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在冷却塔内气流流场特性试验分析的基础上,针对淮北国安电力有限公司2号机冷却塔存在的增容后循环水冷却不够、冷却塔内水流不均的问题,实施了增容改造方案,重新布置了配水系统和淋水装置。淋水区填料采取不等高布置,且不同区域采用不同出水口径达到不同的淋水密度,使配水、配风更趋合理均匀。改造后的应用效果表明,冷却塔的冷却效率大为提高,满足了机组增容改造要求且节能降耗明显。 相似文献
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本文对某高层建筑屋面冷却塔在节能改造后所出现的夏季极端天气无法达到设计冷却能力的状况通过改造工程进行分析,并采用Airpak软件对夏季工况进行了CFD模拟。模拟结果所显示的逆流式冷却塔四周的梁、柱、擦窗机轨道、和核心筒外墙等建筑遮挡物并未对冷却塔散热效果造成影响。夏季屋面风速的变化,未影响冷却塔进风与排风,未出现热湿空气回流现象,间接反映了设备布置合理。此项目对同类型的建筑物屋面放置冷却塔有一定的参考意义。 相似文献
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建立300 MW火电机组实验模型,研究弧形挡板对冷却塔性能的影响,获得最佳弧形挡板布置方式,并对各因素进行回归分析,找出冷却塔高效运行的工况范围。研究表明:存在临界风速vcr,当风速小于该值,随风速增大冷却性能逐渐降低;当风速大于该值,随风速增大冷却性能逐渐提高;弧形挡板可有效减弱环境侧风对冷却性能的不利影响,挡板安装角在45°~75°范围内冷却温差和效率相较于无侧风无弧形挡板都有不同程度的提高;进塔水温(28~38℃)越高时,冷却塔效率越高。 相似文献
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M. P. Maiya 《国际能源研究杂志》1996,20(6):465-481
A single-storey office building in a hot and dry climate is modelled for evaporative cooling. The counterflow cooling tower is modified to precool the tower inlet air by the tower exit air in a heat exchanger. Centralized evaporative air cooling, using the modified cooling tower, and roof evaporative cooling are considered to provide comfortable living conditions in the space. The thermal performance of such a building is analysed for various operating parameters. The study indicates that centralized evaporative air cooling is feasible, to maintain near-perfect comfort conditions in hot and dry climates. Modified cooling tower and roof evaporative cooling further enhance the scope of evaporative cooling for comfort applications. 相似文献
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Simplified analytical models are developed for evaluating the thermal performance of closed‐wet cooling towers (CWCTs) for use with chilled ceilings in cooling of buildings. Two methods of simplification are used with regard to the temperature of spray water inside the tower. The results obtained from these models for a prototype cooling tower are very close to experimental measurements. The thermal performance of the cooling tower is evaluated under nominal conditions. The results show that the maximum difference in the calculated cooling water heat or air sensible heat between the two simplified methods and a general computational model is less than 3%. The analytical model distribution of the sensible heat along the tower is then incorporated with computational fluid dynamics (CFD) to assess the thermal performance of the tower. It is found that CFD results agree well with the analytical results when the air flow is simulated with air supply from the bottom of the tower, which represents a uniform air flow. CFD shows the importance of the uniform distribution of air and spray water to achieve optimum design. Copyright © 2002 John Wiley & Sons, Ltd. 相似文献
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An analytical model was developed to describe thermodynamically the water evaporation process inside a counter‐flow wet cooling tower, where the air stream is in direct contact with the falling water, based on the implementation of the energy and mass balance between air and water stream describing thus, the rate of change of air temperature, humidity ratio, water temperature and evaporated water mass along tower height. The reliability of model predictions was ensured by comparisons made with pertinent experimental data, which were obtained from the literature. The paper elaborated the effect of atmospheric conditions, water mass flow rate and water inlet temperature on the variation of the thermodynamic properties of moist air inside the cooling tower and on its thermal performance characteristics. The analysis of the theoretical results revealed that the thermal performance of the cooling tower is sensitive to the degree of saturation of inlet air. Hence, the cooling capacity of the cooling tower increases with decreasing inlet air wet bulb temperature whereas the overall water temperature fall is curtailed with increasing water to air mass ratio. The change of inlet water temperature does not affect seriously the thermal behaviour of the cooling tower. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
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为了分析不同风量和喷淋水量对填料逆流闭式冷却塔热力性能的影响,建立和验证了带填料逆流闭式冷却塔热质交换的数学模型,基于焓差理论对模型计算的结果进行分析。结果表明:加入填料相当于对盘管区进口的喷淋水进行预冷,降低了喷淋水的平均温度,使带填料闭式冷却塔的冷却性能优于纯盘管闭式冷却塔;风量的增加可以提高带填料逆流闭式冷却塔和纯盘管逆流闭式冷却塔的热力性能,两种塔的冷却性能随风量增加的提升速率相同;喷淋水量的增加对纯盘管逆流闭式冷却塔的热力性能的影响较小,却可以较大幅度提高带填料逆流闭式冷却塔的热力性能。 相似文献
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用空冷器代替冷却塔的技术经济性分析 总被引:5,自引:0,他引:5
本文就电厂中用空冷器代替冷却塔的可行性进行了分析。以给定工况下的电厂为例 ,分别计算了采用冷却塔和空冷器两种系统下的设备费用和运行费用 ,分析了变工况下空冷器的经济性能。通过分析看出 ,若当地气温在 5℃左右 ,风速维持在 2 4m/s时 ,空冷器可以省去风机 ,而且能耗和费用将降低 ,经济性能将优于冷却塔方式。对于一个 1 5 0 0kW的发电机组 ,每年可节约循环水 7 395万t。空冷器同样适用于石化等行业的冷却水循环系统。因此 ,在气候条件适合的北方地区 ,采用空冷器是节水的有效途径。 相似文献
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This study attempts to quantify the potential improvement in a natural draft wet cooling tower (NDWCT) performance that can be attained by optimizing the fill and water distribution profiles across the tower and to provide designers with the modelling tools for such an investigation. A simple two‐dimensional (2D) model is described, which allows rapid evaluation of NDWCT performance for use with an optimization procedure. This model has been coupled with an evolutionary optimization algorithm to determine the optimal fill shape and water distribution profile to maximize the cooling range of a typical NDWCT. The results are compared against a 2D axisymmetric numerical model. The extended 1D model is found to significantly reduce computational time compared with the numerical model, allowing a wide range of parameters to be tested rapidly with reasonable accuracy. The results show that the optimal layout differs significantly from a uniform profile, with both the water flow rate and the fill depth decreasing towards the centre of the tower where the air is warmer with reduced cooling potential. The overall improvement in the tower cooling range is very low under the design conditions tested, due largely to the highly coupled nature of the airflow and heat transfer in the tower. It is concluded that any design modifications of the type considered would need to be carefully optimized to have any possibility of improving performance. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献