Regeneratively cooled scramjet heat transfer calculation and comparison with experimental data

Jiang, Jin; Zhang, Ruoling; Le, Jialing; Liu, Weixiong; Yang, Yang; Zhang, Lei; Zhao, Guangyao

doi:10.1177/0954410013488737

Cited by 9 publications

(7 citation statements)

References 5 publications

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“…In their investigations, alkenes are the major pyrolysis products, and the alkane products are only methane and ethane with low mole fractions. In the pyrolysis of n -decane at supercritical conditions, − a great amount of C 3 –C 9 alkanes can be produced. This indicates that the fuel is mainly consumed via the unimolecular dissociation reactions to form unsaturated hydrocarbons at low pressure, and the reaction conditions of low reactant concentration, but the bimolecular reactions become more and more critical to the pyrolysis of fuel and cannot to be neglected as the pressure increases as fuel with high concentration in experiments. ,, …”

Section: Resultsmentioning

confidence: 99%

“…n -Decane is a typical pure liquid hydrocarbon and a major component in practical fuel with carbon numbers and properties similar to those of jet fuel (for example JP-8), and it is always employed as a surrogate fuel to study the pyrolysis and heat transfer at supercritical conditions. − Some works have been published on the experimental investigation of the pyrolysis of n -decane at supercritical pressure. For example, Bagley et al , used a two-dimensional high-pressure liquid chromatographic separation technique with ultraviolet–visible absorbance and mass spectrometric detection to identify five- to nine-ring polycyclic aromatic hydrocarbons under supercritical conditions at 570 °C, 9.46 MPa.…”

Section: Introductionmentioning

confidence: 99%

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Experimental and Modeling Investigation of n-Decane Pyrolysis at Supercritical Pressures

et al. 2014

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The pyrolysis mechanism of fuel under supercritical conditions is an important concern for developing regenerative cooling technology of advanced aircraft using hydrocarbon fuel as the primary coolant. n-Decane as a component of some jet fuels was studied at the temperature range from 773 to 943 K in a flow reactor under the pressure of 3, 4, and 5 MPa. Gas chromatograph/mass spectrometry was used to analyze the pyrolysis products, which were mainly alkanes from C1–C9 and alkenes from C2–C9. A kinetic model containing 164 species and 842 reactions has been developed and validated by the experimental results including the distributions of products and the chemical heat sink of fuel. The decomposition pathways of n-decane were illustrated through the reaction flux analysis. It is concluded that the C4–C9 alkanes are mainly generated by the recombinations of alkyls, while the small alkanes (C1–C3) are formed by H-abstraction reactions by C1–C3 alkyl radicals. The applicability at supercritical pressure and high fuel concentration condition of previous models was discussed, and the performance of the present model in reproducing the experimental data is reasonably good.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Experimental and Modeling Investigation of n-Decane Pyrolysis at Supercritical Pressures

et al. 2014

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“…n-decane is one of the major components of diesel, and it has been used as a substitute for studying pyrolysis and heat transfer performance of diesel [21][22][23][24]. Therefore, the fluid dynamics, heat and mass transfer, pyrolysis rate and pyrolysis products distribution of oil-based drilling cuttings are studied by taking it as a heterogeneous mixture consisting of n-decane, a substitute for diesel, and water vapor and sediments.…”

Section: Pyrolysis Mechanismmentioning

confidence: 99%

Numerical Study on Pyrolysis Characteristics of Oil-Based Drilling Cuttings in a Two-Layer Screw-Driving Spiral Heat Exchanger

Zhao,

Li,

Liu

2023

Clean Energy and Sustainability

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Oil-based drilling cuttings is a pollutive nearly-solid waste produced in oil exploitation that has to be treated for meeting clean production requirement of oil and gas exploration. A two-layer screw-driving spiral heat exchanger was thus proposed for this purpose. To investigate its effectiveness and performance, a 10-component n-decane one-step product proportional distribution chemical model was used to describe oil-based drilling cuttings pyrolysis process, and numerical simulations were carried out of forced convection inside the heat exchanger with a full consideration of pyrolysis and evaporation effects. The influences of rotation speed, screw pitch and cross-sectional shape of spiral tube on pyrolysis, flow, and heat mass transfer characteristics were studied. The results show that the heat absorbed needed for evaporation is much less than that for pyrolysis, and the heat transfer coefficient with consideration of evaporation and pyrolysis is almost two times greater than that without. The pyrolysis rate increases first, and then decreases once the temperature is higher than 838 K due to the coupled effects of temperature and reactant concentration change. The velocity, heat transfer coefficient and conversion ratio of oil-based drilling cuttings all increase with rotation speed, but the conversion ratio increase becomes slower and slower once the rotation speed exceeds 0.2 rad•s −1 . The average vorticity and flow resistance of oil-based drilling cuttings both decrease with screw pitch monotonously, while heat transfer coefficient increases first and then decreases because of the opposite effects of centrifugal force and thermal entrance length. Reducing screw pitch can increase conversion ratio, but once screw pitch is smaller than 800 mm, the conversion ratio approaches to a constant. Cross-sectional shape of spiral tube also affects pyrolysis performance, and circular cross-sectional spiral tube seems to be the best.

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“…11, in which the values obtained using a three dimensional heat transfer analysis tool 19 and those measured using an infrared thermocamera are also given for comparison. In the three dimensional heat transfer analysis, the following correlation for fuel in transition regime is used   From the comparison between the results of heat transfer analysis and measurement, one can see that the present method gives result agreeing with them at the turbulent region (excluding the laminar and transitional regions).…”

Section: Computation Of a Fuel-cooled Panelmentioning

confidence: 99%

Numerical Studies for Heat Transfer of Hydrocarbon Fuel with Thermal Cracking

Zhang¹,

Zhao²,

Le³

2015

20th AIAA International Space Planes and Hypersonic Systems and Technologies Conference

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Coolant flow and thermal cracking process play key roles in regenerative cooling of a hydrocarbon-fueled scramjet. In order to study the heat transfer and thermal cracking process of regenerative cooling structure, a three dimensional numerical method is established. The Modified Kumar-Kunzru chemical kinetics model consisting of primary reaction and secondary reactions is used to simulate the thermal cracking process. The SIMPLE algorithm is applied to solve the low speed flow field. The data of electrically heated tube tests and a fuel-cooled panel test are adopted to validate the numerical method and chemical model. The comparisons show good agreements between calculated results and test data. The study indicates that the numerical method is an effective tool to investigate the heat transfer and thermal cracking process of regenerative cooling structure for scramjet, and a potential tool to solve the flow design problem. NomenclatureA = flowing area of the tube cross section c p = fluid specific heat capacity at constant pressure d i = the inner diameter of the tube d o = the outer diameter of the tube D k = dissipation term of turbulent kinetic energy k D s = diffusion coefficient of species s h t = total enthalpy (includes the kinetic energy) per unit mass I = the electric current passing through the tube k = turbulent kinetic energy k s = the thermal conductivity of solid wall Δl = the length of one small segment of tube wall m = fluid mass flux m in = mass flux of inlet kerosene Nu = Nusselt number p = fluid pressure p c = critical pressure P k = production term of turbulent kinetic energy k P loss = the thermal loss rate Pr = Prandtl number q = heat flux R i = the electric resistance of one small segment of tube wall Re = Reynolds number T = temperature 1 Ph.D., 2 T air = room temperature T c = critical temperature T iw = the inner wall temperature T f = fluid mean temperature T ow = the outer wall temperature u = fluid velocity x = the Cartesian coordinate Y s = mass fraction of species s= the Kronecker delta λ = thermal conductivity of the fluid μ = fluid viscosity ρ = fluid mean density τ ij = viscous stress tensor ω = specific dissipation rate subscripts i = ith axis in the Cartesian coordinate, species i j = jth axis in the Cartesian coordinate k = quantity related with turbulent kinetic energy k l = laminar s = species s t = turbulent tr = transition ω = quantity related with specific dissipation rate ω

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Regeneratively cooled scramjet heat transfer calculation and comparison with experimental data

Cited by 9 publications

References 5 publications

Experimental and Modeling Investigation of n-Decane Pyrolysis at Supercritical Pressures

Experimental and Modeling Investigation of n-Decane Pyrolysis at Supercritical Pressures

Numerical Study on Pyrolysis Characteristics of Oil-Based Drilling Cuttings in a Two-Layer Screw-Driving Spiral Heat Exchanger

Numerical Studies for Heat Transfer of Hydrocarbon Fuel with Thermal Cracking

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