排序方式: 共有9条查询结果,搜索用时 31 毫秒
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将燃烧器下层一次风咳喘改成谈、稀相燃烧,降低了助燃油耗量和飞灰可燃物含量,用鳍片管式省煤器替换原光管式省煤器,降低了排烟温度并改善了管壁磨损,两项改造后取得发电量增加,锅炉热效率提高1%的效果。 相似文献
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Experimental study on heat and mass transfer characteristics of louvered fin-tube heat exchangers under wet condition 总被引:1,自引:0,他引:1
Thanh-Long PhanKeun Sun Chang Young Chul Kwon Jeong-Tae Kwon 《International Communications in Heat and Mass Transfer》2011,38(7):893-899
An experimental study was conducted to investigate the effect of a tube row, a fin pitch and an inlet humidity on air-side heat and mass transfer performance of louvered fin-tube heat exchangers under wet condition. Experimental conditions were varied by three fin pitches, two rows, and two inlet relative humidities. From the experimental results, it was found that the heat transfer performance decreased and the friction increased with the decrease of a fin pitch, for 2 row heat exchanger. The effect of a fin pitch on heat transfer performance was negligible with 3 row heat exchanger. The change in a relative humidity was not affected heat transfer and friction. However, the mass transfer performance was slightly decreased with the increase of a relative humidity and with the decrease of a fin pitch. The mass transfer performance decreased with the decrease of a fin pitch. The mass transfer performance of the louvered fin-and-tube heat exchanger was different according to the number of a tube row. 相似文献
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Desiccant coated heat exchanger provides a promising option for desiccant cooling system, since it can handle sensible load and latent load simultaneously within one component. It is fabricated by coating desiccant material on the surface of conventional fin-tube heat exchanger. In order to enhance the performance of conventional silica gel coated heat exchanger (SGCHE), a novel composite silica gel coated heat exchanger (CCHE) is proposed and fabricated. An experimental setup is built to test and compare the dynamic performance of SGCHE and CCHE. Influences of main operation parameters including water temperatures and inlet air conditions on system performance are analyzed in terms of average dehumidification capacity (Davg) and thermal coefficient of performance (COPth). Optimization of cycle switch modes is also discussed. Experimental results show that CCHE has better dehumidification performance compared with SGCHE. In addition, pre-cooling before dehumidification process is found to be advantageous to both Davg and COPth. 相似文献
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强化翅片管式换热器换热性能的方法及应用 总被引:3,自引:0,他引:3
通过两种不同的方法改进应用在不同场合的翅片管式换热器的结构,进而提高其换热性能:一种是将低温工况下易结霜的换热器设计成变翅片间距,一种是将空调工况下的换热器设计成变螺距内螺纹管.通过热力计算及实际系统使用,得出传热系数分别提高了9.8%和3.82%. 相似文献
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《International Journal of Hydrogen Energy》2022,47(3):1820-1832
Heat management is crucial to the stable and high-efficiency operation of proton exchange membrane fuel cell (PEMFC) system. However, fin-tube heat exchangers (FTHE) of traditional internal combustion engine vehicles require further optimizations to be applicable to PEMFC vehicles. In the paper, a three-dimensional steady-state radiator model is developed in OpenFOAM to investigate three novel structural designs based on wavy-louvred (WL) fin and vortex generators (VGs). The established model has been carefully validated against experimental data and correlation reference. To comprehensively evaluate radiator performances, the air side heat transfer coefficient, pressure drop, outlet air temperature, heat flux, and JF factor are adopted. It is found that the FTHE with L-VGs has the highest heat transfer coefficient while the FTHE with WL-VGs has the highest pressure drop. The temperature, velocity, and pressure distribution are further demonstrated to reveal performance enhancement mechanisms. It is seen that the heat exchangers with additional VGs produce two sections of high-temperature wakes near the wall, which not only promotes the heat convection but also contributes to the heat exchange in the nearby area. Meanwhile, a low-speed vortex zone behind VGs appears and generates longitude vortex, making the air stream stay longer at fin surfaces. The air flow in FTHE with WL is not as much separated as the conventional FTHE since the zigzag wavy louver restricts flow separation. The paper gives valuable suggestions for cooling capability improvement and radiator volume diminution. 相似文献
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水-空气翅片管换热器变工况、变结构特性模型分析 总被引:1,自引:0,他引:1
翅片管换热器变工况、变结构特性,是指其性能不仅受到工况参数的影响,而且也随结构参数的改变而变化的特性.因此,为深入研究此换热器特性,建立了相关的分析模型.当任一工况或结构参数在其最大可变范围内变化时,该模型可分析预测翅片管换热器相应的性能变化规律.利用实验数据对模型计算结果进行了对比验证:干工况下,模型计算所得的各性能参数值与实测值吻合良好,其平均相对误差均小于6%;湿工况下,计算值与实验值的平均相对误差也在20%内,且其变化趋势一致,从而证明了模型的正确性及有效性.分析模拟所得的变工况、变结构特性,不仅有利于优化产品的结构设计,可辅助换热器的选型,而且还为换热器运行调节方法的选取提供了依据. 相似文献
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