Pressure sensitive paint measurements at high Mach numbers

Abstract

Depending on the case study examined, different PSPs may be used, each applied using a different method onto the model. For polymer PSP the paint is sprayed on. In contrast, the model may first be anodized or covered with a thin-layer chromatography plate and then dipped in PSP. The objective of the present study is to analyse the characteristics of different PSP substrates at high Mach numbers which use two well known PSP molecules: (i) tris-Bathophenanthroline Ruthenium (II) Perchlorate and (ii) Platinum-tetrakis (pentafluorophenyl) Porphyrin. Using a double ramp geometry under a Mach 5 hypersonic flow the feasibility of applying each of the aforementioned PSP methods is investigated and compared to discrete pressure measurements. The flow over a 3D bump under a Mach 1.3 flow is also studied to give a broader Mach number range. In the hypersonic tunnel, all PSP techniques and formulations were able to capture the complex flowfield with the results quantitatively agreeing with the discrete measurements. For the transonic bumps however, it was found that the polymer based Platinum PSP could map the flowfield more accurately.

Static and Wind-on Performance of Polymer-Based Pressure-Sensitive Paints Using Platinum and Ruthenium as the Luminophore

“…Therefore, compared to the PtTFPP polymer-based PSP, the Ru (II) polymer-based PSP shows limited capability in providing qualitative information about the flow features that present in the flow field. Similar conclusion was also drawn by Zare-Behtash et al [38] using a contour bump model coated with Ru (II) polymer-based PSP. It should be noted that the PSP formulation used in [38] is slightly different from the one employed in this study.…”

“…Similar conclusion was also drawn by Zare-Behtash et al [38] using a contour bump model coated with Ru (II) polymer-based PSP. It should be noted that the PSP formulation used in [38] is slightly different from the one employed in this study.…”

“…This is evidenced by the absence of the flow features, like the spanwise vortex pair and the separation line in the surface pressure map shown in Figure 10b. Similar conclusions were also drawn by Zare-Behtash et al [38] and Quinn et al [26,34]. In fact, an interesting phenomenon can be observed by plotting the surface pressure profile, measured by the two PSPs being studied, along the centreline of the contour bump, as shown in Figure 11.…”

“…This indicates that the PtTFPP polymer-based PSP can provide both the qualitative surface pressure map and quantitative information about the flow pattern over the contour bump model. It should be noted that a similar contour map pattern was also documented in [38] using a contour bump model coated with polymer-based PSP with PtTFPP as the luminophore.…”

“…Therefore, the thermal effect that acted on the model during the wind tunnel test was compensated. In addition, although no data of pressure measurements using pressure taps and transducers are provided here, the data shown in [38] using a double-ramp model concluded that accurate surface pressure measurements in supersonic free-stream could be achieved by using the two polymer-based PSPs employed in the present study, as the same polymer-based PSP formulations were also used in [38]. …”