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1、Thermal and Flow AnalysisEstimated time to complete this course: 23 hoursThis course introduces you to the following thermal and flow analysis modules within the Advanced Simulation application:NX ThermalNX Flow NX Thermal and FlowNX Electronic Systems CoolingNX Space Systems ThermalSetup informatio
2、nPart folder: simulation NX role: Advanced with full menus System preparationNX Thermal analysisIntroductionNX Thermal is an NX Advanced Simulation application that you can use to model steady-state or transient thermal analysis for any product or system. Create your simulation using these types of
3、tools: Boundary conditions, modeling, and simulation objects To specify loads, constraints, and other objects that characterize a specific portion of the model. Although assigned to geometric features of the model (points, edges, faces, or solid bodies), boundary conditions are ultimately applied to
4、 the elements by the solver.Solution definition tools To set controls and specify solver parameters that govern the entire model. They are always applied to the solution as a whole, not to specific elements or geometry. Modifying the modelTo change geometry, access the idealized part using the Part
5、Navigator and the Modeling application. A part update applies the change to the idealized part and marks the mesh for update. Mesh changes in the Finite Element model (FEM) are automatically propagated to the Simulation. You can override the mesh collector properties, defined in the FEM file, by usi
6、ng Edit Attributes Overrides, or an Override Set simulation object in in the Simulation file. You can access and modify any simulation entity using the Simulation Navigator. Selecting an object highlights the corresponding elements or graphics symbols in the graphics window. You can also copy or clo
7、ne any boundary condition or solution.Modeling conductionThe thermal solver uses a finite volume formulation for modeling heat conduction between elements that share nodes, provided that:Thermal conductivity and specific heat properties are defined for the elements. Specific heat is required only fo
8、r transient analyses.2D elements have thickness physical property defined.1D elements have a beam section defined. 0D elements have a mass and diameter defined.Modeling convectionYou can model convection implicitly using boundary conditions provided that you define a Convection to Environment constr
9、aint on: Faces of 3D solids2D elements1D elements with cross area defined0D elements with diameter definedYou can use different types according to the phenomena modeled.Convection to Environment Use this option when you know either the Convection Coefficient or Parameter and Exponent and the fluid t
10、emperature. Free Convection to Environment Use this option when you want to use a specific free convection correlation (example: hot air rising). Forced Convection to Environment Use this option when you want to use a specific forced convection correlation (example: fans). Both in transient and stea
11、dy state solves, the solver calculates a single convection coefficient value for the entire convecting surface based on the characteristic information you specify.Convection can also be explicitly model using a coupled NX Thermal and Flow solution by simulating the fluid volume and the embedded volu
12、mes and surfaces in a model.Modeling radiationThe software simulates radiation based on view factors between radiating elements. The solver calculates black body view factors between all radiation elements. To calculate radiative conductances, it combines these factors with thermo-optical properties
13、, which you define for every radiating element. For surfaces that do not obey the gray body approximation, ray-traced view factors can be calculated instead of black body view factors. You can calculate radiation between surfaces defined by:Faces of 3D solid elements.The top and/or bottom of 2D shel
14、l elements based on the orientation of the element normals that you specify.The implied surface of 1D beam elements based on the section properties you define. The implied surface of 0D concentrated mass elements based on the diameters you specify.If you want an element or group of elements to parti
15、cipate in radiation exchange, you must apply Thermo-Optical Properties and define a Radiation simulation object to calculate view factors between these elements. Workflow and file structureStep TaskApplication and file type1. Create or import the model.Modelingpart file (.prt)2. Simplify the model u
16、sing NX Modeling and Advanced Simulation commands.Modeling and Advanced Simulation idealized part file (_i.prt)3.Define materials, physical properties, and thermo-optical properties.Advanced SimulationFEM file (.fem) 4. Mesh the model and define mesh collectors to organize meshes and assign physical properties.Associate all FEMs to their corresponding parts when using an assembly FEM.Advanced SimulationFEM file (.fem)Assembly F
