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Numerical and experimental studies on the influences of flow field on the measurement accuracy of ultrasonic water meters

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Measurement: Sensors 2021年 18卷

作者： Jieqiang Ji Jianying Zheng GuoFu Chen Xiaojie Wu NingNing Zhang Yan Fang Leming Cheng Zhejiang Province Institute of Metrology Hangzhou 310018 China National Centre of Quality Supervision and Testing on Liquid Flow Measuring Instruments Hangzhou 310018 China State Key Laboratory of Clean Energy Utilization Institute for Thermal Power Engineering Zhejiang University Hangzhou 310027 China

CFD modelling and experiments are carried out to study the influences of flow field on the measurement accuracy of ultrasonic water meters. The swirl generator and flow disturber are selected to change the flow field distributions inside the pipe. The calculation results show that the installation of left-handed swirl generator induces a specific flow pattern of the fluid inside the pipe, while the installation of flow disturber leads to the distortion of the axial velocity distributions. The critical distance of the fluid reaching the steady flow is 10D for left-handed swirl generator and flow disturber. In the experiment part, six different ultrasonic water meters are selected for the intrinsic errors tests. The results show that the installations of swirl generator and flow disturber induce the intrinsic errors shift to negative values. Compared with the flow disturber, the swirl generator has greater impact on the measurement accuracy.

关键词： flow field Disturbance generators Ultrasonic water meters CFD

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Fabrication of Cd1-xZnxS modified TiO2 Nanofibers and Their Photocatalytic Water Splitting Activity

Fabrication of Cd1-xZnxS modified TiO2 Nanofibers and Their ...

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中国化学会第三届中国能源材料化学研讨会

作者： Guorui Yang Ling Wang Silan Wang Jianan Wang Wei Yan Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University Xi'an Jiaotong University Suzhou Institute

Photocatalytic water splitting for H evolution based on sunlight represents one of the most promising approaches for renewable energy ***,the hierarchically heterostructured CdZnS/TiO with visible-light response were *** found that the crystallinity of the substrate nanofinbers play a key role in promoting the photocatalytic performance.

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Preparation of hierarchical Cd1-xZnxS/NiTiO3 Nanofibers and Their Photocatalytic Hydrogen Generation Activity

Preparation of hierarchical Cd1-xZnxS/NiTiO3 Nanofibers and ...

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中国化学会第三届中国能源材料化学研讨会

作者： Silan Wang Ling Wang Guorui Yang Jianan Wang Wei Yan Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University Xi'an Jiaotong University Suzhou Institute

Solar-driven photocatalytic water splitting for hydrogen production represents an environmentally friendly and economically viable approach to store solar *** heterojuction is an effective strategy to improve the photocatalytic ***,most of the reported heterjunction were built based on the photocatalyst with wide band gap,such as TiO,

关键词： Preparation of hierarchical Cd1-xZnxS/NiTiO3 Nanofibers and Their Photocatalytic Hydrogen Generation Activity

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Synthesis of Branched TiO2/C Nanofibers and Sodium-ion Storage Performance

Synthesis of Branched TiO2/C Nanofibers and Sodium-ion Stora...

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中国化学会第三届中国能源材料化学研讨会

作者： Ling Wang Guorui Yang Jianan Wang Silan Wang Wei Yan Department of Environmental Science and Engineering State Key Laboratory of Multiphase Flow in Power EngineeringXi'an Jiaotong University Xi'an Jiaotong University Suzhou Institute

Sodium-ion batteries（SIBs） have attracted great attention as one of the potential and promising alternatives to Lithium-ion batteries（LIBs） due to the similar chemical mechanism and abundance of sodium ***,the sluggish reaction kinetics and large volume expansion limit its practical ***,we synthesized continuous branched TiO/C nanofibers（BT/C NFs） via in-situ growth,

关键词： Synthesis of Branched TiO2/C Nanofibers and Sodium-ion Storage Performance TiO

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Estimation of likely accident progression at Fukushima Daiichi unit 2

Estimation of likely accident progression at Fukushima Daiic...

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2017 Transactions of the American Nuclear Society, ANS 2017

作者： Li, Gen Zhang, Jun Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

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Mixed convective heat transfer of supercritical carbon dioxide flowing in a vertically-upward tube with low mass flux 17

Mixed convective heat transfer of supercritical carbon dioxi...

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17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017

作者： Zhang, Qian Li, Huixiong Liu, Jialun Zhang, Jun Lei, Xianliang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'an Shaanxi China

Experimental investigation was carried out to study heat transfer characteristics of supercritical CO2 at low mass flux conditions. A vertical tube with an inner diameter of 16 mm was tested at various heat fluxes and pressures. The flow was driven by mixed convection with strong buoyancy force owing to low mass flux and high heat flux. The experimental results shown that a "no wall temperature peak" heat transfer deterioration with an exactly large temperature difference between the tube and fluid occurred at high enthalpy region, which was especially different from the general deterioration phenomenon with a wall temperature peak occurred at normal mass flux in previous studies. Heat transfer in low mass flux was accompanied with a heat transfer enhancement phenomenon before the pseudo critical point and a deterioration after that. With increasing heat flux, the deterioration was strengthened, but the enhancement was little weakened and moved towards the low enthalpy region due to the combined effect of buoyancy and specific heat of fluid. The effect of pressure on heat transfer in various cases was different. Heat transfer was reduced with a rising pressure at low heat flux cases, but when heat flux became larger, heat transfer was enhanced with the increase of pressure. The parameters representing to buoyancy and thermal acceleration effects were also introduced respectively to explain the mechanism of heat transfer. Results shown the buoyancy effect and the distribution of large specific heat fluid were greatly responsible for the enhancement and the deterioration in heat transfer. While the effect of thermal acceleration on heat transfer in the present study could be neglected. © 2016 Association for Computing Machinery Inc. All Rights Reserved.

关键词： Buoyancy

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Modelling of flame structure using thickened flame model coupled with multi-step reaction mechanism 11

Modelling of flame structure using thickened flame model cou...

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11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Shilong, Guo Meng, Zhang Jinhua, Wang Zuohua, Huang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

Thickened flame (TF) model is one of the effective methods to simulate combustion phenomenon. Theoretically, it could be extended to multi-step chemical reaction mechanism. However, the results in the present work shown that TF model coupled with multi-step mechanism will underestimate burnt gas temperature, whether in confined or unconfined space. Meanwhile, some post-flame species (CO, OH) concentration are overestimated, which means the decrease in burnt gas temperature is mainly caused by enhanced species diffusion. Dynamic thickened flame (DTF) model coupled with multi-step mechanism performs well for predicting species concentration and combustion state. So it is not recommended to use TF model coupled with a multi-step chemical reaction mechanism. However, the dynamically thickened flame thickness is obviously thinner than the theoretical expectations for the dynamic thickening factor, which is always used to determine thickening factor for a certain mesh size. The main heat release rate zone couldn’t be thickened as expected. A new DTF model used for multi-step reaction mechanism was proposed. The results show that it can both predict the flame structure accurately and get the flame thickness as expected. © 2018 Combustion Institute. All Rights Reserved.

关键词： Gas temperature

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Time-resolved investigation of droplet size and velocity inside diesel fuel sprays 11

Time-resolved investigation of droplet size and velocity ins...

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11th Asia-Pacific Conference on Combustion, ASPACC 2017

作者： Feng, Zehao Zhang, Mingzhi Yang, Jiapei Tang, Chenglong Huang, Zuohua State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China

To better understand the microscopic spray characteristics, measurements of temporal changes in the size and velocity of droplets inside diesel fuel sprays were conducted at a fixed measurement position of 40mm downstream from the injector tip. Particle/droplet image analysis (PDIA) system was applied to obtain the microscopic droplet images in a long time scale (0-10 ms) which consists of continuous injection stage (0-2.1 ms) and the spray free development stage (2.1-10 ms). The results show that the droplet size distribution has a significant variation at the beginning, but basically independent of time after 1.6 ms. The Sauter mean diameter (SMD) increases significantly at the continuous injection stage, but slightly decreases at the free development stage. In addition, it is observed that most droplets’ velocity are 2-3 m/s while the maximum value is 25 m/s. An interesting similar bimodal shape of velocity distribution probability curves was found at different time after start of injection. What’s more, the scalar velocities gradually decrease as time goes on, but the direction of the velocities is messy due to the air entrainment. © 2018 Combustion Institute. All Rights Reserved.

关键词： Velocity

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MPS analysis of molten corium jet and structure interaction during nuclear severe accident 17

MPS analysis of molten corium jet and structure interaction ...

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17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017

作者： Li, Gen Zhang, Jun Yan, Junjie State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi’an710049 China

The melt jet and structure interaction is an important phenomenon in the progression of nuclear severe accident. It could happen when molten corium relocates onto core plate and Reactor Pressure Vessel (RPV) lower head, and in the ex-vessel accident, the molten corium may directly impinge onto and Erode concrete. In the present study, a numerical code was developed based on Moving Particle Semi-implicit (MPS) method, to analyze the erosion scenario of RPV wall and dry concrete by melt jet. The numerical modeling was validated by comparing structure erosion configuration and time-dependent erosion depth with the experimental data. In the analysis of RPV wall erosion, it indicates that no crust layer presented at the interaction of stainless steel (SS) melt jet and RPV wall, while for Zr, ZrO2 and UO2 melt jets the crust layer presented. At a superheat temperature equal to 300 K, the erosion rate by SS melt was the fastest, even though the absolute temperature was the lowest compared with other cases. In the analysis of melt jet and concrete interaction, the core melt was divided as metallic material (SS-Zr) and oxide material (ZrO2-UO2). The results indicate that the crust and ablated concrete layer presented at the interface of UO2-ZrO2 melt and concrete, whereas no crust could be found in the interaction of SS-Zr melt with concrete. The erosion progression was faster in the erosion by metallic melt jet than by oxidic melt jet. The present analysis demonstrates that the erosion rate was affected not only by temperature, but also by crust layer, and the major threat to structure was metallic melt, especially at high temperature. © 2016 Association for Computing Machinery Inc. All Rights Reserved.

关键词： Erosion

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Time-domain study on the density wave oscillation of supercritical water in multiple parallel channel system 17

Time-domain study on the density wave oscillation of supercr...

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17th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2017

作者： Liu, Jialun Zhang, Qian Li, Huixiong Kong, Xiangfei Lei, Xianliang State Key Laboratory of Multiphase Flow in Power Engineering Xi’an Jiaotong University Xi'anShaanxi China

A time-domain model suitable for the study on the density wave instability of supercritical water in multiple parallel channel system (the number of channels is more than 2) was established. The present model developed an iterative solution to solve the coupling among parallel channels. Then the program was verified by the experimental data obtained in open literature. After that, the model was used to study the effect of system pressure (23-28 MPa), inlet fluid temperature (240-350 °C), and adding perturbation in different channels on the density wave instability of supercritical water in multiple parallel channel system. It was found that when the same perturbation was added on some of channels at the initial time (the other working conditions were kept unchanged), the number of perturbation channels had almost no effect on the oscillation period and the system stability. The stability of the multiple channel system increased with the increasing in system pressure. It was also found that a critical value about the inlet fluid temperature, denoted by Tin-cr, existed, and when the inlet fluid temperature was lower than the critical value Tin-cr, the stability of the multiple channel system dropped with the increase of inlet fluid temperature, and that was improved when inlet fluid temperature was higher than Tin-cr. The critical value Tin-cr increased gradually with the increasing in the amount of parallel channels. Moreover, Tin-cr was lower than and near the pseudo-critical temperature of supercritical water, and almost had no changes with varying system pressure. © 2016 Association for Computing Machinery Inc. All Rights Reserved.

关键词： System stability

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