ANALYSIS OF THE OPTIMUM PERFORMANCE OF BUFFERED SHOCK TUBES
Interim technical rept. May 1962-Jul 1963
CORNELL AERONAUTICAL LAB INC BUFFALO NY
Pagination or Media Count:
This report presents a general investigation of buffered shock tubes. For the case of strong shocks the number of variables needed for the analysis of buffered shock tubes is reduced to three. An expression is obtained from which the buffer conditions necessary for the production of the maximum shock Mach number are determined. The strong shock analysis is extended to include shock tubes with many buffers and buffered shock tubes with area changes at either or both diaphragms. The concept of using a detonable mixture as a buffer gas is explored and its limitations are indicated. Also, a study is included of different shock tube geometrical configurations to indicate means of achieving the maximum testing time. A number of general conclusions can be drawn from this study. For given over-all conditions a buffered shock tube will produce stronger shocks than a simple shock tube provided that the optimum buffer conditions are used. The performance of a shock tube improves as the number of buffers increases, but the final shock strength soon approaches an asymptotic value. The performance of a buffered tube is improved by using an over-all area contraction the most efficient distribution involves equal area changes at each diaphragm. The gain in performance obtained with a detonation buffer is limited when the final shocks are very strong. For fixed driver conditions and final shock strength, increasing the diameter of the driven section does not significantly increase the testing time.
- Test Facilities, Equipment and Methods