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Bruno Góbi Santolin, Márcio Ferreira Martins, Ramon Silva Martins, Fernando Augusto Ramos
CFD Verification through comparison with LDP measurements of underexpanded gas leak.

A numerical model was performed to represent the expansion phenomenon resulting from the leakage of pressurized gases in a pipe using the Ansys Fluent 2021 R1 software. The free underexpanded jet was produced by a nozzle with an outlet diameter of operating at a stagnation pressure and temperature respectively equal to and , being compared with the experiment conducted by Eggins and Jackson (1974) for qualitative (visual analysis) and quantitative validation requirements (through the statistical model proposed by Hanna (1993)). After the validation of the proposed numerical model, some important results can be highlighted, such as the temperature, pressure and velocity profiles, showing important regions, such as the barrel-shaped shock and the transition limit region from Mach to Mach denominated“Mach disk”, other important results obtained such as a peak velocity of approximately , the Mach disk position obtained at , a position necessary for the correct plotting of the upstream and downstream velocity profile graphs of the Mach disk. In general, the numerical model managed to meet expectations very well, agreeing with the experiment, it had excellent results for the expected velocity profiles, obtaining maximum average error for each of the compared cases of , and for the worst case, thus validating the proposed numerical model clearly showing the main characteristics of an underexpanded free jet so necessary for leak analysis of pressurized gases.

Haiyang Li, Xinhong Yao,Liang Zhang, Xuejing Li
Study on Numerical Simulation Method of Piston Type Micro Liquid Flow Standard Device

The piston type micro liquid flow standard device is a kind of flow standard device with volume-time method. Because it can easily obtain micro flow due to its working principle, this kind of standard device is widely used in micro flowrate value traceability. In addition, the rapid development of precision machining technology also makes the processing of the piston, the master standard in the piston flow standard device, more and more precise, which plays a significant role in reducing the uncertainty of the whole standard device. In this paper, the simplified geometric model of the piston type micro liquid flow standard device is established by using modeling software, the geometric model is meshed, and finally the grid is solved to obtain the internal flow field of this type of flow standard device.

Bo Wu, Xiaopeng Li, Feng Gao, Tao Meng
Research on Online Value Checking Method of Flow Calibration System Based on Double Master Flowmeter Checking Technology

Whether the measurement performance of flow standard facility is normal or not directly affects the final flow measurement result, and the independent checking of quantity value is the key technical means to ensure the steady and reliable performance of flow calibration system. At present, there is a lack of quantitative verification methods for liquid flow standard facilities, and the existing researches mostly focus on expanding the range of operating parameters of facilities and improving their uncertainty level, etc, while the quantitative verification for flow facilities themselves has not been paid attention to and the relevant verification work has not been widely carried out. Based on the mutual verification of the measured values of double flowmeters, a set of intelligent online value verification method for weighing flow standard facility is designed and established. The theoretical basis of the method is described in detail, and the algorithm theoretical model and criterion are provided. Taking the weighing method micro flow standard facility of the National Institute of Metrology as the research object, the verification experiment test of the verification algorithm is carried out, and the results show that: The proposed online value verification method of flow calibration system has good adaptability and high verification accuracy, and can automatically and real-time monitor the operating status of the system in use, thus greatly improving the stability and reliability of the operation process of the facility, which is worthy of further popularization and application.

Jieqiang Ji, Xuemei Geng, Yan Fang, Xiaojie Wu, Guofu Chen, Ningning Zhang, Zhiyu Fang, Leming Cheng
Investigation on the influence of valve opening on measurement accuracy for ultrasonic flowmeters

The applications of portable clamp-on ultrasonic flowmeters in on-line detection have lots of advantages. However, the measurement accuracy of ultrasonic flowmeters is often affected by various factors, such as pipe characteristics, flow fields and fluid medium. In this work, both experiments and CFD simulations are carried out to study the flow field changing caused by valves, and the influences of valve opening on measurement accuracy for ultrasonic flowmeters. The experiment results showed that, with the decrease of valve opening, the value of repeatability of indication error is increasing. At the same valve opening, with the distance closer to the valve, the deviation of the indication error for multiple measurements is increasing. In the simulation section, an error calculation model based on the numerical simulation is proposed, which is in good agreement with the experimental results. Both ball valve and butterfly valve are calculated, and the following conclusions are obtained: (1) for the ball valve, when the distance of measurement point to valve is less than 10D, the indication error is greatly affected by the orientations of linear velocity extracting (UL). When the valve opening is lower than 50 %, the variation tendency of measurement error at different orientations of UL are relatively random. (2) Compared with the ball valve, the variation tendency of measurement error downstream of the butterfly valve are more regular. With the increase of the distance to the butterfly valve, the measurement error is less affected by the orientations of UL. The correction factors of error at different distances downstream of the butterfly valve are given for different valve opening degrees.

Jiguang ZHU, Huizhe CAO
Validity Guarantee of Measurement Data in Application of Big-diameter Heat-meter in China’s Heating System

There are many limitations for the accuracy assurance technology of large-diameter heat meters characterized by laboratory calibration mode, which is hard to adapt to the complicated situation of heating system in China. Aiming to improve the measurement data accuracy of heating system thermal quantity, this paper proposes a new technical method by installing elbow sensor in the natural heating pipe bend to obtain the exact measure reference value. The method is based on the studies of current quality control conditions of big-diameter heat-meters, the flow measuring capability of heat-meters inside the hot water pipeline, the demand of heating operation to flow measurement accuracy, the online-verification technical model of flow measure, and the comparison between external clamp-on ultrasonic heat-meter and elbow heat-meter measurement ability under the situation of heating operation. The measurement data show that the elbow sensor of heat-meter prepared by the industrial ordinary elbow has the accuracy level of 3 % and the long-term stability can reach 0.3 %. Compared with the clamp-on ultrasonic flowmeter, the elbow sensor can better provide a stable measurement reference value at the heating site.

Liang Zhang, Hulin Guo, Guixiang Lu, Yucheng Chen
Performance Improvement of Stack Simulator

In order to improve the performance of the old Stack Simulator, NIM built two new facilities. One is a close loop wind tunnel, which can simulate the real flue gas conditions. The wind tunnel can change the flow rate, temperature, pressure, gas composition and turbulence in the test section. It is used to calibrate the velocity measurement devices such as three-dimensional pitot tubes used in Relative Accuracy Test Audit (RATA). Another facility is a new Stack Simulator, which can simulate the flow field conditions in the real stack. It is used to evaluate the average velocity measurement of RATA devices.

Elsa Batista, Hugo Bissig, John Morgan, Anders Niemann, Annemoon Timmerman, Florestan Ogheard
Metrology for Drug Delivery project – results and impact

This paper presents the major impacts of the work developed in EMPIR Project - MeDD II, Metrology for Drug Delivery in the reference standards used for flow rate determination of drug delivery devices and the results obtained in each work package, with a special focus on the primary standards developed by the partners using different technologies. These new primary standards were validated via an inter-laboratory comparison using two different type of flow meters and a precision syringe pump, in a range from 1500 nL/min down to 5 nL/min. This inter-comparison was performed between nine participating laboratories, each with different methodologies, measurement principles, flow ranges,operating conditions, and measurement uncertainty values.

Jin Song, Chao Chen, Yiping Liu, Haiyang Li
Investigation on Sampling Flow Rate Calibration Method of Air Sampler

In order to obtain the most accurate and effective sampling flow rate calibration method of air sampler, several different equipments were used under two different installation conditions in this paper. According to the experimental results, the calibration results of ultrasonic flowmeter and special orifice flowmeter will be affected by the installation conditions. Consequently, while ultrasonic flowmeter and special orifice flowmeter are used to sampling flow rate calibration, it is necessary to first calibrate the two flowmeters with filter paper, and then use the corrected results to calibrate the sampling flow rate. Based on the results of further experiments, calibration datas of gas roots flowmeter and special orifice flowmeter are consistent with the results obtained from gas flow standard facilities by negative pressure method, at the same time, there is still an error of 3 % ~ 5 % when corrected ultrasonic flowmeter is used. Therefore, gas flow standard facilities by negative pressure method and gas roots flowmeter can be directly used for sampling flow rate calibration of air sampler, if it is not convenient , special orifice flowmeter which calibrated with filter paper is also a good choice, ultrasonic flowmeter is not recommended.

K-H. Cheong, R. Doihara, N. Furuichi, M. Nakagawa, R. Karasawa, Y. Kato, K. Kageyama, T. Akasaka, Y. Onuma, T. Kato
Measurement of the Infusion Flow Rate Produced by a Novel Non-electric-powered Infusion Pump

Intravenous (IV) fluid therapy is a common medical practice that is widespread worldwide, and the method has remained unchanged for more than a century. The IV bag is suspended from an IV stand or pole, and the pressure created by gravity is used to administer the drug. However, this method inevitably reduces the mobility of patients, and may cause accidents such as falls during movement. To solve these problems faced in home care, nursing home, and hospital settings, this study aims to develop a non-hanging, non-electric-powered IV infusion pump with reasonable portability and operability. In this study, instead of gravity, atmospheric pressure is used as the driving force. The infusion device developed is required to achieve a certain level of dosing stability and accuracy, in line with medical guidelines and ideally as comparable to the existing gravity method. We developed a number of prototypes based on different pressurization mechanisms using vacuum piston cylinders as the driving source in order to find an optimum mechanism capable to produce a stable flow rate comparable to the suspended drip system. Tests on performance in terms of discharged flow rate were conducted on three feasible prototypes based on three different pressurization mechanisms, using a gravimetric test bench built for this purpose. The tests show that the pressurization mechanism using an inflating air bag to compress a drip bag has the best performance in terms of flow rate stability.

XING Jing-fang, QU Hong-qiang, HUI Ji, ZHENG Xue-jing, HU Fang-shu, WANG Ying-jie
Simulation and optimization study on the methane combustion chamber

This paper simulated and optimized the combustion chamber of the direct metering of the natural gas calorific value experimental platform. This material conducted a numerical simulation of methane combustion in the combustion chamber using ANSYS Fluent software, and the effects of different mixture inlet pipe length, combustion chamber diameter, and methane nozzle diameter on carbon monoxide emission concentration were studied. Aim to promote the complete combustion of methane, a more appropriate combustion chamber structure, and size were determined through carbon monoxide emission concentration. Through the comparison and analysis of the temperature field, velocity field, and concentration field of each component, it is suggested to set the length of the inlet pipe to 25 mm, and set the diameter of the combustion chamber and methane nozzle as 44 mm and 1.5 mm, respectively. After optimization, carbon monoxide emission concentration decreased from 27.9 PPM to 17.8 PPM, decreasing by 36.2 %.

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