RESEARCH ON ADVANCED GASDYNAMIC TEST FACILITIES. PART I. THEORETICAL AND EXPERIMENTAL STUDIES OF THE ISENTROPIC COMPRESSION TUBE.
Scientific interim rept. 1 Jul 66-31 Mar 68,
CORNELL AERONAUTICAL LAB INC BUFFALO N Y AERODYNAMIC RESEARCH DEPT
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The report describes the current status of the theory of the isentropic-compression tube and discusses several experiments which have been conducted in a pilot facility. The theoretical portion deals with two possible techniques, the braked-piston and the free-piston, for producing the isentropic flow. According to theoretical analysis, an approximation to a focused, nonsteady, isentropic-compression wave can be produced with the braked-piston method which involves a mechanically simple modification to the motion of an otherwise freely moving piston. This method would provide two distinct isentropic test flows at different positions in the tube. In the free-piston method, no modification to a free-piston trajectory is necessary but only one test region is produced. The discussion of the experiments deals with the construction and testing of a low-pressure pilot facility. It is shown that the compression process in the pump tube is very close to isentropic. Initial attempts at producing an isentropic flow using the free-piston method are described. It is shown that a close approximation to the theoretically predicted flow was achieved although the flow duration was smaller than expected. Author
- Test Facilities, Equipment and Methods