Modelling the attached plane jet in a room
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Doctoral thesis (article-based)
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Author
Date
2009
Department
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Mcode
Degree programme
Language
en
Pages
Verkkokirja (1870 KB, 82 s.)
Series
TKK dissertations,
190
Abstract
The application of the attached plane jet has proved to be an effective way to resolve the draught problem and to create a comfortable indoor environment. The objective of this thesis is to give a basis for improving the existing modelling and calculation method applied to predict the jet velocity in both ventilated and air-conditioned rooms using attached plane jet diffusers to avoid the draught problem. A special consideration is to set up models that could be used to predict the jet velocity along the surface more easily, more accurately and more efficiently than the existing methods under attachment and separation conditions. Jet velocity modelling and full-scale experimental measurement have been done to complete the above objectives. Through two measurement phases the whole flow field of the attached plane jet has been investigated experimentally in two full-scale test chambers. A large amount of data on jet velocity, temperature and turbulence intensity has been obtained; beyond that the visualization results are complementary to the understanding of turbulent buoyant jet characteristics. The results showed that: the superimposing model and the free convection velocity are capable of predicting the maximum air jet velocities along the wall under the conditions of the straight downward jet flow and the corner effect jet flow, respectively; the calculated corner-jet velocity profiles by the corner model obtained a good agreement with the measured results; the maximum velocity calculated by the model for the transition zone can be used to predict the maximum velocity decay. This work reveals that the turbulent attached plane jet behaves in a different way compared with the high Reynolds number turbulent jet in a ventilated and air-conditioned room. From the modelling viewpoint, the jet velocity models constructed here can be used to predict the maximum jet velocity decay and velocity profiles from the corner effect region in the indoor airflow studies. The detailed jet information obtained can contribute to the corresponding CFD simulation for further linear slot diffuser development.Description
Keywords
attached plane jet, draught, impingement, airflow modelling, air velocity
Other note
Parts
- [Publication 1]: Guangyu Cao, Jarek Kurnitski, Panu Mustakallio, and Olli Seppänen. 2008. Active chilled beam wall jet prediction by the free convection model. International Journal of Ventilation, volume 7, number 2, pages 169-178.
- [Publication 2]: Guangyu Cao, Jarek Kurnitski, Mika Ruponen, Panu Mustakallio, and Olli Seppänen. 2009. Plane-air-jet corner zone modelling in a room ventilated by an active chilled beam. International Journal of Ventilation, volume 7, number 4, pages 287-298.
- [Publication 3]: Guangyu Cao, Jarek Kurnitski, Mika Ruponen, and Olli Seppänen. 2009. Experimental investigation and modeling of the attached plane jet velocity development characteristics in the transition process in a room. HVAC&R Research, volume 15, number 3, pages 489-508.
- [Publication 4]: Guangyu Cao, J. Kurnitski, M. Ruponen, and O. Seppänen. 2009. Experimental investigation and modelling of a buoyant attached plane jet in a room. Applied Thermal Engineering, volume 29, numbers 13-14, pages 2790-2798.
- [Publication 5]: Guangyu Cao, Jarek Kurnitski, and Panu Mustakallio. 2007. Draught risk evaluation in rooms with chilled beams. In: Proceedings of the 10th International Conference on Air Distribution in Rooms (Roomvent 2007). Helsinki, Finland. 13-15 June 2007, pages 101-110.
- [Publication 6]: Guangyu Cao, Jarek Kurnitski, Panu Mustakallio, and Olli Seppänen. 2007. Performance of chilled beam air distribution close to the wall. In: Proceedings of the 10th International Conference on Air Distribution in Rooms (Roomvent 2007). Helsinki, Finland. 13-15 June 2007, pages 79-86.
- [Publication 7]: Guangyu Cao, Jarek Kurnitski, Panu Mustakallio, and Olli Seppänen. 2007. Chilled beam's air distribution measurements and plane wall jet modeling. In: Proceedings of the 5th International Symposium on Heating, Ventilating and Air Conditioning (ISHVAC 2007). Beijing, China. 7-8 September 2007, pages 288-295.
- [Publication 8]: Jarek Kurnitski, Guangyu Cao, and Panu Mustakallio. 2007. Draft assessment for ceiling vs. wall mounted chilled beams. In: Proceedings of the 10th International Conference on Air Distribution in Rooms (Roomvent 2007). Helsinki, Finland. 13-15 June 2007, pages 11-18.
- [Errata file]: Errata
- [Errata file]: Errata of publications 1, 2 and 4
