Intrinsic permeability of materials ranging from sand to rock-fill using natural air convection tests

2011 ◽  
Vol 48 (5) ◽  
pp. 679-690 ◽  
Author(s):  
Jean Côté ◽  
Marie-Hélène Fillion ◽  
Jean-Marie Konrad
Keyword(s):  
Natural Convection ◽  
Experimental Results ◽  
Heat Extraction ◽  
Test Results ◽  
Intrinsic Permeability ◽  
Square Enclosure ◽  
Rock Fill ◽  
Air Convection ◽  
Effective Particle ◽  
Winter Time

Air convection within coarse rock-fills enhances winter-time heat extraction from underlying soils. Modeling this phenomenon requires the knowledge of intrinsic permeability. This study focuses on the measurement of intrinsic permeability using natural air convection within a 1 m3 test cell. Upward heat flow conditions are applied to various specimens. Test results are analyzed using a theoretical solution of natural convection in a square enclosure. Four materials were studied, with effective particle sizes (d10) ranging from 90 to 150 mm and porosities ranging from 0.37 to 0.41. The results showed that intrinsic permeability increases with increasing d10. The experimental results were adequately predicted by the Kozeny–Carman and Chapuis equations. Only slight deviations were observed, which is considered acceptable given that these equations were developed for materials with much smaller values of d10. The experimental results of this study confirm the value of intrinsic permeability recently used in a study of natural convection within a rock-fill dam in northern Quebec, Canada.

Corrigendum: Intrinsic permeability of materials ranging from sand to rock-fill using natural air convection tests

2011 ◽  
Vol 48 (7) ◽  
pp. 1149-1149
Author(s):  
Jean Côté ◽  
Marie-Hélène Fillion ◽  
Jean-Marie Konrad
Keyword(s):  
Intrinsic Permeability ◽  
Rock Fill ◽  
Air Convection

scholarly journals Establishment of Intrinsic Permeability of Coarse Open-Graded Materials: Review and Analysis of Existing Data from Natural Air Convection Tests

Minerals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 767
Author(s):  
Karlis Rieksts ◽  
Inge Hoff ◽  
Elena Scibilia ◽  
Jean Côté
Keyword(s):  
Heat Transfer ◽  
Large Scale ◽  
Shape Effect ◽  
Intrinsic Permeability ◽  
Graded Materials ◽  
Square Enclosure ◽  
Air Convection ◽  
Degree Of Confidence ◽  
Physical Shape ◽  
Frost Penetration

This paper presents a review and analysis of large-scale air convection tests and the establishment of intrinsic permeability in coarse open-graded materials. Natural air convection can make a significant contribution to heat transfer during cooling periods. In seasonally freezing environments this can result in excessive frost penetration and subsequent frost-related problems. Intrinsic permeability largely defines the onset of convective heat transfer in granular materials. Conventional methods for measuring intrinsic permeability cannot be applied to very coarse materials. Large-scale laboratory experiments on natural air convection can serve as an alternative method for determining this crucial parameter. This paper gives an overview of four different experimental test setups for measuring natural air convection, all differing in physical shape, boundary conditions and heat flux/temperature measurement devices. Comparison between these is difficult because the air convection pattern can differ and in some cases the shape and number of convection cells cannot be validated. Most of the studies available in the literature use theoretical equations to approximate intrinsic permeability. A method based on the analytical Nu-Ra number relationship is employed to establish the values of intrinsic permeability. Tests that provide enough data to enable the use of the Nu-Ra relationship are very limited. The overall results show a reasonable correlation between experiment-based intrinsic permeability and theoretical approximation. However, several issues must be addressed: first, differences may exist between the intrinsic permeability of natural and of crushed materials due to the shape effect. Second, the method used is in theory valid only for two-dimensional air convection within a square enclosure heated from below. Yet the results show that this method could be extended to other conditions with a certain degree of confidence. Third, a good estimate of intrinsic permeability is possible only with accurate experimental measurement.

Natural Convection in a Rocking Square Enclosure: Experimental Results

2011 ◽  
Vol 133 (7) ◽  
Author(s):  
R. Chávez ◽  
F. J. Solorio ◽  
J. G. Cervantes
Keyword(s):  
Natural Convection ◽  
Strong Dependence ◽  
Oscillation Amplitude ◽  
Central Line ◽  
Experimental Results ◽  
Working Fluid ◽  
Closed Cavity ◽  
Square Enclosure ◽  
Image Velocimetry ◽  
Horizontal Symmetry

Experimental results for the natural convection in a rocking enclosure are presented. A square closed cavity heated from below and cooled from above periodically turns around of its horizontal symmetry central line. The oscillation amplitude was from −15 deg to 15 deg, and four time periods were employed (30 min, 60 min, 90 min, and 120 min) for three established Rayleigh numbers (3×104, 6×104, and 1×105). High purity glycerin was used as the working fluid, and particle image velocimetry (PIV) was employed to obtain the velocity fields. The obtained flow patterns have a strong dependence on the Rayleigh number.

Experimental Study and Finite Analysis on Flexural Capacity of Laminated Glass

2011 ◽  
Vol 243-249 ◽  
pp. 258-262
Author(s):  
Jun Chen ◽  
Jia Lv ◽  
Qi Lin Zhang ◽  
Zhi Xiong Tao ◽  
Jun Chen
Keyword(s):  
Experimental Results ◽  
Laminated Glass ◽  
Test Results ◽  
Design Code ◽  
Flexural Capacity ◽  
Equivalent Thickness ◽  
High Rise ◽  
Safety Glass ◽  
Current Design ◽  
Good Agreement

Laminated glass has been increasing widely used in high rise buildings as a kind of safety glass in recent years. So we should analyze its material property. In this paper, we use flexural experiments and ANSYS program to analyze the main factors that affect the flexural capacity of the laminated glass. The test results show that the flexural capacity is closely related to film. And the ANSYS program had got good agreement with the experimental results. Comparison of experimental results with calculated ones indicates that the current design code will lead to conservative results and the equivalent thickness of laminated glasses provided in the code should be further discussed.

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