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Spray drop measurements using depth from defocus

MEASUREMENT SCIENCE AND TECHNOLOGY 2020年第7期31卷 075901-075901页

作者： Zhou Wu Tropea, Cameron Chen Benting Zhang Yukun Luo Xu Cai Xiaoshu Univ Shanghai Sci & Technol Sch Energy & Power Engn Jungong Rd 516 Shanghai 200093 Peoples R China Tech Univ Darmstadt Inst Fluid Mech & Aerodynam Alarich Weiss Str 10 D-64287 Darmstadt Germany Univ Shanghai Sci & Technol Shanghai Key Lab Multiphase Flow & Heat Transfer Jungong Rd 516 Shanghai 200093 Peoples R China

Sprays are typically characterised by providing local drop size and velocity distributions and number density. The present work examines the possibility of obtaining such information using backlight photography, whereby two cameras are employed and the size and position of each imaged drop is obtained using a depth from defocus approach. A simple algorithm for estimating size and position from the two camera images is introduced and the sensitivity of this algorithm to various system parameters is investigated with simulations using synthetic images, measurements from a calibration facility, and measurements conducted in a sparse spray. Comparison measurements using the analysis of focused images are provided.

关键词： depth from defocus (DFD) two-camera imaging system spray sizing

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Co-pyrolysis characteristics of sludge mixed with Zhundong coal and sulphur contaminant release regularity

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JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY 2019年第2期138卷 1623-1632页

作者： Zhao, Bing Jin, Jing Li, Shang Liu, Dunyu Zhang, Ruipu Yang, Haoran Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai Peoples R China

In this work, the pyrolysis characteristics and release of sulphur contaminant were studied under different mass percentages (25%, 50% and 75%) of Zhundong coal in the sample mixtures. The results showed that the yields of volatile products during co-pyrolysis were higher than those calculated from linear combination of corresponding yields of pure sludge and Zhundong coal, which mean that a certain synergistic effect occurs in co-pyrolysis process. The yields of H2S, COS and SO2 decreased with the increase in the content of Zhundong coal in the samples. What's more, when the content of Zhundong coal were 50%, a great significance on the yields of sulphur contaminant occurs in the process of co-pyrolysis.

关键词： Sludge Zhundong coal Co-pyrolysis Sulphur contaminant

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Theoretical Analysis on the Lifetime of Sessile Droplet Evaporation

Theoretical Analysis on the Lifetime of Sessile Droplet Evap...

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作者： Shen, Yang Cheng, Yongpan Xu, Jinliang Zhang, Kai Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy North China Electric Power University Beijing102206 China School of Energy Power & Mechanical Engineering North China Electric Power University Beijing102206 China

There are two stages for a sessile droplet evaporation on the solid substrate, one is the "constant contact radius" (CR) mode, the other is the "constant contact angle" (CA) mode. In this paper, the theoretical model is built up for sessile droplet evaporation for the two modes, the lifetime of evaporating droplet is obtained under different initial contact radius, initial contact angle and critical contact angle for mode transition. It is found that in the CR mode, the variation of initial contact angle is nonlinear with the time. For both CR and CA modes the lifetime is proportional to R02 (R0 is the initial contact radius of droplet) for two modes. When the critical contact angle for mode transition from CR to CA is increased, the lifetime for CR mode is decreased while the lifetime for CA mode is increased, and the overall lifetime is also increased. This result may be of great significance for sessile droplet evaporation. © Springer Nature Switzerland AG 2020.

关键词： Evaporation

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Selective catalytic reduction of NOx with NH3 over cerium-tungsten-titanium mixed oxide catalyst: Synergistic promotional effect of H2O2 and Ce⁴⁺

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JOURNAL OF MATERIALS RESEARCH 2020年第16期35卷 2218-2229页

作者： Xiong, Zhi-bo Qu, Xiao-ke Du, Yan-ping Li, Cheng-xu Liu, Jing Lu, Wei Wu, Shui-mu Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Shanghai Jiao Tong Univ China UK Low Carbon Coll Shanghai 200240 Peoples R China SPIC Powder Plant Operat Technol Beijing Co Ltd Beijing 102209 Peoples R China

A highly active catalyst of cerium-tungsten-titanium mixed oxide was synthesized by introducing Ce4+ and H2O2 in the base sample of Ce20W10Ti100Oz-Ce3+. As a consequence, the NH3-SCR activity of Ce20W10Ti100Oz-Ce3+ is significantly improved as the additives of Ce4+ and H2O2 enlarge the Brunauer-Emmett-Teller (BET) surface area by refining its pore size. Meanwhile, the introduction of Ce4+ increases the Lewis acid sites of Ce20W10Ti100Oz-Ce3+ and decreases its low-temperature BrOnsted acid sites. The further addition of H2O2 improves the BrOnsted acid sites and dispersion of cerium/tungsten species, and thereby enhances the concentrations of the adsorbed oxygen (O-alpha) and the adsorbed oxygen due to the activation of chemisorbed water on the surface of the catalyst. The addition of Ce4+ and H2O2 shows a synergistic promotional effect, which is due to the largest BET surface area and the highest concentrations of O-alpha or/and . Ce20W10Ti100Oz-Ce3+:Ce4+ = 17.5:2.5 + H2O2 exhibits the highest catalytic activity compared with the conventional ones (Fig. 5).

关键词： NOx reduction selective catalytic reduction cerium-tungsten-titanium mixed oxide synergistic promotional effect H2O2

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Numerical Simulation of Acoustic Propagation in Gas Ultrasonic flowmeter

SSRN

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SSRN 2022年

作者： Xiao, Yongqing Zhang, Meng Li, Dong Yang, Yueming Ma, Bingkun Qi, Jianhui School of Energy and Power Engineering Shandong University Jinan250061 China Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power University Beijing102206 China Suzhou Research Institute Shandong University Suzhou215123 China Shandon Academy of Sciences China

Ultrasonic flowmeter has been widely used in chemical smelting, industrial production and other fields. Through the COMSOL Multiphysics software, the non-linear trajectory of the rays in the non-invasive and intrusive UFW is first simulated by the ray tracing method. Then, the transient ultrasonic propagation process is simulated to analyze the reasons for the error of ultrasonic propagation. Finally, the cause of the error of the transducer is analyzed by the sound pressure signal at the receiving end. It was found that it is precisely because of the high-speed flow that the ultrasonic propagation is distorted, which is manifested as the non-linear trajectory and downstream drift of the sound beam. The signal at the receiving end also fails to hit the correct position due to beam drift, resulting in sound pressure falling below the detected value. © 2022, The Authors. All rights reserved.

关键词： flow measurement

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Removal and recovery of SO2and NO in oxy-fuel combustion flue gas by calcium-based slurry 5

Removal and recovery of SO2and NO in oxy-fuel combustion flu...

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2020 5th International Conference on Advances in Energy and Environment Research, ICAEER 2020

作者： Cai, Yuyang Ding, Xiaohan Li, Wei Liu, Dunyu Chen, Jun Ni, Mingguo Xu, Kailong Jin, Jing School of Energy and Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Shanghai Key Laboratory of Multiphase Flow and Heat Transfer in Power Engineering University of Shanghai for Science and Technology Shanghai200093 China Department of Computer Science George Mason University Commonwealth of Virginia United States Dongfang Turbine Co. Ltd Deyang618000 China

This study investigates the use of calcium-based slurry for simultaneous removal NO and SO2 from oxy-fuel combustion flue gas, and recovery of the sulfur and nitrogen species in resulting solutions. The experiments were performed in a bubbling reactor in a transient mode under the pressure of 20 bar. The various influencing factors including the CaO amount, carrier gas (N2/CO2), and absorption time on the simultaneous NO and SO2 removal process, and the solution products were studied comprehensively. The results show that the NO2 removal efficiency can be improved by the presence of CO2, and the gas phase HNO2 produces in this process. The addition of CaO has positive effects not only on the NO2 removal efficiency but also on the formation of stable HNO3. With the presence of CO2, CaCO3 is formed in a solution initially. With the decrease of pH, CaCO3 is gradually converted to CaSO4, and in particular CaCO3 can be fully avoided through decreasing the pH of an absorption solution to 1.14. At the same time, the formation of unstable S(IV) and NO2- can be prevented when the solution pH is lower than 1.37. The nitrogen and sulfur compounds in the absorption solution (at pH 1.14) were further separated by the addition of different amounts of CaO. In particular, 95% of SO42- finally can be recovered in the form of CaSO4.2H2O with nitrogen in solution existing as NO3- by controlling the Ca/S ratio at 4.70. The effectiveness of calcium-based slurry on the removal and recovery of SO2 and NO is confirmed. © The Authors, published by EDP Sciences, 2020.

关键词： Sulfur compounds

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Influence of Different Equations of State on Simulation Results of Supercritical CO_(2) Centrifugal Compressor

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Mechanical engineering Science 2021年第2期3卷 25-33页

作者： Yueming YANG Bingkun MA Yongqing XIAO Jianhui QI Shandong Engineering Laboratory for High-efficiency Energy Conservation and Energy Storage Technology&Equipment School of Energy and Power EngineeringShandong UniversityJinanChina Beijing Key Laboratory of Multiphase Flow and Heat Transfer for Low Grade Energy Utilization North China Electric Power UniversityBeijingChina

Supercritical CO_(2)(SCO_(2))Brayton cycle has received more and more attention in the field of power generation due to its high cycle efficiency and compact ***_(2) compressor is the core component of the cycle,and the improvement of its performance is the key to improving the efficiency of the entire ***,the operation of the SCO_(2) compressor near the critical point has brought many design and operation *** on the Reynolds Averaged Navier-Stokes(RANS)model,the performance and flow field of SCO_(2) centrifugal compressors based on different CO_(2) working fluid models are numerically investigated in this *** stability and convergence of the compressor steady-state simulation are also *** results show that the fluid based on the Span-Wanger(SW)equation can obtain a more ideal compressor performance curve and capture a more accurate flow field structure,while the CO_(2) ideal gas is not suitable for the calculation of SCO_(2) centrifugal *** its flow field can be used as the initial flow field for numerical calculation of centrifugal compressor based on CO_(2) real gas.

关键词： Supercritical CO_(2) Centrifugal compressor Near the critical point Compressor performance Real gas equation of state

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Realization of Multilocal Gradient-Doping Pcn by Alkali Metal Ion Sustained Release Capsules for Enhanced Photocatalytic Water Splitting

SSRN

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SSRN 2023年

作者： Yan, Jiawei Fang, Fenjian Wei, Zhidong Chi, Jiasheng Chen, Mingxia Jiang, Zhi Jiang, Kun Shen, Shaohua Shangguan, Wenfeng Research Center for Combustion and Environment Technology Shanghai Jiao Tong University Shanghai200240 China College of Smart Energy Shanghai Jiao Tong University Shanghai200240 China College of Electrical Energy and Power Engineering Institute of Fuel Cells Shanghai Jiao Tong University Shanghai200240 China International Research Center for Renewable Energy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi’an710049 China

The gradient-doping technique has been widely applied to induce an oriented built-in electric-field. However, it is still not efficient enough for charge mobility especially for particulate semiconductors, as the field is primarily in one direction from inner to surface. Here, we propose a multilocal gradient-doping technique that a nano-capsule is designed to store dopants and then release them into semiconductors nonuniformly. As an illustration, scattered pyrochlore-type K2Ta2O6 nanoparticles have been validated the capability of storing and releasing K+, which subsequently diffuse into the substrate PCN. Multi point-radiative gradient in K+ concentration, confined within the K2Ta2O6’s vicinity, will construct several 3D potential wells which can not only accelerate the carrier separation but also offer more migration channels for both photo-induced electrons and holes to the surface. Consequently, the multilocal K+ gradient-doping PCN shows the longest carriers’ lifetime and highest AQY (~21.8% at 400 nm) compared with the other uniformly doping techniques. © 2023, The Authors. All rights reserved.

关键词： Charge transfer

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Oxygen carriers for chemical-looping water splitting to hydrogen production: A critical review

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CARBON CAPTURE SCIENCE & TECHNOLOGY 2021年 1卷

作者： Zhao, Longfei Dou, Binlin Zhang, Hua Wang, Zilong Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai Key Lab Multiphase Flow & Heat Transfer P Shanghai 200093 Peoples R China

Chemical looping water splitting (CLWS) process using metal oxides or perovskites as oxygen carriers (OCs), is capable of producing pure H 2 in an efficient, simple, and flexible way. The OCs are first reduced by hydrocarbon fuels and then oxidized by steam in a cyclic way. After the condensation of the gaseous mixture of steam and H 2 from the oxidation step, pure H 2 is obtained. In recent years, great efforts for CLWS have been made to improve the redox activity and stability of OCs. In this paper, the development of the OCs for hydrogen production from CLWS were discussed. Effects of supports and additives on the performances of OCs were compared based on redox reactions in CLWS. Fe-based OCs with CeO2, Al2O3, ZrO2, CuO, MoO3, Rh etc. are very attractive for the CLWS process. Issues and challenges for the development of OCs were analyzed.

关键词： Hydrogen Hydrocarbon Chemical looping Water splitting Oxygen carrier

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Investigation of vortex motion mechanism of synthetic jet in a cross flow

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AIP ADVANCES 2022年第3期12卷

作者： Dong, Xiangrui Hao, Chunyang Dong, Yinlin Liu, Chaoqun Li, Yalu Univ Shanghai Sci & Technol Sch Energy & Power Engn Shanghai 200093 Peoples R China Shanghai Key Lab Multiphase Flow & Heat Transfer Shanghai 200093 Peoples R China Univ Cent Arkansas Dept Math Conway AR 72035 USA Univ Texas Arlington Dept Math Arlington TX 76019 USA Second Acad China Aerosp Sci & Ind Corp Inst 25 Beijing 100005 Peoples R China

To investigate the mechanism of vortex motion, a pitched synthetic jet is arranged on the bottom of a cross flow and simulated by incompressible Naiver-Stokes equations with large eddy simulation. The Liutex vector identification method is utilized to quantitatively study the rotation strength and the core size of the vortex structures according to various driving frequencies (St = 0.25, 0.5, 0.75, 1.0) and amplitudes (A(0) = 1.0, 1.5, 2.0, 2.5) of the synthetic jet during 21 periods. The results show that both the frequency and the amplitude play a significant role in the vortex generation mechanism of the synthetic jet. However, the amplitude makes a positive contribution to the rotation strength and the vortex core size, while the frequency makes a negative contribution. The vortex motion mechanism of a synthetic jet in a cross flow can be summarized as follows: low frequency and small amplitude favor the primary clockwise vortex, while high frequency and large amplitude motivate the anticlockwise vortex generation. (c) 2022 Author(s).

关键词： Large eddy simulation

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