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换热器管程流动诱发的管路横向振动特性计算
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作者 苏风 王跃方 《风机技术》 2018年第6期70-74,共5页
针对压缩机管壳式换热器中细长换热管在管程流体激振下产生的横向振动问题,采用多跨梁理论进行动力学建模。以管程流速为参数,建立了横向振动微分方程,采用简便易行的传递矩阵法求解,得到了换热管的自振频率,以及使横向振动失稳的管程... 针对压缩机管壳式换热器中细长换热管在管程流体激振下产生的横向振动问题,采用多跨梁理论进行动力学建模。以管程流速为参数,建立了横向振动微分方程,采用简便易行的传递矩阵法求解,得到了换热管的自振频率,以及使横向振动失稳的管程流动临界流速。通过算例验证了方法的求解精度,指出在失稳临界流速较大时,设计时可将管程流体简化为管材的附加质量,计算其自振频率。 展开更多
关键词 换热器 细长管 管程流动 频率 稳定性
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A New AC Driving Method for a Current-Programmed AM-OLED Pixel Circuit 被引量:2
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作者 司玉娟 徐艳蕾 +2 位作者 郎六琪 陈新发 刘式墉 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第9期1562-1565,共4页
A new,improved pixel-driving circuit is presented based on a current-programmed pixel circuit in order to achieve an AC-driving mode. This driving method realizes an AC-driving mode,removes the threshold voltage varia... A new,improved pixel-driving circuit is presented based on a current-programmed pixel circuit in order to achieve an AC-driving mode. This driving method realizes an AC-driving mode,removes the threshold voltage variation of the driving TFT due to the process variation or long-term operation,which can bring about brightness non-uniformity, and eliminates high peak pulse currents at the beginning and end of recovery time. Simulation is done with AIM-SPICE,and simulation results demonstrate that the OLED is in the reverse-biased state during recovery time. 展开更多
关键词 active matrix OLED AC pixel-driving circuit TFT AIM-SPICE simulation current-programmed pixel-driving circuit
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Influence of Feed Injection on Hydrodynamic Behavior in FCC Riser
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作者 孙国刚 时铭显 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2003年第6期638-642,共5页
This paper studies the influence of feed injection on the hydrodynamic behavior of fluid catalytic cracking riser reactors. Experiments were conducted in a cold model of 186 mm ID with two oppositely inclined secondar... This paper studies the influence of feed injection on the hydrodynamic behavior of fluid catalytic cracking riser reactors. Experiments were conducted in a cold model of 186 mm ID with two oppositely inclined secondary air feed nozzles. The flow structure was determined by means of the axial static pressure measurements and local radial optic fiber probe measurements on different levels with emphasis on the sections downstream of the secondary injection. The measurements reveal that the secondary injection plays a crucial role on riser hydrodynamics. Just above the secondary injection, the flow and mixing are strongly affected, while below the secondary injection the effect is weak. The radial profile just downstream of secondary injection demonstrates wavy features. The effective region of secondary injection could be estimated by the axial pressure gradient profiles and/or the radial profiles of local solids velocity and density. 展开更多
关键词 fluid catalytic cracking riser reactor feed injection region flow structure
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Local Gas Phase Flow Characteristics of a Gas-Liquid-Solid Three-Phase Reversed Flow Jet Loop Reactor 被引量:2
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作者 闻建平 周怀 陈云琳 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2002年第1期119-122,共4页
The local gas-phase flow characteristics such as local gas holdup(εg), local bubble velocity (V_b) and local bubble mean diameter(d_b) at a specified point in a gas-liquid-solid three-phase reversedflow jet loop reac... The local gas-phase flow characteristics such as local gas holdup(εg), local bubble velocity (V_b) and local bubble mean diameter(d_b) at a specified point in a gas-liquid-solid three-phase reversedflow jet loop reactor was experimentally investigated by a five-pointconductivity probe. The effects of gas jet flow rate, liquid jet flowrate, solid loading, nozzle diameter and axial position on the localεg, V_b and d_b profiles were discussed. The presence of solids atlow solid concentrations not only increased the local εg and V_b,but also decreased the local d_b. The optimum solid loading for themaximum local εg and V_b together with the minimum local d_b was0.16×10^-3 m^3, corresponding to a solid volume fraction ε_S=2.5/100. 展开更多
关键词 local gas holdup local bubble velocity local bubble mean diameter gas-liquid-solid three-phase
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Simplified Correlation Equations of Heat Transfer Coefficient during Phase Change for Flow inside Tubes
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作者 Mahmoud A Hammad Abed Alrzaq S Alshqirate 《Journal of Energy and Power Engineering》 2012年第10期1543-1552,共10页
In this work, the easy to use, simple and direct equations were formulated and tested. These equations can be used to calculate the mean values of the heat transfer coefficients of inside tube flow during phase change... In this work, the easy to use, simple and direct equations were formulated and tested. These equations can be used to calculate the mean values of the heat transfer coefficients of inside tube flow during phase change. Analytical and experimental methods were used to correlate these equations. Two different forms were used, one for evaporation case and the other for condensation case. Carbon dioxide, CO2, was used as case study. Correlated values of the mean heat transfer coefficients (hcor,.) were compared with the experimental results (he^e) and with other published result, a good agreement was noticed. The resulted correlations can be used to simplify the design and performance studies of both condensers and evaporators. 展开更多
关键词 Heat transfer two phase flow change of phase REFRIGERATION carbon dioxide correlations.
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An Experimental Investigation on Heat Transfer Performance of Nanofluid Pulsating Heat Pipe 被引量:8
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作者 Hongwei Jia Li Jia Zetao Tan 《Journal of Thermal Science》 SCIE EI CAS CSCD 2013年第5期484-490,共7页
The effect of SiO2 particles on heat transfer performance of a pulsating heat pipe (PHP) was investigated experi- mentally. DI water was used as the base fluid and contrast medium for the PHP. In order to study and ... The effect of SiO2 particles on heat transfer performance of a pulsating heat pipe (PHP) was investigated experi- mentally. DI water was used as the base fluid and contrast medium for the PHP. In order to study and measure the character, there are SiO2/H20 nanofluids with different concentration and applying with various heating powers during the experiment investigation. According to the experimental result, the high fraction of SiO2/H20 will de- teriorate the performance of PHP compared with DI water, i.e. the thermal resistance and the temperature of evaporation section increases. It is in contrary in the case of low fraction of SiO2/H20. Finally, the comparison of the thermal performances between the normal operation system and the static settlement system is given. It is found that both the thermal resistance of nanofluid PHP and the temperature of the evaporation section increase after standing for a period, and it is the same trend for the temperature fluctuation at the identical heating power for PHP. 展开更多
关键词 NANOFLUID Pulsating heat pipe Heat transfer characteristics Suspension characteristics
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Study on asymmetric interior corner flow in microgravity condition 被引量:2
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作者 LI JingHao CHEN XiaoQian +1 位作者 HUANG YiYong BAI YuZhu 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第8期2332-2337,共6页
The capillary flow in asymmetric interior corner consisting of straight vane and curved wall is studied with analytical solution.The concept of equivalent interior corner angle is proposed to convert the asymmetric in... The capillary flow in asymmetric interior corner consisting of straight vane and curved wall is studied with analytical solution.The concept of equivalent interior corner angle is proposed to convert the asymmetric interior corner model into symmetric interior corner model.Then the governing equations of interior corner flow are established,and based on which the interior corner flow is calculated.This method is used to analyze the capillary flow in cylindrical vane-type surface tension tank with outer vanes.The research can provide beneficial reference to the design of vane-type surface tension tank. 展开更多
关键词 asymmetric interior corner flow equivalent interior corner angle vane-type surface tension tank analytical solution
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