Experimental and numerical study on slag deposition in solid rocket motor

Wang, Junlong; Wang, Ningfei; Zou, Xiangrui; Dong, Wei; Wang, Chao; Le, H. Q.; Shi, Baolu

doi:10.1016/j.ast.2022.107404

Cited by 21 publications

(8 citation statements)

References 48 publications

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“…During the agglomeration process of aluminum particles, micron-sized aluminum particles first vaporize and evaporate into aluminum vapor under the heating of the diffusion flame, which then reacts with oxygen in the environment. Some of the oxidized products of aluminum vapor condense on the surface of aluminum droplets to form oxide cap structures, while the rest of the aluminum vapor condenses directly in the environment to form submicron or even nanoscale aluminum oxide particles [35] [36].…”

Section: Analysis Of the Microscopic Morphology Of Ccpsmentioning

confidence: 99%

Effect of Al and AP particle sizes on the condensed combustion products characteristics of aluminized NEPE propellants

2024

Preprint

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Aluminum (Al) is usually added to solid propellants to improve the combustion performance, however the condensed combustion products (CCPs) especially the large agglomerates generated from aluminum combustion can reduce the specific impulse of the engine, and result in two-phase loss, residue accumulation and throat liner ablation. Al and AP, as important components of NEPE propellants, can affect the formation process of the CCPs of aluminized NEPE propellants. To clarify the effect of Al and AP particle sizes on the properties of the CCPs of aluminized NEPE propellants, a constant-pressure quench vessel was adopted to collect the combustion products of four different formulations of NEPE propellants. It was found that the condensed combustion products are mainly divided into aluminum agglomerates and oxide particles, the diameter of the aluminum agglomerates of these four different formulations of NEPE propellants at 7MPa was smaller than that in 3MPa, and the shells of the aluminum agglomerates were smoother and the spherical shape was more perfect. X-ray diffraction analysis of the CCPs of the four NEPE propellants under 3MPa revealed the presence of both Al and Al2O3. With the increase of the particle size of Al and AP, the oxidation degree of aluminum particles decreases. The particle size of the CCPs of the four different formulations of NEPE propellants under 1MPa and 3MPa was analyzed by using a laser particle size analyzer, it is found that the increase of AP particle size is helpful to reduce the size of condensate combustion products. Based on the classical pocket theory, establishing a new agglomeration size prediction model, which can be used to predict the agglomeration size on the burning surface. Compared with the empirical model, the new agglomeration size prediction model is in good agreement with the experimental results.

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Section: Analysis Of the Microscopic Morphology Of Ccpsmentioning

confidence: 99%

Effect of Al and AP particle sizes on the condensed combustion products characteristics of aluminized NEPE propellants

2024

Preprint

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“…The aluminum particles start to vaporize and evaporate to form gas-phase aluminum vapor, and then react with oxygen. The other part is directly condensed in the environment to form sub-micron or even nano-scale "alumina smoke" [14][15]. The surface of the smoke oxide particles is analyzed by using EDS, the content of the composition is shown in Table 2.…”

Section: Smoke Oxide Particlesmentioning

confidence: 99%

Research on aluminum agglomeration characteristics of Al/NEPE propellant

Chengyin,

Xiong,

Yuqian

et al. 2023

J. Phys.: Conf. Ser.

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Adding aluminum particles to solid propellants is used to improve the energy density of the propellant and the specific impulse of the engine. However, the aluminum particles will agglomerate to form large-sized condensed combustion products, which can cause nozzle erosion and two-phase flow loss. Therefore, it is necessary to study the aluminum agglomeration characteristics of solid propellants. In this paper, the combustion process of the Al/NEPE propellant was recorded by a high speed camera and a fiber optic spectrometer, and the condensed combustion products of the propellant were collected. The microstructure of the condensed combustion products was analyzed by a scanning electron microscope coupled with energy dispersive (SEM-EDS). These results show that the agglomeration process of aluminum particles may go through three stages: accumulation, aggregation and agglomeration. The condensed combustion products are mainly divided into aluminum agglomerates and smoke oxide particles. Generally, the size of agglomerates exceeds 50 μm, while the size of smoke oxide particles is less than 1 μm.

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“…In the interstage thermal separation process, the key features of the flow field are the formation of unstable wave system structures in the interstage region by the upperstage engine jet, the interference flow of the lateral jet in the interstage gap, the external supersonic incoming flow, and the severe aerothermal environment instigated by these elements. When separation occurs at a lower altitude, the interaction between the exhaust plume and free stream causes lateral interference, leading to potential aerodynamic issues, such as diminished stability, localized overheating, and reduced control effectiveness [9][10][11][12]. These circumstances trigger substantial shifts in the rocket's attitude, impacting the safety and flight stability of the interstage separation.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study on the Influence of Separation Time Sequence on the Initial Thermal Separation

Ma,

Wang,

2024

Energies

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The process of separating stages is crucial for multistage rockets, directly influencing the success of the launch plan. Different separation timing methods alter the flow field structure within the interlevel zone at separation, influencing the separation of the two-stage rockets. This paper employs the SST k-ω turbulence model to investigate the structure of the flow field and its aerodynamic and motion characteristics under different nozzle baffle opening and separation times, taking into account variable properties, supersonic compressibility, and the upstream–downstream interference. First, we examined the standard flow field structure, considering the engine jet, the lateral jet between stages, and the disturbance from the external supersonic inflow. Then, we discussed the displacement characteristics and axial force coefficient curves of the first and second steps of the separation process. Finally, we explored the impact of baffle opening and separation times on the flow field structure and axial force coefficients of the two stages at the onset of separation. For the flow field structure, a delay in the baffle opening and separation moment led to a gradual increase in downstream and separation regions until they stabilized after a certain range. However, the axial force coefficients displayed different behavior before and after the design point.

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Experimental and numerical study on slag deposition in solid rocket motor

Cited by 21 publications

References 48 publications

Effect of Al and AP particle sizes on the condensed combustion products characteristics of aluminized NEPE propellants

Effect of Al and AP particle sizes on the condensed combustion products characteristics of aluminized NEPE propellants

Research on aluminum agglomeration characteristics of Al/NEPE propellant

Numerical Study on the Influence of Separation Time Sequence on the Initial Thermal Separation

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