Correlation of slag expulsion with ballistic anomalies in Shuttle solid rocket motors

Sambamurthi, Jay K.; Alvarado, Alexis; Mathias, Edward C.

doi:10.2514/3.24082

Cited by 9 publications

(4 citation statements)

References 4 publications

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“…The slag ejection phenomena of the Shuttle SRB has been widely studied and documented. 4,8,9 The effect of slag on the submerged region insulation erosion is a grey area : while impinging slag could lead to localized erosion, accumulated and sticking slag could provide thermal shielding and protection. However, there is no data in the published literature in this regard.…”

Section: Introductionmentioning

confidence: 99%

Investigation of Slag Accumulation in Solid Rocket Motors

JasperLal

Sridharan

Krishnaraj

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Slag accumulation occurs in large solid rocket motors having submerged nozzles. Large solid motors use aluminised solid propellant. During combustion, aluminium forms aluminium oxide (Al 2 O 3 ). This alumina or slag is trapped within the submerged region of the nozzle by the recirculating gas streams. The entrapped slag affects the motor performance by reducing delivered specific impulse, augmenting insulator erosion in the submerged region and influencing the vehicle dynamics. The objective of this work is to experimentally determine the slag accumulation characteristics inside solid rocket motors when fired in horizontal and vertical mode. To determine the slag accumulation and also to compare the slag quantity, solid motor static tests were conducted in horizontal and vertical mode and slag quantity was determined. This paper presents the details of the test scheme, test motor, slag evaluation method, results of the test and comparison of slag in the tests conducted in horizontal and vertical modes. These tests provided valuable inputs on slag accumulation between the horizontal and vertical modes of testing. The results indicated higher slag in the vertically fired test motor than one fired horizontally. Nomenclature Al 2 O 3 = Aluminium Oxide (slag) D = Diameter HTPB = Hydroxy Terminated Polyutadiene IR = Inhibition resin L = Length SRB = Solid rocket booster µ = Microns

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Section: Introductionmentioning

confidence: 99%

Investigation of Slag Accumulation in Solid Rocket Motors

JasperLal

Sridharan

Krishnaraj

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

View full text Add to dashboard Cite

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“…It has been reported that for every 10% of unburned Al, the specific impulse ( I sp ) loss is approximately 1% [ 10 ]. Moreover, the agglomeration of Al also causes adverse effects on the working process of the motor system, such as slag accumulation, nozzle erosion, and unsteady motion inside the combustion chamber [ 11 , 12 ].…”

Section: Introductionmentioning

confidence: 99%

Influence of Fluorinated Polyurethane Binder on the Agglomeration Behaviors of Aluminized Propellants

Shen

Yan

et al. 2022

Polymers

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In this study, fluorinated polyurethane (FPU) was prepared from dialcohol-terminated perfluoropolyether as a soft segment; isophorone diisocyanate (IPDI) as a curing agent; 1,2,4-butanetriol (BT) as a crosslinker; and 1,4-butanediol (BDO) as a chain extender. Fourier transform infrared spectroscopy (FTIR) and 1H NMR were used to characterize the structure of the FPU. The mechanical properties of the FPUs with different BDO and BT contents were also measured. The tensile strength and breaking elongation of the optimized FPU formula were 3.7 MPa and 412%, respectively. To find out the action mechanism of FPU on Al, FPU/Al was prepared by adding Al directly to FPU. The thermal decomposition of the FPU and FPU/Al was studied and compared by simultaneous differential scanning calorimetry-thermogravimetry-mass spectrometry (DSC-TG-MS). It was found that FPU can enhance the oxidation of Al by altering the oxide-shell properties. The combustion performance of the FPU propellant, compared with the corresponding hydroxyl-terminated polyether (HTPE)-based polyurethane (HPU) propellant, was recorded by a high-speed video camera. The FPU propellants were found to produce smaller agglomerates due to the generation of AlF3 in the combustion process. These findings show that FPU may be a useful binder for tuning the agglomeration and reducing two-phase flow losses of aluminized propellants.

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“…The notable progresses in the energetic properties of composite solid propellants usually have been accompanied by the renewal of binder systems 3 . For instance, the energetic properties of the widely used Hydroxyl‐terminated polybutadiene (HTPB) composite propellants with a specific impulse of about 250 s is significantly better than that of the initially developed bituminous composite propellants with a specific impulse of about 176 s. Although new composite solid propellants such as HTPB and NEPE propellants have the better energetic properties, the agglomeration of aluminum combustion, commonly existed in these high‐aluminized HTPB and NEPE propellants, often brings a series of nonignorable problems to the solid rocket motors, seriously reducing the specific impulse and the reliability of motors 4–6 …”

Section: Introductionmentioning

confidence: 99%

Investigation on the thermal decomposition of the elastomer containing fluoroolefin segment by DSC‐TG‐MS‐FTIR

Tang

Zeng

et al. 2021

Polymers for Advanced Techs

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Based on the cross-linking reaction of bisphenol A epoxy resin and liquid carboxyterminated poly(tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride) copolymer (CTTHV), the elastomer containing fluoroolefin segment was prepared. The bis (2,2-dinitropropyl)-acetal/formal (BDNPA/F) was used as an energetic plasticizer for this fluoroolefin segment-containing elastomer (FO elastomer). The compatibility of CTTHV and BDNPA/F was evaluated by the combination of differential scanning calorimetry (DSC) and derivative thermogravimetry (DTG) methods. Thermal decomposition of the FO elastomers was investigated by TG-DSC. The kinetic parameters of the FO elastomers were calculated by Kissinger-Akahira-Sunose method. DSC-TG-MS-Fourier transform infrared spectroscopy analysis was used to detect the thermal decomposition products. The thermal decomposition mechanisms of the FO and FO/BDNPA/F elastomers were discussed. The results show that CTTHV has a good compatibility with BDNPA/F, and the prepared FO/BDNPA/F elastomers have good thermal stability. BDNPA/F can promote the thermal decomposition of the FO elastomer and bring more heat for the binder system according to the thermal decomposition behaviors and kinetic calculation results of FO/BDNPA/F elastomers. The FO elastomer preferentially undergoes depolymerization, HF elimination with the formation of polyene sequences, and subsequent main-chain cleavage, polyaromatization. The H ion fragments of the decomposition of BDNPA/F can be an important factor in the improvement of HF concentration at the initial thermal decomposition of FO elastomer. An abundant HF released during all decomposition of FO/BDNPA/F elastomers may be beneficial to the ignition and combustion of aluminum particles in future applications.

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Correlation of slag expulsion with ballistic anomalies in Shuttle solid rocket motors

Cited by 9 publications

References 4 publications

Investigation of Slag Accumulation in Solid Rocket Motors

Investigation of Slag Accumulation in Solid Rocket Motors

Influence of Fluorinated Polyurethane Binder on the Agglomeration Behaviors of Aluminized Propellants

Investigation on the thermal decomposition of the elastomer containing fluoroolefin segment by DSC‐TG‐MS‐FTIR

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