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《International Journal of Hydrogen Energy》2019,44(11):5564-5572
With the steam obtained by the energy released from ventilation air methane oxidation, the hydrogen production through gasification method is considered more commercial. In order to constrain the steam parameter fluctuation, the shunt honeycomb ceramics are adopted to fill between the heat exchange tubes. However, transient heat transfer characteristics of this kind of heat exchanger have not been fully studied. This paper carried out a numerical simulation study on the transient heat transfer characteristics of H finned tube under periodic reverse-flow conditions. Results show that the existence of shunt honeycomb ceramics enhances the effect of radiation. Gas flow direction reversing destructs the original boundary layer, achieving a sudden rise of the convective heat flux in the new upstream. It takes about 12s to form a new relative stable boundary layer. The apparent heat transfer coefficient achieves a maximum of 108.77 W m−2 K−1 and an average of 99.1 W m−2 K−1. 相似文献
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利用驻点方程和周向相似确定头部边值分布,提出一种宜于工程应用的头部简化处理方法,计算了椭球体有攻角绕流的三维层流边界层流场及三维边界层纵向分离和周向回流.计算结果与实验结果吻合良好. 相似文献
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为了减少大气中VOC排放,利用了一种周期性改变流向的催化燃烧反应器——可逆式催化燃烧器进行了模拟实验,对其性能进行了系统的研究,得到了各种热波波形曲线并对影响热波特性的主要因素进行了分析,结果表明,凡是影响一个周期内反应器热平衡的操作参数都有可能显著地影响反应段的温度水平,为这一类反应器的科学设计、优化操作和模型化研究奠定了实验基础。 相似文献
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本文论述了酒钢200万高炉鼓风机计算机自动控制系统的工艺及其构成和实现的主要功能,对轴流压缩机喘振与静叶角度的关系、防喘振调节及逆流保护进行了重点介绍。 相似文献
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《International Journal of Hydrogen Energy》2020,45(39):20458-20464
Shunt honeycomb ceramics (SHC) are proposed to constrain operation parameter fluctuation within commercial hydrogen production through gasification method with the steam produced with ventilation air methane oxidation heat. However, the effect of SHC thickness on heat extraction trait was ignored in the former studies. An improved numerical simulation was carried out to study the effect of SHC thickness. Results show that the existence of SHC increases pressure drop is increased by 23.5%, decrease the temperature difference between inlet and outlet, increases average heat flux may be increased by 7.4%. Radiation heat transfer accounts for 0.2374–0.3398 of total heat exchange, and as the SHC thickness grows, radiation heat transfer increases gradually. 相似文献
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High inlet solid loading is one of the most important features of cyclone separators in high density circulating fluidized beds (CFB). In this work, the effect of high solid loading on pressure drop in a reverse-flow cyclone was experimentally studied. The particles used were sand and γ-Al2O3. An extended range of inlet solid loadings (M), up to 30 kg of solids/ kg of air was tested at different inlet air velocities (V in=16∼24 m/s), well beyond the solid loading range reported before. The experiments showed that, in the tested range of solid loadings, the cyclone pressure drop decreased dramatically with increasing solid loading when M<7.5 kg/kg and then almost remained constant. A new semi-empirical model for predicting cyclone pressure drop was also developed. The calculated and experimental results showed good agreement for particle free flow and particle laden flow. 相似文献
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