Turbulent Flow, Heat Transfer Deterioration, and Thermal Oxidation of Jet Fuel

Abstract

Computational fluid dynamics simulations can be used to simulate the flow, heat transfer, and fuel chemistry within fuel system cooling passageways. The standard k-ε turbulence model with the standard wall function, renormalization group k-ε model with an enhanced wall function, and the shear stress transport k-ω model were evaluated for their ability to represent turbulent fuel flow and heat transfer under high heat flux and flow rate conditions. The renormalization group k-ε model with an enhanced wall function provided the greatest fidelity in representation of turbulent thermal and flow behavior studied in heated tube experiments conducted at supercritical pressure. Moreover, the renormalization group k-ε model with an enhanced wall function allowed reasonable simulation of heat transfer deterioration, which was more likely for flow conditions involving a large heat flux with low mass flux rate. As the fuel was heated from the liquid to the supercritical phase, the viscosity temperature dependence was the primary transport property leading to heat transfer deterioration. A pseudodetailed chemical kinetic mechanism was used to study the effect of high heat flux and flow rate on dissolved O 2 consumption together with a global submechanism for the simulation of thermal-oxidative surface deposition. The deposition submechanism developed previously for low heat flux conditions provided reasonable agreement between normalized, measured, and simulated deposit profiles.

Supercritical-Pressure Heat Transfer, Pyrolytic Reactions, and Surface Coking of n-Decane in Helical Tubes

“…In the literature, many studies have been carried out on supercritical-pressure heat transfer of various hydrocarbon fuels. Zhong et al, 8 Liu et al, 10 Zhang et al, 11 Jiang et al, 12 and Yang et al 13 conducted experimental investigations on heat transfer of the heavy hydrocarbon fuels, including aviation kerosene and n-decane, under supercritical pressures. Effects of the operating pressure, wall heat flux, and inlet flow velocity were examined.…”

Experimental and Numerical Study on Oxidation Deposition Properties of Aviation Kerosene

“…In addition, the residence time is also affected by the thickness of the deposition layer increasing with the heating time due to the change of the inner diameter. But, the effects of the deposits on the flow were neglected since the thickness of the deposition layer was very thin, which was observed in the morphological investigation on deposition. , The difference in the wall thermal conductivity between the ideal condition of Stainless Steel 316 and that at the end of the experiment indicates the accumulated effect of deposition on heat transfer.…”

“…Many experimental − and numerical investigations − have been performed with the aim of understanding the deposit formation and oxidation processes of hydrocarbon fuels. In general, for the formation of deposition coke in fuel during heat transfer, the amount of dissolved oxygen, , cooling channel geometries, − operational conditions, , fluid dynamics, buoyancy, heat-transfer characteristics, additives, heating time, , and temperature , affect the coking characteristics of a system. In a limited oxidation deposition mechanism study, a nine-step model was developed by Katta and co-workers .…”

Numerical study of supercritical-pressure fluid flows and heat transfer of methane in ribbed cooling tubes

“…The early studies on supercritical-pressure fluid flows and heat transfer focused mainly on water, carbon dioxide, hydrogen, and heavy hydrocarbon fuels [1][2][3][4][5][6][7][8][9][10][11][12][13], because of their practical/potential applications in nuclear reactors, refrigeration, aerospace propulsion and industrial power-generation systems. In recent years, because of the renewed interest in using cryogenic methane as an alternative propellant in aerospace propulsion systems [14,15], many studies on the supercritical-pressure fluid flows and heat transfer of cryogenic methane have been carried out, intended for fundamental understanding and practical applications of the regenerative engine cooling technology [16][17][18][19][20][21][22].…”