UNCONVENTIONAL METHODS FOR INFLUENCING FLUID FLOW. PART V. FLUID PRESSURE TRANSIENTS IN A TAPERED LINE.
Final rept. Jun 64-Jul 65,
CARNEGIE INST OF TECH PITTSBURGH PA DEPT OF MECHANICAL ENGINEERING
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The study includes both an experimental and theoretical analysis of the transient wave behavior through an inviscid liquid filled, rigid tapered line subjected to both step and pulse inputs. The primary objective is to determine the applicability of a tapered line to attenuate the pressure surge associated with water hammer. The analytical approach used is to divide a smoothly tapered section into a finite number of uniform lines of different characteristic impedances to form an approximation of the distributed parameter model readily solved by digital-computer computation. Three taper functions are studied in detail linear, linear area and exponential, with two different terminations long uniform line and reservoir. A step line is also studied, for which the method is exact. To verify the analytical approach and results, experiments were performed using water in a four step line made of copper tubing varying in diameter from 12 in. to 1 in. A special valve arrangement was designed to insure quick closure with minimum shock. Excellent experimental agreement was obtained. The results show that a tapered section can be used to reduce the pressure surge of water hammer when the line is terminated by a reservoir. Author
- Hydraulic and Pneumatic Equipment
- Fluid Mechanics