Improved materials characterization by pressure-dependent ultrasonic attenuation in air-filled permeable solids
نویسندگان
چکیده
Recently developed airborne ultrasonic inspection techniques can supplement other methods routinely used for materials characterization of permeable solids. In particular, the velocity and attenuation of the slow compressional wave transmitted through thin plates of a few millimeter thickness can be used to assess the tortuosity and dynamic permeability of the specimen. The main advantage of the ultrasonic method over conventional flow resistivity, electrical conductivity, and other measurements is that it can be used to study the heterogeneity of the pore structure at scales comparable to the grain size. In the 100–500 kHz frequency range slow wave images can be obtained with resolution on the order of 1 mm or better. However, due to substantial viscous and scattering losses, the sensitivity of the method is relatively low therefore, the technique is limited to materials of at least 10% connected porosity and permeability higher than 200 mD. It is demonstrated in this letter that varying the air pressure significantly enhances the capabilities of slow wave inspection. Using high-pressure air saturation significantly reduces the absorption losses so that better resolution can be achieved by increasing the frequency. Alternatively, materials of lower permeability or specimens of higher thickness can be inspected at the same frequency. In addition, scattering losses can be eliminated by subtracting images taken at the same frequency but at different pressures. © 1996 American Institute of Physics. @S0003-6951~96!00526-8#
منابع مشابه
Slow wave propagation in air-filled permeable solids
The propagation of slow compressional waves in air-saturated permeable solids was studied by experimental means between 10 and 500 kHz. The velocity and attenuation coefficient were measured as functions of frequency from the insertion delay and loss of airborne ultrasonic waves transmitted through thin slabs of 1-5 mm in thickness. Porous ceramics of 2-70 Darcy and natural rocks of 200-700 mDa...
متن کاملDetermination of the viscous characteristic length in air-filled porous materials by ultrasonic attenuation measurements
متن کامل
An Estimation of Wave Attenuation Factor in Ultrasonic Assisted Gravity Drainage Process
It has been proved that ultrasonic energy can considerably increase the amount of oil recovery in an immiscible displacement process. Although many studies have been performed on investigating the roles of ultrasonic waves, based on the best of our knowledge, little attention has been paid to evaluate wave attenuation parameter, which is an important parameter in the determination of the energy...
متن کاملThe Ability of Ultrasonic Characterization to Extract the Dose Distribution of MAGIC-f Polymer Gel
Background & Aims: Today, different imaging techniques have been studied in the reading of radiationsensitive polymer gels dosage. Due to limitations of imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT), ultrasound techniques are proposed for dose-dependent parameter extraction. In this study, using MAGIC-f (methacrylic and ascorbic acid in gelatin initiat...
متن کاملAir-Coupled Low Frequency Ultrasonic Transducers and Arrays with PMN-32%PT Piezoelectric Crystals
Air-coupled ultrasonic techniques are being increasingly used for material characterization, non-destructive evaluation of composite materials using guided waves as well as for distance measurements. Application of those techniques is mainly limited by the big losses of ultrasonic signals due to attenuation and mismatch of the acoustic impedances of ultrasonic transducers and air. One of the wa...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
دوره شماره
صفحات -
تاریخ انتشار 2002