Analysis on compressor blading conditions of helicopter’s gas-Turbine engine working in polluted environment

© Research India Publications.Working in the dusty air pollution the air-gas channel of the engine is polluted. This results in deterioration of engine power plants. In this paper we present the results of studies of mass, density, thickness and microstructure of deposits on the rotor blades of a helicopter gas-turbine engine compressor having a nominal capacity of 883 kW after working 1500 h. The researches were conducted on ten blades of each stage. The blades were weighed before and after treatment, and then the averaged sludge mass was calculated. The results show that at the latter stages of the compressor deposit density was greater than at the first ones. Mode with full manifestation of roughness for a given engine is implemented in the first six stages of the compressor. It is concluded that the characteristics of the boundary layer and the value of the coefficient of friction on the surface of the blades are mostly influenced by the size of the arithmetic average height of irregularities Rz. The resulting data is used to develop methods of purifying of the compressor flow path

Observation of large arrays of plasma filaments in air breakdown by 1.5-MW 110-GHz gyrotron pulses

We report the observation of two-dimensional plasma filamentary arrays with more than 100 elements generated during breakdown of air at atmospheric pressure by a focused Gaussian beam from a 1.5-MW, 110-GHz gyrotron operating in 3-mu s pulses. Each element is a plasma filament elongated in the electric field direction and regularly spaced about one-quarter wavelength apart in the plane perpendicular to the electric field. The development of the array is explained as a result of diffraction of the beam around the filaments, leading to the sequential generation of high intensity spots, at which new filaments are created, about a quarter wavelength upstream from each existing filament. Electromagnetic wave simulations corroborate this explanation and show very good correlation to the observed pattern of filaments.open424

Plasma structures observed in gas breakdown using a 1.5 MW, 110 GHz pulsed gyrotron

Regular two-dimensional plasma filamentary arrays have been observed in gas breakdown experiments using a pulsed 1.5 MW, 110 GHz gyrotron. The gyrotron Gaussian output beam is focused to an intensity of up to 4 MW/ cm2. The plasma filaments develop in an array with a spacing of about one quarter wavelength, elongated in the electric field direction. The array was imaged using photodiodes, a slow camera, which captures the entire breakdown event, and a fast camera with a 6 ns window. These diagnostics demonstrate the sequential development of the array propagating back toward the source. Gases studied included air, nitrogen, SF6, and helium at various pressures. A discrete plasma array structure is observed at high pressure, while a diffuse plasma is observed at lower pressure. The propagation speed of the ionization front for air and nitrogen at atmospheric pressure for 3 MW/ cm2 was found to be of the order of 10 km/s.open322

Nanometric diamond delta doping with boron

Diamond is desired for active semiconducting device because of it high carrier mobility, high voltage breakdown resistance, and high thermal diffusivity. Exploiting diamond as a semiconductor is hampered by the lack of shallow dopants to create sufficient electronic carriers at room temperature. In this work, nanometer thick, heavily boron doped epitaxial diamond ‘delta doped’ layers have been grown on ultra smooth diamond surfaces which demonstrate p type conduction with enhanced Hall mobilities of up to 120 cm2/Vs and sheet carrier concentrations to 6 × 1013 cm–2, thus enabling a new class of active diamond electronic devices

Analysis on compressor blading conditions of helicopter’s gas-Turbine engine working in polluted environment

© Research India Publications.Working in the dusty air pollution the air-gas channel of the engine is polluted. This results in deterioration of engine power plants. In this paper we present the results of studies of mass, density, thickness and microstructure of deposits on the rotor blades of a helicopter gas-turbine engine compressor having a nominal capacity of 883 kW after working 1500 h. The researches were conducted on ten blades of each stage. The blades were weighed before and after treatment, and then the averaged sludge mass was calculated. The results show that at the latter stages of the compressor deposit density was greater than at the first ones. Mode with full manifestation of roughness for a given engine is implemented in the first six stages of the compressor. It is concluded that the characteristics of the boundary layer and the value of the coefficient of friction on the surface of the blades are mostly influenced by the size of the arithmetic average height of irregularities Rz. The resulting data is used to develop methods of purifying of the compressor flow path