当量比对涡轮叶间燃烧性能影响的数值模拟

为探究涡轮叶间燃烧性能,设计了4种不同当量比的工况,利用 FLUENT 软件的 Realizable k-ε湍流模型、PDF 燃烧模型、DO 辐射模型和离散相模型对燃烧室的流动及燃烧进行数值模拟.结果表明:燃烧室能在广泛的当量比(2.59~0.81)下保持性能稳定,燃烧效率保持在96%以上、总压损失低于2.4%,气体温度提高650,K 左右;降低当量比,能够提高燃烧效率,降低 CO、UHC、NOx 等污染物排放,改善温度分布,但会造成更大的总压损失;最优当量比等于1.00,此时燃烧效率在99.95%以上,总压损失相对低(1.5%),出口径向温度呈抛物线型分布,最适合燃烧室设计.与文献对比发现,选取的工况合理,其结果对涡轮叶间燃烧室设计具有参考价值

Numerical Simulation of Influence of Equivalence Ratio on Turbine Inter-Vane Burner

To investigate the performance of turbine inter-vane burner(TIB),4 loading conditions with different equivalence ratios were designed.The realizable k-ε turbulent model,PDF combustion model,DO radiation model and DPM model of FLUENT were used to simulate the turbulent flow and combustion in the burner.The TIB can increase the gas temperature by about 650,K under a wide range of equivalence ratio(2.59—0.81).The combustion efficiency remains above 96% with the total pressure loss less than 2.4%.As the equivalence ratio gets lower,the combustion efficiency is increased and the pollutant emissions of CO,UHC and NOx are decreased,thus improving the temperature distribution,but meanwhile increasing the total pressure loss.The optimal equivalence ratio equals 1.00,and in such a case,the combustion efficiency is above 99.95% and the total pressure loss is relatively low(1.5%).Meanwhile,a parabolic shape radial temperature profile emerges,which is appropriate for gas turbine engine design.The comparison with literature data shows that the loading conditions are reasonable and the numerical results provide an important reference to the design of TIB.