TECHNICAL MECHANICS
ISSN (Print): 1561-9184, ISSN (Online): 2616-6380

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UDC 621.671:532.528

Technical mechanics, 2014, 3, 79 - 86

DETERMINATION OF PARAMETERS OF CAVITATION SELF-OSCILLATION IN HYDRAULIC SYSTEM UNDER SIMULTANEOUS LONGITUDINAL OSCILLATION OF PIPE STRUCTURE AND FLUID

Dolgopolov S. I.

      The paper deals simultaneous longitudinal oscillation of feed pipes of liquid rocket engines (LRE) and flu-ids. Cavities, normally occurring in operations of LRE pumps, can result in self-excited low-frequency of the fluid flow and pressure oscillation designated as cavitation oscillations.

      They may be hazardous because cavitation oscillation can disturb the normal operation of the propulsion system. A range of frequencies of cavitation oscillation (from 0 to 50 Hz) and a range of proper frequencies of oscillation of the pipe structure in a longitudinal direction can cross each other.

      The goal of this work is to develop a nonlinear mathematical model of simultaneous longitudinal oscillation of the feed pipe structure and the fluid and to derive parameters of self-excited cavitation oscillation. Simultane-ous longitudinal oscillation of the LRE feed pipe and fluid are modeled mathematically for the bench hydraulic system with the cavitating centrifugal impeller pump of the LRE.

      It is shown that the most interaction of oscillatory circuits of the fluid and the pipe structure is found with closely related partial frequencies of oscillation of the fluid and the pipe structure. It is accompanied by the drop in values of oscillatory amplitudes of the fluid pressures at the pump inlet as well as maximum values of oscilla-tory amplitudes of longitudinal force and longitudinal displacement of the pipe structure. The calculating results are in good agreement with the experimental results.

liquid rocket engines, cavitating pumps, cavitation oscillation, interactions between oscillation contours of fluid and pipe structure, simultaneous longitudinal oscillation of structure of feed pipe and fluid

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Copyright (©) 2014 Dolgopolov S. I.

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