This study investigates the coupling effects of Kelvin–Helmholtz, Rayleigh–Taylor, and parametric instabilities at gas–liquid interface, considering heat mass transfer. In model constructed in this paper, liquid phase contacts upper wall a relatively low temperature, while gas lower higher temperature. Evaporation from liquid–gas interface into is used to represent transfer, layer supports Leidenfrost phenomenon. The treated as non-Newtonian fluid governed by Oldroyd-B [J. G. Oldroyd, “On...

The reasonably accurate numerical simulation of methane–air combustion is important for engineering purposes. In the present work, validations sub-models were carried out on a laboratory-scale turbulent jet flame, Sandia Flame D, in comparison with experimental data. eddy dissipation concept (EDC), which assumes that molecular mixing and subsequent occur fine structures, was used turbulence–chemistry interaction. standard k-ε model (SKE) or changed constant C1ε, realizable (RKE),...

Based on the real physical model and operating environment of spacecraft tank, numerical tank is established sloshing behavior liquid hydrogen in under different longitudinal excitations studied this work. The Realizable k- ε used to predict fluid turbulence, mixture analyze phase transitions flows. harmonic external excitation loaded by user-defined function (UDF). CFD verified through comparison with experimental results, influences frequencies amplitudes volume fraction are firstly...

In this study, the primary breakup of a high-speed diesel jet is investigated using CFD methodology that combines an LES model with VOF technique for free surface capture. Inner-nozzle turbulence and cavitation are simplified as sinusoidal radial velocity given amplitude frequency. The ligament droplet formation process captured, liquid disturbed by velocity, umbrella-shaped crests created. Meanwhile, ligaments formed from edges because shear stress tension. We investigate effect on...

During the operation of ADN (ammonium dinitramide, (NH4+N(NO2)2−))-based thrusters, ADN-based liquid propellant, a non-toxic green energetic material, tends to flow boil in capillary tube due heat transfer from wall. A three-dimensional transient numerical simulation boiling propellant was carried out using VOF (Volume Fluid) coupled Lee model. The flow-solid temperature and gas–liquid two-phase distribution wall flux at different reflux temperatures were analyzed. results show that...

The atomization process of swirling sprays in gas turbine engines has been investigated using a LES-VOF model. With fine grid resolution, the ligament and droplet formation processes are captured detail. spray structure fully developed flow field observed firstly. A central recirculation zone is generated inside hollow cone section due to entrainment air by liquid sheet strong turbulent structures promote breakup ligaments. At exit injector nozzle, surface instability occurs disturbance...

In this article, the effect of catalytic bed thermal characteristics on combustion processes ammonium dinitramide (ADN)-based environmentally friendly propellant within monopropellant thruster are analyzed. The described by considering outer wall radiation, non-equilibrium temperature models, and dispersion in bed. This is filled with highly effective catalyst particles through computational fluid dynamic simulation software called ANSYS Fluent. results spray hitting wire mesh achieved an...

The indisputable wide use of the Eddy Dissipation Concept (EDC) implies that resulting mean reaction rate is reasonably well modeled. To model turbulent combustions, an amount EDC constants differ from original values was proposed. However, most them were used without following nature or considering effects modification. Starting with energy cascade and models, exact primary secondary are deduced in detail this work. then formulated constants. Based on physical meaning fine structures,...

Understanding the nucleation mechanism and boiling heat transfer characteristics of liquid hydrogen is a key issue in development storage systems. However, current methods experimental mesoscopic or macroscopic scale continuous flow simulations suffer from problems large study scales undetermined initial boundary conditions. The purpose this to reveal bubble process on surface heating plate at molecular scale, investigate effect different temperature growth, during thin film boiling. In...

The Eddy Dissipation Concept (EDC), as a promising flame prediction model, is reviewed comprehensively. Instead of strong modifications the standard EDC constants to fit experiments, modification method based on fuel jet Reynolds number presented in this work and used predict simple nonpremixed syngas Sandia Flame CHN-B piloted CH4/air partially premixed D. Compared with predictions show two flames are properly reproduced modified constants. Some over-predictions might be attributed...