共查询到20条相似文献,搜索用时 15 毫秒
1.
电池实际可放出的瓦时容量与实际可放出的最大瓦时容量的比值定义为荷电状态,准确测定荷电状态对储能应用十分重要。本文从理论和应用角度,讨论全钒液流电池荷电状态的理论概念、工程定义和主要影响因素;提出2种确定最大瓦时容量的方法,其中实测法准确度更高,包含钒离子跨膜迁移、水分子扩散、负极电解液析氢和被氧化的信息,用于表征储能系统的荷电状态具有实际价值;阐述最大瓦时容量、电化学瓦时容量和理论瓦时容量的区别与联系。所提出的荷电状态确定方法,能够用于全钒液流电池SOC的估计。 相似文献
2.
Hongwei MA Haokang JIANG Department of Jet Propulsion Beijing University of Aeronautics Astronautics Beijing China 《热科学学报(英文版)》2005,14(1):15-21
This paper presents an experimental investigation of the characteristics of three-dimensional turbulent wakes of an isolated axial compressor rotor and a single-stage axial compressor rotor. The wakes were measured from hub to tip using a single-slant hot-wire and a four-hole conical high frequency pressure probe. The experiments were made at both design and near stall conditions. Variations of mean velocities, total pressure, static pressure and turbulence stresses in the wakes are shown and interpreted. The experimental data from the isolated compressor rotor wake are compared with that from the single-stage compressor rotor. 相似文献
3.
Dramatic climate change, caused by over consumption of coal, oil and other traditional energy sources, as well as exhaustion of their reserves, imposed technological need to look for their substitution with new, renewable energy sources. The exploitation of these new forms of energy, solar, wind, earth and bio-fuels, initiated the development and application of new technologies, so far unused in practice. Rapid development and wide application of installations for use of renewable energy in many households and companies opened a whole new risk and danger in the fire protection field. With the purpose of introducing this problem to engineers in the area of fire protection, health and safety at work, this paper systematically presents various types of facilities for exploitation of renewable energy sources as well as potential dangers, risks and issues related to their safe operation. 相似文献
4.
《Journal of power sources》2002,110(1):133-137
The effect of the main structural parameters of the current collectors on efficiency of operation of the positive electrode of the lead–acid battery was investigated. 相似文献
5.
《Solar Cells》1982,5(3):269-274
With the help of a general simulation program (the Spice II program from the University of California, Berkeley), adapted to photocell modelling, we studied the behaviour of a large solar photocell consisting of smaller Cu2SCdS unit solar cells in parallel. In particular we examined a theoretical set of photocells identical with the best cell made in the laboratory, a set of 30 real photocells characterized individually and the effect of introducing low efficiency cells.We indicate the role of each parameter characterizing the photocells in order to improve the behaviour of photovoltaic panels of larger dimensions. 相似文献
6.
Reducing heat demand for increasing concentration of HI in the HIx solution of the iodine circuit of the Iodine–Sulphur cycle is considered the most effective way of increasing efficiency of the cycle. Electro-electrodialysis has emerged as an energy efficient way of increasing the HIx concentration above azeotropic value. Simulation of the iodine circuit consisting of an EED, a flash and a decomposer was carried out in Aspen Plus™ simulation platform to study the effect of EED current density and outlet HI concentration on the efficiency of the cycle. Efficiency reduced strongly with increase in current density. For EED current density of 5 A/dm2, maximum efficiency was ∼35.9% and the optimal range of EED catholyte's exit HI concentration, iodine-free, mole fraction was 0.19–0.21. Simulation results showed that reducing EED resistance was most effective, among all EED parameters, in increasing the cycle's thermal efficiency and if the EED resistance is completely eliminated the thermal efficiency value would increase to 39.4%. 相似文献
7.
When an expansion wave propagated along a constant area straight tube reaches at the open end, the negative impulsive wave and the compression wave are formed by the emission and reflection of expansion wave. The negative impulsive wave is emitted toward the surrounding area and causes an impulsive noise like the sonic boom. The compression wave propagates in the tube toward the upstream and may cause the impulsive noise at the surrounding area of tube portal. With the advance of industrial engineering, it seems that the discharging of the expansion wave will become important problems. In this study, the experimental and numerical investigations are carried out using the shock tube and the TVD numerical method. The formation process of compression wave near the open end, the relationship with the compression wave and the expansion wave and the characteristics of compression wave are discussed. 相似文献
8.
Yoichi Kinoue Toshiaki Setoguchi Tomohiko Kuroda Kenji Kaneko Manabu Takao Ajit Thakker 《热科学学报(英文版)》2003,12(4):323-327
The Wells turbine for a wave power generator is a self-rectifying air turbine that is available for an energy conversion in an oscillating water-air column without any rectifying valve. The objective of this paper is to compare the performances of the Wells turbines in which the profile of blade are NACA0020, NACA0015, CA9 and HSIM15-262123-1576 in the small-scale model testing. The running characteristics in the steady flow, the start and running characteristics in the sinusoidal flow and the hysteretic characteristics in the sinusoidal flow were investigated for four kinds of turbine. As a conclusion, the turbine in which the profile of blade is NACA0020 has the best performances among 4 turbines for the running and starting characteristics in the small-scale model testing. 相似文献
9.
TheStudyoftheDamageLawsofPoolFires¥YuDeming;FengChanggen;ZengQingxuan;GuoXinya(Mechanics&EngineeringDepartment,BeijingInstitu... 相似文献
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11.
LI Tingxun GUO Kaihua WANG Ruzhu. FAN Shuanshi Shanghai Jiaotong University Shanghai China Guangzhou Institute of Energy Conversion CAS Guangzhou China 《热科学学报(英文版)》2001,(2)
IntroductionThere are mainly tWo well-known methods for thecalculation of fluid Phase equilibriUm, the method ofusing equation of state (EOS) or achvity coeffident.The later needs a plenty Of vapor-liquid equilibriumexperimental data in Order tO regress the calculatingmodel's parameters (such as non-random tWo liquidequation, (NRTL) etc). All means to describethermodynndc prOPelties are theoretically fonddedwith the equation Of state. If the EOS is suitable for theentire thermodyntalc … 相似文献
12.
The asymptotic behavior of solutions of a discrete Schrödinger equation is studied via the perturbation theory approach and by the method based on the reduction to the Riccati equation. Solutions of WKB type are constructed which exhibit a dichotomy property similar to that known for differential equations. Provided that the potential is regularly varying in a certain sense, these solutions can be asymptotically represented as products of continued fraction approximants related to the corresponding Riccati equation. 相似文献
13.
Thermal Emission of a Disc Body of Semitransparent
Material 总被引:2,自引:0,他引:2
INTRODUCTIONThethermalemissionofseveraJshapesofsemi-transparelltbodieshasbeeninvestigatedinthepastdecades.Forexample,Mcmahonderivedananalyt-icalexPressionforthehemisphericalendssivityofasemitransparentparallelslabl1];Gardonpresentedamethodforevaluatingtheemissivityofaglassslabl21;byimprovingtheGardon'smethod,Isardcalculatedtheendssivitiesofglassspheres,cylindersandtubes,andobtainedanapproximateexpressionwithtwoex-ponentialtermsl3];TuInerandLove,byusingtheMollterCarlomethod,simulatedthe… 相似文献
14.
Based on the method to change blade loading type along blade height, that is, applying aft-loading at both end zones of cascade while applying fore-loading in the mid zone of cascade, HTC (Harbin Turbine Company) de- signed a twisted and bowed stationary cascade with low aspect ratio and large enthalpy drop. To verify the aero- dynamic performance of such cascade, firstly, low-speed wind tunnel tests were conducted to validate the calcula- tion results of commercial software CFX, and then numerical simulations were made for the aerodynamic per- formance of the cascade at different Mach numbers. The simulation results show that the large enthalpy drop sta- tionary cascade designed by HTC can offer good aerodynamic performance while keeping its high-load charac- teristics in the change range of outlet Mach number as stated in this paper. 相似文献
15.
MichaelJ.CIALKOWSKI 《热科学学报(英文版)》2002,11(2):163-171
The work presents the application of heat polynomials for solving an inverse problem. The heat polynomials form the Treffetz Method for non-stationary heat conduction problem. They have been used as base functions in Finite Element Method. Application of heat polynomials permits to reduce the order of numerical integration as compared to the classical Finite Element Method with formulation of the matrix of system of equations. 相似文献
16.
《International Journal of Hydrogen Energy》2023,48(60):23031-23043
The aim of this study is to maintain and increase the activity of the catalyst in the presence of H2S with the addition of iron to the Ni catalyst. Alumina-supported monometallic iron and bimetallic nickel-iron catalysts with different weight percentages (8% Fe, 3% Ni – 3% Fe and 8% Ni – 8% Fe) were synthesized using the wet impregnation method in this study. Alumina was prepared by the sol-gel method. The activities of these synthesized catalysts in the methane dry reforming reaction were investigated at different H2S concentrations (0 ppm, 2 ppm, and 50 ppm) with a total flow rate of 60 mL/min containing an equimolar ratio of CH4, CO2, and Ar at 750 °C and atmospheric pressure. To investigate the effect of sulfur compounds on the catalytic activity, the catalysts were also exposed to different gas compositions such as the mixture of H2S + He, H2S + CO2 + He, and H2S + CO2 + CH4 + He. In this case, FT-IR with a gas cell was used to determine the components in the gas stream at the reactor outlet. To explain catalytic performance, characterization studies were carried out using XRD, N2 adsorption/desorption, DRIFT, SEM, TGA, and XPS analysis. All-synthesized materials showed Type-IV isotherm with a hysteresis loop corresponding to an ordered mesoporous structure. The DRIFT analysis showed a decrease in the Lewis acid sites after the addition of iron into the Ni-catalysts. In the activity test carried out in the presence of 50 ppm H2S, it was observed that the iron-containing 8Ni–8Fe@SGA catalyst increased the sulfur resistance slightly, compared to the monometallic 8Ni@SGA catalyst. TGA analysis showed that Fe addition reduced coke deposition, as the Ni–Fe catalyst had a lower nickel crystal size than the Ni-based catalyst. FTIR analysis with a gas cell showed that sulfur in H2S transformed to other sulfur compounds such as COS and/or SO2 during dry reforming of biogas over alumina-supported Ni–Fe catalysts. 相似文献
17.
InfluenceofHeatingRateontheOnsetofOscillationinLiquidBridgeofHalfFloatingZone¥Jing-ChengXie;Wen-RuiHu(InstituteofMechanics,Ch... 相似文献
18.
H.F.Zhao Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing ChinaG.C.Benelli L.Miglietta C.Tanzini ENEL-CRTN Via A.Pisano PISA Italy 《热科学学报(英文版)》1992,1(2):135-139
The technique of the use of multi-annular opposed jets as different from using swirl and bluff body createsan excellent recirculation zone with desired size in a large space.The size of recirculation,the magnitude ofreverse velocity and turbulence intensity are much greater than those formed by bluff body.Factors affectingthe flowfield include the velocity ratio of the opposed jets to the primary air J,the diameter and constructionof the opposed jet ring,secondary air velocity and configuration,and confined or unconfined flow condition andso on.This method is a promising way for flame stabilization in combustion technology. 相似文献
19.
Effect of Annular Slit Geometry on Characteristics of Spiral Jet 总被引:1,自引:0,他引:1
Shigeru Matsuo Kwon-Hee Lee Shinsuke Oda Toshiaki Setoguchi Heuy-Dong Kim 《热科学学报(英文版)》2003,12(3):225-230
A spiral flow using an annular slit connected to a conical cylinder does not need special device to generate a tangential velocity component of the flow and differs from swirling flows. Pressurized fluid is supplied to an annular chamber and injected into the convergent nozzle through the annular slit. The annular jet develops into the spiral flow. In the present study, a spiral jet discharged out of nozzle exit was obtained by using a convergent nozzle and an annular slit set in nozzle inlet, and the effect of annular slit geometry on characteristics of the spiral jet was investigated by using a Laser Doppler Velocimeter (LDV) experimentally. Furthermore, velocity distributions of the spiral jet were compared with those of a normal jet. 相似文献
20.
IntroductionThe latest Studies of the ovens characteristics ofhypersonic fifor vehicles with ~ engineshave shown that these vehicles are fairly prondsing.Some addihonal. PbolelnS arise, how~ that arerelated tO the dedrihon Of the geneal shape of theaircraft, the choice Of Propulsion type and operationmpbo, the enghe size and POsition on the body.The ~ version under consideration boltesthe use of a COmbined PtOPulsion act with a twO-modecombustor (subsonic or supersonic combustion). sucha… 相似文献