Flow Analysis of Industrial Equipment using the native ... · PDF fileFlow Analysis of Industrial Equipment using the native OpenFOAM GUI HELYX. ... Pipe stress calculations ... Extended

Flow Analysis of Industrial Equipment using the native OpenFOAM GUI HELYX Dutch OpenFOAM® Users Group – 6th user meeting

September 17th, 2013

2/54 © Dynaflow Research Group, all rights reserved

Agenda

Introduction HELYX: Improved OpenFOAM® version with GUI HELYX-MESH: Mesh enhancements Case 1: Analysis of a pump suction line Case 2: Analysis of an actuated butterfly valve Final words


Profile Dynaflow Research Group (DRG)

Engineering consultant Pipe stress calculations Stress calculations in vessels, heat exchangers, other equipment Transient pipe flow calculations Since 5 years increasingly CFD (either directly or within project scope)

Clients mostly Oil and Gas industry Benefits of OpenFOAM Cheaper than commercial CFD (HELYX 11,500 EUR annual fee) Low additional parallelization Access to source code


Challenges using OpenFOAM® solved by using HELYX

Clients have doubts about using OpenFOAM® compared to commercial CFD Mostly ignorance at the client results in concerns about reliability of results Solved by an alliance with ENGYS to use and act as a reseller of HELYX CFD

Meshing Robustness Quality in complex industrial geometries Fast and reliable meshing allows faster project handling


Agenda



What exactly is HELYX CFD?

HELYX-GUI: Propriety Native GUI tailored for the HELYX-CORE.

HELYX-MESH: Improved version of snappyHexMesh leading to much better layer

generation, faster mesh generation times (up to 50%) and faster convergence (up to 30%) compared to the standard OpenFOAM® mesher.

HELYX-CORE: Extended OpenFOAM® library with many improvements originating from industrial projects.

HELYX-CORE Documentation: Extensive documentation (500+ pages) of the HELYX-CORE, including detailed description of all standard OpenFOAM® modules.

Unlimited 1st Class Support: Telephone/email help line.

Simple, single file installer: Installers available for Linux and Windows platforms.


Significant enhancement based on industrial projects (I)

Based on OPENFOAM® 2.1 (2.2 integration Q3 2013) Full integration of Engys Edition enhanced features Instant updates with online repository Support for ParaView with parallel cases Single file caseSetup for batch execution Multiphase Arbitrary mesh interfaces User customisable modules for a large range of solvers

Improved, fully integrated radiation (thermal and solar) Humidity transport with wall evaporation/condensation swak4Foam integration


Significant enhancement based on industrial projects (II)

General solver support for porous-thermal-MRF zones 50+ new boundary conditions Improved wall functions and simplified turbulent inlets 0D lumped capacitance transient thermal boundaries Resistive outlet

Coupling with RadTherm, a professional thermal simulation tool Accelerated Conjugate Heat Transfer (CHT) analysis Improved solver stability (DES, multiphase) Run time output of Ensight data Enhanced meshing


Agenda



HELYX-Mesh overview: comparison with OF 2.2.0 Feature HELYX snappyHexMesh 2.2.0 snappyHexMesh

Automatic blockMesh

Feature Line (Automatic and Implicit) (Manual and Explicit)

Searchable surface feature Lines

Multi-region support

Non-manifold splitting (robustness) Edge collapsing

Proximity refinement

Volumetric smoothing

Parallel (scaling above 60 cores) (no scaling above 60 cores)

Layer control (10 different methods available) (3 different methods available)

Small leak closure

Wrapping

Interior Layers

Automatic AMI setup


Automatic feature edge capturing (no need .eMesh) Improved surface snapping and full projection of near-wall layers to inlets, outlet, symmetry planes

Standard v2.2 HELYX 2.1

Comparison snappyHexMesh (searchableCylinder)

Standard v2.2

HELYX v2.1


Extended boundary layer control

N 10 R 1.3 T0 1mm

N 5 R 1.3 Tf 0.4

T 2 tf 0.3 t0 1mm Specify any three of the following

parameters: First cell height (t0) Final cell height (tf) Expansion ratio (R) Number of layers (N) Total layer thickness (T)

Improved handling of high aspect ratio elements


Enhanced layering on concave and convex edges Important for resolving boundary layer flows for internal/external flows

Standard v2.2 HELYX 2.1


Internal boundaries and virtual surfaces

Layers on internal boundaries and virtual surfaces

CHT / FSI mesh generation Improved interior boundary capturing Interior feature lines 2 sided layer generation

Virtual surface layer generation for wakes and mixing layers Specification using tri-surface (STL files)

or a defined primitive shape


Small leak and crack detection in geometry Closing the user-defined tolerance

Automatic repair of gaps in the CAD generated surface

Increases usability and robustness for complex industrial cases


Automatic wrapping of mesh around geometry Missing geometry and big holes will be fixed

A gap lead to internal meshing Automatic wrapping


Example benchmark

HELYX Mesh 50% faster than standard snappyHexMesh

Solution 30% faster than on standard snappyHexMesh

Near wall layers: 97% coverage (95.7% from standard 2.2.x version)

1.7M cells

improved scaling on 32+ processors

Presenter

Presentation Notes

Notes: - Added the image of the hull on the bottom right side here.


Agenda



B

C

B

Layout suggested by client Layout required by pump manufacturer

In field no space to fit extra pipe section

Pump suction nozzle

Problem description 5D straight section required by pump manufacturer to obtain flat flow profile


Problem breakdown and approach Short project duration ~ 3 weeks (typical)

© Dynaflow Research Group, all rights reserved

Inlet side

Gate valve

Filter unit

Setup models in HELYX (short, with 5D, with(out) filter)

Mesher: HELYX snappyHexMesh

Solver: laminar simpleFoam /

pimpleFoam

Analyse results in paraView − Qualitative analysis of flow patern − Quantitative analysis of pump

entry flow

Pump suction nozzle


System overview; pump suction line


Inlet side

Gate valve

Filter unit

Pump suction nozzle


Naming the case and setting parallel run options

Automatic decomposition


Selecting multiple .stl files to define geometry/features


Defining surface refinement levels on the patches Possibility to set levels of multiple patches simultaneously


Defining volume refinement regions Using primitives or .stl files


Selecting .stl files to define detailed filter zones


Naming the cell zones and specify refinement levels Each cell zone can independently be refined


Setting the inside point and Create Mesh snappyHexMesh includes an automatic blockMesh functionality

snappyHexMeshDict

snappyHexMesh runs automatically


Setting up solver parameters after mesh generation


Defining the fluid properties Possible to append an user fluid to the database


Specify boundary conditions on the different patches Intuitive boundary conditions based on best practices


Define the porous media on the cell zones Cell zones generated in meshing phase


Change runtime controls


Start the simulation All initial conditions in dictionary files are generated automatically

Case structure is setup

solver runs automatically


Meshing at zone edges has steadily improved in OF HELYX appears to be more robust concerning surface snapping

OF 2.2.x – edge snapping OF 2.2.x OF 2.1.x HELYX

2.2.x has clearly improved meshing on zone edges

2.2.x less robust at surface snapping


Feature edge snapping has been incorporated in OF 2.2 HELYX performs more reliable in feature edge snapping without use of .eMesh

OF 2.2.x – edge snapping HELYX

Edge snapping has been improved , However is not as robust as in HELYX

OF 2.2.x


OF 2.2.x Feature edge snapping is very sensitive to number of snapping iterations

OF 2.2.x – edge snapping; n=3 OF 2.2.x – edge snapping; n=2


HELYX results in smoother and more homogeneous refinement


HELYX – snappyHexMesh OF 2.2.x – with edge snapping


HELYX refines consistently at sensible locations

HELYX OF 2.2.x – with edge snapping

Red lines are the zone edges

Irregular refinement around zone edges


HELYX reliably makes the defined zones

HELYX OF 2.2.x – two zones have failed


HELYX results in a smoother zone surface

HELYX – smooth zone surface OF 2.2.x – more castellated surface


Results, qualitative

Pressure drop results in flow perpendicular to the filter surface

Two vortex structures are found in the filter’s downstream flow


Results, quantitative Each quadrant may not deviate by more than 8% from the cross-sectional mean, this ensures acceptable balancing conditions inside the vanes of the pump’s impeller

2 3

4 1

Filter, with pipe extension No filter Filter

OK FAIL Just OK


Problem solution as discussed and approved with client

Original filter design New filter design


Agenda



Problem description

Investigation of transient fluid-dynamic forces on actuated butterfly valve during closing Valve loading can cause problems for actuator Steady state investigation revealed no excessive flow

induced forces upon valve


Problem summary

HELYX • transient, incompressible, moving

mesh (pimpleDyMFoam), automatic AMI setup

• Moving mesh + sliding interface • Dt=0.001 .. 0.002 (variable) • Simulated time T=20s ≡ 90°

valve rotation • K-omega SST model

Material: water

Two different cases:

• Variable flow – (nominal volume flow ~700m³/h)

• Fixed flow – (high flow case 2600m³/h)


Transient simulation of closing valve Run time: 120 hrs / 12 cpus


Variable Flow Case

Shedding induced vibration

Case: Fixed pressure loss


Case: Fixed High Flow Rate

Within spread of straight pipe valve measurements

Greater flow bleed due to lack of valve seat


Conclusions

Transient results agree well with steady CFD results and literature references No excessive forces on valve could be observed

Actuator problems likely caused by mechanical influences

HELYX successfully employed to mesh and run transient moving mesh simulation

AMI + dynamic mesh performs very well with minimal artefacts at the interface

Partial overlap AMI required for full closure of valve


Agenda



The strategic alliance with ENGYS gives DRG the opportunity to: Help our clients by doing CFD themselves using OpenFOAM® and HELYX

Using HELYX to improve our efficiency on CFD projects Provide and sell support packages including HELYX Supply training courses in HELYX and OpenFOAM® (November 25 & 26, 2013)

Use of HELYX allows DRG to: Reliably meshing of complex geometries

Fast setup of cases

Opportunities for you: HELYX: with GUI, MESH and CORE (to move from commercial CFD) HELYX-OS: GPL GUI tailored for standard OpenFOAM® instead of HELYX-CORE (to

occasionally solve CFD problems) HELYX-MESH: Stand-alone version of the HELYX mesh generator

Final words

T +31 79 361 5150 F +31 79 361 5149 E [email protected] W www.dynaflow.com

Houtsingel 95 2719 EB Zoetermeer The Netherlands Reg nr. 27320315

Documents

Flow Analysis of Industrial Equipment using the native ... · PDF fileFlow Analysis of Industrial Equipment using the native OpenFOAM GUI HELYX. ... Pipe stress calculations ... Extended