基于协同优化算法的流速仪检定系统设计

提出了一种小型轻便的流速仪检定系统的设计方案,并运用改进的多学科协同优化方法求解各学科设计变量的最优解。首先介绍了算法思想及改进措施,并根据系统设计要求建立了各学科的设计变量、目标函数和约束条件；其次,运用遗传算法求解各学科设计变量的最优解,并根据优化结果完善了系统的设计方案,同时运用计算机仿真等方法验证了优化结果的可行性。结果表明,优化后的检定系统满足流体力学效应、匀速运动时间、系统重量等设计要求,同时证明了协同优化算法解决多学科设计优化问题的有效性。     

TRIZ创新方法剖析路面渗水仪底座和路面的密封性能

针对路面渗水仪底座和路面的密封性能不良问题，运用TRIZ创新方法的因果链、技术矛盾、物理矛盾、进化分析等工具找到原因，获得解决方案。通过调研及试用，不断优化及调整所选方案，达到最优解决效果。应用效果证明TRIZ理论有助于创新并快速解决工程实际问题。     

A system for time-fluctuating flow rate measurements in a single-blade pump circuit

Commonly used flow rate measurement systems provide an accurate and stable output value of the quasi-stationary flow rate. In some pump types as e.g. single-blade pumps significant flow rate fluctuations may occur even in steady operation points due to rotor-stator interaction. For the analysis of the time-resolved flow rate a new measurement and evaluation method is presented based on an electromagnetic flow meter. Internal averaging of the flow meter is deactivated and the raw signal is evaluated directly with a sampling rate of 3 kHz. With ensemble-averaging in combination with an impeller position detection, interfering signals acting on the time-resolved measurement signal are filtered out. Accompanying numerical simulations of the pump flow circuit are carried out with a 1D method of characteristics and validated against well-established time-resolved pressure measurements of the pump flow. Experiment and simulation show a resembling trend of pressure as well as flow rate fluctuations over the entire operation range of the pump. Thus, by the combined utilisation of measurement and simulation technique, we assure the validity of the ensemble-averaged flow rate fluctuation results. We find that the flow rate fluctuations show a consistent phase shift to the pressure fluctuations that increases towards overload. The flow rate amplitude is an order of magnitude smaller than the amplitude of the pressure fluctuations.     

室内照明统一眩光值(UGR)校准装置的研制

统一眩光值UGR是表征室内照明眩光程度高低和视觉舒适度的重要参数,在室内照明检测和照明设计中有着广泛应用。目前国内对于眩光测试仪的溯源方法一般只采用光亮度标准装置校准亮度值,而对于照明光源的亮度分布和几何位置信息都没有进行相关校准,造成眩光测量结果的失准和不统一。针对此问题,本文研制了一套统一眩光值UGR校准装置,介绍了装置原理和结构,并对其不确定度进行分析。该装置的研制对于保障眩光测量结果的准确统一,有效提升照明设计质量,保护视觉健康有着重要作用。     

镜面杂质与水汽吸放对露点仪影响的实验研究

显微成像露点仪在研制和测试过程中发现镜面杂质和内腔材质吸放水汽等影响测量精度的问题。针对镜面杂质对显微成像露点仪测量的影响开展了镜面图像特征的实验研究，结果表明：镜面杂质点处露珠凝结具有优先性，且反复凝结消散后镜面出现杂质沉降现象。针对水汽吸放对显微成像露点仪的影响开展了水汽释放与吸附效应的实验研究，结果表明：当温度发生变化时，显微成像露点仪感应舱内壁氧化铝材质存在释放（或吸附）水汽现象，使得显微成像露点仪测量值偏大（或偏小）。研究结果为露点仪在功能设置及镜面与腔体材料选择方面提供了参考。     

新生儿经皮黄疸检测仪的校准

针对经皮黄疸检测仪在使用过程中测量结果无法溯源的问题,通过分析经皮黄疸检测仪的检测原理,研究其测量结果与血清法测胆红素的相关性,提出可尝试采用标准溶液法、标准板法和胆红素浓度模拟法对经皮黄疸检测仪进行校准,并探讨了校准方法的可行性。     

Qualification of an ultrasonic flow meter as a transfer standard for measurements at Reynolds numbers up to 4×106 between NMIJ and PTB

The quality of any laboratory intercomparison depends to a large extent on the performance of the used flow meter. To find a flow meter that is capable of reaching a reproducibility better than 0.05% requires bounding all involved influence quantities down to the required level. The present paper describes the efforts performed while qualifying a time-of-flight ultrasonic flow meter as a transfer standard. It was determined that the most relevant influence quantity besides the flow profile within the bulk flow is the effect caused by the transducer pockets in the meter body. By taking advantage of a specially designed window chamber, it was possible to determine the magnitude of the errors introduced by the transducer pockets and to define, based on the findings, a procedure to perform a bilateral comparison between the hot water calibration facilities of the Physikalisch-Technische Bundesanstalt and the National Institute of Advanced Industrial Science and Technology. The results of the bilateral comparison are presented.     

基于ARM7的高精度频率计的设计

文章通过对相位重合检测技术的分析，提出了基于此理论并用ARM7作为主控芯片的高精度频率计的设计方法。该设计方法通过捕捉相位之间的重合点，能够有效消除±1个字的计数误差。在此基础上由于ARM7具有32位的处理器内核以及流水线技术，使得频率计的测量速度和精度比传统的使用16位单片机设计的频率计要高很多。本频率计最大测量频率为10MHz。同时本设计采用安捷伦公司生产的恒温晶振10811A作为标准频率，能够有效保证测量精度能够达到10-10量级。为了降低成本，在设计中选用采用ARM7芯片内部的计数器以及用简单的逻辑电路进行设计。由于其测量精度要超过多周期同步测量法，而成本又比模拟内插法和游标法低很多，因此此频率计拥有很广泛的市场前景。     

Modeling temperature effects on a Coriolis mass flowmeter

Coriolis mass flowmeters are used for many applications, including as transfer standards for proficiency testing and liquified natural gas (LNG) custody transfer. We developed a model to explain the temperature dependence of a Coriolis meter down to cryogenic temperatures. As a first step, we tested our model over the narrow temperature range of 285 K to 318 K in this work. The temperature dependence predicted by the model agrees with experimental data within ± 0.08 %; the model uncertainty is 0.16 % (95 % confidence level) over the temperature range of this work.Here, basic concepts of Coriolis flowmeters will be presented, and correction coefficients will be proposed that are valid down to 5 K based on literature values of material properties.     

Experimental Investigations of the Flow Field Structure and Interactions between Sectors of a Double-Swirl Low-Emission Combustor

In this paper,the flow field characteristics of a double-swirl low-emission combustor were analyzed by using Particle Imaging Velocimetry(PIV)technology in an optical three-sector combustor test rig.The interactions between sectors and the flow field structure were explained.The results illustrated that there was a big difference between the flow field structures of the middle sector and the side sector under the same pressure drop,which was mainly induced by the interactions between sectors.The interactions made the swirl intensity of the middle sector weaker than that of the side sector,which made the recirculation zone of the middle sector be smaller than that of the side sector.With the increase of swirler pressure drop,the jet velocity at the exit of the swirler,the jet expansion angle,the width of the recirculation zone and the recirculating speed of the central axis became larger,enhancing the interactions between air streams from middle sector and side sector.The flow velocity in the central plane between sectors was small,especially the radial velocity,mainly because of the loss of the swirl intensity by the interactions between flow field of adjacent sectors.The expansion angle determined the position of the vortex in the primary recirculation zone;the axial and radial position of the vortex move downstream and radial outward with the increase of the jet expansion angle.The results of the mechanism of flow field organization in this study can be used to support the design of new low-emission combustor.