TRR 75:  Droplet Dynamics Under Extreme Ambient Conditions

• Subject Area: Thermal Engineering/Process Engineering ; Chemistry ; Computer Science, Systems and Electrical Engineering ; Mathematics
• Term: from 2010 to 2021
• Website: Homepage
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 84292822

Droplets play a central role in many areas of nature and technology. Many droplet dynamic processes occur under extreme ambient conditions and are often already in use in technical systems, though extensive gaps in the basic understanding of the processes remain.The stated goal of the SFB-TRR 75 is to gain an in-depth, detailed physical understanding of processes with droplets under extreme ambient conditions. Based on that, analytical and numerical methods for the description of such processes are identified and implemented. Accurate predictions of their development and a better understanding of the underlying elementary processes allow improving the prediction of larger systems. The findings are exemplarily applied to five selected systems (“guiding examples”). Comparisons of the predictions with the actual behavior of the systems serve the ongoing, critical review of all examination results.The SFB-TRR 75 is divided into three project areas (PB): In PB-A (“Fundamentals”), the fundamentals required for the projects are developed and made available for all other sub-projects. These are physical, mathematical and numerical fundamentals as well as methods for visualizing data and the provision of thermophysical properties, which are needed for many sub-projects. In PB-B (“Free Droplets”) droplets without wall contact are investigated. This reaches from investigations on supercooled droplets in clouds over drops in cryogenic rocket combustion chambers to droplet and spray system in the vicinity of the critical point. In PB-C (“Droplets with Wall Interaction”) the interaction of droplets with a solid wall is researched for various processes. Here, transport processes for droplet-wall-interactions with phase changes liquid/gas and liquid/solid and under the influence of strong electric fields are examined in detail.Starting with the investigation of single droplets (FP1) and small droplet groups (FP2), the SFB-TRR 75 is oriented increasingly towards complex systems in the third funding period (FP3) as described by the guiding examples. Of course, the development of fundamental methods will not be ignored. At the end of the SFB-TRR 75 unique experimental data and validated numerical tools will be available for predicting droplet processes under extreme ambient conditions.

• DFG Programme: CRC/Transregios
• International Connection: France

Completed projects

• A01 - Interactive Visualisation of Droplet Dynamics (Project Heads Boblest, Sebastian ;  Ertl, Thomas ;  Sadlo, Filip )
• A02 - Development of Numerical Methods for the Simulation of Compressible Droplet Dynamics under Extreme Ambient Conditions (Project Head Munz, Claus-Dieter )
• A03 - Analysis and Numerics of sharp and diffuse interface models for droplet dynamics (Project Heads Rohde, Christian ;  Schleper, Veronika )
• A04 - Molecular Dynamics Simulations of Droplet Evaporation in the Non-Linear Response Regime (Project Head Müller-Plathe, Florian )
• A05 - Simulation of the mechanical deformation and movement of droplets under the influ-ence of strong electric fields (Project Heads Gjonaj, Erion ;  Schöps, Sebastian ;  Weiland, Thomas )
• A06 - Development and application of new thermodynamic models for interfaces based on classical density func-tional theory (Project Head Groß, Joachim )
• A07 - Modeling and Simulation of droplet collisions at modified ambient pressure, with high gradients in velocity or concentration and for non-miscible fluids (Project Heads Bothe, Dieter ;  Schulte, Kathrin )
• B01 - Investigation of the behavior of supercooled droplets concerning evaporation, con-densation and freezing at different boundary conditions (Project Heads Roth, Norbert ;  Weigand, Bernhard )
• B02 - Experimental investigation of droplet evaporation under extreme conditions by tempo-rally highly resolved laser diagnostic methods (Project Heads Dreizler, Andreas ;  Lamanna, Grazia )
• B03 - Modeling and simulation of droplet evaporation in different gas environments under supercritical conditions (Project Heads Janicka, Johannes ;  Sadiki, Amsini )
• B04 - Experimental investigation of transient injection phenomena with flash evaporation in rocket combustors at vacuum conditions (Project Heads Manfletti, Chiara ;  Oschwald, Michael )
• B05 - Modeling and simulation of flash evaporation of kryogenic liquids (Project Head Kronenburg, Andreas )
• B06 - Droplets under gradients of temperature and velocity by atomistic simulation (Project Head Vrabec, Jadran )
• C01 - Numerical simulation of the transport processes during drop impingement onto heat-ed walls with special consideration of the evaporating three-phase contact line (Project Heads Gambaryan-Roisman, Tatiana ;  Stephan, Peter )
• C02 - High-resolution measurements of heat transport during drop impingement onto a hot wall with special consideration of the evaporation near the three-phase contact line (Project Heads Gambaryan-Roisman, Tatiana ;  Stephan, Peter )
• C03 - Impact of supercooled droplets onto cold surfaces (Project Heads Jakirlic, Suad ;  Tropea, Cameron )
• C04 - Interaction of a single drop with a heated wall at high ambient pressures (Project Heads Roisman, Ilia ;  Tropea, Cameron )
• C05 - Mechanical and Electrical Phenomena of Droplets under the Influence of Strong Electric Fields (Project Head Hinrichsen, Volker )
• T02 - Ultrafast cooling and lubrication during hot die forging (Project Heads Roisman, Ilia ;  Tropea, Cameron )
• Z - Central Tasks (Project Head Weigand, Bernhard )

• Applicant Institution: Universität Stuttgart
• Co-Applicant Institution: Technische Universität Darmstadt
• Participating Institution: Deutsches Zentrum für Luft- und Raumfahrt e.V. (DLR)
• Participating University: Universität Paderborn
• Spokesperson: Professor Dr.-Ing. Bernhard Weigand