Undergraduate and Graduate Use of STAR-CCM+ at Brigham Young - PowerPoint PPT Presentation

Undergraduate and Graduate Use of STAR-CCM+ at Brigham Young University Steve Gorrell Greg Jensen Tadd Truscott Dan Maynes STAR Global Conference 2013 18-20 March, 2013

Outline  Introduction  Coursework – Applications of Fluid Dynamics – Computer-Aided Engineering Applications  Capstone – Minimizing drag on locomotive  Graduate Research – Cavitation in water turbopump inducer  Summary 2

Introduction  CFD is a useful tool that can help students learn – Not just fluid mechanics  STAR- CCM+ has features that help students quickly learn and use CFD – CAD to mesh to solution  The risk – The code gave a solution therefore it is correct – Not understanding why a solution does not converge  Students can do amazing things – Undergraduate as well as graduate  Warning! Unedited comments included – Useful to see and appreciate students perspective – Comments do not represent opinion of Faculty or BYU

Applications of Fluid Dynamics  Class has 3 overarching themes to solving fluid problems – Analytical solutions – Numerical solutions – Experimental solutions  One example sphere in a cross flow – Use STAR-CCM+ to visualize and predict drag coefficients and pressure distributions. Student comments: 4 “I appreciated the time we took to learn about CFD, potential flow, and experimental fluid dynamics”

Computer-Aided Engineering Applications  Over course of semester use suite of CAx and communication tools to model, analyze, and rapid prototype parts of an RC vehicle  Demonstrate the appropriate application of 3D CFD to ensure appropriate air flow over the surface of your vehicle 5

Computer-Aided Engineering Applications  A senior with no CFD or STAR-CCM+ experience wrote tutorials to help students on CFD portion of project – Preprocessing and Solving based on James Clement’s Surface Wrapping a Motorcycle video – Postprocessing based on James Clement’s Understanding Scenes video 6

CFD Industries & Introduction Investments Workforce Strategy Demographics Aging Population Modeling US Citizens in Israel Optimization Inflation FEA GDP & Wealth Distribution PPP& Exchange Mass Rates Motion Sim CFD Visualization

Computer-Aided Engineering Applications  Student Comments about CFD – Much simpler than we thought it would be, except for meshing – Easy way to make awesome images and videos – Makes fluids seem interesting again… barely

Capstone  Design of Aerodynamic Railroad Trains  Objectives – Design of an aerodynamic freight locomotive – Minimize drag coefficient Student comment 9 “Vector fields allowed for visual confirmation”

Capstone  Tools Used in STAR-CCM+ – Meshing – Drag analysis – Vector fields Student comments: “Varying mesh sizes saved computational time” “Allowed for amazing pictures during presentations” 10

Capstone  Common reasons for failed simulations – Floating point errors – Meshing issues  Optimate plug-in was unusable due to lack of instructional material or support Student comments: “Errors during meshing wasted valuable time”  Successes – Able to run iterations on various models – Predict the optimal value through our optimization script 11

Water Turbopump Inducer Research  Cavitation – Local static pressure drops below the vapor pressure – Fluid begins to boil and vapor bubbles Centrifugal Pump Portion form. – Unsteady two phase flow Inducer  Time-accurate simulations an enabling technology Image taken from July 2004 Newsletter , Lawrence Pumps Inc http://www.lawrencepumps.com/Newsletter/news_v01_i2_july.html 12

Water Turbopump Inducer Research  Turbopump Inducers – Designed to work under cavitating conditions  Off-Design Operation – Inducers are designed for a given flow coefficient – Off-design flow coefficient explored 60% of design 13

Cavitation Comparison Off-Design On-Design 𝜏 ≈ 0.05 𝜏 ≈ 0.02 14

Off-Design Flow Instabilities  The main reason for the increase in flow instabilities is the reversed flow at the tip  Reversed flow is caused by flow separation on the inducer blade On-Design Off-Design 15

Cavitation Instabilities  When the inlet pressure drops to a low enough value the core drops below the vapor pressure 16

Cavitation Instabilities  The cavitation core grows and collapses causing a large cavitation surge 17

Summary  STAR-CCM+ a great tool for university classroom, capstone, and research use  Teaching CFD to undergraduates gives them an important skill and tool – Used while a student – Desirable skill in workforce  Students can do amazing things – Undergraduate as well as graduate

Acknowledgments  From CD-adapco – Lisa Mesaros – Tammy de Boer – James Clement – Bill Kester – Deryl Snyder  BYU Fulton Supercomputing Laboratory – 12,356 CPU cores and 30.3 TB of memory across 928 compute nodes.