Method for predicting vibration performance of movable guide vane of water turbine

Abstract

The invention relates to a method for predicting vibration performance of a movable guide vane of a water turbine and belongs to the technical field of hydraulic machines and system coupling simulation thereof. The method comprises the following steps: acquiring a steady flow field as the initial value condition of the flow field under the initial design configuration of the guide vane by utilizing design condition flow as the inlet boundary condition of fluid calculation; alternately calling a structural calculation module and a fluid calculation module in one time step, and integrally and synchronously advancing the fluid calculation and structural calculation after the condition of convergence is met; transmitting fluid-solid boundary information through an interface information switching module; outputting structural vibration displacement in time history. According to the method provided by the invention, coupling calculation of the guide vane and the flow field is realized; the method is obviously improved in accuracy in comparison with traditional simple structural dynamics methods and unidirectional coupling methods, and moreover, the whole vibration development process of the guide vane can be observed, and therefore, the structural design can be helped better guided, so that fluid-solid coupling goes into practical engineering application from theoretical study.

Description

technical field [0001] The invention relates to a method for predicting the vibration characteristics of movable guide vanes of a water turbine, and belongs to the technical field of hydraulic machinery and system coupling simulation thereof. Background technique [0002] The problem of unit vibration and blade cracks has become a key technical problem that needs to be solved urgently in hydropower stations. However, the mechanism of hydraulic vibration of hydraulic turbines is very complicated, with many difficulties and involves many disciplines, such as hydraulic disturbance caused by Karman vortices behind the blades, cavitation and shedding The hydroelastic vibration of the water and the vibration induced by the cavity vortex in the draft tube, etc. These are extremely difficult problems, and they are also the main reasons for the vibration of the turbine, which have been paid great attention by the academic and engineering circles for many years. However, due to the co...

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Problems solved by technology

However, due to the complexity of the problem, no satisfactory results have been obtained so far

[0003] However, there are some obvious deficiencies in the traditional blade vibration analysis method: for example, the traditional structural dynamics analysis method isolates the flow field from the deformation of the guide vane, ignores the influence of the deformation of the guide vane on the flow field, and introduces a large number of linearization Hypothesis, weakening or even eliminating nonlinearity, greatly reducing simulation accuracy

In the past, a single flow field calculation or a single structure calculation played a guiding role in unit efficiency, cavitation prediction, or structural design, but it was powerless to study hydraulic vibration, blade crack formation, etc., so the method of fluid-solid coupling calculation was adopted , it is imperative to study the coupled vibration between this type of complex turbulent flow and large thin-walled structures, and it is also one of the most challenging topics

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