Jet impingement

News

A video contribution submitted to the Gallery of Fluid Motions of the 67th APS Meeting in San Francisco was published in the Video Gallery of the Conference. The video shows the impingement of a submerged jet on a vertical plate by means of experiments (visualization by the injection of dye) and numerical simulations. The influence of vortices emerging in the shear zone on the local and instantaneous local heat transfer is visualized by a detailed examination of the numerical results. Video Link

Thermo-sensitive paint illustrating jet-to-jet interaction

Latest results from the PhD student Johannes Jörg show the very impressive response of a substrate coated with thermo-sensitive crystals (see video below). The three glass tubes are nozzles through which hot air impinges on the black surface below. Note that the blue color corresponds to a higher temperature then red color.

The immediate color response demonstrates the occurrence of a vortex pair in between two neighboring jets leading to a variation in the local heat transfer coefficient. These vortices and the local variations of the heat transfer coefficient have also been confirmed with fully resolved numerical simulations.

 

Collaborations

Herman Haustein – Tel Aviv University (Israel)

Wilhelm Schabel – KIT Karlsruhe (Germany)

 

 

References

Rohlfs, W., Ehrenpreis, C., Haustein, H., Kneer, R.: Influence of viscous flow relaxation time on self-similarity in free-surface jet impingement, Int. J. of Heat and Mass Transfer, 78, 435-446, 2014.

Rohlfs, W., Haustein, H., Garbrecht, O., Kneer, R.: Insights into the local heat transfer of a submerged impinging jet: Influence of local flow acceleration and vortex-wall interaction, Int. J. of Heat and Mass Transfer, 55, 7728-7736,2012.

Haustein, H., Tebrügge, G., Rohlfs, W., Kneer, R.: Local heat transfer coefficient measurement through a visibly-transparent heater under jet-impingement cooling, Int. J. of Heat and Mass Transfer, 55, 23-24, 6410-6424, 2012.

Haustein, H., Rohlfs, W., Al-Sibai, F., Kneer, R.: Evaluation of the Sensitivity and Response of IR Thermography from a Transparent Heater in the Case of Liquid Jet Impingement, J. of Physics: Conference Series, 395, 012083, 2012.

Rohlfs, W., Ehrenpreis. C., Haustein, H.D., Garbrecht, O., Kneer, R.: Influence of local flow acceleration on the heat transfer of submerged and free-surface jet impingement, IHTC15-8378, Proceedings of the 15th International Heat Transfer Conference, IHTC-15, August 10th -15th , 2014, Kyoto, Japan.

Kneer, R., Haustein, H.D., Ehrenpreis, C., Rohlfs, W.: Flow Structures and Heat Transfer in Submerged and Free Laminar Jets, IHTC15-KN11, Proceedings of the 15th International Heat Transfer Conference, IHTC-15, August 10th -15th , 2014, Kyoto, Japan.

Haustein, H.D., Jörg, J., Rohlfs, W., Al-Sibai, F., Kneer, R.: Influence of Micro-scale Aspects and Jet-to-jet Interaction on Free-surface Liquid Jet Impingement for Micro-jet Array Cooling, Proceedings of the IEEE Intersociety Conference on Thermal and Thermomechanical Phenomena in Electronic Systems – ITHERM 2014, May 27th-30th, Orlando, FL, USA, 2014.