Kazunori Mitsuo

Temperature Correction of PSP Measurement Using Dual-Luminophor Coating

We developed a dual-luminophor pressure/temperature sensitive paint (DPTSP) to correct the temperature dependence of pressure-sensitive paint. The DPTSP is composed of two sensor molecules, PtTFPP and Rhodamine B (RhB), and Poly-IBM-co-TFEM as a binder. Temperature was determined from the image of RhB, and the temperature dependence of PtTFPP was corrected using the calculated temperature. To validate the capability of DPTSP for temperature correction, the pressure field on a delta wing model was measured by the DPTSP measurement system. The pressure values obtained with DPTSP were in good quantitative agreement with pressure tap data. It has been validated that DPTSP is effective in correcting the temperature dependence of PSP.

Practical pressure-sensitive paint measurement system for industrial wind tunnels at JAXA

Japan Aerospace Exploration Agency (JAXA) has constructed the JAXA practical pressure-sensitive paint (PSP) measurement system for their large industrial wind tunnels. Its system and application tests were introduced. Contents of the system which included PSP paint, pressure calculation method and apparatus were described. A high accuracy pressure calculation method, a priori/in situ hybrid method, was also introduced and applied to the data processing. For validating this PSP system, an experiment using an ONERA M5 standard model was conducted in a transonic wind tunnel. PSP results represented global quantitative pressure distribution. The PSP data accuracy, 2σ, of the system compared with pressure taps was 1.9 kPa (Cp = 0.06 at M = 0.84). Then, the JAXA practical PSP measurement system was applied to the Japanese regional jet development test. Its results also represented a detailed and global flow structure on the test model. 2σ of PSP data was Cp = 0.06 at cruising condition. It was proved that the present PSP system could be applied to practical tests at a large industrial transonic wind tunnel.

Advanced lifetime PSP imaging system for pressure and temperature field measurement

The newly designed lifetime imaging system (LIS), which was composed of a multi-gated CCD camera and LED illuminators, has been developed to measure simultaneously pressure and temperature field from luminescent lifetime decay of pressure-sensitive paint (PSP). The new system could reduce the measurement error due to shot noise of a CCD and laser speckle, compared to the previous lifetime imaging system. Optimization of PSP film thickness on white basecoat was also conducted for improving measurement accuracy, and could minimize the measurement error. As a verification test, pressure and temperature images on a simple delta wing were visualized by the newly designed LIS. The quality of the pressure image was considerably improved in comparison with that measured by the previous system. These results indicated that the new LIS was a practical measurement tool to acquire simultaneously pressure and temperature field on an aerodynamic model surface.

Development of Lifetime Imaging System for Pressure-Sensitive Paint

We developed a lifetime imaging system to simultaneously measure pressure and temperature from the luminescent decay of PtTFPP. Analysis of PtTFPP-PSP by a streak camera showed that this PSP exhibited a transient behavior after pulsed excitation, similar to that suggested by Smoluchowski. Utilizing this characteristic, one could determine pressure and temperature by taking three images with different gated times. We built a lifetime imaging system composed of a pulsed laser and an intensified CCD (ICCD) camera. The three gated times of the ICCD were determined referring to the streak camera data. The performance of this system was evaluated over the wide range of pressure and temperature using a PSP-coated flat plate as a test article. As a result, we found that we could fit the ratios of the gated images with a smooth function of pressure and temperature. This allowed us to reconstruct pressure and pressure fields from the measured images. The accuracy of the lifetime imaging system was determined for various pressures and temperatures, and, as a verification test, pressure and temperature patterns induced by a sonic impingement flow were visualized by using this system.

Temperature Correction of Pressure-Sensitive Paint for Industrial Wind Tunnel Testing

Pressure-sensitive paint measurement can obtain a much more detailed surface pressure distribution than can be obtained using conventional pressure taps. However, the pressure-sensitive paint is sensitive not only to pressure but also to temperature, and where high accuracy is required, it is essential to compensate for this temperature dependency. This paper discusses data processing methods for pressure-sensitive paint measurement in transonic industrial wind tunnel testing, and proposes three methods to compensate for temperature dependency of the pressure-sensitive paint: an in situ method, an a priori method, and a hybrid of a priori and in situ methods. The pressure distributions from the pressure-sensitive paint data obtained by these proposed methods are compared with pressure tap data measured by conventional pressure transducers, and it is confirmed that the proposed methods are effective in compensating the temperature dependency of pressure-sensitive paint and improve the accuracy of the obtained data. It is also found that the hybrid of a priori and in situ methods is widely applicable to the industrial wind tunnel testing even if the pressure range of the pressure tap data is limited.

Temperature Correction of PSP Measurement for Low-Speed Flow Using Infrared Camera

Pressure-Sensitive Paint (PSP) system combined with an infrared (IR) camera has been developed at 2 m x 2 m low-speed wind tunnel at WINTEC/JAXA. The temperature correction of PSP was conducted using both temperature image acquired by the IR camera and wind-off images immediately after the wind tunnel shutdown. As a verification test, the pressure distribution on a supersonic transfer (SST) model was measured by the PSP/IR combined system. The measurement accuracy was fairly improved compared to the previous method, i.e., the temperature correction of PSP using only wind-off PSP images immediately after wind tunnel shutdown.

Advanced Lifetime PSP Imaging System for Simultaneous Pressure and Temperature Measurement

The newly designed lifetime imaging system (LIS), which consisted of a multi-gated CCD camera and LED illuminator, has been developed to simultaneously measure temperature and pressure. The new system could reduce the measurement error due to shot noise of a CCD and laser speckle. Optimization of PSP film thickness and renewal of data reduction method were also conducted for improving measurement accuracy. As a verification test, pressure and temperature images on a simple delta wing were visualized by the newly designed LIS. The quality of pressure image was considerably improved in comparison with one measured by the previous system and biluminophor paint. These results indicated that the new LIS has a useful tool to simultaneously measure pressure and temperature image on an aerodynamic model surface. Besides, measurement accuracy of the new system was evaluated in comparison with pressure tap data.

Data Processing of Pressure-Sensitive Paint for Industrial Wind Tunnel Testing

Data processing methods for pressure-sensitive paint measurement in industrial wind tunnels are discussed in this paper. Key tasks are to shorten the processing time and to improve the accuracy of data. To complete data processing within a limited time frame, it has to be performed as continuously and automatically as possible. The methods to promote automation of the data processing are discussed. Solving an issue of temperaturedependency of pressure-sensitive paint is indispensable for enhancing accuracy of data. Two approaches to compensate for the temperature-dependency, i.e. a-priori method and temperature-corrected in-situ method, are applied in this study. As the result, processing time has been shortened by solving problems preventing automation of image registration process. The PSP data processed by both a-priori method and temperature-corrected in- situ method showed reasonable agreement with the pressure tap data measured by pressure transducers, indicating the validity and accuracy of the present data processing methods.

Optical oxygen-sensing properties of porphyrin derivatives anchored on ordered porous aluminium oxide plates

An optical oxygen-sensing activity of anchored porphyrin derivatives on ordered porous aluminium oxide plates was studied in relevance to development of new oxygen-sensing systems. Porphyrin derivatives, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrin, 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrin, 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrin, and their platinum complexes, 5,10,15,20-tetrakis(4-carboxylundecane-1-oxy)porphyrinatoplatinum(II), 5-[4-(11-carboxylundecane-1-oxy)-10,15,20-triphenyl]porphyrinatoplatinum(II), 5-(4-carboxylphenyl)-10,15,20-triphenylporphyrinatoplatinum(II), were synthesized and anchored by an equilibrium adsorption method on aluminium oxide plates, which were prepared by an anodic oxidation. The excitation spectra of the porphyrin-anchored layers showed a broadened and blue-shifted Soret band compared with the corresponding porphyrins in DMSO. The luminescence intensity decreased with increasing oxygen concentrations. The oxygen-sensing ability estimated from I(0)/I(100) (I(0) and I(100) denote the luminescence intensity in 0 and 100% oxygen) was 9.08, 6.78, 8.71, 81.9, 35.5, and 39.1, which are greater than those of corresponding porphyrin derivatives in DMSO under the measured conditions, and indicates the remarkable enhancement effect of platinum(II). Non-linear Stern-Volmer plots were well fitted by the two component system to give the oxygen-sensitive constant (K(SV1)/%(-1)), the oxygen-insensitive constant (K(SV2)/%(-1)), and the former contribution (f(1)): 0.232, 3.32 x 10(-2), and 0.642; 0.141, 2.05 x 10(-2), and 0.687; 0.143, 1.05 x 10(-2), and 0.882; 17.3, 7.04 x 10(-3), and 0.980; 10.2, 1.43 x 10(-2), and 0.935; 16.3, 8.35 x 10(-3), and 0.954. The response time for the change of the atmospheric gas from argon to oxygen was 9.4 s, 12.5 s, 9.6 s, 5.0 s, 8.9 s, and 4.6 s, indicating the shortening effect of platinum. The reverse effect of platinum was observed in the change from oxygen to argon: 15.5 s, 17.0 s, 20.8 s, 667.4 s, 590.1 s, and 580.4 s, indicating the specific interaction of oxygen to the platinum(II) center.

Lift Enhancement of a Pitching Airfoil in Dynamic Stall by DBD Plasma Actuators

A dielectric barrier discharge (DBD) plasma actuator was applied to control leading-edge flow separation on periodically oscillated NACA 0012 airfoil. The effectiveness of flow control by the plasma actuator was investigated through pressure measurements on the surface of the airfoil. All of the cases exhibited a higher cycle-integrated lift and an improvement in the lift cycle hysteresis. The lift enhancement by the plasma actuator was sensitive to frequency of unsteady actuator operation. The maximum peak of efficiency of lift enhancement was observed around F=0.5. The time-resolved PIV measurement was also conducted to understand the flow control mechanism by the plasma actuator. The clear vortices appeared at the leading-edge at high angle of attack, and moved along the airfoil surface toward trailing edge. These vortices bring entrainment of main flow and the lift enhancement of the oscillating airfoil can be achieved.