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IntroductionThe present work is devoted to particle dispersionin confined two-phase turbulent jets, which has become amajor domain of research attracting increasingly interestand with challenging fundamental aspects. Describingthe motion of a dispersed phase is complex and is ofgreat interest in several practical systems. Theapplications that require the solution of this problem areas varied as the dispersion of passive pollutant particlesin the atmosphere to combustion systems with dispersing… 相似文献
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This paper reports an investigation into the characterisation of liquid-vapor electrolyte solutions at high pressure and high temperature,A procedure to enable calculations of methane,carbon dioxide and hydrogen sulphide solubilities in brines(0-6m.) for temperature from 25 to 350℃ and for pressures from 1 to 1800 bar is presented.The model is based on Helgeson,Kirkham and Flowers modified equations of state(HKF)and on the semi-empirical interaction model introduced by Pitzer,HKF modified equations of state are used to calculate the reference fugacity of gas species,and the Pitzer ionic interaction model is used to calculate the activity coefficient of dissolved species(i.e.ionic or neutral).The efficiency of the combination of the two models is confirmed by several comparisons with data in the literature. 相似文献
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Mathematical modeling of gasification of high‐ash Indian coals in moving bed gasification system 下载免费PDF全文
Simulation of gasification of high‐ash Indian coal in an updraft moving bed gasification system is presented in this paper. A steady one‐dimensional numerical model, which takes into account of drying, devolatilization, combustion and gasification processes, is used to solve the mass and energy balances in the gasification system. The results from the model have been validated against the experimental data available in literature for various types of coals. The predicted product gas composition, its calorific value and the exit temperature are in agreement with the reported results. The validated model is used to study the effect of input parameters such as oxygen content in air stream, steam flow rates and the pressure of the gasification system. Results indicate that the value of oxygen mole fraction around 0.42 in the oxidizer stream can provide optimum performance in oxygen‐based gasification systems. There is a range of steam‐to‐coal ratio that is dependent on the oxygen content in oxidizer stream. For air‐based systems, this value is around 0.4 and for oxygen‐based systems it is 1.5. The gasification performance improves with operating pressure significantly. An operating pressure of around 8 bar and higher, based on the application, can be used for achieving the required performance with high‐ash coals. The model is useful for predicting the performance of high‐ash Indian coals in a moving bed gasification system under different operating parameters. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
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利用仿真软件GT-Suit构建了高压共轨燃油喷射系统的仿真模型,分析了不同长径比下的共轨管内的压力波动规律、平均压力波动规律、喷油压力波动规律,进而分析了对喷油率的影响.通过仿真数据对比,在共轨管长为310 mm、长径比为16时,可使喷油系统的稳定性最优. 相似文献
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James P. Diebold 《Biomass & bioenergy》1994,7(1-6):75-85
Complex interactions occur between the many competing and sequential chemical reactions during the pyrolysis of cellulose, making the prediction of the pyrolysis products relatively difficult. The purpose of this paper is to present cellulose pyrolysis as a comprehensible interaction of time, temperature and pressure. Appropriate kinetic data for seven first-order global reactions for the pyrolysis of cellulose were found in the literature. A mathematical model was developed, in which the seven reactions occurred simultaneously so long as the feedstock for the particular reaction existed. The seven differential equations representing the reaction rates were numerically integrated simultaneously to obtain the products of pyrolysis as a function of time, temperature, heating rate and pressure. This program was used to predict many results and trends observed in both slow and fast pyrolysis: very high yields of condensible vapors (primary oils) were predicted under high heating rates to modest final temperatures; high char yields were predicted for slow heating rates at low temperatures; high gas yields were predicted for fast pyrolysis at high temperatures. 相似文献
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Yukio Sudo 《亚洲传热研究》1997,26(1):16-29
A quantitative analysis of critical heat flux (CHF) under high mass flux with high subcooling at atmospheric pressure was successfully carried out by applying a new transition region model for a macro-water sublayer on heated walls to the existing model of a vapor blanket over the macro-water sublayer. The CHF correlation proposed in this study could predict well the experimental data obtained for water mass flux of 940 to 20,300 kg/m2s using circulate tubes 2 to 4 mm in diameter and 30 to 100 mm in length with inlet subcooling of 30 to 90 °C and rectangular channels heated from one side with gaps of 3 to 20 mm, length of 50 to 305 mm, and inlet subcooling of 30 to 77 °C and revealed a unique feature of CHF, namely, that the effects of wall friction of subcooled boiling flow and the velocity of the steam blanket above the macro-water sublayer at atmospheric pressure become the dominant factors while they were not dominant at higher pressures. © 1997 Scripta Technica, Inc Heat Trans Jpn Res, 26 (1): 16–29, 1997 相似文献
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光谱消光法测量高压湿蒸汽的研究 总被引:7,自引:0,他引:7
在前人工作的基础上发展了光谱消光法在线测量技术,并将其应用于高压湿蒸汽两相流湿度和水滴尺寸分布的测量.在数据处理上,提出了改进的 optimized regularization 反演算法,该算法比以往的 Phillip-Twomey-NNLS 算法有更大的抗噪性、准确性和稳定性.还进行了标准颗粒测量实验和高压湿蒸汽在线测量实验.结果表明:通过增大测量区与接收光纤间距和减小接收光纤面积,可大大降低颗粒前向散射光(包括低浓度时的不相关单散射光和高浓度时的复散射光)对消光光谱的影响,从而保证了在高浓度情况下湿蒸汽测量的准确性.湿蒸汽实验结果表明:在高压状态下湿蒸汽中的水滴尺寸比低压汽轮机内湿蒸汽中的水滴小,并且分布也较窄,这也是核电高压汽轮机水蚀较少的原因之一. 相似文献
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Dynamic pressure measurements are introduced as powerful tool to detect filter failures at early stage. Data of single recleaning pulses or a time series of recleaning pulses can be used to detect filter failures and changes in filter candle conditions during commissioning and operation. High frequency sensors were used to record recleaning back pressure pulses enabling the detection of filter failures such as leakages or blockages. Changes in filter wall resistance due to patchy cleaning or depth filtration can be detected much faster with dynamic pressure measurements than with conventional differential pressure measurements. Parameters derived from dynamic pressure data were monitored over time and compared with reference data. The method complements standard pressure difference measurements. Dynamic pressure measurements were conducted at a hot gas filter applying a coupled pressure pulse (CPP) recleaning system. 相似文献
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应用有限元分析程序对亚临界600MW汽轮机高压隔板套进行三维有限元应力分析,提出采用截面应力与最大应力比值作为判断结构设计是否合理的标准,并与原二维有限差分法计算结果比较,提出采用带有一半圆槽的新型高压隔板套设计方案,可有效降低高压隔板套应力。 相似文献
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进行汽轮机高背压出力试验,可以明确机组在高背压条件下的出力。简要阐述了汽轮机高背压出力试验过程,包括条件准备、参数调整方法和数据调整依据,并提供了2个试验实例,介绍了试验简化实施方案和估算方法。 相似文献
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柴油机在高原地区运行时,由于受到特殊的地理环境和气候条件的影响,其动力性、经济性、可靠性和废气排放性等指标都大幅下降。为了满足高原地区柴油机的使用要求,分析了高原温度、气压和空气密度等条件与海拔高度的对应关系及其各自对柴油机造成的影响,提出了一系列的改进措施。 相似文献