Experimental Study on Combustion of Aluminum in Composite Propellant

Liu, Xin; Liu, Peijin; Jin, Bingning

doi:10.2514/6.2015-3977

Cited by 6 publications

(7 citation statements)

References 13 publications

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“…During the velocity measurements, we were able to observe that some agglomerates move along the burning surface during their formation and evolution, prior to their separation. This phenomenon also was observed by Liu et al 34 Figure 10 illustrates this phenomenon. The dotted yellow circle marks the zone where an aluminum agglomerate is formed.…”

Section: 12supporting

confidence: 80%

“…Higher combustor pressures yield increased velocities for all particles sizes. Liu et al 34 also noted this behavior when they studied the dynamic combustion process of aluminum particles in an AP composite propellant using optical methods. Their results are presented in Figure 9.…”

Section: 12mentioning

confidence: 83%

“…Flow velocity of the aluminum agglomerates near the burning surface. 34 pressure inside the combustion chamber of the pulser shows a sudden increase (Figures 13 and 14) and the combustion products of the black powder are injected into the duct to create the desired pressure disturbance in the combustor, and thus the pressure shows a sharp but only slight rise, followed by a steady decline. The desired pressure fluctuations in the combustor occur only in the first 100-200 ms after the initiation of the pulser.…”

Section: Controlled Casementioning

confidence: 99%

“…This tendency of the aluminum agglomerates with respect to the mean pressure for different solid propellant was confirmed before by many works. [32][33][34][35] Solid combustion products are known to provide for damping of combustion instabilities. The amount of particle damping depends on size; large droplets dampen lower frequencies, while smaller particles damp out higher frequencies.…”

Section: Natural Case (Pulser System Inactive)mentioning

confidence: 99%

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Flame response of solid propellant AP/Al/HTPB to a longitudinal acoustic wave

Rezaiguia

Liu

Yang

2017

International Journal of Spray and Combustion Dynamics

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This paper is devoted to an experimental work which consists of the analysis of the flame of a small solid propellant sample, AP/Al/HTPB, subjected to a longitudinal acoustic wave. Experiments were conducted in a closed tube under two mean pressures: 1 and 2.5 MPa. The qualitative and quantitative analysis of the flame snapshots, using a microscope and a high-speed camera, revealed that the acoustic wave created at the end of the chamber by a pulser system strongly affects the flame and the combustion products dynamic above the solid propellant surface, namely, the flame and the hot products oscillate around a line perpendicular to the propellant surface. This dynamic of the hot gas disturbs the local burning rate and the regression surface profile. Thus, the thrust and the burning duration will change, therefore, the flight path of the rocket may shift and can lead to failure of the mission.

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Section: 12supporting

confidence: 80%

Section: 12mentioning

confidence: 83%

Section: Controlled Casementioning

confidence: 99%

Section: Natural Case (Pulser System Inactive)mentioning

confidence: 99%

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Flame response of solid propellant AP/Al/HTPB to a longitudinal acoustic wave

Rezaiguia

Liu

Yang

2017

International Journal of Spray and Combustion Dynamics

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“…The experimental test rig is schematically shown in Figure 1. The same combustion chamber was used in our previous studies [21].C ombustion experiments were conducted in an itrogen environment at room temperature (293 K). Monochrome high-speed images of the reaction zone near the burning surface were taken through al ong distance microscope equippedw ith an eutral density filter to capture the image of the aluminum agglomerates.…”

Section: Experimental Testmentioning

confidence: 99%

Aluminum Agglomeration on Burning Surface of NEPE Propellants at 3-5 MPa

Liu

et al. 2016

Prop., Explos., Pyrotech.

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Aluminum agglomeration and agglomerate sizes of NEPE propellants were studied by cinephotomicrography at pressures of 3 and 5 MPa. Accumulation, aggregation, and agglomeration of aluminum particles similar to that at pressures below 1 MPa were observed. Coalescence of two agglomerates on the burning surface is obtained for the first time. A decrease in the burning rate from 8 to 5 mm s−1 leads to about 20 % increase in the agglomerate diameter. The pressure is found to have no direct influence on the agglomerate diameter when the burning rate is kept constant. The evolution of the agglomerate diameter according to the increase of the virgin aluminum size from 16 to 36 μm is convex in shape and reached its maximum at a particle diameter of 29 μm. Increasing the amount of RDX crystals added in the propellants causes a larger agglomerate diameter. The experimental mass average agglomerate diameters were compared with various agglomeration models. It is found that Hermsen and Salita empirical models have a higher accuracy for NEPE propellants rather than Becksted, Liu, or pocket models.

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Experimental Investigation on Combustion Characteristics and Agglomeration of Al/NEPE Propellants

Zhang

Feng³

et al. 2021

Propellants Explo Pyrotec

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In order to understand the ignition and combustion characteristics of NEPE propellants under different pressure conditions and the agglomeration behavior of aluminum particles on the burning surface, the Al/NEPE propellant was tested on a sealed high-pressure laser ignition platform. Laser ignition experiments show that both ignition delay time and combustion time are inversely proportional to ambient pressure. With the increase of pressure, the reduction of ignition delay time and self-sustaining combustion time is reduced. The impact of pressure on ignition and combustion is very complex. We then analyze the effect of pressure on ignition delay time using a theoretical mechanism. High-speed microscopic images display the agglomeration of aluminum particles in propellants mainly through the following three processes: accumulation, aggregation, and agglomeration. It is also found that many aluminum particles are agglomerated on the surface, the aluminum droplet agglomerates formed on the combustion surface are separated from the combustion surface, and the agglomerates rupture and flow out of the liquid alumina during the combustion process. The phenomenon of secondary agglomeration is also observed. The microstructure and elemental composition of combustion products of aluminum particles in NEPE propellant were obtained by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). The detection results confirmed some agglomeration phenomena. At 3.0 MPa, the combustion of the propellant sample is sufficient, and the aluminum particles are smooth spherical alumina particles. At 1.0 MPa, the combustion of the propellant sample is insufficient, and the aluminum particles are rough. The particle size under different pressure was analyzed by a laser particle size analyzer. The results show that increasing the pressure can reduce the average agglomeration size of aluminum particles and improve combustion efficiency. The number of large particle aggregates is more at 3 MPa. From the perspective of overall particle size results, within the same diameter interval, the percentage of particle number does not increase or decrease significantly with the increase of pressure.

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Experimental Study on Combustion of Aluminum in Composite Propellant

Cited by 6 publications

References 13 publications

Flame response of solid propellant AP/Al/HTPB to a longitudinal acoustic wave

Flame response of solid propellant AP/Al/HTPB to a longitudinal acoustic wave

Aluminum Agglomeration on Burning Surface of NEPE Propellants at 3-5 MPa

Experimental Investigation on Combustion Characteristics and Agglomeration of Al/NEPE Propellants

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