URCOOL, an Experimental Platform for Sloshing Investigation in Microgravity

Paper number

IAC-05-A2.2.10

Author

Ms. Ines Fuente, Spain

Coauthor

Ms. Mercedes Ruiz, Universidad Politecnica de Madrid, Spain

Coauthor

Mr. Ricardo Navarro Vásquez, Spain

Coauthor

Dr. Sara García, Universidad Politecnica de Madrid, Spain

Coauthor

Dr. Benigno Lázaro, Universidad Politecnica de Madrid, Spain

Year

2005

Abstract

This report presents URCOOL in microgravity “Unsteady Response of COnfined Observable Liquids in microgravity” experiment, carried out during the 7th Student Parabolic Flight Campaign organised by the European Space Agency and developed at the Fluid Dynamics Laboratory of ETSIA, Polytechnic University of Madrid. The goal of this experiment is to study the behaviour of confined liquids subjected to acceleration levels that undergo rapid temporal variations in their absolute value. This scenario appears in the cryogenic fuel tanks of spacecraft during many space manoeuvres, such as the end of powered phases in spacecraft’s upper stages, sudden ignition of a propulsion element, or orientation manoeuvres. The temporal variation in the acceleration perturbation level results in liquid undergoing small motions in the presence of the dominant acceleration field (sloshing motions). If, in this condition, the acceleration is suddenly reduced, the residual kinetic energy stored in the liquid can greatly amplify. It is important to understand well the behaviour of liquids in such condition, since the resulting liquid amplified motion can create significant forces and torques over the spacecraft structure, give rise to problems in the fuel injection system, or generate over-pressure in the tanks.

The first part of the report is a theoretical approach to the sloshing dynamics, including a discussion of the parameters having influence on this phenomenon and some preliminary numerical simulations. The second section includes the description of the experimental set up built to fulfil the goals determined in the theoretical study. The experiment hardware consists basically of a spinning platform of 800 mm in diameter, contained inside an external structure designed to comply with the specifications for a parabolic flight. The spinning platform’s movement is controlled by means of several electronic devices whose main operation parameters can be adapted in order to reproduce different acceleration profiles. This provides the experimental platform with high flexibility to perform different experiments. On the spinning platform, two different experiment cells, partially filled with liquid, are mounted, developed to simulate different experiments. This paper provides a complete description of each system, as well as a definition of the working parameters for the different experiments performed during the campaign. It also describes the importance of the diagnostic methods used to get the experimental data, which include image recording along with experiment acceleration and speed profiles capture.

Finally, this paper reports the preliminary data analysis process that has been carried out in order to understand the phenomena appearing in the liquid-gas interface motion. It is based on digital image processing of the liquid-gas interface and allows the identification of different flow development phases that occur during the experiment.

Abstract document

IAC-05-A2.2.10.pdf

Manuscript document

IAC-05-A2.2.10.pdf (🔒 authorized access only).

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