Modeling and Simulation of Supercritical-Pressure Turbulent Heat Transfer of Aviation Kerosene with Detailed Pyrolytic Chemical Reactions

Abstract

Regenerative cooling of the high-temperature components in propulsion and power-generation systems plays a paramount role in maintaining the systems' reliability and durability. In this paper, a mathematical model is developed for studying fluid dynamics and heat transfer characteristics of the aviation kerosene RP-3 at supercritical pressures. The model accommodates a detailed pyrolytic chemical reaction mechanism, which consists of 18 species and 24 elementary reactions (Jiang et al., Energy Fuels, 2013, 27, 2563-2577). Accurate calculations of thermophysical properties at supercritical pressures are properly incorporated. After rigorous model validations, numerical studies of turbulent heat transfer of RP-3 in a micro cooling tube at a supercritical pressure of 5 MPa are conducted under operating conditions of both constant wall heat flux and constant surface temperature to obtain fundamental understanding of the complex physicochemical processes. Results indicate that the endothermic fuel pyrolysis, which prevails once the bulk fluid temperature rises above 750 K, dictates the fluid flow and heat transfer process in the high fluid temperature region. Significant variations of the fluid thermophysical properties also make strong impacts; two scenarios of heat transfer enhancement resulting from property variations under the tested conditions are analyzed. This work has fundamental and practical implications for effective thermal management in propulsion and power-generation systems.

Flow distribution of hydrocarbon fuel in parallel minichannels heat exchanger

“…It should be noted that, the reaction mechanism was established based on 1‐D semiempirical model, in which the temperature was measured and predefined by a fourth‐order polynomial, without solving the conservation equations of energy and momentum . The dash line in Figure a is the result of multidimensional CFD simulation provided by Xu et al The multidimensional result is very close to the present 1‐D result, indicating that the errors caused by the approximation of 1‐D plug flow are acceptable under these conditions. The profiles of the pressure drop of single Ch.…”

“…3 jet fuel proposed by Jiang et al, consisting of 18 species and 24 reactions, is used to calculate the chemical reaction rates. This mechanism has been verified and applied by Xu et al and Liu et al…”

“…Although the heat convection, pyrolysis and coke deposition of hydrocarbon fuel in single minichannel have been investigated by many researchers, the flow maldistribution of fuel in multichannels is concerned only in recent years and have not been studied fully. Feng et al investigated the distribution of n ‐decane without pyrolysis flowed around a fuel injector in fuel‐cooled plate .…”

Investigation of Pressure Effect on Thermal Cracking of n-Decane at Supercritical Pressures

“…The model is able to predict thermal cracking behaviors of RP-3 at a high conversion up to 86%. Using this molecular kinetic model, numerical studies have been performed to investigate the effects of thermal cracking on the regenerative cooling process. , However, the effect of pressure on the pyrolysis of RP-3 was not included in these researches because of the lack of the necessary kinetic parameters for other pressures.…”

Viscosity Measurement of Endothermic Fuels at Temperatures from 303 K to 673 K and Pressures up to 5.00 MPa

“…The thermal management of high-temperature propulsion components of scramjet engines has become a crucial issue. , In all emerging cooling technologies, the regenerative cooling system using the “endothermic fuel” onboard to meet the cooling requirements attracts significant research interests. Endothermic fuel is used not only as propellant for the scramjet with a high heat sink, high density, and excellent stability, but also as a primary coolant absorbing excessive aerodynamic heat by its endothermic cracking reactions. − Properties of these endothermic fuels such as heat sink capacity, , thermochemical and physical properties, − combustion process, , and heat transfer characteristics , have been under study. As an important thermophysical parameter, the viscosity of the fuel was valued in the flow Reynolds number and kinetic modeling in the cooling process.…”