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The effect of evaporator operating parameters on the flow patterns inside horizontal pipes

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Journal of Thermal Science 2011年第4期20卷 324-331页

作者： Lige Tong Haiyan Li Li Wang Xinxing Sun Yunfei Xie Department of Thermal Science and Energy Engineering University of Science and Technology Beijing Beijing 100083 China

A general and simple model for simulating the steady state behaviors of air-to-refrigerant fin-and-tube evaporator is introduced with the focus on the detailed flow patterns inside the tubes.In order to simulate the heat transfer between air and the working fluid,the evaporator is divided into a number of control volumes.Empirical correlations from literature were also adopted to estimate the void fraction,the internal and external heat transfer coefficients,and the pressure drops.Simulations were performed to study the effects of varying inlet air temperature,refrigerant mass flow rate and evaporation pressure on the flow patterns inside the horizontal pipe of the evaporator.The simulation results indicate that the proposed model can be used to predict flow patterns well.The predicted results of the model agree well with experimental results,the difference is within ±3% for the cooling capacity,and is within ±0.2% for refrigerant evaporation temperature.

关键词：翅片管式蒸发器流动模式水平管道运行参数空气温度稳态行为压力下降蒸发压力

OWC air chamber performance prediction under impulse turbine damping effects

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Science China(Technological Sciences) 2016年第4期59卷 657-666页

作者： LIU Zhen HYUN BeomSoo JIN Ji Yuan HONG KeyYong LEE YoungYeon Shandong Provincial Key Laboratory of Ocean Engineering Ocean University of China Qingdao Municipal Key Laboratory of Ocean Renewable Energy Ocean University of China College of Ocean Science and Technology Korea Maritime and Ocean University Ocean Plant Research Division Korea Research Institute of Ships and Ocean Engineering

Oscillating water columns(OWCs)are most widely used in coastal wave energy conversion.The air duct opens into the atmosphere through the air turbine,which is the power take-off device,and this results in a pressure drop across the air chamber.However,because of the complex configure of the impulse turbine and its high rotation speed,it is difficult to install it in the experimental simulator and numerical model.Therefore,the turbine damping effects on the operation of the OWC air chamber are induced to predict its performance more accurately.Orifice plates are used as a substitute for the impulse turbine as it generates a similar pressure drop and power output;the experimental and numerical pressure drops and output powers are compared.A 3D numerical wave tank based on the two-phase VOF model is established using the commercial CFD code Fluent,which can predict air flow and pressure variations in the chamber and duct.Water surface elevations,air flow velocity and pressure variation inside the chamber with the orifice plate are studied numerically,and validated by the corresponding experimental data.The air chamber of the Yongsoo OWC pilot plant is used as the engineering project case.The operating performance of the air chamber installed with a 0.428D orifice plate as the substitute for the designed impulse turbine is computed and analyzed.It is found that the turbine damping effects will cause around 30%reduction in the peak values of the pneumatic energy output of the OWC air chamber in the resonant wave domain.

关键词：冲击式水轮机性能预测阻尼作用 OWC 气室气涡轮机压力下降动力输出装置

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TG轮主机起动空气漏泄故障排除及启示

航海技术 2010年第3期 61-62页

作者：谢云鹏上海远洋运输有限公司

大型船用柴油机，几乎全部采用压缩空气启动。按照我国《钢制海船建造和人级规范》，启动空气瓶的容量（2．5—3．0MPa）必须能保证在不补充空气的情况下，能冷车倒顺车交替起动不少于12次。所以，启动主机消耗的空气量（起动气源压力... 详细信息

大型船用柴油机，几乎全部采用压缩空气启动。按照我国《钢制海船建造和人级规范》，启动空气瓶的容量（2．5—3．0MPa）必须能保证在不补充空气的情况下，能冷车倒顺车交替起动不少于12次。所以，启动主机消耗的空气量（起动气源压力下降）越小越好。

关键词：压缩空气故障排除起动主机漏泄 TG 船用柴油机压力下降

Ignition and combustion of pyrotechnics at low pressures and at temperature extremes

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Defence Technology（防务技术） 2017年第3期13卷 119-126页

作者： Clive Woodley R.Claridge N.Johnson A.Jones QinetiQ MOD Fort Halstead

Rapid and effective ignition of pyrotechnic countermeasure decoy flares is vitally important to the safety of expensive military platforms such as aircraft. Qineti Q is conducting experimental and theoretical research into pyrotechnic countermeasure decoy flares. A key part of this work is the development and application of improved models to increase the understanding of the ignition processes occurring for these flares. These models have been implemented in a two-dimensional computational model and details are described in this paper. Previous work has conducted experiments and validated the computational model at ambient temperature and pressure. More recently the computational model has been validated at pressures down to that equivalent to 40,000 feet but at ambient temperature(~290 K).This paper describes further experimental work in which the ignition delays of the priming material in inert countermeasure decoy flares were determined for pressures down to 40,000 feet and at temperature extremes of -40℃ and 100℃ Also included in this paper is a comparison of the measured and predicted ignition delays at low pressures and temperature extremes. The agreement between the predicted and measured ignition delays is acceptable.

关键词：压力下降极端温度点火过程烟火二维计算模型燃烧实验工作点火延迟

Effects of bending on heat transfer performance of axial micro-grooved heat pipe

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Journal of Central South University 2011年第2期18卷 580-586页

作者：蒋乐伦汤勇潘敏强 School of Mechanical and Automotive Engineering South China University of Technology

Heat pipe is always bent in the typical application of electronic heat dissipation at high heat flux,which greatly affects its heat transfer performance. The capillary limit of heat transport in the bent micro-grooved heat pipes was analyzed in the vapor pressure drop,the liquid pressure drop and the interaction of the vapor with wick fluid. The bent heat pipes were fabricated and tested from the bending angle,the bending position and the bending radius. The results show that temperature difference and thermal resistance increase while the heat transfer capacity of the heat pipe decreases,with the increase of the bending angles and the bending position closer to the vapor section. However,the effects of bending radius can be ignored. The result agrees well with the predicted equations.

关键词：传热性能热弯曲微槽道热管热效应轴向压力下降弯曲角度

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大豆粕在鲑鳟鱼类饲料中的利用（二）

中国水产 2009年第5期 87-88页

作者： Ronald W. Hardy

三．鲑鳟鱼类膨化饲料之开发膨化饲料的制造是将湿的原料混合后加热至100—150℃在压力下挤出膨化，然后将饲料水分干燥至10％以下。饲料水分在膨化机内为液态，当饲料经由模孔挤出时压力下降使得水分瞬间转变为蒸气。这个现象使饲料颗... 详细信息

三．鲑鳟鱼类膨化饲料之开发膨化饲料的制造是将湿的原料混合后加热至100—150℃在压力下挤出膨化，然后将饲料水分干燥至10％以下。饲料水分在膨化机内为液态，当饲料经由模孔挤出时压力下降使得水分瞬间转变为蒸气。这个现象使饲料颗粒迅速膨胀，密度下降成为浮性饲料。原料混合物的差异、水分含量以及膨化条件的方式，膨化饲料的密度可被改变而使下沉速率增快、减缓或甚至浮在水面。

关键词：鲑鳟鱼类鱼类饲料大豆粕膨化饲料饲料水分原料混合压力下降饲料颗粒

Influence of background pressure on the microstructure and optical properties of Mo/Si multilayers fabricated by magnetron sputtering

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Science China(Physics,Mechanics & Astronomy) 2013年第9期56卷 1689-1693页

作者： LV Peng ZHANG ZaiQiang GUAN JinTong WANG XiaoDong HOU XiuLi ZHANG LingYan WANG JiJun CHEN Bo GUAN QingFeng School of Materials Science & Engineering Jiangsu University Faculty of Science Jiangsu University State Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of Sciences

Mo/Si multilayers were fabricated by using magnetron sputtering method at different background pressures:6×10-5 Torr,3×10-5 Torr,and 3×10-6 Torr.The reflectivity of the Mo/Si multilayers increased from 1.93% to 16.63%,and the center wavelength revealed a blue shift to 0.12 nm with the decrease of background pressure.Grazing incident X-ray diffraction(GIXRD) indicated that multilayers fabricated at high background pressure possessed better periodic structure and thinner Mo-on-Si interlayers.Low crystallization degree in(110) preferred the orientation of Mo layers and serious interdiffusion in the Mo/Si multilayers fabricated at low background pressure were observed by transmission electron microscopy(TEM).According to quantitative analysis of microstructural parameters,the Mo layers thickness and thickness ratio of Mo/Si multilayers both decreased and approached the design value gradually by the decrease of background pressure.In addition,the thicknesses of Mo-on-Si and Si-on-Mo interlayers were 1.17 nm and 0.85 nm respectively.It is suggested that the influence of background pressures on the microstructure has a critical role in determining the optical properties of Mo/Si multilayers.

关键词：压力下降磁控溅射法周期性结构 Mo Si 光学性能溅射制备掠入射X射线衍射

Two Phase Pressure Drop Performance of Refrigerant in a Small Horizontal Smooth Tube with 2.5 mm inside Diameter

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Journal of Shanghai Jiaotong university(Science) 2005年第1期10卷 66-71页

作者：魏文建丁国良王凯建 Dept.of Power & Environment Zhongyuan Inst. of Technology Zhengzhou 450007 China Inst. of Refrigeration and Cryogenics Shanghai Jiaotong Univ. Shanghai 200030 Inst.of Refrigeration and Cryogenics Shanghai Jiaotong Univ.Shanghai 200030 Fujitsu General Inst.of Air-Conditioning Technology Limited KawasakiJapan

Two-phase flow pressure drop measurements were made during the phase change heat transfer process of R22 in a small horizontal smooth tube with 2.5 mm inside diameter. Conclusions can be drawn that the quality corresponding to the pressure gradient peak value of small tubes became higher than that of large tubes. The effect of quality to pressure drop becomes weak as the mass flux increases. The experiment data were compared with the predicated values of the state-of-the-art correlations from the open literature. The comparisons between the data and the predictions indicate that most of the state-of-the-art correlations fails to predict the experimental data. Chisholm model shows a relatively better predictive ability than the other empirical correlations although it has a mean deviation of 26.7%. But the predicated values of Chisholm model are lower by 50% than the experimental data when the quality becomes larger.

关键词：致冷剂流动沸腾压力下降小管

CFD Analysis of Flow Characteristics of Corrugated Louvered Fins at Low Reynolds

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Journal of Shanghai Jiaotong university(Science) 2005年第1期10卷 72-75页

作者：祁照岗陈江平 Inst.of Refrigeration and Cryogenics Shanghai Jiaotong Univ. Shanghai 200030 China

A 2-D laminar flow model was established for CFD analysis of air-flow between louvered fins. Two louvered fins are studied based on commercial software FLUENT. Air-flow pressure drop characteristics are derived on the calculation of Reynolds number from 75.3 to 600. The numerical results are in good agreement with the experimental data when Reynolds is lower.

关键词： CFD 百叶窗翅片流动特性压力下降热交换