Fast-Responding Pressure Sensitive Paint

Fast-Responding Pressure Sensitive Paint

Unsteady aerodynamics has been difficult to measure since the beginning days of wind tunnel testing. Distributed dynamic loads have been determined by using special (dynamic) transducers that measure pressure fluctuations at a few to several hundred points on a wind tunnel model and then integrating the pressure fluctuations over a specified area.

Response of a Porous Fast Pressure Sensitive Paint at 20 kHz in Jet Injection Test

Conventional polymer-based pressure sensitive paint formulations have response times on the order of ~1 second, making them unsuitable for evaluating unsteady aerodynamic phenomena. The temporal-response characteristics of PSP are primarily governed by the thickness of the paint formulation and the diffusion coefficient of the binder material. The response time due to diffusion (tau) increases with the paint thickness (h) squared and decreases with increasing diffusion coefficient (Dm).

Some fast responding paints have focused on decreasing the thickness of the paint in order to improve the temporal response characteristics. This approach sacrifices luminescent output from the paint, and thus the signal-to-noise ratio, for a faster response time and a lower signal-to-noise ratio. Porous binders have been developed with the goal of enhancing the oxygen diffusion within the paint layer and, thus, improving the temporal response without reducing the signal-to-noise ratio. The experimental setup for fast PSP data acquisition is identical to traditional PSP setup.

Jet Impingement into Supersonic Cross-flow Visualized with Fast Pressure Sensitive Paint Time History

ISSI’s Porous, Fast PSP is an example of this type of PSP structure, exhibiting good pressure sensitivity (more than 0.6%/kPa), strong signal and excellent temporal response of 20-kHz. The paint may be applied to clean, dry, materials such as Aluminum, Glass, Plastic, or Steel, and no base coat or heat treating is required. Porous, Fast PSP is recommended for applications that require a bright paint with frequency response of up to 20-kHz.

Fast Pressure Sensitive Paint Applications

ISSI Fast Pressure Sensitive Paints


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