Study on a High-efficiency Combustor using Rotary Heat-strage Regenerator

对旋转蓄热式高效燃烧器的特性进行了研究。燃烧器由热交换器(蓄热器)和燃烧室组成。回热器是由陶瓷蜂窝制成的旋转式蓄热式换热器。再生器的出口作为燃烧器的出口，靠近蜂窝表面形成一维火焰。燃烧的气体通过蓄热室流出，废热储存在陶瓷通道壁中，进而预热城市燃气和空气的入口混合物。测量了燃烧室内的温度分布和气体浓度。对不同的燃空比进行了实验，发现0.2&lt；F&lt；6可以稳定燃烧，其中F表示入口预混气体的化学计量比，而传统的可燃范围为0.5&lt；F&lt；1.8。回热器对尾气的回热效率约为90%，与数值分析结果吻合较好。预热的未燃烧气体的温度高于燃烧气体的温度，这表明火焰对蜂窝芯体的加热是显著的。在贫油可燃极限附近测得的火焰温度明显高于通常的绝热火焰温度，表明蓄热式换热成功地扩大了可燃范围。NOx浓度在F=1.3时有一个最大值8ppm，在F&lt；0.7和F&gt；1.5时降到1ppm以下。对蓄热室内的换热、蜂窝芯体表面的辐射换热等各种换热过程进行了定量计算，建立了适用于现有燃烧室的预测方法。此外，在燃烧室壁上安装了热电组件，并提取了与组件性能相对应的电能。

Characteristics of a high-efficiency burner using a rotary regenerator have been investigated. The burner consists of a heat exchanger (regenerator) and a combustion chamber. The regenerator is a rotary heat-storage-type heat exchanger made by a ceramic honeycomb. The exit port of the regenerator is used as the burner port, and one-dimensional flame is formed close to the honeycomb surface. The burned gas flows out through the regenerator, and the exhaust heat is stored in the ceramics channel wall, which in turn preheats the inlet mixture of city gas and air. The temperature distribution and gas concentration in the combustor were measured. Experiments were made for various fuel-air ratios, and it was found that stable combustion is possible for 0.2<F<6, where F denotes the stoichiometric ratio of the inlet premixed gas, in contrast to the conventional flammable range of 0.5<F<1.8. The effectiveness of the regenerator for the heat reconvery from the exhaust gas was about 90%, which coincides well with the result of a numerical analysis. The temperature of the preheated unburned gas was higher than that of burned gas, which indicates that the heating of honeycomb core by the flame is significant. The measured flame temperature near the fuel-lean flammable limit was significantrly higher than the usual adiabatic flame temperature, which shows that the regenerative heat exchange successfully enlarges the flammable range. The NOx concentration has a maximum value, 8ppm, at F=1.3, and decreases below 1ppm for F<0.7 and F>1.5. Various heat transfer processes, such as the heat exchange in the regenerator, radiative heat transfer from the surface of honeycomb core, etc., were evaluated quantitatively to construct a predictive method for the present combustor. In addition, a thermo-electric module was attached to the combustor wall, and a electric power corresponding to the module performance was extracted.