Thermal performance analysis on a two composite material honeycomb heat regenerators used for HiTAC burners
Thermal performance analysis on a two composite material honeycomb heat regenerators used for HiTAC burners
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DOI：
10.1016/j.applthermaleng.2005.03.004
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发表时间：
2005-12
影响因子：
6.4
通讯作者：
Nabil Rafidi;W. Blasiak
中科院分区：
文献类型：
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作者：
Nabil Rafidi;W. Blasiak
蜂窝蓄热体不仅可以降低高温空气燃烧（HiTAC）燃烧系统的燃料消耗，而且还可以提供必要的高温燃烧空气。建立了复合材料蜂窝蓄热体内气体和固体蓄热材料的二维动态温度场和速度场的数值模拟模型。在此基础上，计算了蜂窝蓄热体在不同切换次数和不同负荷下的蓄能和压降，评价了蜂窝蓄热体的热工性能。该模型考虑了固体和流动气体在平行于和垂直于流动方向的导热系数。它考虑了固体材料和气体的所有热性质随温度的变化。此外，在分析中考虑了燃烧烟气对储存材料的辐射。结果以无量纲形式呈现，以便也成为设计工具。这些分析应用于由两层陶瓷材料制成的蓄热体，一层是纯氧化铝，另一层是堇青石。该回热器包含在用于HiTAC的100kW双型回热燃烧系统中。在回热器的正常运行范围内，回热器的效率和能量回收率分别为88%和72%，双回热器系统的压降为1.16kPa。在大约11分钟后达到周期性稳态条件，并且仅需要2分钟的操作，直到燃烧空气的温度保持在HiTAC所需的自燃温度以上。此外，这些数学分析表明，在同一回热器上进行的实验很好的协议。在实验中，考虑了回热器操作的动态行为，以补偿这种影响的测量读数。
Honeycomb heat regenerators do not only reduce the fuel consumption in a high temperature air combustion (HiTAC) burning system but also provide the necessary high temperature of combustion air. A two-dimensional simulation model was developed to numerically determine the dynamic temperature and velocity profiles of gases and solid heat-storing materials in a composite material honeycomb regenerator. Consequently, the energy storage and the pressure drop are calculated and the thermal performance of honeycomb heat regenerator is evaluated at different switching times and loading. The model takes into account the thermal conductivity parallel and perpendicular to flow direction of solid and flowing gases. It considers the variation of all thermal properties of solid material and gases with temperature. Moreover, the radiation from combustion flue gases to the storage materials was considered in the analysis. The results are presented in a non-dimensional form in order to be a design tool as well. These analyses were applied on a regenerator made of two layers of ceramic materials, one is pure alumina and other is cordierite. This regenerator is contained in a 100kW twin-type regenerative-burning system used for HiTAC. The effectiveness and the energy recovery rate were 88% and 72% respectively at nominal operating range of the regenerator and the pressure drop across the twin regenerator system was 1.16kPa. The periodic steady state condition is reached after about 11min and it takes only 2min of operation until the temperature of combustion air remains above the self-ignition temperature that is required for HiTAC. Furthermore, these mathematical analyses show good agreement with experiments made on the same regenerator. In the experiments, the dynamic behavior of the heat regenerator operation was considered in order to compensate measurement readings for this effect.