NASA STTR 2004 Solicitation


RESEARCH SUBTOPIC TITLE:Rocket Propulsion Testing Systems
PROPOSAL TITLE: Energy Based Acoustic Measurement Sensors

NAME: STITechnologies, Inc. NAME:Brigham Young University
ADDRESS:1800 Brighton-Henrietta Town Line Rd ADDRESS:Brigham Young University
CITY:Rochester CITY:Provo
STATE/ZIP:NY  14623-2508 STATE/ZIP:UT  84602-4673
PHONE: (585) 424-2010 PHONE: (801) 422-2205

Timothy   Nichols

TECHNICAL ABSTRACT ( Limit 2000 characters, approximately 200 words)
This research focuses on fully developing energy density sensors that will yield a significant benefit both for measurements of interest to NASA, as well as for general acoustic measurements. Previous research has developed prototype energy density sensors. The Phase I research focused on developing effective calibration techniques for these probes, testing and validating the probes to identify the most effective design, developing a sofware interface to facilitate user-friendly data acquisition, and developing software to measure acoustic directivity and sound power using the energy sensors. Phase II research objectives extend the use of these sensors to measure source directivity and sound power. Energy propagation will be determined from these measurements. A major Phase II focus will be the development of a high-temperature, high pressure design for the energy density sensor, as well as investigating nonlinear effects on these energy-based measurements.
NASA applications of the technology include characterizing radiation from rocket plumes to better understand the mechanisms involved and to match numerical codes. Non-Nasa applications are many, including such tasks as in-situ measurements of sound, power and radiation characteristics of sources.

POTENTIAL NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
The proposed research will contribute directly to NASA interests. The energy density measurements will provide information about the combustion and flow processes which occur during the burn cycle of the rocket motor. The sound field characterization data could be used to update CFD and FEA models, as well as to provide data to determine acoustic loads on surrounding structures of concern. These energy density sensors could also be used in conjunction with active noise control techniques to alter the acoustic field and thereby probe the field to gain a better understanding of the radiation mechanisms.

POTENTIAL NON-NASA COMMERCIAL APPLICATIONS ( Limit 1500 characters, approximately 150 words)
The energy density sensors developed will be capable of making acoustic sound power measurements, in both free-field and reverberant field conditions, and under less stringent conditions than is currently required. The sensors will also be useful for acoustic holography applications, and will significantly reduce the measurement time required for this application. With these reconstruction techniques, the energy density measurements can be processed to determine source directivity, and can possibly be used for source identification. A final potential application is for sound field equalization, in which the sound field is equalized using energy density sensors, rather than pressure sensors.

Form Printed on 01-27-06 14:58