Papers by Cristian Pantea
This work reports, for the first time, the direct
measurement of sound speed in liquid water at t... more This work reports, for the first time, the direct
measurement of sound speed in liquid water at temperatures up
to 250°C and pressures up to 14 MPa. These measurements
enabled the determination of the acoustic nonlinearity
parameter, B/A, an important property of liquids. From an
applications perspective, B/A determines the efficiency of devices
that are based on acoustic nonlinear mixing. The objective of the
present work was to use a specialized measurement cell for sound
speed measurements and the determination of B/A in liquid
water as a function of temperature and pressure. Sound speed
was measured using Swept Frequency Acoustic Interferometry,
while B/A was determined from the derivatives of the sound
speed with respect to pressure and temperature. B/A at ambient
pressure and temperature was determined to be 4.8, in good
agreement with literature values. At 250°C and 14 MPa, B/A was
found to be roughly twice its ambient temperature value
Ultrasonics, 2012
We have devised a method, based on a parametric array concept, to create a low-frequency (300-500... more We have devised a method, based on a parametric array concept, to create a low-frequency (300-500 kHz) collimated ultrasound beam in fluids highly attenuating to sound. This collimated beam serves as the basis for designing an ultrasound visualization system that can be used in the oil exploration industry for down-hole imaging in drilling fluids. We present the results of two different approaches to generating a collimated beam in three types of highly attenuating drilling mud. In the first approach, the drilling mud itself was used as a nonlinear mixing medium to create a parametric array. However, the short absorption length in mud limits the mixing length and, consequently, the resulting beam is weak and broad. In the second improved approach, the beam generation process was confined to a separate ''frequency mixing tube'' that contained an acoustically non-linear, low attenuation medium (e.g., water) that allowed establishing a usable parametric array in the mixing tube. A low-frequency collimated beam was thus created prior to its propagation into the drilling fluid. Using the latter technique, the penetration depth of the low frequency ultrasound beam in the drilling fluid was significantly extended. We also present measurements of acoustic nonlinearity in various types of drilling mud.
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Papers by Cristian Pantea
measurement of sound speed in liquid water at temperatures up
to 250°C and pressures up to 14 MPa. These measurements
enabled the determination of the acoustic nonlinearity
parameter, B/A, an important property of liquids. From an
applications perspective, B/A determines the efficiency of devices
that are based on acoustic nonlinear mixing. The objective of the
present work was to use a specialized measurement cell for sound
speed measurements and the determination of B/A in liquid
water as a function of temperature and pressure. Sound speed
was measured using Swept Frequency Acoustic Interferometry,
while B/A was determined from the derivatives of the sound
speed with respect to pressure and temperature. B/A at ambient
pressure and temperature was determined to be 4.8, in good
agreement with literature values. At 250°C and 14 MPa, B/A was
found to be roughly twice its ambient temperature value
measurement of sound speed in liquid water at temperatures up
to 250°C and pressures up to 14 MPa. These measurements
enabled the determination of the acoustic nonlinearity
parameter, B/A, an important property of liquids. From an
applications perspective, B/A determines the efficiency of devices
that are based on acoustic nonlinear mixing. The objective of the
present work was to use a specialized measurement cell for sound
speed measurements and the determination of B/A in liquid
water as a function of temperature and pressure. Sound speed
was measured using Swept Frequency Acoustic Interferometry,
while B/A was determined from the derivatives of the sound
speed with respect to pressure and temperature. B/A at ambient
pressure and temperature was determined to be 4.8, in good
agreement with literature values. At 250°C and 14 MPa, B/A was
found to be roughly twice its ambient temperature value