SiPER – Smoothed Particle Hydrodynamics in Process Engineering

Simulation package for structure formation and transport in porous media.

Changing and moving phase interfaces can only be described with great difficulty using classical mesh-based methods. Therefore, mesh-free simulation methods have been investigated at the ICVT for many years. With the program package SiPER developed at the institute various problems can be investigated with the Smoothed Particle Hydrodynamics method.

The Smoothed Particle Hydrodynamics method is a Lagrangian mesh-free discretization method for partial differential equations. Compared to grid-based discretization methods such as the finite-element method or the finite-volume method, the interpolation points (the so-called "particles") can move freely in space and, thus, enable simulations in complex geometries and systems with free surfaces without extensive remeshing and computational effort. An accurate movement and change of interfaces is possible without any additional effort, since the phase boundary between discretization points is defined and moved with them.

SiPER is a highly parallelized program package for the direct numerical simulation of morphology evolution and multiphase transport in porous media. One focus is on interface interaction, wetting properties and the change of porous systems through heat and mass transport processes. An extension to nanoscale transport processes, where thermal fluctuations are relevant, enables the simulation of problems across many length scales.

Past and current application examples for SiPER are shown below.

Wetting behavior in porous media

Multiphase flows in porous structures are dominated mainly by capillary and surface forces. Different wetting properties can lead to very different flow behavior. Research at the ICVT covers the investigation of dynamic wetting processes in single capillaries and pore networks and the description of the wetting behavior of fluid drops on different surfaces.

© Institut für Chemische Verfahrenstechnik, Universität Stuttgart | Source: YouTube

Simulation of the imbibition of a microstructure

Morphology evolution

Structure formation processes are usually based on transport processes on different time and length scales. An important scale is the mesoscopic scale, which is the range of nanometers and micrometers. Using the example of the precipitation process of porous polymer membranes, the pore-forming process during phase separation was investigated in order to obtain conclusions about the transport properties on the structure of polymer membranes. The Smoothed Particle Hydrodynamics method has been extended to models for the kinetic modeling of the phase separation as well as for multicomponent transport. By comparison with experiments, the numerical results were qualitatively validated.

© Institut für Chemische Verfahrenstechnik, Universität Stuttgart | Source: YouTube

Simulation of the formation of sponge pores in the precipitation of a polymer solution

Simulation of a polymer chain in solution

Polymer solutions in wall-bounded shear flow

Fouling in technical reactors for polymerization reactions represents a major challenge in the development of new processes. In addition to the reaction mechanism, the properties of the reactor surfaces and the flow field also play an important role. By extending the Smoothed Dissipative Particle Dynamics method with a "bead-spring" model for polymers, the adsorption behavior of macromolecules in near-wall shear flows can be simulated. The aim is to improve the mechanistic understanding of the initial states of fouling in order to support the process development with regard to the avoid fouling.

Bubble and drop coalescence

In chemical engineering reactors and apparatus in which suspensions of several fluid phases are present are often used. Examples of these can be bubble column reactors or spray towers. At ICVT, the SPH method is applied to problems where the interaction between dozens of bubbles is of interest. The emphasis is on the interaction of the phases at their phase boundaries, which is of importance in coalescence behavior.

© Institut für Chemische Verfahrenstechnik, Universität Stuttgart | Source: YouTube

Simulation of bubble rising in a structure

Further information about the SiPER program package

Compared to other software packages, SiPER specializes in incompressible flow, but also offers common compressible approaches. With the so-called "truly incompressible smoothed particle hydrodynamics" (ISPH) method, based on the established projection method of grid-based CFD, flow problems can be solved efficiently and with high accuracy. For example, pressures of the incompressible flow that are central to multiphase flow in porous media are calculated accurately.

The Smoothed Particle Hydrodynamics method, established for macroscopic and mesoscopic problems, offers an algorithmically simple extension to microscopic problems where thermal fluctuations are relevant due to their molecular nature. With the Smoothed Dissipative Particle Dynamics (SDPD) method, which is an extension of the Smoothed Particle Hydrodynamics method including thermal fluctuations, it is possible to study problems at a coarse-grained level using the Continuum Approach.

The following physical and methodical models / approaches are available in SiPER:

Parallelization with MPI
Different approaches for incompressible flow (ISPH, TWO STEP, implicitly ISPH, Stokes flow)
Different Approaches to Compressible Flow (WCSPH)
Extension to mesoscopic problems (SDPD)
Boundary conditions: periodic, symmetric, solid wall, inflow / outflow
Corrected SPH
Surface Tension Models (CSF, Particle-Particle WW, Tensor (Adami))
Contact Lines (CLF, Tensor (Breinlinger), Tensor (Adami))
Phase decay with Cahn-Hilliard equation
Rheology (Newton, viscoplastic, viscoelastic, elastic)
Multi-component transport (Maxwell-Stefan, Generalized Fick)
Interface for fluid-fluid coupling with grid-based methods
Stick-slip for rough surfaces

The SiPER program package is freely available on request. If you are interested, contact Manuel Hopp.


  1. C. Zander, M. Hopp-Hirschler, U. Nieken
    Mesoscopic Simulation and Characterization of the Morphological Evolution in Phase Separating Fluid Mixtures
    2018, Computational Materials Science 149, 267--281
  2. P. Kunz, S. M. Hassanizadeh, U. Nieken
    A Two-Phase SPH Model for Dynamic Contact Angles Including Fluid--Solid Interactions at the Contact Line
    2018, Transport in Porous Media 122(2), 253--277
  3. M. Hirschler, G. Oger, U. Nieken, D. L. Touzé
    Modeling of Droplet Collisions Using Smoothed Particle Hydrodynamics
    2017, International Journal of Multiphase Flow 95, 175--187
  4. M. Hopp-Hirschler
    Modeling of porous polymer membrane formation
    2017, Dissertation, Universität Stuttgart
  5. P. Kunz, M. Hirschler, M. Huber, U. Nieken
    Inflow/Outflow with Dirichlet Boundary Conditions for Pressure in ISPH
    2016, Journal of Computational Physics 326, 171--187
  6. M. Hirschler, W. Säckel, U. Nieken
    On Maxwell–Stefan Diffusion in Smoothed Particle Hydrodynamics
    2016, International Journal of Heat and Mass Transfer 103, 548--554
  7. M. Huber, F. Keller, W. Säckel, M. Hirschler, P. Kunz, S. M. Hassanizadeh, U. Nieken
    On the Physically Based Modeling of Surface Tension and Moving Contact Lines with Dynamic Contact Angles on the Continuum Scale
    2016, Journal of Computational Physics 310, 459--477
  8. M. Hirschler, P. Kunz, M. Huber, F. Hahn, U. Nieken
    Open Boundary Conditions for ISPH and Their Application to Micro-Flow
    2016, Journal of Computational Physics 307, 614--633
  9. P. Kunz, I. M. Zarikos, N. K. Karadimitriou, M. Huber, U. Nieken, S. M. Hassanizadeh
    Study of Multi-Phase Flow in Porous Media: Comparison of SPH Simulations with Micro-Model Experiments
    2016, Transport in Porous Media 114(2), 581--600
  10. M. Huber, D. Dobesch, P. Kunz, M. Hirschler, U. Nieken
    Influence of Orifice Type and Wetting Properties on Bubble Formation at Bubble Column Reactors
    2016, Chemical Engineering Science 152, 151--162
  11. F. Keller
    Simulation of the Morphogenesis of Open-porous Materials
    2014, Dissertation, Universität Stuttgart
  12. M. Hirschler, M. Huber, W. Säckel, P. Kunz, U. Nieken
    An Application of the Cahn-Hilliard Approach to Smoothed Particle Hydrodynamics
    2014, Mathematical Problems in Engineering 2014, 10
  13. M. Hirschler, F. Keller, M. Huber, W. Säckel, U. Nieken
    Ein Gitterfreies Berechnungsverfahren Zur Simulation von Koaleszenz in Mehrphasensystemen
    2013, Chemie Ingenieur Technik 85, 1099--1106
  14. F. Keller, U. Nieken
    Application of Smoothed Particle Hydrodynamics to Structure Formation in Chemical Engineering
    2011, Springer Berlin Heidelberg, Berlin, Heidelberg, ISBN: 978-3-642-16229-9
  15. F. Keller, U. Nieken
    Simulation Der Morphologieausbildung von Offenporigen Materialien
    2010, Chemie Ingenieur Technik 82, 1391


Dieses Bild zeigt Hopp-Hirschler

Manuel Hopp-Hirschler

Wissenschaftlicher Mitarbeiter

Dieses Bild zeigt Zander

Christian Zander

Wissenschaftlicher Mitarbeiter