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EXPERIMENT
Bubble Jet Impingement in Microgravity Conditions
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 | Fluid Physics: Fluid and interface physics |
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 | Drop Tower Bremen - DYT2010 |
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 | F. Suñol (1), O. Maldonado (1), A. García-Sabaté (1), R. González-Cinca (1) |
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 | | (1) | * Francesc Suñol e-mail is: francesc@fa.upc.edu / Ricard González-Cinca e-mail is: ricard@fa.upc.edu
Departament de Fisica Aplicada
Universitat Politecnica de Catalunya (UPC)
c/ Esteve Terradas 5, Ed. C3
08860 Castelldefels (Barcelona)
SPAIN
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 | | [1] | K. Gabriel, (2007), "Microgravity two-phase flow and heat transfer", Springer. | | [2] | J. McQuillen, C. Colin, J. Fabre, (1998), "Ground-based gas-liquid flow research in microgravity conditions: state of knowledge", Space Forum, 3, pp. 165 - 203. | | [3] | J.Y. Eckestein, J. Chen, C.P. Chou, J. Janicka, (2000), "Modeling of turbulent mixing in opposed jet configuration: one-dimensional Monte Carlo probability density function simulation", Proceedings of the Combustion Institute, 28, pp. 141-148. | | [4] | C.P. Chou, J.Y. Chen, J. Janicka, E. Mastorakos, (2004), "Modeling of turbulent opposed-jet mixing flows with k-e model and second order closure", International Journal of Heat and Mass Transfer, 47, pp. 1023-1035. | | [5] | H. Eren, (2006), "Numerical study of unsteady interacting compressible jet flows using finite difference method for small Reynolds numbers", Applied Mathematics and Computation, 172, pp. 876-891. | | [6] | L. Weifeng, S. Zhigang, L. Haifeng, W. Fuchen, Y. Zunhong, (2008), "Experimental and numerical study on stagnation point offset of turbulent opposed jets", Chemical Engineering Journal, 138, 1-3, pp. 283-294. | | [7] | S.I. Voropayev, Y.D. Afanasyev, (1992), "Two-dimensional vortex-dipole interactions in a stratified fluid", The Journal of Fluid Mechanics, 236, pp. 665-689. | | [8] | Y.D. Afanasyev, S.I. Voropayev, P.G. Potylitsin, I.A. Filippov, (1995), "Interaction of vortex dipoles: The theory and laboratory experiment", Atmospheric and Oceanic Physics, 30, 5, pp. 665-671. | | [9] | S.I. Voropayev, Y.D. Afanasyev, V.N. Korabel, I.A. Filippov, (2003), "On the frontal collision of two round jets in water", Physics of Fluids, 15, 11, pp. 3429-3433. | | [10] | K. Tsujimoto, T. Shakouchi, S. Sasazaki, A. Toshitake, (2006), "Direct numerical simulation of jet mixing control using combined jets", JSME International Journal - Series B, 49, 4, pp. 966-973. | | [11] | J. Carrera, X. Ruiz, L. Ramírez-Piscina, J. Casademunt, M. Dreyer, (2008), "Generation of a monodisperse microbubble jet in microgravity", AIAA Journal, 46, 8, pp. 2010-2019. | | [12] | S. Arias, X. Ruiz, J. Casademunt, L. Ramírez-Piscina, R. González-Cinca, (2007), "Experimental study of a microchannel bubble injector for microgravity applications", Microgravity Science and Technology, 21, pp. 107-111. | | [13] | F. Suñol, R. González-Cinca, (2010), "Opposed bubbly jets at different impact angles: jet structure and bubble properties", International Journal of Multiphase Flow, 36, 8, pp. 682-689. | | [14] | I.E. Lima Neto, D.Z. Zhu, N. Rajaratnam, (2008), "Bubbly jets in stagnant water", International Journal of Multiphase Flow, 34, pp. 1130-1141. | | [15] | I.E. Lima Neto, D.Z. Zhu, N. Rajaratnam, (2008), "Horizontal injection of gas-liquid mixtures in a water tank", Journal of Hydraulic Engineering, 134, 12, pp. 1722-1731. | | [16] | F. Suñol, O. Maldonado, R. Pino, R. González-Cinca, (2009), "Design of fan experiment for the study of bubble jet interactions in microgravity", Microgravity Science and Technology, 21, 1-2, DOI: 10.1007/s12217-008-9082-8, pp. 95-99. | | [17] | F. Suñol, R. González-Cinca, (2010), "Bubbly jet impingement in different liquids", Microgravity Science and Technology, 23, 2, DOI: 10.1007/s12217-010-9219-4, pp. 151-158. | | [18] | H. Schlichting, (1979), "Boundary-Layer Theory", 7th edition, McGraw-Hill Classic Textbook Reissue. | | [19] | F. Suñol, R. González-Cinca, (2011), "Droplet collisions after liquid jet breakup in microgravity conditions", Journal of Physics: Conference Series, 327, 1, doi:10.1088/1742-6596/327/1/012026. | | [20] | N. Méndez, R. González-Cinca, (2011), "Numerical study of bubble dynamics with the Boundary Element Method", Journal of Physics: Conference Series, 327, 1, DOI: 10.1088/1742-6596/327/1/012028. |
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 | The main purpose of this project is to study the interactions between two bubble jets in microgravity. The designed experimental setup is based on an injection device that can control bubble generation frequency, size and velocity, injection angle and separation between jets. We have obtained numerous on ground results on both individual as well as collective behavior of bubbles. In order to get insight into the role played by gravity on bubble jet structure, the obtained results can be compared with zero-gravity experiments. In particular, coalescence of bubbles and jet structure in microgravity can be studied at different velocity regimes inside two overlapping jets with different separation between nozzles. In the current project, we maintained a constant impact angle, φ=0º (i.e. frontal collision), and we focused on the study of the effects of different separation between nozzles and different flow rates on the final structure of the resulting jets. |
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 | The BubJet experiment was carried out from 11 to 29 of October 2010.
The effects of two parameters have been studied: The effect of the jet flow rate (controlled by the gas and liquid flow rates, Qg and Ql respectively) and the effect of separation between jets. We planned to use three different values of the separation between jets (s = 100 mm, s = 75 mm and s = 50 mm) and different values of the flow rates.
Once that we had the setup properly assembled in the rack, and the rack is placed inside the capsule, we needed to do the following operations at each drop:
- Turn on the alimentation from the batteries.
- Activate the Illumination system, liquid pump, controllers and camera.
- Run the LabView program:
- Activate the liquid pump at the proper flow rate.
- Activate the gas flow rate sensor.
- Open the pressure controller valve in order to let the gas circulate through the gas line. Choose a proper aperture value (between 2.5% and 5%).
- Wait a few seconds in order to stabilize the system.
- Trigger the high-speed camera to start recording.
- Drop the capsule.
- Stop the LabView program.
- Turn off the alimentation from the batteries.
- Recover the recorded high-speed video and check the results of all the acquisition devices.
- Check the mechanical integrity of the whole setup.
The separation between jets had to be changed manually between drops.
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 | The experiment results will be published soon in the Final Report. After release you can find the Report in the attachment below. |
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 |  | Fig. 1 The BubJet experimental setup. |  | | Fig. 2 Close-up view of the upper part of experiment set-up. | | | Fig. 3 Overall view of the drop capsule. | | | Fig. 4 Close-up of work on the drop capsule. | |
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 | Natacha Callens (e-mail: natacha.callens@esa.int) |
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