Trapped air mass thermodynamic characteristic simulation method based on three-dimensional CFD

Abstract

The invention discloses a method for simulating trapped air mass thermodynamic characteristic in the pipeline rapid water filling process on the basis of computational fluid dynamics (CFD). Firstly, three-dimensional modeling and mesh generation are conducted, and a volume of fluid (VOF) method is adopted for conducting gas and water two-phase transient flow calculation; finally, post-processing software is used for processing a calculated result. According to the method, on the basis that the compressibility of water and the compressibility of gas are considered at the same time, the heat conduction among water, gas and a solid wall surface and the convective heat transferring effect are considered, energy dissipation in the rapid water filling process can be more accurately simulated, and then the gas-water coupling effect and the air mass thermodynamic characteristic in the process are more deeply studied.

Description

technical field [0001] The invention relates to a three-dimensional simulation method for air mass thermodynamic characteristics when water flow impacts and retains air mass in a water delivery overcurrent system, and belongs to the technical field of hydraulic numerical simulation of hydropower stations (pumping stations). Background technique [0002] In actual water pipeline systems such as hydropower stations and pumping stations, air masses may be trapped in the raised sections, closed ends, and vented maintenance sections along the lines. The hydraulic transients caused by expansion deformation, fission and collapse will cause pressure fluctuations and vibrations in the pipeline system, and even cause damage to the pipeline system. Most of the destruction accidents in the actual water delivery system are related to the transient flow with trapped air mass. However, so far, the design standards of the actual pipeline system only consider the situation that the pipeline...

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Problems solved by technology

For the air mass volume at any time, because the water-air interface is free to change, the high degree of air-water mixing makes it difficult to accurately measure the position and volume of the air mass

In addition, in the existing experimental research on trapped air mass, there is no accurate temperature record because the response time of the temperature sensor is much longer than the first compression process of the air mass.

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