Design and Airflow Distribution Characteristics of a Louver-Type Pulverized Coal Distributor Integrated into a Swirl-Straight Flow Synergistic Combustion Stabilization System
With the increasing proportion of renewable energy generation, the demand for deep peak-shaving operation of coal-fired power units has been continuously intensified. Under low-load conditions, combustion stability issues caused by reduced pulverized coal feed, decreased furnace heat load, and lowered pulverized coal concentration have become increasingly prominent. Unlike conventional louver-type pulverized coal concentration separators, a pulverized coal distributor was coupled with a swirl-straight flow synergistic combustion stabilization system in this study. By regulating the air extraction ratio on the swirl side, the directional redistribution of the primary air-pulverized coal flow was achieved, thereby providing favorable aerodynamic conditions for the formation of a stable ignition zone under low-load operation. A combination of numerical simulation and cold-state experimental modeling was employed to investigate the internal flow characteristics, airflow distribution behavior, and pressure loss characteristics of the louver-type pulverized coal distributor. The results show that the louver blade structure can effectively alter the flow direction of the primary airflow, allowing a portion of the airflow to enter the swirl-side passage and achieving primary airflow redistribution. The inlet height of the swirl-side passage has a significant influence on the airflow distribution ratio, whereas the gradually expanding or contracting structures have a relatively limited effect on the pressure loss characteristics of the distributor. Considering the swirl-side airflow ratio, outlet velocity matching, and pressure loss characteristics comprehensively, when the swirl-side inlet height is set to 137 mm, the airflow entering the swirl side accounts for 15.17% of the total airflow, the velocity ratio between the two outlets is 1.03, and the overall pressure loss coefficient is 0.853. Although the pressure loss of this structure is slightly higher than that of some cases with lower inlet heights, it can satisfy the airflow supply requirement of the swirl side and achieve better outlet jet matching performance. Therefore, it is selected as the recommended structure. The results indicate that this structure can provide a reasonable primary airflow organization basis for the subsequent swirl-straight flow synergistic combustion system. However, the effects on pulverized coal concentration distribution and combustion stability improvement still require further verification through pulverized coal concentration measurements and combustion experiments. The
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