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Velocity fields measured in the vicinity of the perforated leading edge of a turbine nozzle vane using the particle image visualization technique are presented. Noncontact measurements were performed in a plane segment consisting of three nozzle vanes and having an optically transparent inlet section offering visual access to the region of the leading edge of the central vane for a high-speed camera and to the laser sheet. The experimental investigations were performed at a fixed incoming flow velocity of 33 m/s, and the relative air flowrate through the cooling holes varied from 1.6 to 6.4%. The cooling film flow near the leading edge was visualized for three models of vanes differing in the air supply method to the holes, hole diameter, and number. Supply of the coolant to the cooling holes from one cavity resulted in a high degree of nonuniformity in the distribution of the film over the leading edge, which was caused by a high blowing ratio for the jets injected through holes located closer to the suction side. The experimental results have revealed that separate supply of cooling air to the holes on the pressure side, leading edge, and suction size minimizes sensitivity of the formed film thickness to the relative flow rate of the coolant and provides a more uniform distribution of the coolant over the vane surface in a wide range of the blowing ratio for the jets that varies from 0.5 to 2.5. Visualization has demonstrated extensive unsteadiness of the film flow along the vane airfoil. In this case, the cooling jet fed through the central hole oscillates, thereby leading to periodic formation of a film on either the pressure side or the suction side. [ABSTRACT FROM AUTHOR]

A calibration device intended for metrological assurance of instruments used to measure deformations and displacements by methods of electronic speckle interferometry and shearography is developed. The optical methods presented here may be applied to different types of materials possessing rough surfaces. The proposed device reproduces stress-strain states by means of elastic deformation of the surface of a membrane through the use of a rod and leverage. Calibration of the device is performed, its transfer characteristics are investigated, and the nonlinearity of the displacement of the surface of the membrane is estimated. Results of experiments designed to measure the stress-strain state with the use of the noncontact method of shearography are presented. The phase image produced by deformation of the membrane is described and the metrological characteristics of the calibrated device are estimated. It is shown that through the use of the present calibration device it is possible to use optical methods not only for qualitative assessment of the deformation of objects of complex shape, but also for quantitative estimation of the geometric characteristics of these objects. [ABSTRACT FROM AUTHOR]

A model simulating the interaction of a uniform 50 Hz power-line electric field with an idealised human body is described. The conclusions drawn can be used to construct a simple instrument which can monitor respiratory and plethysmographic signals, even though attention is focused on respiration. An experimental arrangement has been evaluated and provided a good agreement with the theoretical model. [ABSTRACT FROM AUTHOR]