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  4. Process Engineering
  5. Multiphase Flow, Heat and Mass Transfer
Mann mit Labor Kittel nimmt Proben aus einer moderen Maschine

In the department "Multiphase Flow, Heat and Mass Transfer" the research activities are concentrated on processes for the production, handling and conditioning of disperse phases (e.g. powders, particles or droplets) in liquid or solid form. In particular, the analysis of the interaction processes at the phase interfaces of particles with their fluid environment, which are characterized by multi-phase impulse, heat and mass transfer processes, is in the foreground.

Essential applications of the investigations in this area are processes with spray and jet flows from the production and handling of metallic and ceramic powders and thermal process technology.

Basic investigations in multiphase flow systems and practice-oriented questions of application in e.g. multiphase cooling processes in the context of heat treatment of metals are treated.

Projects of Multiphase Flow, Heat and Mass Transfer

VerA distortion compensation in aluminum die casting process chains

The aim of the VerA project is to develop a method of compensating for process-induced residual stresses in aluminum die casting during production. The complete process chain from casting to heat treatment is considered.

The motivation of the project is the economical production of large-area, of thin-walled die-cast integral components that meet the lightweight construction requirements of the automotive industry. Currently, cost-intensive measures such as straightening operations are necessary to compensate for distortion. In the process chain under consideration, from casting to heat treatment, locally controlled quenching is used to influence distortion and internal stresses during heat treatment. Quenching is performed by adaptive spray field systems. When adapting the spray field, component-specific data from process monitoring are used so that warpage can be compensated for by optimum local cooling rates.

This project was funded by the German Federation of Industrial Research Associations (AiF).

Processing: IWT departments of Process Engineering and Lightweight Materials

Funding: BMWi-AiF

Duration: 01.04.2022 - 30.09.2024

Contact:
M.Sc. Lisa Husemann
Tel.: +49421 218 51325
E-Mail: husemann@iwt-bremen.de

Dilyan Kamenov
Tel.: +49421 218 51231
E-Mail: d.kamenov(at)iwt.uni-bremen.de

 

Grafik, die verschiedene Phasen eines Fertigungsprozesses zeigt, darunter Druckguss, Abkühlen (Wasser), Stanzen, Lösungsglühen, Abkühlen (Luft), Warmauslagern und Spannungsarmglühen. Jede Phase ist mit einer farbcodierten Temperaturverteilung dargestellt.
Distortion development over the die casting process chain (Project DIMTAL, AiF 15687 N, [Schimanski, K., von Hehl, A. Thin-walled and warpage-free die cast components in automotive engineering - A contradiction? Casting of chassis and body components, VDI Special Day, Magdeburg, 07 February 2013.])
Influence of nozzle field arrangements consisting of jet and full-cone nozzles on the intensive cooling of moving thick plates

In this project, the intensive cooling of hot sheets with water from single nozzles and nozzle arrays was investigated.

For this purpose, experimental investigations with full-jet and spray nozzles were carried out at the University of Magdeburg (Research Unit 1) and numerical modeling and simulations were performed at the Leibniz Institute for Materials Engineering IWT Bremen (Research Unit 2).

The subject of the experimental investigations were single full jet and full cone nozzles as well as nozzle arrays consisting of 9 to 10 full jet nozzles, 2 full cone nozzles, 2 flat jet nozzles and combinations of full and flat jet nozzles. During the cooling process, the temperatures of the cooled sheets on the back side were measured with an infrared camera. An essential result of the experimental investigations is the concrete proof of the influence of technical parameters such as initial temperature, jet velocity, sheet velocity, metal type, etc. on the DNB or Leidenfrost temperature, the heat transfer and the progress of the wetting front.

The numerical simulation is based on a modified Euler-Euler multiphase model. With the developed 3D simulation model, the entire cooling process with all associated boiling phases can be calculated. Based on the simulation results, process states such as the Leidenfrost region, the heat transfer coefficient (HTC), the local heat flux or the temperature gradient at the impinging surface, which cannot be directly detected in experiments, can be analyzed in detail. The model allows the calculation of different nozzle types, nozzle arrangements and three-dimensional nozzle fields as well as the analysis of the cooling of a moving plate (thick sheet).

There is sufficient agreement in the results from experiment and simulation. In particular, experiment and simulation show the same tendencies depending on the change of technical parameters of cooling.

With the results of the project, characteristic values are available which are suitable for the design and optimization of cooling or quenching systems of moving plates. The possibilities of a transfer to industry are given.

The final report of the project can be obtained from the Forschungskuratorium Maschinenbau (FKM) e. V. (postal address: Lyoner Str. 18, 60528 Frankfurt am Main, e-mail: info@fkm-net.de).

Processing: Otto von Guericke University Magdeburg, Institute of Fluid Mechanics and Thermodynamics, Leibniz Institute for Materials Engineering, IWT Bremen.

Duration: 01.05.2018 - 31.10.2021

Funding: BMWi-AiF

The IGF project 20107 BG/1 of the Research Association Forschungskuratorium Maschinenbau e. V. - FKM, Lyoner Straße 18, 60528 Frankfurt am Main was funded by the Federal Ministry of Economic Affairs and Climate Action via the AiF within the framework of the program for the promotion of joint industrial research (IGF) based on a resolution of the German Bundestag.

Contact:
Prof. Dr.-Ing. habil. Udo Fritsching
Tel.: +49421 218 51230
E-Mail: ufri(at)iwt.uni-bremen.de

M.Sc. Nithin Mohan Narayan
Tel.: +49421 218 64509
E-Mail: n.narayan(at)iwt.uni-bremen.de