Thermal Stability of Energetic Hydrocarbon Fuels for Use in Combined Cycle Engines

Wohlwend, K.; Maurice, Lourdes; Edwards, Tim; Striebich, Richard C.; Vangsness, M. D.; Hill, A. S.

doi:10.2514/2.5873

Cited by 62 publications

(59 citation statements)

References 7 publications

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“…The unimolecular decomposition of JP-10 proceeds in less than 0.8 ps of simulation time through a stepwise mechanism involving sequential cleavage of C-C bonds between carbons 8 and 9, then carbons 1 and 2, and finally carbons 6 and 7 (for the atom-labeling scheme, see Figure 1), resulting in cyclopentene and 1,4-pentadiene. Indeed cyclopentene has been observed experimentally, 7,8,11,12 and Rao and Kunzru 12 and Davidson et al 4 determined cyclopentene to be an initial decomposition product in their experiments. We find that two additional JP10s decompose to form ethylene and 1,5-cyclooctadiene at 34.7 and 49.5 ps.…”

Section: Resultsmentioning

confidence: 99%

“…7,8 Thermal decomposition, catalytic cracking, and shock tube studies have provided insight into the overall chemistry of JP-10 decomposition, but the details of the initiation reactions and the high-temperature chemistry are still not well-established. 1,4,5,[7][8][9][10][11][12][13][14] The products observed experimentally from the thermal decomposition of JP-10 are summarized from the literature in Table 1. The pyrolysis products common to all of the experiments are benzene and cyclopentadiene (CPD), but there is no agreement on whether the formation of these products results from primary or secondary chemistry.…”

Section: Introductionmentioning

confidence: 99%

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Initiation Mechanisms and Kinetics of Pyrolysis and Combustion of JP-10 Hydrocarbon Jet Fuel

et al. 2009

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In order to investigate the initiation mechanisms and kinetics associated with the pyrolysis of JP-10 (exotricyclo[5.2.1.0 2,6 ]decane), a single-component hydrocarbon jet fuel, we carried out molecular dynamics (MD) simulations employing the ReaxFF reactive force field. We found that the primary decomposition reactions involve either (1) dissociation of ethylene from JP-10, resulting in the formation of a C 8 hydrocarbon intermediate, or (2) the production of two C 5 hydrocarbons. ReaxFF MD leads to good agreement with experiment for the product distribution as a function of temperature. On the basis of the rate of consumption of JP-10, we calculate an activation energy of 58.4 kcal/mol for the thermal decomposition of this material, which is consistent with a strain-facilitated C-C bond cleavage mechanism in JP-10. This compares well with the experimental value of 62.4 kcal/mol. In addition, we carried out ReaxFF MD studies of the reactive events responsible for oxidation of JP-10. Here we found overall agreement between the thermodynamic energies obtained from ReaxFF and quantum-mechanical calculations, illustrating the usefulness of ReaxFF for studying oxidation of hydrocarbons. The agreement of these results with available experimental observations demonstrates that ReaxFF can provide useful insights into the complicated thermal decomposition and oxidation processes of important hydrocarbon fuels.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Initiation Mechanisms and Kinetics of Pyrolysis and Combustion of JP-10 Hydrocarbon Jet Fuel

et al. 2009

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“…All of these have their pros and cons for varying levels of simulation fidelity, complexity, control, and quantitative determination of results. The bulk of the data generated has been from heated tubes and the conduction heated thermal concentrator [1][2][3][4][5][6][7][8][9][10][11][12] . Direct ohmic heating of both pure metal and bimetallic coannular tubes produces high wall temperatures and circumferential heat transfer to the fuel coolant.…”

Section: Subject Termsmentioning

confidence: 99%

Design of a High Heat Flux Facility for Thermal Stability Testing of Advanced Hydrocarbon Fuels

Bates¹,

Maas²,

Irvine³

et al. 2004

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With both the Air Force and NASA interested in developing reusable hydrocarbon-fueled engine technologies for reusable launch vehicles, there is an increased need to better understand the thermal stability of hydrocarbon fuels under high heat fluxes encountered during regenerative cooling. Currently, no existing thermal stability test rig can accurately simulate the high heat flux conditions that will exist in the cooling channels of these new high-pressure hydrocarbon engines. To meet the high reliability and reusability requirements proposed for these engines, the Air Force Research Laboratory (AFRL) has designed a High Heat Flux Facility (HHFF) using experience gained from past and present thermal stability test rigs. CFD++, a Metacomp Technologies Inc. computational fluid dynamics software suite, was employed to optimize the design prior to manufacture. Conjugate heat transfer calculations were performed in a single computational domain containing the copper heater block and the fluid channel of the new test rig design. The first tests conducted in the facility will be highly instrumented and will be used to validate the CFD++ calculations. The parameters of interest for a given geometry are the heat transfer coefficient, the degree of coking and corrosion in the channel, and the pressure drop as functions of heat flux, wall temperature, Reynolds number, channel material, fuel composition and pressure. The HHFF will be an important tool to facilitate the development and transition of new advanced hydrocarbon fuels under study by AFRL.

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“…Wall temperatures, from 500-1100 °F for copper walls, can vary from mild to pushing the safety factor for the structural integrity of the wall material and heat flux rates vary from 1 to 100 BTU/in 2 /sec, producing a range of boundary layer thicknesses and potential striations. Facilities used for studying heat transfer behavior and fuel thermal stability in the United States are resistively heated tube facilities (such as NASA Glenn Research Center's Heated Tube Facility Rig, and UTRC 5,6 and Rocketdyne's 7,8 heated tube rigs), conductively heated thermal concentrators (such as Aerojet's Carbothermal rig 9,10 ), combustion, arc lamp and laser heating facilities, with the bulk of the data generated coming from the heated tube and conductively heated concentrators [1][2][3][4][5][6][7][8][9][10][11][12] . For the heated tube facilities, direct ohmic heating of both pure metal and bimetallic co-annular tubes is used to produce high wall temperatures and circumferential heat transfer to the fuel coolant.…”

Section: Introductionmentioning

confidence: 99%

“…For the heated tube facilities, direct ohmic heating of both pure metal and bimetallic co-annular tubes is used to produce high wall temperatures and circumferential heat transfer to the fuel coolant. External wall temperature measurements and electrical power consumption are used to infer the internal wall temperature [2][3][4][5][6][7][8]11,12 . The implementation is relatively simple and allows for easy post-test specimen interrogation of coking and corrosion behavior.…”

Section: Introductionmentioning

confidence: 99%

A High Heat Flux Facility Design for Testing of Advanced Hydrocarbon Fuel Thermal Stability

Maas

Irvine

Bates

et al. 2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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The Air Force Research Laboratory's Propulsion Directorate is developing higher energy density hydrocarbon fuels for application in reusable liquid rocket engines. For increased performance and operability, next generation engines will require better thermal stability understanding of hydrocarbon fuels under high heat fluxes. Of the existing thermal stability test rigs, none have the ability to accurately simulate the high heat flux conditions that will exist in the cooling channels of these new high-pressure hydrocarbon engines. To design and test fuels to meet the high reliability and reusability requirements proposed for these engines, the Air Force Research Laboratory (AFRL) at Edwards AFB has designed the High Heat Flux Facility (HHFF) using experience gained from past thermal stability test rig experiments. In order to design a facility capable of simulating the higher heat fluxes expected in the channels, CFD++, a Metacomp Technologies Inc. computational fluid dynamics software suite, was employed to optimize the design prior to manufacture. Conjugate heat transfer calculations were performed in a single computational domain containing the copper heater block and the fluid channel of the new test rig design. The parameters of interest during each experiment will be heat transfer coefficient, degree of coking and corrosion in the channel, and pressure drop as a function of heat flux, wall temperature, Reynolds number, channel material, fuel composition and pressure. AFRL's HHFF will be an important tool for facilitating the development and transition of new advanced hydrocarbon fuels.

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Thermal Stability of Energetic Hydrocarbon Fuels for Use in Combined Cycle Engines

Cited by 62 publications

References 7 publications

Initiation Mechanisms and Kinetics of Pyrolysis and Combustion of JP-10 Hydrocarbon Jet Fuel

Initiation Mechanisms and Kinetics of Pyrolysis and Combustion of JP-10 Hydrocarbon Jet Fuel

Design of a High Heat Flux Facility for Thermal Stability Testing of Advanced Hydrocarbon Fuels

A High Heat Flux Facility Design for Testing of Advanced Hydrocarbon Fuel Thermal Stability

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