Measuring Nozzle Erosion in a Rocket Motor Using Ultrasound

In this research, nozzle erosion in a small scale hybrid rocket motor is measured using ultrasonic methods. Nozzle throat erosion can lead to large performance losses in long burning rockets, and ultrasonic methods could provide real time information on the nozzle throat geometry in a flight weight package. A challenge arising in the usage of ultrasonic methods is the thermal problem. The speed of sound in the nozzle material can change by a factor of two due to the intense heating experienced during a motor firing. Furthermore, thermal properties of the nozzle material change drastically over the range of temperatures experienced at the throat region, which results in nonlinear thermal behavior in the nozzle material. To account for these changes, it is required to have accurate heat transfer models, thermal properties, and temperature measurements within the nozzle material. An inverse heat transfer algorithm has been developed to compute temperature profiles in the nozzle as well as heat flux experienced at the inner nozzle throat surface from experimental temperature measurements. The temperature profiles are then used in conjunction with ultrasound data to give an accurate time-varying estimate of the nozzle throat diameter.

References
  1. Sutton, G.P. and O. Biblarz, Rocket Propulsion Elements, Hoboken, NJ: John Wiley & Sons, Inc., 2010.
  2. Hill, P. and C. Peterson, Mechanics and Thermodynamics of Propulsion, Addison-Wesley Pub. Co., 1992.
  3. Zilliac, G. and M. A. Karabeyoglu, "Hybrid Rocket Fuel Regression Rate Data and Modeling," in 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference, 2006.
  4. Chandler A., E. Jens, B. J. Cantwell and G. S. Hubbard, "Visualization of the Liquid Layer Combustion of Paraffin Fuel for Hybrid Rocket Applications," AIAA/ASME/SAE/ASEE Joint Propulsion Conference, Atlanta, Georgia, 2012.
  5. Omega Engineering Inc., "Thermocouple Response Time," [Online]. Available: http://www.omega.com/temperature/Z/ThermocoupleResponseTime.html. [Accessed 5 January 2015].
  6. Linseis Inc., "LFA 1000/1000 HT, Thermal Diffusivity & Thermal Conductivity," 15 Noveber 2014. [Online]. Available: http://www.linseis.com/uploads/media/Laserflash_LFA_1000_ENG.pdf.
  7. Page, D., The Industrial Graphite Engineering Handbook, Danbury, CT: UCAR Carbon Co., 1991.
  8. Uher, C., "Temperature dependence of thermal conductivity of graphite," in Thermal Conductivity of Pure Metals and Alloys, Berlin, Springer Berlin Heidelberg, 1992, pp. 430-439.
  9. Zagzebski, J.A., Essentials of Ultrasound Physics, St. Louis, Missouri: Mosby, Inc., 1996.
  10. Marlowe, M., "Elastic Properties of Three Grades of Fine Grained Graphite to 2000C," General Electric Company, Pleasanton, CA, 1970.
  11. Incropera, F.P., D. P. Dewitt, T. L. Bergman and A. S. Lavine, Fundamentals of Heat and Mass Transfer, Hoboken, NJ: John Wiley & Sons, Inc., 2007.
  12. Moin, P., Fundamentals of Engineering Numerical Analysis, New York: Cambridge University Press, 2010.
  13. The Scipy Community, "Scipy v0.14.0 Reference Guide," 11 May 2014. [Online]. Available: http://docs.scipy.org/doc/scipy-0.14.0/reference/generated/scipy.optimize.fmin.html. [Accessed January 5 2015].
  14. Beck, J.V., B. Blackwell and C. R. St. Clair, Inverse Heat Conduction, Ill-posed Problems, New York: John Wiley & Sons, Inc., 1985.
Metrics
Usage Shares
Total Views
73 Page Views
Total Shares
0 Tweets
73
0 PDF Downloads
0
0 Facebook Shares
Total Usage
73