A Numerical Study On The Extinction Characteristics Of Droplet Combustion Under Microgravity Conditions

2012 ◽  
Author(s):  
Tanvir Farouk ◽  
Frederick Dryer
Keyword(s):  
Numerical Study ◽  
Droplet Combustion ◽  
Microgravity Conditions ◽  
Extinction Characteristics

scholarly journals Effect of the coefficient of restitution and friction in the granular Leidenfrost effect in the absence of gravity. A numerical study

2021 ◽  
Vol 249 ◽  
pp. 14016
Author(s):  
Daniel Schiochet Nasato ◽  
Heiko Briesen
Keyword(s):  
Coefficient Of Friction ◽  
Parametric Study ◽  
Granular Media ◽  
Numerical Study ◽  
Packing Fraction ◽  
Coefficient Of Restitution ◽  
Granular System ◽  
The Coefficient Of Friction ◽  
Leidenfrost Effect ◽  
Microgravity Conditions

In this study the granular Leidenfrost effect in the absence of gravity is investigated numerically by means of the discrete element method. Apart from identifying the phenomena, a parametric study to quantify the influence of the coefficient of restitution and friction in the packing fraction of the granular media is carried on numerically. Surprisingly, both the coefficient of restitution and the coefficient of friction exhibit an influence of the same magnitude in the packing fraction of the granular system, which has not been reported in experiments and simulation of granular Leidenfrost regime under gravity or microgravity conditions.

Eddie Leonardi Memorial Lecture: “Natural Convection From Earth to Space”

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
Victoria Timchenko
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Numerical Solutions ◽  
Numerical Study ◽  
Three Dimensional ◽  
Experimental Investigations ◽  
Memorial Lecture ◽  
Numerical Studies ◽  
Fluid Properties ◽  
Microgravity Conditions

This lecture is dedicated to the memory of Professor Eddie Leonardi, formerly International Heat Transfer Conference (IHTC-13) Secretary, who tragically died at an early age on December 14, 2008. Eddie Leonardi had a large range of research interests: he worked in both computational fluid dynamics/heat transfer and refrigeration and air-conditioning for over 25 years. However starting from his Ph.D. ‘A numerical study of the effects of fluid properties on natural convection’ awarded in 1984, one of his main passions has been natural convection and therefore the focus of this lecture will be on what Eddie Leonardi has achieved in numerical and experimental investigations of laminar natural convective flows. A number of examples will be presented which illustrate important difficulties of numerical calculations and experimental comparisons. Eddie Leonardi demonstrated that variable properties have important effects and significant differences occur when different fluids are used, so that dimensionless formulation is not appropriate when dealing with flows of fluids with significant changes in transport properties. Difficulties in comparing numerical solutions with either numerically generated data or experimental results will be discussed with reference to two-dimensional natural convection and three-dimensional Rayleigh–Bénard convection. For a number of years Eddie Leonardi was involved in a joint US-French-Australian research program—the MEPHISTO experiment on crystal growth—and studied the effects of convection on solidification and melting under microgravity conditions. Some results of this research will be described. Finally, some results of experimental and numerical studies of natural convection for building integrated photovoltaic (BIPV) applications in which Eddie Leonardi had been working in the last few years will be also presented.

Numerical Study of Circular Hydraulic Jump Using Volume-of-Fluid Method

2011 ◽  
Vol 133 (1) ◽  
Author(s):  
Mohammad Passandideh-Fard ◽  
Ali Reza Teymourtash ◽  
Mohammad Khavari
Keyword(s):  
Ethylene Glycol ◽  
Parametric Study ◽  
Hydraulic Jump ◽  
Numerical Study ◽  
Volumetric Flow Rate ◽  
Volume Of Fluid ◽  
Vof Method ◽  
Sudden Increase ◽  
Different Types ◽  
Microgravity Conditions

When a vertical liquid jet impacts on a solid and horizontal surface, the liquid starts spreading radially on the surface, until a sudden increase in the fluid height occurs and a circular hydraulic jump (CHJ), easily seen in the kitchen sink, is formed. In this study, the formation of CHJ is numerically simulated by solving the flow governing equations, continuity and momentum equations, along with an equation to track the free surface advection using the volume-of-fluid (VOF) method and Youngs’ algorithm. The numerical model is found to be capable of simulating the jump formation and its different types. Extensive comparisons are performed between the model results and those of the available experiments and modified Watson’s theory. The model is shown to accurately predict the jump location and its behavior. Also a parametric study for the effects of different parameters including volumetric flow rate, downstream height, viscosity and gravity on the jump radius, and its characteristics is carried out. Compared with previous works on CHJ available in the literature, employing the VOF method considering the surface tension effects and performing a full parametric study and a complete comparison with experiments and theory are new in this paper. The simulations are performed for two different liquids, water and ethylene glycol, where it is found that the jump is more stable and its location is less sensitive to the downstream height for the more viscous liquid (ethylene glycol). When the downstream height is increased, the radius of the circular hydraulic jump reduces up to a certain limit after which there would be no stable jump. If the gravity is decreased, the radius of the jump and the length of the transition zone will both increase. The radius of the jump in microgravity conditions is less sensitive to the downstream height than it is in normal gravity.

Apparatus to investigate liquid oxygen droplet combustion in hydrogen under microgravity conditions

2020 ◽  
Vol 91 (10) ◽  
pp. 105110
Author(s):  
Florian Meyer ◽  
Christian Eigenbrod ◽  
Volker Wagner ◽  
Wolfgang Paa ◽  
James C. Hermanson
Keyword(s):  
Liquid Oxygen ◽  
Droplet Combustion ◽  
Microgravity Conditions
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