Проблемы обнаружения отрыва потока датчиками давления на беспилотных летательных аппаратах с пропеллером

An experimental study of pulsations characteristics of the zone of flow separation arising at a small airplane-type UAV with a pushing two-blade propeller were carried out. The measurements were done in wind tunnel by unsteady pressure sensors and microphones built into the skin of the UAV for the test cases with and without a rotating propeller. A significant effect of the propeller on the level of pulsations was found. An increase of the incoming flow velocity led to a weakening of this effect. Analysis of the spectral data of the disturbances did not reveal a direct relationship between the propeller noise and the unsteady characteristics of the separation zone.

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Field Experiment of Blade Surface Pressure of a HAWT

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.291-294.445 ◽

2013 ◽

Vol 291-294 ◽

pp. 445-449

Author(s):

De Shun Li ◽

Ren Nian Li

Keyword(s):

Experimental Study ◽

Numerical Calculation ◽

Wind Tunnel ◽

Field Experiment ◽

Wind Turbine ◽

Surface Pressure ◽

Pressure Sensors ◽

Horizontal Axis ◽

Blade Surface ◽

Horizontal Axis Wind Turbine

Field experimental study is performed on a 33 kW horizontal axis wind turbine with rotor diameter of 14.8 m. The distribution of pressure is gathered by disposed 191 taped pressure sensors span-ward on seven particular sections of a blade. The results will provide a comparative basis to wind tunnel experiment and numerical calculation of the flow of the wind turbine.

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Experimental Study on Dynamic Combustion Characteristics in Swirl-Stabilized Combustors

Energies ◽

10.3390/en14061609 ◽

2021 ◽

Vol 14 (6) ◽

pp. 1609

Author(s):

Donghyun Hwang ◽

Kyubok Ahn

Keyword(s):

Experimental Study ◽

Heat Release ◽

Dynamic Pressure ◽

Combustion Instability ◽

Flame Structure ◽

Pressure Sensors ◽

Necessary Condition ◽

Rayleigh Criterion ◽

Pressure Oscillations ◽

Geometric Conditions

An experimental study was performed to investigate the combustion instability characteristics of swirl-stabilized combustors. A premixed gas composed of ethylene and air was burned under various flow and geometric conditions. Experiments were conducted by changing the inlet mean velocity, equivalence ratio, swirler vane angle, and combustor length. Two dynamic pressure sensors, a hot-wire anemometer, and a photomultiplier tube were installed to detect the pressure oscillations, velocity perturbations, and heat release fluctuations in the inlet and combustion chambers, respectively. An ICCD camera was used to capture the time-averaged flame structure. The objective was to understand the relationship between combustion instability and the Rayleigh criterion/the flame structure. When combustion instability occurred, the pressure oscillations were in-phase with the heat release oscillations. Even if the Rayleigh criterion between the pressure and heat release oscillations was satisfied, stable combustion with low pressure fluctuations was possible. This was explained by analyzing the dynamic flow and combustion data. The root-mean-square value of the heat release fluctuations was observed to predict the combustion instability region better than that of the inlet velocity fluctuations. The bifurcation of the flame structure was a necessary condition for combustion instability in this combustor. The results shed new insight into combustion instability in swirl-stabilized combustors.

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