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The thermal diffusivity of two bulk thermoelectric elements and a thermoelectric module was measured by an infrared camera using a thermographic method without any contact in air at room temperature. The estimated values for the elements (3.45 × 10−6 m2/s for a BiSb sample and 1.60 × 10−6 m2/s for a BiTe sample) were slightly larger than those measured in vacuum. The difference was explained as the effect of heat convection on the surface of the samples by solving the one-dimensional heat conduction equation numerically. The thermal diffusivity of thermoelectric elements in a thermoelectric module was also estimated using the thermographic method, and values of (1.1–1.7) × 10−6 m2/s in air were obtained, depending on the element. On the basis of the measurement results, the performance of the module was estimated using impedance spectroscopy, which can estimate not only the dimensionless figure of merit but also the thermal loss and response. The thermal response and thermal loss in air were similar to those in vacuum; however, the dimensionless figure of merit was 0.82 in vacuum and 0.70 in air.

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Abstract-An aerofoil is a streamline body. Symmetric aerofoil (NACA 0015) is used in many applications such as in aircraft submarine fins, rotary and some fixed wings. The ultimate objective of an aerofoil is to obtain the lift necessary to keep an airplane in the air. But construction of the blade with proper angle of attack and implementation has significant effect on lift force. Insufficient lift force might cause fail of airplane flying, especially at high speed. Modern technologists use different simulation techniques to avoid costly model testing. But simulation is based on some assumption. Thus practically results are not fully authentic and have a deviation. In this work numerical and experimental investigation of NACA 0015 is studied at different angle of attack (degree) at different velocity of air by determining the forces at every two degrees from 0 0 to 18 0 . The experiment is conveyed in a low speed wind tunnel. The numerical analysis is conducted using ANSYS (combined with CFD and FLUENT FLOW). The use of the CFD technology greatly reduces the overall investment and efforts for aerofoil design. CFD method contributes to visualize the flow pattern inside aerofoil and takes less time and comparatively faster than experiment. After completing the experimental, numerical data is compared. Therefore, the objective of this paper is to find the deviation and validation of aerodynamics characteristics of NACA 0015 aerofoil for experimental and numerical method.

NACA 0015 and NACA 4415 aerofoil are most common four digits and broadly used aerodynamic shape. Both of the shapes are extensively used for various kind of applications including turbine blade, aircraft wing and so on. NACA 0015 is symmetrical and NACA 4415 is unsymmetrical in shape. Consequently, they have big one-of-a-kind in aerodynamic traits at the side of widespread differences of their utility and performance. Both of them undergo the same fluid principle while applied in any fluid medium giving dissimilar outcomes in aerodynamics behavior. On this work, experimental and numerical investigation of each NACA 0015 and NACA 4415 is done to decide their performance. For this purpose, aerofoil section is tested for a prevalence range attack of angle (AOA). The study addresses the performance of NACA 0015 and NACA 4415 and evaluates the dynamics of flow separation, lift, drag, pressure and velocity contour and so on. This additionally enables to layout new optimistic aerofoil, which is critical to enhance the efficiency and performance of an aircraft in terms of lift enhancement and drag reduction.