Mathematical Models of the Interaction of Structures With Liquid and Calculations on the Strength and Resonance of Blade Hydraulic Machines

Abstract

The analysis of the complex interaction "fluid – structure" (Fluid Structure Interaction, FSI) is an actual scientific problem for many industries, such as hydroturbobuilding, shipbuilding, construction, etc., the solution of which is devoted to a significant amount of theoretical research. The paper analyzes works on the problems of approaches, models, research methods and the most famous FSI modeling software systems. Despite significant existing theoretical developments, the analysis of deformation of highly loaded structures, including hydroturbines and pumps, requires the development and adaptation of appropriate models and software systems. As a result of a series of studies, a mathematical model of the stress-strain state was developed and numerical modeling of blade hydraulic machines was performed. To reproduce the movement of elements of structures and fluids, the relations of the mechanics of continuous media are used. During calculations, it is possible to determine the fields of movements, stresses and deformations; natural frequencies of oscillations of elements of hydroturbines and pumps, as well as their sensitivity to changes in structural parameters. At the same time, a set of measures is provided for the creation and improvement of blade hydraulic machines with increased technical characteristics, as well as such design and operational parameters are determined that satisfy the conditions for increased strength. The developed technique makes it possible to purposefully carry out reconstruction from resonances at the design stage of blade hydraulic machines of various structural forms and to evaluate the impact of manufacturing and operational errors. Reduction of vibration of pumps, building structures and pipelines by 5–10 times at the Kharkiv bioremediation station, which is equipped with centrifugal pumps of the FDV-9000/45 type, n = 500 min–1 , was achieved by installing additional supports on pressure pipelines after vibration tests and calculation of pipelines for resonance, recommendations for further operation of the station are also provided.