A method for evaluating the hydroelastic instability of a planar tube bundle

Abstract

The invention provides a method for evaluating the hydroelastic instability of a planar tube bundle, which comprises the following two parts: modal analysis and Connors formula calculation. The modalanalysis part is responsible for calculating the natural frequency and the corresponding vibration mode of the heat exchanger tube. The Connors formula is used to calculate the equivalent velocity andcritical velocity in different modes according to the results of modal analysis. The invention has the following advantages: by utilizing the discrete characteristics of the finite element itself, the modal analysis and calculation of different fluid parameters outside the tube, non-uniform transverse velocity and complex heat exchange tube shape can be realized; based on the finite element modalanalysis results, the Gaussian integral method is used to calculate the Connors formula, and the weighted effect of vibration mode on the equivalent velocity is realized.

Description

technical field [0001] The invention relates to a method for evaluating the fluid elastic instability of a plane tube bundle. Background technique [0002] Shell-and-tube heat exchangers are widely used in the fields of electric power and chemical industry, and mainly use heat exchange tube bundles to realize large-area heat exchange of fluid media inside and outside the tubes. When the fluid outside the tube flows through the tube bundle, its flow direction can be decomposed into longitudinal and transverse. If the lateral flow velocity is too large, fluid elastic instability will occur, causing the heat exchange tube to vibrate greatly and eventually fail. [0003] Fluid elastic instability is a fluid-structure coupling problem. The movement of each heat exchange tube will affect the fluid force and the movement of other heat exchange tubes, and generate self-excited force. For the occurrence of instability, it is generally believed that the fluid-solid coupling has an ...

AI Technical Summary

Problems solved by technology

[0006] 1) It is impossible to calculate the problem of various fluid media outside the pipe;

[0007] 2) The problem that non-uniform lateral flow velocity cannot be calculated;

[0008] 3) It is impossible to calculate the shape of complex heat exchange tubes and the form of variable-span support

[0010] Encountered the above problems can only rely on past experience, causing a lot of trouble in the design

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