CN-121615565-B - Valve cavitation prediction and inhibition method under high-temperature working condition

CN121615565BCN 121615565 BCN121615565 BCN 121615565BCN-121615565-B

Abstract

The invention discloses a valve cavitation prediction and inhibition method under a high-temperature working condition, and belongs to the technical field of fluid machinery and control. The method aims at the problem of inaccurate valve cavitation numerical simulation under a high-temperature working condition, accurately reflects the change of physical parameters of a working medium in an actual high-temperature environment by introducing temperature correction under the high-temperature working condition into an interface capture model, a cavitation model and the physical parameters of the working medium in simulation, improves the simulation accuracy of a cavitation flow field, analyzes a cavitation area by applying an entropy-pressure cooperation criterion on the basis, and carries out targeted optimization on a valve body structure according to analysis results. The invention effectively solves the problem of inaccurate numerical simulation of the valve hollowing phenomenon under high-temperature working conditions, and can provide accurate guidance for reliable design and performance optimization of the valve under high-temperature working conditions such as metallurgy.

Inventors

LIN ZHE
YANG JINGPING
TAO JUNYU
DING SHIMING
CHEN DESHENG

Assignees

浙江理工大学

Dates

Publication Date: 20260505
Application Date: 20260203

Claims (8)

1. The valve cavitation prediction and inhibition method under the high-temperature working condition is characterized by comprising the following steps of: s1, constructing a flow field model of a valve; S2, carrying out grid division and encryption on the flow field model to obtain a flow field grid model; S3, performing simulation calculation on the flow field grid model to obtain a simulation result, wherein the simulation needs to set a turbulence model, an interface capturing model and a cavitation model, boundary conditions and physical parameters of a working medium according to actual working conditions, and correcting temperature changes of the interface capturing model, the cavitation model and the physical parameters of the working medium under high-temperature working conditions; s4, processing the simulation result to obtain a total volume of gas phase in a flow field, a pressure cloud picture and an entropy yield distribution cloud picture; S5, analyzing a pressure cloud chart of the flow field and an entropy yield distribution cloud chart by using an entropy pressure cooperation criterion to evaluate cavitation, wherein the entropy pressure cooperation criterion is that a cavitation area is divided into high, medium and low entropy yield areas according to the ratio of local entropy yield to peak entropy yield in the entropy yield distribution cloud chart; And S6, optimizing a high entropy yield area and a low pressure area in the valve flow channel according to an analysis result of the entropy pressure cooperation criterion, and taking the total volume of gas phase in the flow field as a calculation basis until the cavitation suppression coefficient is greater than or equal to a set threshold value.
2. The method for predicting and suppressing valve cavitation under high-temperature working conditions as claimed in claim 1, wherein constructing a flow field model of the valve comprises: Modeling is carried out through three-dimensional modeling software according to structural parameters of the valve, and a valve geometric model is processed by using Boolean operation, volume extraction or filling methods to obtain a flow field model of the valve.
3. The method for predicting and suppressing valve cavitation under high-temperature working condition as claimed in claim 1, wherein the mesh division and encryption are performed on the flow field model to obtain a flow field mesh model, comprising: And carrying out primary grid division on the flow field model, then carrying out local encryption on grids near the valve chokes or the flow channel throats, and carrying out global encryption on the grid model after local encryption on the basis, thereby generating the flow field grid model.
4. The method for predicting and suppressing valve cavitation under high-temperature conditions as claimed in claim 1, wherein the modification of the interface capture model comprises: Considering the influence of surface tension on cavitation interface evolution, and equivalent the surface tension effect as a volume force source term acting on a momentum equation The definition is as follows: ; In the formula, Is the surface tension coefficient of working medium; Is the interface curvature; Is a phase fraction gradient; Wherein the surface tension coefficient of the working medium The temperature-affected calculation was performed using the following correction formula: ; Wherein σ 0 is the surface tension coefficient at the reference temperature; temperature coefficient of surface tension, T 0 is the selected reference temperature, and T is temperature.
5. The method for predicting and suppressing valve cavitation under high-temperature conditions as claimed in claim 1, wherein the modification of the cavitation model comprises: In order to characterize the temperature dependence of saturated vapor pressure, the saturated vapor pressure related to an evaporation source item and a condensation source item in the cavitation model is corrected by adopting the following functional relation: ; In the formula, The saturated vapor pressure, the temperature and the constant A, B, C are respectively T and A, B, C, and the saturated vapor pressure and the temperature are related to the saturated vapor pressure and the temperature of the working medium.
6. The method for predicting and suppressing valve cavitation under high-temperature working conditions as claimed in claim 1, wherein the modification of the physical parameters of the working medium comprises: When the physical parameters of the working medium are set, the influence of the viscosity of the working medium on cavitation phenomenon along with the temperature change is considered, and in order to accurately represent the dependence, the dynamic viscosity of the working medium at different temperatures is corrected by adopting the following formula: ; In the formula, The viscosity is the dynamic viscosity of working medium, T is the temperature, and a and b are constants.
7. The method for predicting and suppressing valve cavitation under high temperature condition according to claim 1, wherein optimizing the high entropy yield area and the low pressure area according to the analysis result of the entropy-pressure cooperation criterion, taking the total volume of gas phase in the flow field as the calculation basis until the cavitation suppression coefficient is greater than or equal to the set threshold value, comprises: S61, calculating the total volume of the first gas phase in the flow field grid model before optimization; S62, optimizing a high entropy yield area and a low pressure area according to an analysis result of the entropy pressure cooperative criterion; s63, calculating the second total gas phase volume in the optimized flow field grid model; And S64, calculating a cavitation suppression coefficient according to the total volume of the first gas phase and the total volume of the second gas phase, judging that the cavitation suppression meets the requirement if the cavitation suppression coefficient is greater than or equal to a set threshold value, ending the flow, and otherwise, returning to S62 to continue iteration.
8. The valve cavitation prediction and suppression method under high temperature conditions according to claim 1 or 7, wherein the expression of the cavitation suppression coefficient is as follows: ; In the formula, Is the cavitation suppression coefficient; The total volume of the first gas phase in the flow field grid model before optimization; and (3) the second total volume of gas phase in the optimized flow field grid model.

Description

Valve cavitation prediction and inhibition method under high-temperature working condition Technical Field The application relates to the technical field of fluid machinery and control, in particular to a valve cavitation prediction and inhibition method under a high-temperature working condition. Background The valve is used as a core element for fluid transmission and control in chemical process, energy power and aerospace, and the performance reliability of the valve directly determines the running stability of the whole equipment. In high-temperature industrial scenes such as metallurgical continuous casting process, the hydraulic system needs to face severe thermal working conditions for a long time. For example, in a shell guide section of a continuous caster or a descaling system of a hot rolling mill, ambient radiant heat and process heat loads can continuously maintain hydraulic oil temperatures above 60 ℃ even short term breakthrough of 80 ℃. Under such high temperature working conditions, cavitation is more easily caused in the valve by throttling effect, namely when the local pressure of the flow field is lower than the saturated vapor pressure corresponding to the current oil temperature, liquid is severely vaporized to generate cavitation bubbles, the cavitation bubbles move to a high pressure area along with the fluid to collapse, and generated microjet and shock waves can sharply aggravate cavitation abrasion of valve core and valve body materials, cause high-frequency vibration and noise of a system and seriously threaten the continuity and safety of production. At present, the research method for valve cavitation mainly comprises two types of experimental research and numerical simulation. However, under high-temperature industrial environments such as metallurgy, experimental research faces great challenges that the flow field is extremely difficult to visualize due to the high-temperature and high-pressure closed working condition, the experimental cost is high, the period is long, and the details of the transient flow field are difficult to capture. While the numerical simulation method based on Computational Fluid Dynamics (CFD) can compensate for experimental short plates, the accuracy of the numerical simulation method still depends on physical property parameter setting. The conventional numerical analysis method cannot fully consider the decisive influence of the change of key parameters such as saturated vapor pressure, surface tension coefficient, viscosity and the like of hydraulic oil along with temperature on cavitation dynamics behavior under a high-temperature working condition. The simulation result is deviated from the working condition of high Wen Shiji, so that effective guidance cannot be provided for cavitation inhibition and structural optimization of the valve, and the simulation result becomes a technical bottleneck for restricting the improvement of the performance of high-heat load equipment such as metallurgy. Disclosure of Invention In view of the above, the embodiment of the application provides a valve cavitation prediction and inhibition method under a high-temperature working condition, which aims to solve the problem that the cavitation numerical simulation result and the actual deviation are larger because the influence of temperature on the physical property of hydraulic oil is not fully considered in the prior art. According to the embodiment of the application, a valve cavitation prediction and inhibition method under a high-temperature working condition is provided, which comprises the following steps: s1, constructing a flow field model of a valve; S2, carrying out grid division and encryption on the flow field model to obtain a flow field grid model; S3, performing simulation calculation on the flow field grid model to obtain a simulation result, wherein the simulation needs to set a turbulence model, an interface capturing model and a cavitation model, boundary conditions and hydraulic oil physical parameters according to actual working conditions, and correcting temperature changes of the interface capturing model, the cavitation model and the hydraulic oil physical parameters under high-temperature working conditions; s4, processing the simulation result to obtain a total volume of gas phase in a flow field, a pressure cloud picture and an entropy yield distribution cloud picture; S5, analyzing a pressure cloud chart of the flow field and an entropy yield distribution cloud chart by using an entropy pressure cooperation criterion to evaluate cavitation, wherein the entropy pressure cooperation criterion is that a cavitation area is divided into high, medium and low entropy yield areas according to the ratio of local entropy yield to peak entropy yield in the entropy yield distribution cloud chart; and S6, optimizing the high-entropy yield area and the low-pressure area according to the analysis result of the entropy-pressure cooperation criterion,