An optimised preconditioning procedure for gas permeability measurement

2002 ◽  
Vol 35 (1) ◽  
pp. 22-27 ◽  
Author(s):  
M. Carcassès ◽  
A. Abbas ◽  
J. -P. Ollivier ◽  
J. Verdier
Keyword(s):  
Gas Permeability ◽  
Permeability Measurement

Evaluation of Pettys Nonlinear Model in Wood Permeability Measurement

Holzforschung ◽  
2001 ◽  
Vol 55 (1) ◽  
pp. 82-86
Author(s):  
J. Lu ◽  
F. Bao ◽  
Y. Zhao
Keyword(s):  
Nonlinear Model ◽  
Gas Permeability ◽  
Optimization Algorithms ◽  
Optimization Techniques ◽  
Curvilinear Relationship ◽  
Grid Search ◽  
Permeability Measurement ◽  
Iterative Optimization ◽  
Starting Values ◽  
Least Squares Fit

Summary To calculate the effective radii of two conductive elements in series in wood specimens by using the gas permeability measurement, the four parameters from the curvilinear relationship of superficial specific permeability against reciprocal mean pressure as illustrated in Petty's model must be evaluated. This paper describes a detailed procedure for obtaining such parameters by using the least-squares fit calculated from a statistical analysis system (SAS) program. Three different iterative optimization algorithms and starting points were used separately to fit the Petty's nonlinear model based on the same experimental data from one specimen of birch. The estimate of the parameters: A = 35.38 darcy, B = 80.51 darcy, l = 0.19 darcy atm, m = 6.34 darcy atm was recommended for the fitted model. Compared to the results on the estimate of parameters obtained in the previous papers, this estimate for the parameters was a global minimum, thus it was a refinement and more accurate. Since the Gauss-Newton method resulted in almost the same convergence results for all the three sets of starting values with the least iterations in the evaluation, it was the preferred optimization algorithm both for simplicity and accuracy in solving the Petty's model. Because the same solutions for all three iterative optimization algorithms were obtained by using two different sets of starting points produced from the grid search, a grid search seemed to be very helpful for finding reasonable starting values for various iterative optimization techniques.

Optimization of 3-D Gas Permeability Measurement: Utilization of Field Data

2009 ◽  
Author(s):  
Hadi Belhaj ◽  
Bechir Mtawaa ◽  
Mohammed Haroun ◽  
Terry Lay
Keyword(s):  
Field Data ◽  
Gas Permeability ◽  
Permeability Measurement

Gas permeability measurement in polyethylene and its copolymer films

2007 ◽  
Vol 28 (9) ◽  
pp. 2528-2532 ◽  
Author(s):  
M. Gholizadeh ◽  
J. Razavi ◽  
S.A. Mousavi
Keyword(s):  
Gas Permeability ◽  
Permeability Measurement ◽  
Copolymer Films

The flexible Ca-test: An improved performance in a gas permeability measurement system

2011 ◽  
Vol 82 (5) ◽  
pp. 054702 ◽  
Author(s):  
Eun Ho Song ◽  
Young Wook Park ◽  
Jin Hwan Choi ◽  
Tae Hyun Park ◽  
Jin Wook Jeong ◽  
...  
Keyword(s):  
Measurement System ◽  
Gas Permeability ◽  
Permeability Measurement ◽  
Improved Performance

In-Situ Measurement and Monitoring of Fiber Preform Permeability for Liquid Composite Molding

2000 ◽  
Author(s):  
Zhiyong Liang ◽  
Chuck Zhang ◽  
Ben Wang ◽  
Chiang Shih
Keyword(s):  
Gas Flow ◽  
Gas Permeability ◽  
Pressure Profile ◽  
Air Permeability ◽  
Experimental Results ◽  
Liquid Composite Molding ◽  
Permeability Measurement ◽  
Fiber Preform ◽  
Composite Molding

Abstract In a liquid composite molding (LCM) process such as resin transfer molding (RTM), quality control depends on an in-situ permeability profile of the fibrous preform taken just before resin injection. However, the conventional permeability measurement method, which uses liquid (oil or resin) as its working fluid, only measures the average preform permeability in an off-line mode. It cannot be used to create an in-situ permeability profile because of fiber pollution, and cannot be used to reveal local permeability variations of preform. This study develops a new permeability characterization method that uses gas flow and pressure profiles to measure preform permeability variation in a closed mold assembly. This method is based upon two research findings: (1) that the air permeability of a preform can be obtained through measuring the pressure profile of gas flow, and (2) that resin permeability is highly correlated with air permeability for the same fiber preform. In this paper, the validity of this method is discussed. Experimental results of gas permeability measurement with defective and defect-free preforms are presented, and quantitative models for correlation of gas permeability versus pressure profile and of gas permeability versus resin permeability are also provided. Finally, the efficacy of the proposed method is illustrated through experimental results.

Non-Klinkenberg slippage phenomenon at high pressure for tight core floods using a novel high pressure gas permeability measurement system

2017 ◽  
Vol 156 ◽  
pp. 62-66 ◽  
Author(s):  
Wei-qing An ◽  
Xiang-an Yue ◽  
Xue-gang Feng ◽  
JosephYuchun Fu ◽  
Xing Fang ◽  
...  
Keyword(s):  
High Pressure ◽  
Measurement System ◽  
Gas Permeability ◽  
Permeability Measurement

Permeability Measurement of High Performance Concrete at Elevated Temperature Employing a New Test Set-Up

2015 ◽  
Vol 1124 ◽  
pp. 288-293
Author(s):  
Michaela Fiedlerová ◽  
Johannes Kirnbauer ◽  
Heinrich Bruckner
Keyword(s):  
Elevated Temperature ◽  
High Performance ◽  
Building Materials ◽  
High Performance Concrete ◽  
Gas Permeability ◽  
Permeability Measurement ◽  
Test Set ◽  
Testing Procedures ◽  
Heating And Cooling ◽  
Set Up

This paper is focused on clarifying behaviour of concrete at elevated temperature with employing new test set-up constructed at Institute of Building Construction and Technology, Vienna University of Technology. This unique test set-up allows measuring gas permeability of different building materials such as concrete or ceramic at both high temperature (up to 400°C) and pressure (up to 6 bars). Present paper illustrates a new set up for permeability measurement during the heating and cooling and different testing procedures and evaluation of their influence on results.

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