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Green biopolymer-CNT films exhibit high thermoelectric power factor and electrical conductivity for low temperature heat energy harvesting

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JOURNAL OF MATERIALS CHEMISTRY A 2022年第48期10卷 25740-25751页

作者： Wang, Yizhuo Li, Kuncai Wang, Jing Dai, Xu Sun, Xu Chong, Daotong Yan, Junjie Zhang, Liuyang Wang, Hong Xi An Jiao Tong Univ Frontier Inst Sci & Technol State Key Lab Multiphase Flow Power Engn Xian 710054 Peoples R China Xi An Jiao Tong Univ Sch Energy & Power Engn Xian 710054 Peoples R China Xi An Jiao Tong Univ Sch Mech Engn Xian 710054 Peoples R China

Exploring high performance flexible thermoelectric materials with biopolymer hybrids fulfills the concept of green energy produced by green materials. The power generation ability of a thermoelectric (TE) device is strongly related to the thermoelectric power factor and the electrical conductivity of TE materials. However, it is very challenging to have a high power factor of >2000 mu W m(-1) K-2 together with a high electrical conductivity of >1000 S cm(-1) in biopolymer-based TE materials since biopolymers are typically non-conductive. In this work, we reported a high power factor of >2500 mu W m(-1) K-2 with a high electrical conductivity of about 7450 S cm(-1) which was achieved in biopolymer and carbon nanotube (CNT) hybrids at a relatively low CNT concentration of 33.3 wt%. This power factor is comparable to or even larger than that of many state-of-the-art only CNT films/fibers, and even inorganic TE films, such as Bi2Te3 films. The reason for the high power factor accompanied by a high electrical conductivity is attributed to the anisotropic electrical conductivity and isotropic Seebeck coefficient of the one-dimensional CNTs. Besides, the flexible films were pretty stable after being bent 10000 times, or washed 220 times, or wiped 5000 times. Such flexible and green TE materials with high performance are promising for future green energy harvesting.

关键词： Biopolymers

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THE VISCOUS EFFECT ON THE TRANSIENT DROPLET DEFORMATION PROCESS UNDER THE ACTION OF SHOCK WAVE

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ATOMIZATION AND SPRAYS 2019年第2期29卷 105-121页

作者： Shen, Shuai Li, Jianling Tang, Chenglong Liu, Jinhong Ma, Xiao Fan, Wei Northwestern Polytech Univ Sch Power & Energy Xian 710072 Shaanxi Peoples R China Shaanxi Key Lab Internal Aerodynam Aeroengine Xian 710072 Shaanxi Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China China Acad Engn Phys Inst Fluid Phys Natl Key Lab Shock Wave & Detonat Phys Mianyang 621900 Sichuan Peoples R China

The transient droplet deformation behaviors induced by shockwaves were experimentally recorded by high-speed shadowgraphic technique. Three Ohnesorge number (Oh) conditions (0.07, 0.32, and 0.66) and Weber number (We) ranges between 45 and 4000 were tested. Results show that the effects of viscosity on deformation are correlated with the extent of interaction inertia. At small We conditions, the time-dependent deformation (d(c)/d(0)) shows three stages before breakup. Initially, d(c)/d(0) stays constant for all Oh conditions. d(c)/d(0) increases as a function of time, and increased viscosity leads to a slower d(c)/d(0) rate due to a higher rate of dissipation. A less viscous droplet shows a flat d(c)/d(0) period, while for more viscous droplets, d(c)/d(0) oscillates before breakup. For higher We cases, only the constant d(c)/d(0) stage followed by a steady increase is observed, and higher viscous droplets still result in a lower d(c)/d(0) increase rate in the second stage. (d(c)/d(0))(max) decreases with the increase of viscosity at low We because the viscous dissipation consumes more inertia. However, at higher We, (d(c)/d(0))(max) increases because at this We, the increase of viscosity actually postpones the breakup, resulting in a larger (d(c)/d(0))(max). The initiation time (T-ini, the time scale of droplet deformation), decreases with the increase of We due to accelerated breakup through enhanced disruptive inertia. Increased Oh lengthens this time scale because a more viscous droplet consumes the inertia faster, counteracting the effect of We. This time scale variation also explains the (d(c)/d(0))(max) dependence on Oh and We.

关键词： shockwave droplet interaction droplet deformation and breakup viscous effect

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Experimental study on post-dryout heat transfer of dispersed flow in vertical narrow annuli

Experimental study on post-dryout heat transfer of dispersed...

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12th International Conference on Nuclear engineering (ICONE12) - 2004

作者： Myint, Aye Qiu, Suizheng Tian, Wenxi Jia, Dounan Li, Zhihui Su, Guanghui State Key Lab. Multiphase Flow P.E. 710049 Xi'an China Department of Nuclear Engineering Xi'an Jiaotong University 710049 Xi'an China

Forced convective post dryout heat transfer in narrow channel with 1.2 mm gap has been experimentally investigated with deionized water. The experiment was carried out with pressure ranging from 1.38 to 5.9 MPa and low mass velocity from 52.9 to 84.2 kg/m2 s. The experimental data were compared with well known empirical correlations such as Groeneveld, Polimik, Miropolskiy and Slaughterbeck and it was found that these correlations could not predict very well in narrow annular gap at low mass velocity. Based on the experimental data, the heat transfer coefficient increases with increasing heat flux, mass flux and pressure. A new empirical correlation for narrow annuli at low mass velocity was then developed which has a good agreement with the experimental data.

关键词： Forced convection

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A novel design of rotary regenerative condensing heat exchanger for the dehydration from high humidity flue gas

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INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER 2019年 131卷 517-526页

作者： Wang, Limin He, Yang Tang, Chunli Wang, Yikun Che, Defu Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China Xi An Jiao Tong Univ Sch Human Settlements & Civil Engn Xian 710049 Shaanxi Peoples R China Xian Thermal Power Res Inst Co Ltd Xian 710054 Shaanxi Peoples R China

A rotary regenerative condensing heat exchanger was proposed for dehydration of the flue gas outflowing from the desulfurization tower in coal-fired power plant. An analytical model of heat and mass transfer processes in the regenerative condensing heat exchanger was developed. A calculation program was built by using an iterative solution technique to compute the heat transferred from flue gas to cooling air and the condensation rate of water vapor in the flue gas. The distributions of flue gas temperature, matrix temperature, water vapor mass fraction and condensate water mass were analyzed. The effects of matrix materials, operational and structural parameters of the rotor on the condensation efficiency were examined. The condensation efficiency from high to low for different matrix materials are in the sequence: SiC ceramic > carbon steel > fluorine plastic > Borosilicate Glass. Once the rotation speed, the height and radius of the rotor are larger than specific values, their changes are less effective on the condensation efficiency. Compared with the fluorine plastic tube condensing heat exchanger, the rotary regenerative condensing heat exchanger was more effective and economical on the whole volume and the capital cost to meet the same requirement of condensation efficiency. (C) 2018 Elsevier Ltd. All rights reserved.

关键词： Rotary regenerative condensing heat exchanger Water recovery Analytical model Heat and mass transfer Condensation efficiency

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PHEBUS FPT-1 simulation, using MELCOR: Blockage model analysis 16

PHEBUS FPT-1 simulation, using MELCOR: Blockage model analys...

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16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics, NURETH 2015

作者： Wang, Jun Corradii, Michael L. Haskin, Troy State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University Xi'an710049 China Unite State Eagle Height 915 College of Engineering University of Wisconsin-Madison MadisonWI53705 United States

ISBN: (纸本)9781510811843

Recently, MAAP and MELCOR research teams completed a set of accident simulations to reconstruct the Fukushima-Daiichi accident in order to better understand severe accident progression. One result from this work was that the predicted hydrogen generation in MELCOR is notably more than in MAAP. The fuel rod degradation process (i.e., debris formation and blockage models) may likely be responsible for this hydrogen generation difference and an opportunity exists to understand the key reasons for this difference. To examine this hypothesis, the PHEBUS FPT1 experiment is selected as a benchmark test, and MELCOR is used as the analysis tool. In the past, the core degradation process of PHEBUS tests was simulated with MELCOR for fission product release insights. In this work, our calculation results are compared to PHEBUS FPT1 data to verify our MELCOR calculation. Given this validation of a nominal MELCOR simulation of the FPT1 test, we start the second step to use the volume fractions of each component as a way to visualize the debris-blockage geometric arrangement for PHEBUS FPT1 as the fuel degradation event proceeds. These results could also provide a logical approach for improving the fuel degradation (i.e., debris formation and blockage models). Relevant research is still ongoing, and will be provided in the final paper. © Copyright (2015) by American Nuclear Society All rights reserved.

关键词： Debris

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Further investigation of empirically derived models with multiple predictors in estimating monthly average daily diffuse solar radiation over China

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RENEWABLE ENERGY 2012年 44卷 469-473页

作者： Li, Huashan Bu, Xianbiao Lian, Yongwang Zhao, Liang Ma, Weibin Chinese Acad Sci Guangzhou Inst Energy Convers Key Lab Renewable Energy & Gas Hydrate Guangzhou 510640 Peoples R China Chinese Acad Sci Grad Univ Beijing 100049 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Shaanxi Peoples R China

Two models based on Li et al. (2011) are developed for general application in estimating the monthly average daily diffuse solar radiation in China. The validation of these models is performed by comparing with four existing empirical models against the measured data. It is found that the proposed models have better performance than these existing models. This study further argues that ambient temperature and relative humidity incorporated into empirical models can generally improve its estimates. Hence, the two models can be recommended for general application in estimating the monthly average daily diffuse solar radiation in China. (C) 2012 Elsevier Ltd. All rights reserved.

关键词： Diffuse solar radiation Clearness index Relative sunshine duration Ambient temperature Relative humidity

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EXPERIMENTAL STUDY OF MERCURY REMOVAL AND ELECTROLYTIC REGENERATION BY CA(CLO)₂ SOLUTIONS

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ASME power Conference 2017

作者： Luo, Qinlan Jia, Ruiya Feng, Bin Zhou, Qulan Li, Na Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian Shanxi Peoples R China Weifu High Technol Grp Co Ltd Wuxi Jiangsu Peoples R China

ISBN: (纸本)9780791857601

The trace element mercury (Hg-0) released from fossil fuel combustion in thermal power plants is difficult to be collected by pollution control equipment as its high volatility, high volatility and low solubility. The removal of Hg-0 is the most critical part of mercury removal technology. The existing technologies of mercury removal include activated carbon adsorption, fly ash adsorption, calcium-based adsorbent adsorption, and wet scrubbing method. While these existing technologies have some disadvantages, like high absorbent consumption, high absorption cost and existence of secondary pollution. Much attention has been devoted to the development of new mercury removal technology in recent years. In this study, the Ca(ClO)(2) solution was proposed for the absorption of elemental mercury as its strong oxidizing property and low expenditure. The chemical reaction mechanism, reaction kinetics and reaction thermodynamic in both absorption and regeneration processes were explored, which verified the feasibility of mercury removal and absorbent regeneration. Effects of solution concentration, absorption temperature and solution pH value on absorption performance of Ca(ClO)(2) solution were investigated in micro bubbling reactor. The experimental results revealed that acid environment (pH=1-5) and high solution concentration were beneficial to mercury removal. A high removal efficiency (over 90%) and a low outlet mercury concentration (below 0.01mg.m(3)) was obtained under optimal experimental parameters (with the pH value of 3, the solution concentration of 15 mmol.L-1 and the temperature of 25 degrees C). The performance of electrolytic regeneration in Ca(ClO)(2) rich solutions were carried out, and the effect of electrolysis time on current efficiency and energy consumption in electrolytic-regeneration processes were specifically studied. The regeneration results showed that the oxidation reaction of Cl-with a series of other oxidation reactions will occur at the anod

关键词： elemental mercury absorption calcium hypochlorite electrolytic regeneration

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Experimental study on heat transfer in vertical cooling tube cooled by downward flow in the passive heat removal system of SCWR

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APPLIED THERMAL engineering 2020年 179卷 115680-115680页

作者： Lv, Haicai Bi, Qincheng Chen, Guangming Zhang, Yichuan Deng, Liang Shenzhen Univ Coll Mat Sci & Engn Shenzhen 518055 Peoples R China Shenzhen Univ Coll Phys & Optoelect Engn Shenzhen 518060 Peoples R China Xi An Jiao Tong Univ State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China

Experimental investigations were conducted into the heat transfer characteristics of supercritical water in a downward flowing cooling tube surrounded by pool boiling for the passive cooling system of the Generation-IV Supercritical-Water-Cooled Reactor (SCWR). The experimental parameters cover the extreme high ranges of pressure (23-27 MPa), mass flux (600-1000 kg.m(-2).s(-1)), bulk fluid temperature (150-500 degrees C), and inner heat flux (98-1143 kW.m(-2)). A new thermal amplification system was applied to measure the heat transfer coefficient near the pseudocritical region under various mass fluxes and pressures. A sharp jump in the wall temperature and maximum heat transfer coefficient was observed at the pseudocritical point, and the mass flux and pressure exhibited different influences below and above the pseudocritical point. Based on the experimental data, a new heat transfer correlation for predicting the Nu is proposed for the subject cooling scenario. The proposed heat transfer correlation includes the density ratio and requires only the fluid properties at the bulk temperature. The mean absolute and root-mean-square error of the proposed correlation were about 7.94% and 9.60%, respectively. The proposed correlation can serve as a reference in the design of the passive cooling system of the SCWR.

关键词： Supercritical water Heat transfer Heat transfer correlation Pool boiling

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Anomalous enhancement in thermal conductivity of nanofluid induced by solid walls in a nanochannel

Anomalous enhancement in thermal conductivity of nanofluid i...

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作者： Sun, Chengzhen Lu, Wen-Qiang Bai, Bofeng Liu, Jie State Key Laboratory of Multiphase Flow in Power Engineering Xi'An Jiaotong University Xi'an 710049 China College of Physical Sciences Graduate University Chinese Academy of Sciences Beijing 100049 China

Thermal conductivity of Ar-Cu nanofluid confined between two parallel walls (in a nanochannel) is calculated by equilibrium-molecular-dynamics (EMD) simulation through Green-Kubo formula. The results show that the vibration of nanoparticle in the channel height direction (z-direction) is inhibited due to the presence of solid boundaries and accordingly the thermal conductivity of the confined nanofluid is obviously anisotropic. Anomalous enhancement in the thermal conductivity perpendicular to the z-direction (λ) appears as a result of the strong coupling interactions between the fluid atoms, especially the nanoparticle atoms, and the wall atoms. The thermal conductivity λ of the nanofluid confined in the channel of width h = 5.148 nm increases with the increase of the nanoparticle diameter for the strengthened couplings. The nanoparticle volume fraction effect on the thermal conductivity of the confined nanofluid is more obvious than that in macroscale. In addition, the thermal conductivity λ of the nanofluid with diameter of nanoparticle d = 1.370 nm decreases with the channel width increasing owing to the weakened couplings resulted by a longer interacting distance. © 2011 Elsevier Ltd. All rights reserved.

关键词： Molecular dynamics

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Preliminary optimization of emergency core cooling system with accident-tolerant fuels

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ANNALS OF NUCLEAR ENERGY 2020年 142卷 107411-107411页

作者： Wu, Di Gui, Minyang Zhang, Ran Zhang, Jing Ye, Tianzhou Yang, Hongfa Peng, Jingyang Wu, Yingwei Wang, Chenglong Su, G. H. Xi An Jiao Tong Univ Sch Nucl Sci & Technol Shanxi Key Lab Adv Nucl Energy & Technol State Key Lab Multiphase Flow Power Engn Xian 710049 Peoples R China Nucl Power Inst China Sci & Technol Reactor Syst Design Technol Lab Chengdu 610213 Peoples R China Minist Ecol & Environm Peoples Republ China Nucl & Radiat Safety Ctr Beijing 100082 Peoples R China

Based on the excellent performance of accident-tolerant fuels (ATFs), the optimization schemes for the safety system of Chinese advanced three-loop pressurized water reactor during loss of coolant accident (LOCA) were proposed and corresponding feasibility analysis was carried out in this study. The modified system analysis code was used to safety evaluation and four ATF systems were investigated. Several modifications were made to the rod geometries in partial ATF systems to make up the poor neutron economic performance of FeCrAl and Mo-MAX. The emergency core cooling system (ECCS) was optimized during LOCA with different break sizes. The results show that it is feasible for all ATF systems to cancel the high pressure safety injection (HPSI) or cancel both HPSI and low pressure safety injection (LPSI) but add an extra accumulator (ACC). Also the safety of reactors fueled with ATFs can be guaranteed with only 0.35 times the original flowrate of LPSI during large break LOCA (LB-LOCA). In the scheme of replacing the original ECCS with two extra ACCs during LB-LOCA, reactors loaded with partial ATFs are safe, while UO2-Zr systems are in danger as a contrast. This work could provide reference for the design of reactor safety system in the future. (C) 2020 Elsevier Ltd. All rights reserved.

关键词： PWR ECCS optimization ATFs LOCA

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