火箭推进

波瓣混流器是一种典型的燃烧室气体混合装置,某预冷组合发动机燃烧室采用了波瓣混流器进行氢气/空气的掺混组织。为了获得不同波瓣混流器修型结构对氢气/空气的掺混性能的影响,分别采用导流结构和锯齿尾缘对波瓣混流器进行修型。通过开展数值仿真和对热混合效率公式的修正,从流场速度分布、流向涡和正交涡以及性能参数方面进行了掺混特性的对比分析。结果表明:导流结构对流场中回流区的分布具有显著影响,导流结构的平面面积越大,回流区范围越大; 回流区范围增大会增加初始位置的内外涵速度差2.4倍到6倍,减小平均流向涡强度,增大平均正交涡强度,进而影响热混合效率,其中圆形导流结构在流动初期提高3%,后期降低5.9%; 锯齿尾缘修型降低了热混合效率,其中三角形修型结构降低约2.8%,较其他结构最明显。

Lobe mixer is a typical combustion chamber gas mixing device. A precooling combined engine combustion chamber adopts lobe mixer to mix hydrogen and air. In order to obtain the influence of different modified structures on the hydrogen-air mixing performance of the lobe mixer,based on the hydrogen fuel combustor of a precooled combined engine,the guide structure and sawtooth trailing edge were used to modify the lobe mixer. By carrying out numerical simulation and revising the thermal mixing efficiency formula,a comparative analysis was carried out from the aspects of the velocity distribution of the flow field,the streamwise vortex,the normal vortex,and the performance parameters.The results are as follows:1)The guide structure has an important influence on the distribution of the recirculation zone in the flow field, and the larger the plane area of the guide structure,the larger the recirculation zone; 2)The increase of the recirculation zone would increase the velocity difference between the inner and outer culverts at the initial position by up to 6 times,reduced the average streamwise vorticities,increased the average normal vorticities and then affected the mixing performance,which of the circular guide structure increased by 3% at the initial stage and decreased by 5.9% at the later stage of flow. 3)The sawtooth trailing edge modified structure reduced the thermal mixing efficiency which of the triangular modified structure reduced by about 2.8%,which was the most obvious than other structures.

引言
1 数值计算方法
2 流场影响分析
3 性能影响分析
4 结论

图1 波瓣混合器中的各种涡<br/>Fig.1 Various vortices in lobed mixer

图1 波瓣混合器中的各种涡
Fig.1 Various vortices in lobed mixer

图2 导流结构及锯齿尾缘结构示意图<br/>Fig.2 Schematic of guide structure and sawtooth trailing edge

图2 导流结构及锯齿尾缘结构示意图
Fig.2 Schematic of guide structure and sawtooth trailing edge

图3 波瓣混流器结构示意图<br/>Fig.3 Schematic of lobe mixer

图3 波瓣混流器结构示意图
Fig.3 Schematic of lobe mixer

表1 入口边界条件<br/>Tab.1 Inlet boundary conditions

表1 入口边界条件
Tab.1 Inlet boundary conditions

图4 计算域网格示意图<br/>Fig.4 Schematic of computing domain mesh

图4 计算域网格示意图
Fig.4 Schematic of computing domain mesh

图5 流向沿程的总压变化<br/>Fig.5 Variation of total pressure with downstream distance

图5 流向沿程的总压变化
Fig.5 Variation of total pressure with downstream distance

图6 对称截面速度等值线图及流线分布<br/>Fig.6 Velocity contour and streamline distribution of symmetrical plane

图6 对称截面速度等值线图及流线分布
Fig.6 Velocity contour and streamline distribution of symmetrical plane

图7 流向不同位置的轴向速度等值线图<br/>Fig.7 Axial velocity contour of flow to different planes

图7 流向不同位置的轴向速度等值线图
Fig.7 Axial velocity contour of flow to different planes

图8 流向不同位置的无量纲流向涡强度等值线图<br/>Fig.8 Non-dimensional streamwise vorticity contour of flow to different planes

图8 流向不同位置的无量纲流向涡强度等值线图
Fig.8 Non-dimensional streamwise vorticity contour of flow to different planes

图9 流向沿程的平均无量纲流向涡绝对值强度<br/>Fig.9 Variation of average non-dimensional absolute streamwise vorticities with downstream distance

图9 流向沿程的平均无量纲流向涡绝对值强度
Fig.9 Variation of average non-dimensional absolute streamwise vorticities with downstream distance

图10 流向沿程不同位置的无量纲正交涡强度等值线图<br/>Fig.10 Non-dimensional normal vorticity contour of flow to different planes

图10 流向沿程不同位置的无量纲正交涡强度等值线图
Fig.10 Non-dimensional normal vorticity contour of flow to different planes

图11 流向沿程的平均无量纲正交涡强度<br/>Fig.11 Variation of average non-dimensional normal vorticities with downstream distance

图11 流向沿程的平均无量纲正交涡强度
Fig.11 Variation of average non-dimensional normal vorticities with downstream distance

图12 热混合效率公式对比<br/>Fig.12 Comparison of thermal mixing efficiency formulas

图12 热混合效率公式对比
Fig.12 Comparison of thermal mixing efficiency formulas

图13 流向沿程的热混合效率<br/>Fig.13 Variation of thermal mixing efficiency with downstream distance

图13 流向沿程的热混合效率
Fig.13 Variation of thermal mixing efficiency with downstream distance

图14 流向沿程的总压恢复系数<br/>Fig.14 Variation of total pressure recovery coefficient with downstream distance

图14 流向沿程的总压恢复系数
Fig.14 Variation of total pressure recovery coefficient with downstream distance

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备注

引言

1 数值计算方法

2 流场影响分析

3 性能影响分析

4 结论

期刊信息