Ignition of HTPB-based fuels loaded with and without micron-sized metals

Zhao, Qi; Tang, Yue; Paravan, Christian; Colombo, G; Shen, Ruiqi; DeLuca, Luigi T.

doi:10.2495/feem140581

Cited by 2 publications

(4 citation statements)

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“…By comparing the images under different pressure conditions, it can be observed that when the ambient pressure increases from 0.1 MPa to 3 MPa, the diameter of aluminum particles separated from the propellant decreases relatively. However, it should be noted that increasing environmental pressure will also increase the combustion rate of the propellant, resulting in particles falling off the combustion surface faster [24]. As can be seen from Figure 3, with the increase of pressure, the number of aluminum particles shedding in the combustion process also increases.…”

Section: Resultsmentioning

confidence: 97%

“…It is found that a reasonable selection of alloy elements can optimize aluminized propellants. Zhao Qin [24] studied the effects of magnesium (Mg), amorphous aluminum(am_Al), and magnesium-boron composites on the agglomeration and combustion properties of propellants. The addition of some other additives, such as fluorine-containing polymer coating [25], CL-20 [26], Fe 2 O 3 [27], and Ta/PH-Fe [28], also has a certain influence on the ignition, combustion, and agglomeration characteristics of the propellant.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

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

Zhang

Feng³

et al. 2021

Propellants Explo Pyrotec

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“…The following figure (from Ref. 28) shows that addition of Mg, MgB or nano size aluminum only increases the regression rate in the 10-40% range. The maximum increase is with the nano aluminum at high fluxes.…”

Section: Effect On Regression Ratementioning

confidence: 94%

“…• Effect of Alex particle addition to HTPB has been investigated in Ref. 28. The oxidizer was gaseous oxygen and a very small burner has been used in the tests.…”

Section: A Hybrid Rocket Fuel Additives -Reviewmentioning

confidence: 99%

Evaluation of Fuel Additives for Hybrid Rockets and SFRJ Systems

Karabeyoğlu¹,

Arkun²

2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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A comprehensive assessment of fuel additives that are expected to improve the performance of hybrid rockets and solid fuel ramjet (SFRJ) systems is reported in this paper. A ranking of the selected fuel additives and binders have been made based on performance and other practical considerations including cost, availability and handling properties. One of the important conclusions of this study is that incorporating fuel additives into a binder is not an effective method to enhance the regression rate of hybrid rocket or SFRJ fuels. The key driver should be specific impulse and density impulse improvement. For low energy oxidizers such as nitrous oxide, aluminum turns out to be an excellent additive that strikes a good balance between the performance gain and key practical considerations such as availability/cost. Aluminum or other metals included in this study are not effective in improving Isp when they are used with oxygen. For hybrid rockets, AlH3 delivers the best performance benefit among all of the additives considered in this study. However its poor availability in the Western world diminishes its usefulness. Boron as an additive did not have a major performance impact for hybrid systems. It is believed that at the current energy and unit cost levels of the performance additives, they are not expected to generate an economical benefit (i.e. cost/payload mass) even for applications demanding high Isp's such as orbital launch vehicles. For SFRJ systems, boron and its compounds deliver significant performance improvement. Paraffin ranks as the best binder for both hybrids and also SFRJ's due to its high regression rate, good availability, hydrophobic nature, easy handling and low cost. NomenclatureAB = Ammonia Borane ADN = Ammonium dinitramide AMROC = American Rocket Company DCPD = Dicyclopentadiene GOX = Gaseous oxygen HTPB = Hydroxyl Terminated Polybutadiene LOX = Liquid oxygen NTO = Dinitrogen Tetraoxide (N2O4) pDCPD = Polydicyclopentadiene PE = Polyethylene polymer PMM = Polymethylmethacrylate SFRJ = Solid Fuel Ramjet Tf = Flame temperature, K

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Ignition of HTPB-based fuels loaded with and without micron-sized metals

Cited by 2 publications

References 0 publications

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

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

Evaluation of Fuel Additives for Hybrid Rockets and SFRJ Systems

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