Improvement suction lines of hydraulic systems taking into account cavitation
Design, construction and manufacturing of flying vehicles
Irkutsk National Research Technical University, 83, Lermontov str., Irkutsk, 664074, Russia
Research is directed to the solution of the task of designing and modernization of suction pipelines structure of hydraulic systems to improve resource using systems engineering analysis.
Purpose — development and testing the search technique and eliminating of hydrodynamic and vibratory cavitation in suction pipelines structure at various mode, including transient.
In this paper proposed solution technique of similar task. Technique consists of several basic steps.
Hydrodynamic analysis of structure for search of hydrodynamic cavitation and determine flow resistance of the suction pipelines.
Analysis of proper frequency and vibration mode of suction pipelines structure of hydraulic systems.
Modernization of structure by changing of spatial configuration of pipelines (for reducing flow resistance and eliminating of hydrodynamic cavitation) with frequency equalization fr om resonance frequencies (for eliminating of vibratory cavitation).
Hydrodynamic analysis, by-turn, consists of the following steps:
Analysis of operating conditions of suction pipelines to detection the most dangerous modes (transient process of increase pump delivery from minimum to maximum, minimum pressure is provided in the pipeline, temperature conditions);
Hydrodynamic analysis in nonstationary formulation on transient process to detection the critical drop of pressure moment — the worst moment of transient process;
Hydrodynamic analysis in static formulation taking into account cavitation with boundary condition, conforming to the worst moment of transient process;
Technique approbation was made by the example of suction pipelines section of hydraulic systems of modern aircraft wh ere possible cavitation.
Cavitation occurrence was noted during transient process of increase pump delivery from minimum to maximum. For a certain time inside of solution of quasistationary task the origins and the points of cavitation occurrence and the volumetric concentration value of saturated vapor.
The developed technique allowed to identify the pipelines section, including the points which are dangerous in the view of hydrodynamic cavitation occurrence and the points which are dangerous in the view of vibratory cavitation occurrence. Two variants of modernization were suggested. It was considered using the described technique. As a result of assessment changes the efficiency of one of the samples. At that, the data received as a result of simulation goes with real pattern inside the pipeline, it confirms correctness and justifiability of the suggested technique.
Keywords:hydraulic systems, pipeline, cavitation, vibration, resonance
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