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06:46 Mar-02-1998
Guang Li
Transducer for High Pressure Gas Flow Measurements

I am currently involved with development of transducer systems for high pressure (>1500 psi) gas flow measurements.
The requirement of high acoustic efficiency and high pressure seems to create a challenge for the design of transducers based on conventional approaches using quarter wavelength matching layers.
The main difficulty here is to find a matching material that has a low acoustic impedance and at the same time a high mechanical strength.
Without the matching layer(s), the acoustic efficiency appears too small to be useful.
Any comments or suggestions from the experts?
By the way, does anyone know of good computer simulation software for acoustics?


 
07:36 Mar-02-1998

Lucio

Consultant
COMPUTALOG RESEARCH INC,
USA,
Joined Nov 1998
1
Re: Transducer for High Pressure Gas Flow Measurements : I am currently involved with development of transducer systems for high pressure (>1500 psi) gas flow measurements.
: The requirement of high acoustic efficiency and high pressure seems to create a challenge for the design of transducers based on conventional approaches using quarter wavelength matching layers.
: The main difficulty here is to find a matching material that has a low acoustic impedance and at the same time a high mechanical strength.
: Without the matching layer(s), the acoustic efficiency appears too small to be useful.
: Any comments or suggestions from the experts?
: By the way, does anyone know of good computer simulation software for acoustics?

I know of Specialty Engineering Ass. (Dr. Alan Selfride). They sell a program model based on the KLM transmission line model using "ABCD" matrix formalism. I built transducers in the past that work in oil & gas wells. The best approach is to encapsulate the transducer with High-Temp epoxy. Make sure you know where the crystal is reference to the end of the mold (that is lambda/4). Vaccum to 50 millitorr to take all air out. This device works up to 20,000 psi or 138 MPa. and over 300 deg F.
Regards. Lucio.


 
09:42 Mar-22-1999
Dipl.-Ing. Martin Heinz
Re: Transducer for High Pressure Gas Flow Measurements Dear Mr. Guang Li,

our research and development department has collected
many experiences in the development of ultrasonic
transducers for many applications. If you need partners
for technology transfer or development support you can
contact our main office in St. Ingbert, Germany.
The contact person ist Dipl.-Ing. Thomas Hahn-José,
email: thomas.hahn@ibmt.fhg.de .

You can visit our homepage at http://www.ibmt.fhg.de .

Best regards,

Dipl.-Ing. Martin Heinz




 
07:25 Mar-09-2000
Eva
Re: Transducer for High Pressure Gas Flow Measurements : I am currently involved with development of transducer systems for high pressure (>1500 psi) gas flow measurements.
: The requirement of high acoustic efficiency and high pressure seems to create a challenge for the design of transducers based on conventional approaches using quarter wavelength matching layers.
: The main difficulty here is to find a matching material that has a low acoustic impedance and at the same time a high mechanical strength.
: Without the matching layer(s), the acoustic efficiency appears too small to be useful.
: Any comments or suggestions from the experts?
: By the way, does anyone know of good computer simulation software for acoustics?


I am faced with a similar challenge. May I ask for whom you work?



 
05:00 Mar-10-2000
Hermann Landes
Re: Transducer for High Pressure Gas Flow Measurements Dear Mr. Guang,

a collegue from the university of Linz, Austria, forwarded me your inquiry on
ultrasonic modeling tools. We have developed the
finite-element-boundary-element simulation program CAPA, which is dedicated
to the modeling of electromechanical transducers (incl. piezoelectric,
magneto-mechanical and electrostatic), acoustic wave propagation in media at
rest and in flow (incl. nonlinear acoustic waves). This program is in use at
several industrial companies and universities, worldwide, allthough primarily
based in Europe. As far as I can see from your inquiry, these problems can be
simulated with our program very efficiently.
For a first information on CAPA, you may have a look at the web-page of the
institute of Prof. Lerch at the university of Erlangen. Just point your
browser to the following address:
http://www.lse.uni-erlangen.de/CAPA/index.htm.
We have also produced a CD providing an overview over the software system.
Furthermore, the slides of the shortcourse 'Computer modeling of
electromechanical transducers' held by Lerch, Kaltenbacher, and Landes at the
IEEE ultrasonics symposium in Lake Tahoe, October 1999, are also included. In
case that you are interested in this CD, please let me know. We would be
happy to send you a copy as well as some of our recent publications.

Yours sincerely

Hermann Landes
Wissenschaftliche Software
Eisenstr.35
D-91054 Buckenhof

Germany




 


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