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The dust storm on the surface of Mars is a severe threat to Mars exploration missions. Taking adequate measures to avoid the impact of the harsh wind-blown dust environment is indispensable. Ground simulation of the Martian high-speed windblown dust environment is helpful for analysis of the environmental effects and evaluations of the suitability of the components and materials. In this paper, a novel reflux subsonic low-density dust wind tunnel is presented to simulate the high-speed windblown dust environment of the Martian atmosphere with a velocity of more than 100 m/s. The sand and dust are fed into the wind tunnel through the ejector assembly together with the compressed gas, resulting in high uniformity of particles in the test section. The construction design of the Mars wind tunnel is introduced. The key parameters, which are the nozzle parameters and the contraction curve, are discussed in detail. The convergent nozzle is most suitable for the ejector assembly. Moreover, the bicubic curve is selected as the contraction curve. The gas-particle two-phase computational fluid dynamic (CFD) simulations demonstrate the rationality of the wind tunnel design. [ABSTRACT FROM AUTHOR]

The dust storm on the surface of Mars is a severe threat to Mars exploration missions. Taking adequate measures to avoid the impact of the harsh wind-blown dust environment is indispensable. Ground simulation of the Martian high-speed windblown dust environment is helpful for analysis of the environmental effects and evaluations of the suitability of the components and materials. In this paper, a novel reflux subsonic low-density dust wind tunnel is presented to simulate the high-speed windblown dust environment of the Martian atmosphere with a velocity of more than 100 m/s. The sand and dust are fed into the wind tunnel through the ejector assembly together with the compressed gas, resulting in high uniformity of particles in the test section. The construction design of the Mars wind tunnel is introduced. The key parameters, which are the nozzle parameters and the contraction curve, are discussed in detail. The convergent nozzle is most suitable for the ejector assembly. Moreover, the bicubic curve is selected as the contraction curve. The gas-particle two-phase computational fluid dynamic (CFD) simulations demonstrate the rationality of the wind tunnel design.

A low-density wind tunnel called the Mars wind tunnel, has been developed at Tohoku University that can produce a high subsonic flow at low pressures for aerodynamic measurements of low-Reynolds-number aircraft wings aimed at developing aircraft applicable to the atmosphere on the planet Mars. Accurate surface pressure measurements on the wing are essential for analysis of not only aerodynamic performance, including lift and drag, but also the flow fields around the wing. This paper presents a surface pressure measurement technique using pressure-sensitive paint (PSP) applicable for Mars wind tunnel tests under low-pressure conditions. The results show that a PSP composed of palladium tetra(pentafluorophenyl) porphyrin (PdTFPP) and poly[1-(trimethylsilyl)-propyne] [poly(TMSP)] exhibits a high-pressure sensitivity at pressures as low as 1 kPa, and the absolute values of the static pressures measured by the PSP accorded well with the values derived from static pressure sensors used as a reference. A calibration methodology for the non-uniform pressure sensitivity on the test model, including a temperature calibration, is also established. The PSP technique clearly demonstrated pressure sensitivity over a distinctive low-pressure region inside a leading edge separation bubble on a flat plate at low Reynolds numbers. Graphical Abstract: [Figure not available: see fulltext.] [ABSTRACT FROM AUTHOR]