F-8401 Nozzle Turbulance Check

Flow Analysis of Fluid through Nozzle Having Variance in Inside Diameter

1. Introduction

Flow analysis of fluid through nozzle with Having Variance in inside Diameter is carried out using CFD. Computational fluid dynamics (CFD) is a branch of fluid mechanics that use numerical methods and algorithms to solve and analyze problems that involve fluid flows.

2. Objective

The objective of this analysis is to investigate and study, the possibility of turbulence development when product flows through a nozzle with slightly varying inside diameter of pipe and flange for 10 inch and 12 inch nozzles.

3. Software Used

ANSYS WorkbenchTM 2.0 Framework, Version 15.0.7: - ANSYS WORKBENCH manages the solvers with the project management tools necessary for the project workflow. In ANSYS WORKBENCH, analyses are built as systems, which can be combined into a project. The project is driven by a schematic workflow that controls the connectivity between the systems. Applications that can be accessed from Workbench include: ANSYS DESIGN MODELER (for geometry creation); ANSYS Meshing (for mesh generation); ANSYS FLUENT (for setting up and solving fluid dynamics analyses) and ANSYS CFD-POST (for post processing the results

ANSYS DESIGN MODELER: - The DESIGN MODELER application is designed to be used as a geometry editor of existing CAD models. The DESIGN MODELER application is a parametric feature-based solid modeler designed for drawing 2D sketches, modeling 3D parts, or uploading 3D CAD models for engineering analysis preprocessing. DESIGN MODELER can also be used to import 3D geometry modeled using other solid modeling software.

ICM CFD: - ANSYS ICEM CFD provides advanced geometry acquisition, mesh generation, and mesh optimization tools to meet the requirement for integrated mesh generation for sophisticated analyses. Maintaining a close relationship with the geometry during mesh generation, ICEM CFD is used especially in engineering applications such as computational fluid dynamics and structural analysis. ANSYS ICEM CFD’s mesh generation tools offer the capability to parametrically create meshes from geometry in numerous formats namely Multi block structured, Unstructured hexahedral, Unstructured tetrahedral, Cartesian with H-grid refinement, Hybrid meshes comprising hexahedral, tetrahedral, pyramidal and/or prismatic elements and Quadrilateral and triangular surface meshes. ANSYS ICEM CFD provides a direct link between geometry and analysis. Beginning with a robust geometry module which supports the creation and modification of surfaces, curves and points, ANSYS ICEM CFD’s open geometry database offers the flexibility to combine geometric information in various formats for mesh generation. The resulting structured or unstructured meshes, topology, inter-domain connectivity and boundary conditions are then stored in a database where they can easily be translated to input files formatted for a particular solver.

ANSYS FLUENT: - ANSYS FLUENT is a state-of-the-art computer program for modeling fluid flow, heat transfer, and chemical reactions in complex geometries. ANSYS FLUENT provides complete mesh flexibility, including the ability to solve flow problems using unstructured meshes that can be generated about complex geometries with relative ease. Supported mesh types include 2D triangular/ quadrilateral, 3D tetrahedral/ hexahedral/pyramid/ wedge/polyhedral, and mixed (hybrid) meshes. ANSYS FLUENT also enables you to refine or coarsen your mesh based on the flow solution. After a mesh has been read into ANSYS FLUENT, all remaining operations are performed within ANSYS FLUENT. These include setting boundary conditions, defining fluid properties, executing the solution, refining the mesh, and post processing and viewing the results.

ANSYS CFD-POST: - CFD-POST is a graphical user interface that includes a viewer pane in which all graphical output from CFD-POST is plotted. It provides support for a variety of graphical and geometric objects used to create post-processing plots, to visualize the mesh, and to define locations for quantitative calculation.

4. Tank Details Tank No: F-8401 Tank Service: Demin Water Tank Tank Type: Stainless Steel Cone Roof Tank Inside Diameter: 15700 mm. Height of Tank: 17100 mm (up to top of curb angle) Density: 992 kg/m3 Viscosity: 8.9 e-4 kg./m/s

5. Nozzle Details Nozzle Mark N2 Nozzle size: 10 inch NPS Pipe used: 10 inch schedule 80S (12.7 mm thick) Flange used: 10 inch B 16.5 WNRF Flange weld end thickness Schedule 80 (15.08 mm thick) Taper provided at flange to pipe weld: 1:3 Nozzle Mark N9B Nozzle size: 10 inch NPS Pipe used: 10 inch schedule 80S (12.7 mm thick) Flange used: 10 inch B 16.5 WNRF Flange weld end thickness Schedule 80 (15.08 mm thick) Taper provided at flange to pipe weld: 1:3 Nozzle Mark N8 Nozzle size: 12 inch NPS Pipe used: 12 inch schedule 80S (12.7 mm thick) Flange used: 12 inch B 16.5 WNRF Flange weld end thickness Schedule 80 (17.48 mm thick) Taper provided at flange to pipe weld: 1:3

6. Boundary Condition Maximum and Minimum Flow rate provided by process team is 186 and 30 m^3/hr which cause 4.3 m/s and 0.7 m/s average velocity inside the pipe. From design point of view maximum inlet velocity considered is 5 m/s and minimum 0.5 m/s and analysis is done fo0r both conditions to evaluate the turbulence. Evaluation is done for following conditions a. 10 inch nozzle (Nozzle N2 and N9B) with velocity 0.5 m/s b. 10 inch nozzle (Nozzle N2 and N9B) with velocity 5.0 m/s c. 12 inch nozzle (Nozzle N8) with velocity 0.5 m/s d. 12 inch nozzle (Nozzle N8) with velocity 5.0 m/s

7. Modeling

The 3D modeling of the section of liquid is done using ANSYS WORKBENCH DESIGN MODELER. Model created is in scale 1:1 for accurate results.

3D Model of Fluid Flow through 10 inch nozzle with transition area

3D Model of Fluid Flow through 12 inch nozzle with transition area

8. Meshing

Separate Meshing of the model is done using ANSYS mesh tool ICM CFD Details of Mesh is as follows

Initial size seed: Active Assembly Smoothing: High Transition: Slow Span Angle Center: Fine Inflation option: Smooth Transition Transition Ratio: 0.272 Maximum Layers: 5 Growth rate: 1.2 Inflation Algorithm: Pre

3D Model of Fluid Flow through 10 inch nozzle with transition area:- After Meshing

3D Model of Fluid Flow through 12 inch nozzle with transition area:- After Meshing

9. Solution. Flow analysis of the loading system is carried out using ANSYS FLUENT.

10. Results Result Generation is done using CFD Post. Detailed results are depicted in below figures

Velocity Streamline Distribution through 10 inch Nozzle (N2 and N9B) when average velocity is 5 m/s at high, medium and low streamline density

Velocity Streamline Distribution through 10 inch Nozzle (N2 and N9B) when average velocity is 0.5 m/s at high, medium and low streamline density

Velocity Streamline Distribution through 12 inch Nozzle (N8) when average velocity is 5 m/s at high, medium and low streamline density

Velocity Streamline Distribution through 12 inch Nozzle (N8) when average velocity is 0.5 m/s at high, medium and low streamline density

11. Inference

From the results it is clear that no considerable modification of flow pattern occurs due to diameter transition area. It can be seen that the velocity pattern is same at both ends of transition area. Also it is clear that no turbulence induced due to transition in diameter. Hence chance of turbulence and erosion due to inside diameter difference is negligible.