温度过冲和环路热管中气液两相流变化导致的温度振荡;同时存在一个较优的双铜层毛细芯厚度比,大粒径(180～280μm)铜层厚度为3 mm可提高蒸发效率,小粒径(56～71μm)铜层厚度为2 mm可提供足够毛细抽吸力保证环路热管稳定运行。搭载该厚度毛细芯的环路热管不仅启动速度快(125 s),而且总热阻和蒸发器壁面温度均最低,最大加热功率达到120 W(21.10 W/cm~2),对应热阻为0.17 K/W。     

The control of paracetamol particle size and surface morphology through crystallisation in a spray dryer

The parameters governing the crystallisation of paracetamol using various conventional techniques has been extensively studied, however the factors influencing the drug crystallisation using spray drying is not as well understood. The aim of this work was to investigate the crystallisation of an active pharmaceutical ingredient through evaporative crystallisation using a spray dryer to study the physicochemical properties of the drug and to use semi-empirical equations to gain insight into the morphology and particle size of the dried powder. Paracetamol solutions were spray dried at various inlet temperatures ranging from 60 °C to 120 °C and also from a series of inlet feed solvent compositions ranging from 50/50% v/v ethanol/water to 100% ethanol and solid-state characterisation was done. The size and morphology of the dried materials were altered with a change in spray drying parameters, with an increase in inlet temperature leading to an increase in particle Sauter mean diameter (from 3.0 to 4.4 µm) and a decrease in the particle size with an increase in ethanol concentration in the feed (from 4.6 to 4.4 µm) as a result of changes in particle density and atomised droplet size. The morphology of the dried particles consisted of agglomerates of individual crystallites bound together into larger semi-spherical agglomerates with a higher tendency for particles having crystalline ridges to form at higher ethanol concentrations of the feed.     

Adaptive neuro-fuzzy algorithm applied to predict and control multi-phase flow rates through wellhead chokes

A Takagi-Sugeno adaptive neuro-fuzzy inference system (TSFIS) model is developed and applied to a dataset of wellhead flow-test data for the Resalat oil field located offshore southern Iran, the objective is to assist in the prediction and control of multi-phase flow rates of oil and gas through the wellhead chokes. For this purpose, 182 test data points (Appendix 1) related to the Resalat field are evaluated. In order to predict production flow rate (Q_L) expressed as stock-tank barrels per day (STB/D), this dataset includes four selected input variables: upstream pressure (Pwh); wellhead choke sizes (D64); gas to liquid ratio (GLR); and, base solids and water including some water-soluble oil emulsion (BS&W). The test data points evaluated include a wide range of oil flow rate conditions and values for the four input variables recorded. The TSFIS algorithm applied involves five data processing steps: a) pre-processing, b) fuzzification, c) rules base and adaptive neuro-fuzzy inference engine, d) defuzzification, and e) post-processing of the fuzzy model. The developed TSFIS model for the Resalat oil field database predicted oil flow rate to a high degree of accuracy (root mean square error = 247 STB/D, correlation coefficient = 0.9987), which improves substantially on the commonly used empirical algorithms used for such predictions. TSFIS can potentially be applied in wellhead choke fuzzy controllers to stabilize flow in specific wells based on real-time input data records.