Resistance distribution-based method for analyzing sub-channel with grid mixing effect

Abstract

The invention discloses a resistance distribution-based method for analyzing a sub-channel with a grid mixing effect. The method comprises the steps of collecting experimental data of multiple mixing grids including a mixing grid of a to-be-analyzed reactor core in different working conditions, fitting a momentum source term relational expression capable of reflecting mixing performance of key parts of the mixing grids, and adding the momentum source term relational expression to a corresponding momentum conservation equation; and by solving a mass conservation equation, the momentum conservation equation and an energy conservation equation, obtaining more accurate local thermo-hydraulic parameters in the reactor core, thereby enabling prediction of a critical heat flux (CHF) value and a CHF position to be more accurate. The method is not limited by a structure and a solving method of a sub-channel program, and can be widely applied to the calculation of various types of sub-channel programs including a sub-channel program of a uniform flow model, a drift flow model or a two-fluid model.

Description

technical field [0001] The invention belongs to the technical field of fluid dynamics simulation and analysis of reactor fuel assemblies, and in particular relates to a sub-channel analysis method based on resistance distribution including grid agitation effect. Background technique [0002] In the design and operation of nuclear power plants, critical heat flux (CHF) and critical power are one of the most important parameters that limit the operation of nuclear power plants. Below the critical power, the reactor can convert nuclear energy into electricity with maximum safety. The CHF of the fuel bundle is closely related to the local thermal-hydraulic parameters of the core. Due to the complex geometric structure of the reactor core channel and the operating conditions of a wide parameter range, an analytical solution for CHF cannot be given theoretically. [0003] The CHF relational expression of traditional nuclear fuel bundles is developed based on the experimental data...

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Problems solved by technology

However, the above method cannot accurately reflect the mixing characteristics of the grid, and cannot eliminate the inaccuracy in the calculation of local thermal-hydraulic parameters, because the form resistance coefficient relation used is still irrelevant to the geometric structure of the grid.

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