Experimental Investigation of an Axisymmetric Air Jet Impinging on a Flat Plate PDF Download

Author: Saibal Basu
Publisher:
ISBN:
Category : Air jets
Languages : en
Pages : 210

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Author: Lan Xiao
Publisher:
ISBN:
Category : Air jets
Languages : en
Pages : 216

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Author: Stefan Jachna
Publisher:
ISBN:
Category : Aerodynamics
Languages : en
Pages : 171

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Book Description
This experimental study was conducted on an axisymmetric air jet impinging normally on a smooth, hemispherical, concave plate. The jet Reynolds numbers, based on bulk nozzle velocity and nozzle exit air properties, were between 14,000 and 75,000. The impingement plate used in this work was a hemispherical surface with the radius of 94 mm. Calibrated Pitot tubes and a micromanometer were used for pressure and velocity measurements. The Pitot tubes were mounted on precision positioning mechanisms permitting the accurate traversing of any direction in space. The test air flow rate was measured with calibrated rotometers. The following results of this work are considered a contribution to the knowledge of the jets: 1. It was observed in the free jet zone that the minimum value of negative static pressure depends upon Reynolds number and that the location of the minimum is independent of Reynolds number. If the nozzle-to-plate distance is smaller than 20 nozzle diameters, this location is closer to nozzle exit in proportion to plate proximity. For any nozzle-to-plate distance larger than 20 nozzle diameters, the location of minimum static pressure is constant and equal to eight nozzle diameters from the nozzle exit which is in essential agreement with other researchers. 2. Maximum velocity decay in the wall jet studied was determined to be less rapid than in the case of the flat plate wall jet. 3. A semi-empirical equation for maximum velocity decay in the wall jet was obtained. The development of this equation was based on integral momentum analysis. 4. Empirical equations for "reference boundary velocity" decay and maximum velocity decay in the wall jet were found. The results obtained from the equations are close to experimental results. 5. The developed hemispherical wall jet boundary layer was found to be much thinner than it is in the flat plate case. This fact may be significant in heat transfer.

Author: Eugene P. Symons
Publisher:
ISBN:
Category : Laminar flow
Languages : en
Pages : 28

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An experimental investigation was conducted to determine dynamic characteristics of a circular, fully developed, laminar free jet. Complete velocity profiles are presented at Reynolds numbers of 437 and 1839 at 0, 3, 6, 10, 15, and 25 diameters from the nozzle exit. Centerline velocity decay was obtained over a range of Reynolds numbers from 255 to 1839. Also presented are the angles of spread associated with the diffusion of the jet downstream of the nozzle. Where possible, results are compared with those obtained for laminar jets having an initially flat or uniform velocity profile at the nozzle exit.

Author: Norman S. Land
Publisher:
ISBN:
Category : Dust
Languages : en
Pages : 44

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Author: Samir Sethi
Publisher:
ISBN:
Category : Air jets
Languages : en
Pages : 448

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Author: Ryoichi Amano
Publisher:
ISBN:
Category :
Languages : en
Pages : 414

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Author: R. A. Antonia
Publisher:
ISBN: 9780869340011
Category : Jets
Languages : en
Pages : 54

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Author: Richard S. Snedeker
Publisher:
ISBN:
Category :
Languages : en
Pages : 112

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An experimental investigation was made of the general behavior of an air jet impinging obliquely on a circular flat plate. Surface pressure distributions and velocity profiles of the resulting wall jet were measured. Typical stagnation point radial velocity gradients, their dependence on impingement angle, and their correlation with local free jet properties were also determined. Throughout the range of impingement angles studied the wall jet thickness was found to be relatively constant around the plate perimeter. The azimuthal variation of momentum flux per radian depended strongly on impingement angle and only slightly on jet strength and impingement distance. (Author).

Author: Hayri Acar
Publisher:
ISBN:
Category :
Languages : en
Pages :

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The objective of this study is to investigate experimentally the rectangular jet flow that impinges to a flat plate normally and obliquely. The aspect ratio (nozzle exit height / nozzle exit width) of the rectangular nozzle is 2.First, to investigate the characteristics of the coming flow to the impingement surface, the free jet conditions are examined by using three different Reynolds numbers based on the nozzle exit width as 3.47x 10 4, 6.94x 10 4 and 1.04x 10 5. Then, the effect of the ratio of the nozzle-to-plate distance to nozzle exit width, H/w, on the jet impingement flow is studied for the Reynolds number of 1.05x10 5. H/w ratio is taken as 2.0, 3.08, 4.0, 6.0 and 8.0. To examine the effect of the 8, which is the angle between the jet centerline axis and the surface normal axis, on the jet impingement characteristics, q is taken as 0 o, 5 o, l0o, 15 o and 20 o.The mean velocity and turbulence intensity profiles are measured by using hot-wire anemometer. The outputs of the hot-wire system are taken and drown by a personal computer with a hot-wire software and data acquisition card. Impingement surface pressures, according to the pressure at settling chamber are measured by using a micro manometer which is connected to a personal computer with a data acquisition card. In this study, the surface oil-film technique is used to visualize the impingement surface flow pattern and smoke method is used to visualize the flow pattern of the free jet and jet impingement to a flat surface.This study consists of five main sections (Chapter 1-5) and 6 appendix (Appendix A-F).Chapter 1 is introduction. The importance of the subject, the purpose of the study and the experimental techniques that were used are mentioned..In Chapter 2., information about free jet flow and jet impingement according to literature review is given.Chapter 3., explains the instrumentation and experimental techniques.In Chapter 4. results and discussion are given. Concluding remarks are made in Chapter 5.