Design and Performance Analysis of the Multi-Point Lean Spray Combustor

Based on the traditional single-head combustor, two multi-point spray combustors with 3×3 swirl cups are constructed, which are composed respectively of the same swirl directions of nearby swirl cups (called co-swirl) and the inverse swirl directions (called counter-swirl). The characteristics of the traditional single-head combustor and these two new multi-point combustors are calculated and analyzed under cold and combustion conditions. The results indicate that, for multi-point spray combustors, independent recirculation zones are generated downstream of each swirl cup, while an integral recirculation zone is formed in the region downstream of the traditional single-head combustor. The recirculation zones of co-swirl combustor are the clockwise rotation, while those of counter-swirl are close to each other. Meanwhile, the recirculating velocity and the length of the recirculation zones for counter-swirl combustor are larger than those of co-swirl combustor. In combustion conditions, the mixture effect of fuel and air in both multi-point spray combustor is better than that in the traditional one, and the combustion efficiency of fuel is also higher. Then it causes the high temperature in the primary zone which reaches to 2400K, uneven distribution of temperature in the outlet where the difference of temperature between the center and high temperature zone is about 300K, and therefore much more NOx emission over the traditional combustor. Compared with the co-swirl combustor, the residence time of airflow in the counter-swirl increases more significantly, and the NOx emission shares the same increasing trend. In the future research, the fuel/air flow ratio and the structure of combustor should be ameliorated.