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991.
A method for evaluating and predicting the performance of a newly developed plate‐type heat exchanger as an evaporator for water‐refrigerant systems such as chillers has been developed. The main component of the developed heat exchanger consists of plates packed together in a casing with winding tubes connected to both sides of the plates. Refrigerant flows inside the tubes, and water flows in the space between the plates. A herringbone‐like pattern is formed in this space by the cross sections of the winding tubes. The newly developed method estimates evaporation performance of the developed heat exchanger using new empirical correlations. There are correlations for heat transfer and pressure drop in winding‐tube banks on the water side, and correlation for the pressure drop on the refrigerant side. © 2004 Wiley Periodicals, Inc. Heat Trans Asian Res, 33(4): 245–257, 2004; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20009 相似文献
992.
A mathematical model for predicting evaporation in the thin film region was developed and its analytical solutions were obtained for thin‐film thickness, the heat transport per unit length and the total heat flux transport in the thin‐film region. These analytical solutions show that the higher heat flux through the thin film region occurs due to the higher superheat. The maximum evaporative rate occurs when the effects of the increase in the temperature difference and in the thin film thickness on the heat flux q stay equal. A nanofluid, which is a colloidal mixture of nanoparticles (1 nm to 100 nm) and a base liquid (nanoparticle fluid suspensions), is employed as the working fluid. In a certain range, increasing the volume fraction of nanoparticles in the base fluid leads to decreasing the kinematic viscosity of the nanofluid and increasing the thermal conductivity, which influences the evaporation in the thin film region. The heat transfer rate per unit length and the total heat flux in the thin film region display various characteristics among the different type of nanofluids due to the differences of the kinematic viscosity and the thermal conductivity. 相似文献
993.
优质氧化锌透明导电膜 总被引:1,自引:0,他引:1
报道了采用反应电子束蒸发技术制备优质氧化锌透明导电膜的工艺和结果。典型的结果:电阻率低达2×10-4Ω.cm,霍尔电子迁移率为52cm2(Vs)-1,厚4000×10-10m膜的方块电阻为8.9Ω/□,可见光透过率大于90%。分析了源掺杂、镀膜气氛、衬底温度等参数与膜的电导和透光特性的关系。 相似文献
994.
Macroscopic ZnO nanocombs and nanobelts have been synthesized by thermal evaporation with the catalyst of CuO. The lengths of these nanostructures range from several millimeters to more than one centimeter. The longest one is even beyond 2 cm. It was demonstrated that the nanostructures were affected by the proportion of the reaction mixture, the reaction source and the growth temperature. Our experimental results indicated that CuO plays an important role in the growth of macroscopic nanocombs and nanobelts. Furthermore, a possible growth mechanism of macroscopic nanocombs and nanobelts has been proposed. 相似文献
995.
Muhammad Riaz Nasir Abbas Ronald J. M. M. Does 《Quality and Reliability Engineering International》2011,27(4):415-424
The control chart is an important statistical technique that is used to monitor the quality of a process. Shewhart control charts are used to detect larger disturbances in the process parameters, whereas CUSUM and EWMA charts are meant for smaller and moderate changes. Runs rules schemes are generally used to enhance the performance of Shewhart control charts. In this study, we propose two runs rules schemes for the CUSUM charts. The performance of these two schemes is compared with the usual CUSUM, the weighted CUSUM, the fast initial response CUSUM and the usual EWMA schemes. The comparisons revealed that the proposed schemes perform better for small and moderate shifts, whereas they reasonably maintain their efficiency for large shifts as well. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
996.
997.
通过介绍喷雾降温蒸发冷却技术,指出国内首次将喷雾降温蒸发冷却技术大量应用在室外无建筑为依托的广场,实施了对室外空气进行等焓、降温、加湿处理;对比分析了西安和上海的典型气象年逐时参数,提出喷雾降温蒸发冷却技术在中等湿度地区、干燥地区会比高等湿度地区有较大应用前景和价值。 相似文献
998.
999.
针对葡西油田原油性质差异较大的特点,对油气藏类型进行了判断,并在确定为凝析气藏的基础上,通过开展油源对比:油气运聚史及断层发育史等研究工作,揭示了葡西油田葡萄花油层凝析气藏分布规律以及地质成因,并预测了储量规模,为确定油藏的开发方式及油田的大面积开发奠定基础。 相似文献
1000.