Experimental research on aerodynamic force effect of multiple plumes based on pressure-sensitive paint technique

The interaction of multiple plumes may cause interacted plumes with complex flow field. To experimentally study the aerodynamic force effects of interacted plumes, an optical measurement technique for surface pressure based on Pressure-Sensitive Paint (PSP) was employed to globally measure the aerodynamic force of a plate model impinged by single-and dual-nozzle plumes which used normal-temperature air as the working gas with high resolution. The strength and region of the aerodynamic force under different distances and angles between the nozzles and the plate were analyzed. The experimental results show that PSP using poly(TMSP) as the binder and PtTFPP as the luminophore exhibits fast response and can distinguish tiny pressure variation of Pa level in the plume aerodynamic force measurement. Compared to the conventional method based on discrete pressure taps, PSP is low temperature-dependent, is capable of measuring large pressure gradient, and can accurately describe the aerodynamic force effect of plume. It is found that the aerodynamic force is significantly enhanced by the interacted plumes, and the enhancement effect decreases as the incident distance reduces. The aerodynamic force of the interacted plumes cannot be directly superimposed by those of single plumes linearly. Plume interaction enhances the backflow intensity, and thus the plume shield after multi-plume interaction should be taken into account in spacecraft design.