Alain Degiovanni

Fast and Accurate Simplified Radiative Model for Modeling Coupled Heat Transfers in Glass Forming Process

Hoang Quan NGUYEN* , Benjamin REMY* b and Alain DEGIOVANNI* c Laboratoire d’Energétique et de Mécanique Théorique et Appliquée (LEMTA – ENSEM) UMR – CNRS 7563 – UHP – Nancy I, Institut National Polytechnique de Lorraine. 02, avenue de la Forêt de Haye B.P. 160, 54504 Vandoeuvre – lès – Nancy Cedex, France. Correspondence author. Fax: +33-(0)3-83-59-55-51 email: Hoang-Quan.Nguyen@ensem.inpl-nancy.fr email: Benjamin.remy@ensem.inpl-nancy.fr email: Alain.degiovanni@ensem.inpl-nancy.fr

Thermal Properties Measurement of Materials

The control of energy in the industrial sector and the reduction of consumption in the building sector will be key elements in the energy transition. In order to achieve these objectives it is necessary to use, in the first case, materials with energy performance adapted to their use and, in the second case, insulators, or rather super-insulators. In both cases, a perfect knowledge of their thermal properties will be a requirement for optimal success. This book enables the reader to choose the measurement method best suited to the material they are characterizing, and provides all of the information required in order to implement it with maximum precision. This work is intended to be accessible to anyone who needs to measure the thermal properties of a material, regardless of whether they are a thermal engineer.

A passive guard for low thermal conductivity measurement of small samples by the hot plate method

Hot plate methods under steady state conditions are based on a 1D model to estimate the thermal conductivity, using measurements of the temperatures T 0 and T 1 of the two sides of the sample and of the heat flux crossing it. To be consistent with the hypothesis of the 1D heat flux, either a hot plate guarded apparatus is used, or the temperature is measured at the centre of the sample. On one hand the latter method can be used only if the ratio thickness/width of the sample is sufficiently low and on the other hand the guarded hot plate method requires large width samples (typical cross section of 0.6??×??0.6 m2). That is why both methods cannot be used for low width samples. The method presented in this paper is based on an optimal choice of the temperatures T 0 and T 1 compared to the ambient temperature T a, enabling the estimation of the thermal conductivity with a centered hot plate method, by applying the 1D heat flux model. It will be shown that these optimal values do not depend on the size or on the thermal conductivity of samples (in the range 0.015?0.2 W m?1 K?1), but only on T a. The experimental results obtained validate the method for several reference samples for values of the ratio thickness/width up to 0.3, thus enabling the measurement of the thermal conductivity of samples having a small cross-section, down to 0.045??×??0.045 m2.

Improved Temperature Extrapolation Methods for Powerplant Systems

The certification of a powerplant requests through CS 25.1041 ‘Cooling’ that: “the powerplant cooling provisions must be able to maintain the temperatures of powerplant components, and engine fluids, within the temperature limits established for these components and fluids, underground and flight operating conditions, and after normal engine shutdown.” This has to be demonstrated by test results corrected by a factor to cover the extreme conditions as per CS 25.1043. Currently applied corrections are quick and simple but rough and too conservative for some of the systems. The aim of this study is to develop a comprehensive methodology for establishing extrapolation models more powerful than the actual methods used for certification.

Physical Mechanisms During the Drying of a Porous Medium

The aim of this paper is to summarize the physical aspects of the drying process in order to model it.

Identification of Subsurface Defects by a Thermal Method Using a Sensibility Analysis

A subsurface defect in a composite material can be characterized in term of depth and thermal resistance after a heat pulse — “flash” — perturbation on its front side. A sensitivity analysis of the rear-side contrast thermogram is done and various methods of identification of these two parameters are reviewed. The use of experimental Laplace transforms seems to bring better results than the classical one-point evaluation.