CONVERGE Training

Upon the completion of this course, you will know how to:

• Begin a new project in CONVERGE Studio
• Import a surface geometry from a CAD program
• Create boundaries
• Manually repair surface defects
• Create an engine sector geometry for efficient computations
• Prepare moving boundaries for motion in IC Engines

• Set up solver parameters and data files
• Set up appropriate boundary and initial conditions based on available data
• Control grid settings throughout the computational domain
• Set up fuel injection via spray modeling
• Set up detailed chemical kinetics for accurate combustion and emissions modeling
• Set up wall heat transfer modeling in CONVERGE and output heat transfer quantities for thermal analysis
• Set up additional modeling options such as turbulence and sources
• Run CONVERGE and monitor your simulation
• Post-process results in CONVERGE Studio

CONVERGE Studio contains powerful tools for cleaning even geometries with significant problems. In this workshop we will discuss the advantages and limitations of several of these new features. The Coarsen tool can be used to reduce the number of triangles in a geometry, which may be useful when working with a large geometry. The Boolean tool can perform Boolean operations such as union, intersection, or difference. The Surface Healing tool, which was requested by many clients, can fix a variety of geometry problems at the click of a button. Finally, the Surface Wrapper tool can create watertight models by wrapping the existing geometry to create a new surface.
*This lecture includes hands-on CONVERGE Studio practice.

In this workshop we will discuss timely and popular topics in internal combustion (IC) engine modeling and some of the unique features of CONVERGE that yield efficient and accurate simulations. Ever wonder why predicted cylinder quantities do not match the measured data when you think you have set up the case correctly? We will talk about what you need to consider when the predicted cylinder pressures do not agree with measurements and how to assess the accuracy of your input parameters. With optimized cell counts via Adaptive Mesh Refinement and fast flow and detailed chemistry solvers, you can extend your simulation domain to include multiple cylinders to analyze cylinder-to-cylinder variation, run multiple cycles to understand cycle-to-cycle variation, and capture propagating pressure waves to resolve engine knock. We will discuss published cases and how to set up similar cases in CONVERGE.
*This lecture includes hands-on CONVERGE Studio practice.

CONVERGE contains several options for three-dimensional combustion modeling in internal combustion engines. In this workshop, we will discuss five advanced combustion models: delta PDF (SAGE), G-Equation, Representative Interactive Flamelet (RIF), 3-Zone Extended Coherent Flame Model (ECFM3Z), and Flamelet Generated Manifold (FGM). SAGE and FGM are generalized combustion models that can be applied to diffusion-controlled diesel engine simulations or premixed gasoline engine simulations. G-Equation is suitable for simulating premixed spark ignition processes in gasoline engines, while RIF and ECFM3Z are used for simulating diffusion-controlled diesel engines. This workshop will focus on the underlying theory and the advantages and disadvantages of each combustion model, as well as how these models are coupled with the CFD solver in CONVERGE.
*This lecture does not include hands-on CONVERGE Studio practice.

For several years CONVERGE has been able to interface with other software packages to model heat transfer in solids. Now CONVERGE can do both CFD and solid heat transfer modeling in the same simulation, which can simplify the process of predicting the temperatures in solids that are dependent on fluid interfaces, e.g., heads and valves in engines. This workshop will discuss conjugate heat transfer modeling in CONVERGE, including supercycling, which accounts for the disparate timescales in the solid and fluid domains by allowing the solid side of the simulation to progress with faster timescales than the fluid side of the simulation, and valve/seat contact resistance in engines, which is critical to accurate prediction of valve and head temperatures.
*This lecture includes hands-on CONVERGE Studio practice.

CONVERGE and GT-SUITE can be coupled in a variety of ways. This workshop will discuss two coupling options. In conventional 1D-3D coupling, CONVERGE performs a 3D simulation while GT-SUITE performs a 1D simulation. The information at the interfaces is exchanged or mapped between the two programs. In hydromechanical coupling, you define a system with rigid bodies in GT-SUITE and subject the rigid bodies to fluid forces and constraints using CONVERGE. CONVERGE calculates the forces on the object and relays this information to GT-SUITE. GT-SUITE then solves the rigid body dynamics equations to update the object’s state and sends this information back to CONVERGE. Finally, CONVERGE moves the object.
*This lecture does not include hands-on CONVERGE Studio practice.

CONVERGE contains two detailed soot models – particulate mimic (PM) and particulate size mimic (PSM). Although it is computationally expensive to run a three-dimensional simulation with a detailed soot model and the SAGE detailed chemistry solver, CONVERGE contains acceleration strategies to make it feasible to include detailed soot modeling in engine simulations. In this workshop we will discuss the methodologies of these models, acceleration strategies for detailed soot modeling coupled with gas-phase chemistry, and the effects of important soot parameters. We will also discuss other emissions models (e.g., NOx) and give recommendations for these models.
*This lecture does not include hands-on CONVERGE Studio practice.

This workshop will focus on Urea/SCR engine aftertreatment modeling in CONVERGE. We will discuss urea decomposition and hydrolysis to ammonia, and we will describe how to set up urea-water spray modeling in CONVERGE. In addition, we will review wall film and wall interaction models, phenomena (filming, rebounding, stripping, and separating) that can lead to urea deposit formation, and the application of conjugate heat transfer modeling to obtain accurate wall thermal boundary conditions. We will discuss SCR surface chemistry approaches that use CONVERGE coupled with GT-SUITE. This workshop will include sample cases for practical Urea/SCR systems as well as validation cases. Finally, we will discuss future plans for improved engine aftertreatment modeling.
*This lecture includes hands-on CONVERGE Studio practice.

Rigid body fluid-structure interaction (FSI) modeling describes how the presence of one or more immersed objects affect the flow field and how the forces from the surrounding fluid influence the dynamics of the object. In this workshop we will discuss the theory behind FSI, the numerics of the dynamics solver, and the coupling of the dynamics solver to the flow solver in CONVERGE. We will consider several examples (a pressure relief valve, a spool valve, and an injector armature) that highlight the current capabilities of FSI modeling in CONVERGE. Finally, we will discuss complex examples that invoke a user-defined function coupled with FSI to model deforming bodies such as reed valve petals or a spring-close ball valve.
*This lecture does not include hands-on CONVERGE Studio practice.

This workshop will focus on the application of CONVERGE to gas turbine combustion and combustor analysis. We will review how to set up liquid and gaseous fuels for gas turbines and discuss the use of both the SAGE detailed chemistry solver and the Flamelet Generated Manifold model for gas turbine models. In addition, we will discuss wall temperature predictions with conjugate heat transfer; transient RANS and LES simulations and steady-state analysis in reacting and non-reacting cases; gas turbine ignition at high altitude, lean blow out, and extinction; flashback; and emissions analysis for NOx, CO, and soot.
*This lecture includes hands-on CONVERGE Studio practice.

In this workshop we will discuss mapping CONVERGE CFD results to different surface files for uncoupled heat transfer analysis in third party software. We will discuss the CONVERGE htc_map utility, including the methodology of cycle averaging, details of the mapping method, how the geometry is aligned for surfaces, and best practices for mapping. We will review an example of a heat transfer analysis and explain how to bring the spatial temperature boundary condition prediction back to CONVERGE. Additionally, we will briefly discuss the best practices for heat transfer prediction in CONVERGE CFD simulations.
*This lecture does not include hands-on CONVERGE Studio practice.

In CONVERGE you can select a solver for each governing equation. In this workshop we will describe the differences between the point-wise successive over-relaxation (SOR) algorithm and the biconjugate gradient stabilized (BiCGSTAB) method. We will also explain preconditioning and discuss when it might be useful. We will use examples to discuss tradeoffs between the different methods and when each option may be appropriate.
*This lecture does not include hands-on CONVERGE Studio practice.

This workshop will focus on model optimization in CONVERGE, including Genetic Algorithm (GA) optimization and Design of Experiments model interrogation. We will discuss different types of optimization and the details of the GA methodology, and we will use examples to illustrate how to set up the utility, select parameters, and run an optimization. Finally, we will discuss the best practices of optimization (e.g., model setup, parameter and range selection, and search space considerations) and advanced applications such as geometry modification.
*This lecture does not include hands-on CONVERGE Studio practice.

CONVERGE Studio is not just for pre-processing! There are several powerful post-processing tools in the Line Plotting module in CONVERGE Studio. This workshop will discuss (1) how to generate and customize plots and create reports, (2) how to combine output files from multiple restarts, (3) how to use the Fast Fourier Transform calculator to transform the signal between the time and frequency domains and to complete engine knock analysis, (4) how to use the Apparent Heat Release Rate calculator to calculate the apparent heat release from a pressure signal, and (5) how to use the Engine Performance calculator to calculate the work and indicated mean effective pressure (IMEP) from cylinder pressure.
*This lecture includes hands-on CONVERGE Studio practice.

Radiative energy transfer is important in high temperature simulations that include gases and surfaces that emit, absorb, and scatter radiative energy. In this workshop we will discuss the theory of the Discrete Ordinates Finite Volume Method, the different radiation submodels, and how to model radiative energy transfer in CONVERGE simulations. We will set up example cases that have thermal radiation in flows with and without combustion as well as a case that uses non-thermal ultraviolet radiation.
*This lecture does not include hands-on CONVERGE Studio practice.

In this workshop we will introduce utilities for people who use CONVERGE on a Linux-based platform. We will discuss scripts that expedite I/O file management, assist in monitoring CONVERGE jobs, and parallelize CPU-intensive post-processing tasks.
*This lecture does not include hands-on CONVERGE Studio practice.

CONVERGE contains a sealing tool, which will close gaps between parts that are moving relative to one another. The sealing process is dynamic in that the surface enclosing the computational domain is recreated at each time-step based on the boundary motion and the seal definitions, and thus this tool can be applied to a variety of cases, including two-stroke engines, Wankel engines, components connected by pins and bearings, pumps, and rotating machinery. We will give an overview of the sealing algorithm and explain the geometric approach used to recreate the sealed surface from the boundaries and seal definitions. We will discuss best practices for surface preparation and case setup, and we will demonstrate examples of applying seals to a check valve, a two-stroke engine, a Wankel engine, crankcase components, a gerotor pump, and a supercharger.
*This lecture does not include hands-on CONVERGE Studio practice.

CONVERGE includes state-of-the-art models for simulating liquid spray phenomena. In this workshop, we will describe the models in CONVERGE for liquid breakup, collision and coalescence, vaporization, drag, turbulent dispersion, and drop/wall interaction. In particular, we will discuss numerical mesh and parcel number settings for achieving grid convergence for RANS and LES simulations. This workshop will also describe CONVERGE’s VOF-spray one-way coupling option, in which CONVERGE collects detailed fluid flow information near the nozzle exit during a VOF simulation of the injector flow and then uses this information to inject parcels for Lagrangian spray calculations. Finally, in this workshop we will discuss the future of spray modeling in CONVERGE.
*This lecture does not include hands-on CONVERGE Studio practice.

CONVERGE v2.4 contains a new steady-state solver, which is much more stable (and, for most cases, faster) than the previous steady-state solvers. The steady-state solver can be used for a host of applications, including flowbench, turbocharger, gas turbine, and aftertreatment simulations. This solver can be used with other CONVERGE features including moving reference frames and combustion, conjugate heat transfer, and volume of fluid modeling. In this workshop we will discuss the theoretical background of this solver and how to set up a variety of steady-state cases.
*This lecture includes hands-on CONVERGE Studio practice.

CONVERGE includes a variety of tools to complement the SAGE detailed chemistry solver. In this workshop we will discuss the zero-dimensional ignition delay, mechanism reduction, one-dimensional laminar flame speed, and mechanism merge tools.
*This lecture includes hands-on CONVERGE Studio practice.

CONVERGE includes a full spectrum of methodologies, from RANS to LES, to model turbulence. In this workshop, we will discuss the theory behind different methodologies and different turbulence models, as well as recommendations for and limitations of each model. In addition, we will discuss the results of some published RANS and LES simulations.
*This lecture does not include hands-on CONVERGE Studio practice.

In this workshop we will explore the vast array of user-defined functions (UDFs) that can be used to adjust existing models, implement new models, direct CONVERGE to calculate additional quantities, or initialize or reinitialize physical variables. We will discuss the different types of UDFs that CONVERGE supports as well as the process of compiling the UDFs and the necessary header files.
*This lecture includes hands-on CONVERGE practice.

Volume of fluid (VOF) methods are some of the most popular numerical techniques for locating moving and deforming interfaces between fluids in multiphase flow simulations. In this workshop we will discuss numerical details, example cases, and some validation calculations for the various VOF options in CONVERGE. One VOF method in CONVERGE is based on the species mass fraction equation and is appropriate for miscible or compressible multiphase flow calculations. One option in CONVERGE, which is based on the mass fraction VOF, is VOF-spray one-way coupling. In this option CONVERGE collects detailed fluid flow information near the nozzle exit during a VOF simulation and then uses this information to inject parcels for Lagrangian spray calculations. Another VOF method, which solves for the void fraction directly, is available in CONVERGE as two separate schemes: Piecewise-Linear Interface Calculation (PLIC) and High-Resolution Interface-Capturing (HRIC). These schemes have been tested on a range of problems including a breaking dam, a rising droplet, and spray injection, and each test case illustrates the ability of the method to track interfaces sharply.
*This lecture includes hands-on CONVERGE Studio practice.