Youssef Mébarki

Dual luminophor pressure-sensitive paint: III. Application to automotive model testing

Porphyrins play key roles in natural energy conversion systems, including photosynthesis and oxygen transport. Because of their chemical stability, unique optical properties and synthetic versatility, porphyrins are well suited as chemical sensors. One successful application is the use of platinum porphyrin (PtP) in pressure-sensitive paint (PSP). Oxygen in the film quenches luminescence, and oxygen pressure was initially monitored by measuring the ratio of I(wind-off)/I(wind-on). But this ratio is compromised if there is model motion and if the paint layer is inhomogeneous. Furthermore it requires careful monitoring and placement of light sources. Moreover, this method is seriously affected by temperature. The errors caused by model motion and temperature sensitivity are eliminated or greatly reduced using dual luminophor paint. This paper illustrates a successful application of a dual luminophor PSP in auto model testing. The PSP is made from an oxygen sensitive luminophor, Pt tetra(pentafluorophenyl)-porpholactone, which provides Isen, and Mg tetra(pentafluorophenyl)porphine, which provides temperature-sensitive paint (TSP) as the pressure-independent reference. The ratio PSP/TSP in the FIB polymer produced ideal PSP measurements with a very low-temperature dependence of −0.1% °C−1.

Closed-Loop Control Validation of a Morphing Wing Using Wind Tunnel Tests

In this paper a rectangular finite aspect ratio wing, having a wing trailing edge airfoil reference airfoil cross section, was considered. The wing upper surface was made of a flexible composite material and instrumented with Kulite pressure sensors and two smart memory alloys actuators. Unsteady pressure signals were recorded and visualized in real time while the morphing wing was being deformed to reproduce various airfoil shapes by controlling the two actuators displacements. The controlling procedure was performed using two methods which are described in the paper. Several wind-tunnel test runs were performed for various angles of attack and Reynolds numbers in the 6 × 9 foot wind tunnel at the Institute for Aerospace Research at the National Research Council Canada. The Mach number was varied from 0.2 to 0.3, the Reynolds numbers varied between 2.29 and 3.36 x 10 6 , and the angle-of-attack range was within -1 to 2 degrees. Wind-tunnel measurements are presented for airflow boundary layer transition detection using high sampling rate pressure sensors.

Modeling and Testing of a Morphing Wing in Open-Loop Architecture

This paper presents the modeling and experimental testing of the aerodynamic performance of a morphing wing in open-loop architecture. We show the method used to acquire the pressure data from the external surface of the flexible wing skin, using incorporated Kulite pressure sensors and the instrumentation of the morphing controller. The acquired pressure data are analyzed through fast Fourier transforms to detect the magnitude of the noise in the surface airflow. Subsequently, the data are filtered by means of high-pass filters and processed by calculating the root mean square of the signal to obtain a plot diagram of the noise in the airflow. This signal processing is necessary to remove the inherent noise electronically induced from the Tollmien-Schlichting waves, which are responsible for triggering the transition from laminar to turbulent flow. The flexible skin is required to morph the shape of the airfoil through two actuation points to achieve an optimized airfoil shape based on the theoretical flow conditions similar to those tested in the wind tunnel. Two shape memory alloy actuators with a nonlinear behavior drive the displacement of the two control points of the flexible skin toward the optimized airfoil shape. Each of the shape memory actuators is activated by a power supply unit and controlled using the Simulink/MATLAB® software through a self-tuning fuzzy controller. The methodology and the results obtained during the wind-tunnel test proved that the concept and validity of the system in real time are discussed in this paper. Real-time acquisition and signal processing of pressure data are needed for further development of the closed-loop controller to obtain a fully automatic morphing wing system.

A hybrid fuzzy logic proportional- integral-derivative and conventional on-off controller for morphing wing actuation using shape memory alloy Part 1: Morphing system mechanisms and controller architecture design

The present paper describes the design of a hybrid actuation control concept, a fuzzy logic proportional-integral-derivative plus a conventional on-off controller, for a new morphing mechanism using smart materials as actuators, which were made from shape memory alloys (SMA). The research work described here was developed for the open loop phase of a morphing wing system, whose primary goal was to reduce the wing drag by delaying the transition (from laminar to fully turbulent flows) position toward the wing trailing edge. The designed controller drives the actuation system equipped with SMA actuators to modify the flexible upper wing skin surface. The designed controller was also included, as an internal loop, in the closed loop architecture of the morphing wing system, based on the pressure information received from the flexible skin mounted pressure sensors and on the estimation of the transition location. The controller’s purposes were established following a comprehensive presentation of the morphing wing system architecture and requirements. The strong nonlinearities of the SMA actuators’ characteristics and the system requirements led to the choice of a hybrid controller

A hybrid fuzzy logic proportional- integral-derivative and conventional on-off controller for morphing wing actuation using shape memory alloy Part 2: Controller implementation and validation

The paper presents the numerical and experimental validation of a hybrid actuation control concept – fuzzy logic proportional-integral-derivative (PID) plus conventional on-off – for a new morphing wing mechanism, using smart materials made of shape memory alloy (SMA) as actuators. After a presentation of the hybrid controller architecture that was adopted in the Part 1, this paper focuses on its implementation, simulation and validation. The PID on-off controller was numerically and experimentally implemented using the Matlab/Simulink software. Following preliminary numerical simulations which were conducted to tune the controller, an experimental validation was performed. To implement the controller on the physical model, two programmable switching power supplies (AMREL SPS100-33) and a Quanser Q8 data acquisition card were used. The data acquisition inputs were two signals from linear variable differential transformer potentiometers, indicating the positions of the actuators, and six signals from thermocouples installed on the SMA wires. The acquisition board’s output channels were used to control power supplies in order to obtain the desired skin deflections. The experimental validation utilised an experimental bench test in laboratory conditions in the

On–off and proportional–integral controller for a morphing wing. Part 2: Control validation – numerical simulations and experimental tests

The second part of this article describes the numerical simulation and experimental validations of actuators control system for a morphing wing application, which was developed and designed in the first part of this article. After the description of the finally adopted control architecture, the validation for the non-linear system model is presented. First, the integrated controller is validated numerically with MATLAB/Simulink software, followed by a physical implementation of the control and experimental validation in the wind tunnel. To implement the controller on the physical model, two programmable switching power supplies, AMREL SPS100-33, and Quanser Q8 data acquisition card were used. The inputs of the data acquisition card were the two signals issued by the linear variable differential transformer potentiometers, indicating the positions of the actuators, and the six signals recorded by thermocouples installed on the SMA wires. The acquisition board output channels were used to control the required power supply to obtain the desired skin deflections. The control experimental validation was performed first on a bench test and then in the wind tunnel test. A number of optimized airfoil shapes, used in the design phase, were translated into actuators vertical displacements which were used as input signals for the controller. In the wind tunnel tests, a comparative study was realized around the transition point position for the reference airfoil and for each optimized airfoil.

Water-Based Oxygen-Sensor Films

The luminescent cyclometalated iridium complex [Ir(fppy)(2)(t-Bu-iCN)(2)]CF(3)SO(3), 1 (fppy = 4-(2-pyridyl)benzaldehyde, and t-Bu-iCN = tert-butyl isocyanide), was synthesized and characterized by X-ray crystallography and (1)H NMR, absorption, and emission spectroscopies. Complex 1 was quantitatively bound to the water-soluble amine-functionalized polymer Silamine D208-EDA by reductive amination, to produce 2. The quantum yield of emission and excited state lifetime of 2 (varphi(em) = 0.23 and tau = 20.6 mus) are comparable to that of the model complex [Ir(tpy)(2)(t-Bu-iCN)(2)]CF(3)SO(3), 3 (tpy = 2-(p- tolyl) pyridine) with varphi(em) = 0.28 and tau = 35.6 mus. Aqueous blends of 2 with Silamine and colloidal microcrystalline cellulose (MC) were used to prepare oxygen-sensor films. Oxygen sensitivities of these films were determined as a function of Silamine:MC ratio and obeyed Stern-Volmer kinetics. The optimum oxygen-sensor film composition was 2 in 1:1 Silamine:MC, which had an oxygen sensitivity of 0.502 over an atmospheric pressure range of 0.007-45 psi. Temperature sensitivity (percentage loss of intensity per degrees C) of this film was determined to be -1.1 and -1.4% degrees C(-1) at vacuum and 1 bar atmospheric pressure, respectively. These results were compared to those of films incorporating dispersions of 1 and 3. Luminescence microscopy of 9:1, 1:1, and 1:5 Silamine:MC films of 2 show that the charged iridium complex in 2 associates with the surface of MC and lifetime measurements of these films show an increase in lifetime with increasing MC fraction. The optimum quenching sensitivity observed for the 1:1 Silamine:MC film suggests that the diffusion of oxygen must decrease with increasing fraction of MC and thereby decrease oxygen sensitivity. These novel materials offer an environmentally friendly alternative to the preparation of oxygen-sensor films.

Pressure Sensitive Paint Evaluation on a Supercritical Wing at Cruise Speed

A comparative wind tunnel test of various Pressure Sensitive Paint (PSP) formulations has been performed at the Institute for Aerospace Research (IAR) 1.5 m×1.5 m Trisonic Blowdown Wind Tunnel. The model under study is a prototype supercritical wing of a half model. The results are presented at the cruise Mach number:M=0.74. The effect of the Reynolds number on the pressure distribution is assessed by varying the stagnation pressure of the flow. The evaluated paints all use the same porphyrin molecule as the luminescent sensor and the differences in sensitivity to pressure and temperature are a result of the PSP binder, which differs for each formulation. Examples of the processed results are given and the accuracy of the different PSP formulations is also discussed.

Aerostructural Model for Morphing Laminar Wing Optimization in a Wind Tunnel

An aerostructural numerical model of a two-dimensional morphing laminar wing prototype is built and validated for different flight conditions: Mach numbers ranging from 0.2 to 0.3 and angles of attack ranging from -1 to 2C. The active structure of the wing is modeled using the ANSYS commercial finite element software. The aerostructural interaction is achieved by coupling the XFoil free-license aerodynamic solver to ANSYS. This model is used to minimize the drag force under constant-lift conditions during wind-tunnel testing using a two-step optimization algorithm (global and local search). The wake pressure wind-tunnel measurements show that extrados morphing results in an average 18.5% drag reduction for eight flow cases covering the flow condition range of interest. Simultaneously, the infrared thermography measurements record an average laminar flow extension of 25% of the wing chord over the upper wing surface. The experimental and numerical results are in good agreement, thus validating the use of an aerostructural model to efficiently manage the shape of a morphing laminar wing.

Automotive Testing Using Pressure-Sensitive Paint

AbsractMeasurements of the surface pressure on a simplified automobile model have been performed using pressure-sensitive paint (PSP). The program was undertaken to investigate the use of commercial and in-house PSP at low speed (between 11 m/s and 92 m/s) and to find techniques to improve the measurement accuracy. A comparison ofa priori andin situ calibration methods was also conducted. A linearin situ calibration ora priori methods combined with one tap pressure, correcting for bias errors, were found to provide the best accuracy.