Parametric Study on Influence of an Array of Air Jets on the Performance of Supersonic Air Intake by Varying the Jet Injection and Back Pressure

Experiments were carried out to determine entrainment rates by turbulent air jets generated with square-edged inlet round nozzles. A parametric study was made which included the effects of Reynolds number, nozzle length, partial confinement and geometry of the jet plenum chamber. Measurements were made for the region extending from the nozzle exit to 24 jet hole diameters downstream. There is a large difference in the rate of fluid entrainment between jets generated with relatively short nozzles and those discharged through long tubes.

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Starting characteristics of a rectangular supersonic air-intake with cowl deflection

The Aeronautical Journal ◽

10.1017/s0001924000003626 ◽

2010 ◽

Vol 114 (1153) ◽

pp. 177-189 ◽

Cited By ~ 10

Author(s):

S. Das ◽

J. K. Prasad

Keyword(s):

Flow Field ◽

Turbulence Model ◽

Small Angle ◽

Deflection Angle ◽

Back Pressure ◽

Air Intake ◽

Performance Results ◽

Starting Characteristics ◽

Basic Configuration

Abstract Experimental and computational investigations have been made to obtain the details of the flow field of a supersonic air-intake with different cowl deflection angles and back pressures at the exit. The flow field obtained with an inviscid computation on the basic configuration, designed for Mach 2·2, shows starting behaviour whereas computation with k-ω turbulence model and experiments indicate unstart characteristics. Both experiments and computations indicate that provision of a small angle at the cowl tip leads to start of the same intake and also improves it’s performance. Results obtained with cowl deflection shows a better performance in comparison to performance achieved with a basic intake and with a bleed of 2·8%. Sustainable back pressure could be obtained through the computations made at different back pressures for different cowl deflection angles. Overall results suggest that provision of small cowl deflection angle itself leads to improvement in performance achieved in comparison to a bleed of 2·8%, even with back pressure at the exit.

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Numerical Study of Supersonic Mixed Compression Air Intake with an Array of Air Jets

Journal of Fluids Engineering ◽

10.1115/1.4049370 ◽

2020 ◽

Author(s):

Neeraj Kumar Gahlot ◽

N. K. Singh

Keyword(s):

Stream Flow ◽

Numerical Study ◽

Computational Study ◽

Pressure Ratio ◽

Injection Pressure ◽

Flow Distortion ◽

Air Jets ◽

Air Jet ◽

Air Intake ◽

Equal Spacing

Abstract Computational study of flow physics inside the mixed compression air intake has been carried out with and without air jets at design Mach number of 2.2. RANS equations were solved with k-? turbulence model by using commercially available software ANSYS. The scope of this research is to improve the flow field inside the air intake and efficiency of supersonic air intake by implementing air jets on the ramp surface. An array of air jets containing two, four and five air jet holes respectively have been made on the ramp surface perpendicular to the flow with equal spacing between them. The injection pressure through air jet has kept constant for all the cases. Flow Distortion and Total pressure recovery were selected to measure the performance of air intake. All the simulations have been performed at a back-pressure ratio of 6. The results obtained suggest that implementation of proper spacing between air jets can improve the performance of air intake due to the mixing of vortices generated by air jets with free stream flow. It is revealed that an array of air jets containing four holes on ramp surface works best and helps in controlling the shock induced separation.

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Air jets imaging tactile sensing device for automation applications

Robotica ◽

10.1017/s0263574700018361 ◽

1995 ◽

Vol 13 (5) ◽

pp. 521-529 ◽

Cited By ~ 3

Author(s):

R. Benhadj ◽

B. Dawson

Keyword(s):

Flexible Manufacturing ◽

Pressure Sensors ◽

Continuous Variable ◽

Back Pressure ◽

Tactile Sensing ◽

Air Jets ◽

Line Array ◽

Air Cushion ◽

Piezoresistive Pressure Sensors ◽

Detection And Recognition

SummaryThis paper details the design principles of operation of a pneumatic proximity-to-tactile sensing device for part handling and recognition in a flexible manufacturing environment. The sensing device utilises a densely packed line array of piezoresistive pressure sensors, providing continuous variable outputs. The sensing plane of the device incorporates a corresponding line array of air jets which develop an air cushion when striking a target of interest. The back pressure levels from these air jets form the basis for the task of target detection and recognition.

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Drag Reduction of Ground Vehicles Using Air-Injected Wheel Deflectors

Volume 7: Fluids Engineering ◽

10.1115/imece2019-10454 ◽

2019 ◽

Author(s):

Kaloki L. Nabutola ◽

Sandra K. S. Boetcher

Keyword(s):

Reynolds Number ◽

Flow Field ◽

Drag Coefficient ◽

Parametric Study ◽

Ground Vehicles ◽

Ground Vehicle ◽

Flow Modification ◽

Air Jets ◽

Air Jet ◽

The Impact

Abstract Numerical simulations of flow modification devices on a simplified ground vehicle are conducted. A parametric study on the size and distance upstream of conventional wheel deflectors is conducted on a simplified body at a Reynolds number of 1.6 × 105 to observe the impact on drag coefficient. Results show that wheel drag is decreased as the height of the conventional wheel deflector is increased. Additionally, the further the conventional wheel deflector is from the wheelhouse, the more sensitive the wheel is to changes in drag coefficient. The conventional wheel deflectors are then replaced by air-jets which are used to manipulate the flow field in and near the wheelhouse to reduce the wheel drag of the simplified body. The air-jet successfully decreases the wheel drag and it is observed that the closer the air-jet is to the wheelhouse the less impact it has on the single wheel drag, but the greater the impact on the overall drag of the simplified body.

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Influence of Rain Protection Louver on the Noise Generated by Ship Engine Room Air Intake

Volume 4: Ocean Engineering; Offshore Renewable Energy ◽

10.1115/omae2008-57363 ◽

2008 ◽

Author(s):

Manoj Kumar ◽

S. L. Nikam

Keyword(s):

Flow Field ◽

Parametric Study ◽

Noise Level ◽

Supply System ◽

Current Work ◽

Significant Source ◽

Angular Orientation ◽

Engine Room ◽

Air Supply ◽

Air Intake

The air supply system, of a ship engine room, is a tremendous source of noise. Apart from the noise from air-intake fan, the rain protection louver, which guides the airflow and protects the fan and the duct from rain, is also a significant source of noise. The influence of the air-intake louver, on the noise generated by the engine room air-intake, has been studied by numerically simulating the flow field as well as on the basis of on-board measurements and simple experiments. In order to analyze the noise generated by the louver, a parametric study has been carried out based on two variables, the angular orientation of the slats of the louver and the spacing between the slats. The study shows that the noise level reduces significantly by changing the angular orientation of the slats, making them inline with the flow. It is also observed that, by increasing the spacing between the slats, the noise level can be reduced. The current work is a part of a study to develop guidelines to limit noise level, due to engine room air intake, on-board a ship.

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Investigation for Aerodynamics of Supersonic Air-intake/Airframe Integration Models Using Back Pressure Control by Secondary Air Injection.

The Journal of the Japan Society of Aeronautical Engineering ◽

10.2322/jjsass1969.45.458 ◽

1997 ◽

Vol 45 (523) ◽

pp. 458-466

Author(s):

Takeshi ITO ◽

Shigemi SHINDO ◽

Kimio SAKATA ◽

Kazuo SHIRAISHI ◽

Junsuke OMI

Keyword(s):

Pressure Control ◽

Back Pressure ◽

Air Injection ◽

Secondary Air Injection ◽

Air Intake ◽

Secondary Air

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Temperature Profile Development in Turbulent Mixing of Coolant Jets With a Confined Hot Crossflow

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.3239534 ◽

1984 ◽

Vol 106 (1) ◽

pp. 193-197 ◽

Cited By ~ 25

Author(s):

S. L. K. Wittig ◽

O. M. F. Elbahar ◽

B. E. Noll

Keyword(s):

Temperature Profile ◽

Momentum Flux ◽

Jet Injection ◽

Field Methods ◽

Opposite Wall ◽

Hot Gas ◽

Air Jets ◽

Primary Zone ◽

Exit Temperature ◽

Wall Injection

The mixing of coolant air jets with the hot gas exiting the primary zone is of major importance to the combustor exit temperature profile. Geometry and momentum flux ratios are the dominant parameters. A theoretical and experimental study of single as well as opposite-wall jet injection into a hot crossflow reveals the applicability and limitations of existing correlations. Modified correlations are presented for opposite-wall injection with jets of different momentum flux ratios. The advantages in applying field methods for describing the flow are discussed.

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КОНЦЕПЦІЯ СТВОРЕННЯ СИЛОВОЇ УСТАНОВКИ СІМЕЙСТВА РЕГІОНАЛЬНИХ ПАСАЖИРСЬКИХ ЛІТАКІВ АН-148/АН-158

Open Information and Computer Integrated Technologies ◽

10.32620/oikit.2019.84.02 ◽

2019 ◽

pp. 50-63

Author(s):

О. Д. Донець ◽

В. П. Іщук

Keyword(s):

Power Plant ◽

Noise Reduction ◽

Fuel Consumption ◽

Electronic System ◽

Electronic Control ◽

Level Of Automation ◽

Auxiliary Power ◽

Power Plant Control ◽

Technical Status ◽

Air Intake

The basic results of calculation and research works carried out in the process of creation of power unit of regional passenger airplanes’ family are given. The design features of the propulsion engines and engine of the auxiliary power plant are described. The aforementioned propulsion system includes propulsion engines D-436-148 and engine AI-450-MS of auxiliary power plant. In order to comply with the requirements of Section 4 of the ICAO standard (noise reduction of the aircraft in site), in part of ensuring the noise reduction of engines, when creating the power plant of the An-148/An-158 aircraft family, a single- and double-layer acoustic filler was used in the structure of the engine nacelle and air intake. The use of electronic system for automatic control of propulsion engines such as FADEC and its integration into the digital airborne aircraft complex ensured the operation of engines, included in the power plant provided with high specific fuel consumption, as well as increased the level of automation of the power plant control and monitoring, and ensured aircraft automation landing in ICAO category 3A. In addition, the use of the aforementioned electronic system, allowed to operate the power plant of the aircraft in accordance with technical status. The use of the AI-450-MS auxiliary power plant with an electronic control system such as FADEC, and the drive of the service compressor from a free turbine, eliminated the effect of changes in power and air takeoff, on the deviation of the engine from optimal mode, which also minimized the fuel consumption. The use of fuel metering system TIS-158, allowed to ensure control of its condition and assemblies, without the use of auxiliary devices, built-in control means. In the fire protection system, the use of the electronic control and monitor unit, as well as the use of digital serial code for the exchange of information between the elements of the system and the aircraft systems, has reduced the number of connections, which increased the reliability of the system and reduced its weight characteristics.

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