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Stefan number

About: Stefan number is a research topic. Over the lifetime, 482 publications have been published within this topic receiving 32056 citations.


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Journal ArticleDOI
TL;DR: In this paper, the authors carried out extensive numerical simulations on the melting of the Phase Change Material n-octadecane subjected to thermocapillary driving at a free surface on geometries with the form of circular sections of radius in order of centimeters.

47 citations

Journal ArticleDOI
TL;DR: In this article, a mathematical model that is used to estimate heat conduction losses in laser cutting by employing integral methods to solve the three-dimensional, heat-conduction equation is presented.
Abstract: Numerical models of laser cutting are essential for an improved understanding of the process. In order for the models to closely represent real physics the heat lost by conduction during cutting has to be incorporated into them. This paper outlines the details of a mathematical model that is used to estimate heat conduction losses in laser cutting by employing integral methods to solve the three-dimensional, heat-conduction equation. Simple, yet accurate, correlations are presented for the conduction heat loss rate, as well as for characteristic thicknesses of the heat affected zone (HAZ). These variables are functions only of Peclet number (Pe), which may be thought of as a dimensionless cutting speed. The correlations are then used to predict (i) the cutting speed in laser cutting, and (ii) the temperature field in the HAZ. The predictions show an excellent match with experimental results. Cutting speed is predicted using an energy balance at the cutting front. An implicit, nonlinear equation for Pe as a function of Stefan number (Ste) and dimensionless heat of combustion results. Ste gives the ratio of sensible heat to latent heat in the workpiece. Detailed analysis of beam absorptivity, coupled with the dimensionless cutting speed result suggests that the dimensional cutting speed, uo, may be correlated as a unique function of the ratio of incoming laser power to workpiece thickness, Qlas/d. This is corroborated by measured cutting rates over a wide range of sample thicknesses and two beam power settings.

46 citations

Journal ArticleDOI
TL;DR: In this article, a thermal energy storage (TES) system with octadecane-coated copper panels arranged in a vertical configuration to promote a self-induced internal natural convection mechanism is presented.

45 citations

Journal ArticleDOI
TL;DR: In this paper, the Brinkman-Forchheimer extension to Darcy's law is used to model the porous resistance of a solid/liquid phase change in a rectangular container with and without metal foams.
Abstract: Solid/liquid phase change occurring in a rectangular container with and without metal foams subjected to periodic pulsed heating is investigated. Natural convection in the melt is considered. Volume-averaged mass and momentum equations are employed, with the Brinkman-Forchheimer extension to Darcy's law used to model the porous resistance. A local thermal nonequilibrium model, assuming equilibrium melting at the pore scale, is employed for energy transport through the metal foams and the interstitial phase change material (PCM). Separate volume-averaged energy equations for the foam and the PCM are written and are closed using a heat transfer coefficient. The enthalpy method is employed to account for phase change. The governing equations for the PCM without foam are derived from the porous medium equations. The governing equations are solved implicitly using a finite volume method on a fixed grid. The coupled effect of pulse width and natural convection in the melt is found to have a profound effect on the overall melting behavior. The influence of pulse width, Stefan number, and Rayleigh number on the temporal evolution of the melt front location and the melting rate for both the cases with and without metal foams is investigated.

45 citations

Journal ArticleDOI
TL;DR: In this article, the melting and solidification processes and thermal conductivity enhancement of the phase change material (PCM) inside a sphere have been experimentally investigated to facilitate a greater understanding and improvement of phase change heat transfer.

45 citations

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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
20224
202136
202033
201929
201819
201726