Nuclear Reactor Core Fluid Flow Simulation Using Head Loss Coefficients
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Solution Overview
Problem
Current methods for simulating fluid flow inside nuclear reactor vessels are not optimal, leading to inadequate modeling of mechanical deformations in fuel assemblies, which can disrupt reactor operation and require excessive computing power.
Innovation Solution
A method that determines head loss coefficients and computes fluid pressure and speed using equations involving a matrix of head loss coefficients, allowing for efficient simulation of fluid flow and mechanical deformation calculation without excessive computing power, by interpolating values based on Reynolds numbers and clearance dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional CFD (Computational Fluid Dynamics) methods are used to simulate fluid flow in the reactor core, then measurement precision of fluid flow is improved, but computing power requirements become excessive
Solution Approach 1:
The reactor core is divided into multiple control volumes, with each control volume representing a specific region containing fuel assemblies. This segmentation allows the complex fluid flow problem to be broken down into manageable discrete units, reducing computational complexity while maintaining simulation accuracy.
Solution Approach 2:
The invention changes the simulation approach from traditional CFD to a method based on head loss coefficients and simplified pressure-speed equations. By transforming the governing equations and using empirical correlations for head loss coefficients as functions of Reynolds number, the computational burden is significantly reduced while preserving essential flow characteristics.
2Device complexity
If homogeneous modeling of the core is used, then device complexity is reduced, but manufacturing precision of deformation modeling deteriorates
Solution Approach 1:
The core model is segmented into control volumes corresponding to specific regions with fuel assemblies, allowing different hydraulic characteristics to be modeled in different regions. This enables precise deformation modeling by capturing local flow variations while maintaining overall model manageability.
Solution Approach 2:
The invention applies local quality by determining head loss coefficients specific to each control volume based on local Reynolds numbers and clearance dimensions. This allows the model to capture local flow variations and their impact on assembly deformations, improving precision without requiring excessive complexity throughout the entire model.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach provides a more precise and efficient modeling of fluid flow and mechanical deformations, improving reactor performance and reducing computational requirements.
Implementation Method 1
computing the pressure of the fluid and the component(s) of the speed of the fluid in the core, using the following equation: ∇P=−K×V where K is a matrix including the head loss coefficients
Implementation Method 2
a transverse head loss coefficient in the assemblies is determined as a function of a transverse Reynolds number in the transverse direction
Data Source
AI summary
A method for simulating the flow of a fluid in a vessel of a nuclear reactor is provided. The nuclear reactor includes the vessel and a core inside the vessel, the core including nuclear fuel assemblies, each one extending in an axial direction, including nuclear fuel rods and a grid for maintaining the rods, and being spaced apart from another by a clearance between the grids in a transverse direction.This method for simulating a fluid flow in the vessel of a nuclear reactor includes determining of head loss coefficients in the core, and computing the fluid pressure and speed component(s) in the core using the equation: ∇P=−K×V where P is the component of the fluid pressure, K is a matrix including the determined head loss coefficients, and V is a vector including the fluid speed component(s).A transverse head loss coefficient in the assemblies is determined from a transverse Reynolds number, and an axial head loss coefficient in the clearance is from the dimension of the clearance in the transverse direction.