通过数值模拟研究了长径比（ L/D）和偏径比（ S/D）对双 S形二元喷管性能的影响，基于轴对称喷管，建立了长径比分别为 2、2.5、3和偏径比分别为 0.493、0.523、0.553的双 S形二元喷管。结果表明：长径比越大推力越大，偏径比越大推力越小；相比基准轴对称喷管,长径比分别为 2、2.5、3的双 S形二元喷管推力分别下降了 6.31%、3.15%、1.24%，偏径比分别为 0.493、0.523、0.553的双 S形二元喷管推力分别下降了 3.15%、3.66%、4.17%；所有双 S形二元喷管红外辐射强度相对基准轴对称喷管均有明显下降，在喷管出口正后方降幅均达到 97%以上，全方位角降幅最小值均在 30％以上；所有双 S形二元喷管红外辐射强度空间分布规律基本相似，幅值差异在 15.8%之内。

The influence of length-diameter ratios(L/D) and offset-diameter ratios(S/D) on the performance of a serpentine 2-D nozzle was simulated numerically. Based on an axisymmetric nozzle, two groups of serpentine 2-D nozzles were designed. One had various L/D of 2,2.5, and 3, while the other had various S/D of 0.493, 0.523, and 0.553.The results show that thrust rises as L/D increases, whereas it decreases as S/D increases. In comparison to the axisymmetric nozzle, thrusts of the serpentine 2-D nozzle with L/D of 2, 2.5, 3 and S/D of 0.493, 0.523, 0.553 are reduced by 6.31%, 3.15%, 1.24%, 3.15%, 3.66%, and 4.17%, respectively. The integral infrared radiation intensity of all these serpentine 2-D nozzles is significantly lower than the axisymmetric nozzle, and it is reduced at least by 97% in the direction right behind the exit of the nozzle, while it is reduced by at least 30% in all other directions. All above-mentioned serpentine 2-D nozzles have a similar spatial distribution, and the maximum deviation among them is maintained within 15.8%.