Pressure Losses in Combining Subsonic Flows Through Branched Ducts

1992 ◽  
Vol 114 (1) ◽  
pp. 264-270 ◽  
Author(s):  
N. I. Abou-Haidar ◽  
S. L. Dixon
Keyword(s):  
High Speed ◽  
Working Fluid ◽  
Local Flow ◽  
Subsonic Flows ◽  
Pressure Losses ◽  
Combined Flow ◽  
Speed Flow ◽  
Flow Through ◽  
Wide Speed Range ◽  
Good Agreement

An investigation of the “additional” total pressure losses occurring in combining flow through several sharp-edged three-leg junctions has been made. Experimental results covering a wide speed range up to choking are presented for three flow geometries of a lateral branch off a straight duct using dry air as the working fluid. A new theoretical flow model provided results in fairly good agreement with the experimental data obtained. Flow visualization of the high-speed flow using the Schlieren method revealed the presence of normal shock waves in the combined flow about one duct diameter downstream of the junction. The highest attainable Mach number (M3) of the averaged downstream (combined) flow was 0.66 for several of the flow geometries. This value of M3 appears to be the maximum possible and is the result of a combination of flow separation and local flow choking.

Pressure Losses in Combining Subsonic Flows Through Branched Ducts

1990 ◽  
Author(s):  
N. I. Abou-Haidar ◽  
S. L. Dixon
Keyword(s):  
High Speed ◽  
Working Fluid ◽  
Flow Visualisation ◽  
Local Flow ◽  
Subsonic Flows ◽  
Pressure Losses ◽  
Combined Flow ◽  
Speed Flow ◽  
Flow Through ◽  
Wide Speed Range

An investigation of the “additional” total pressure losses occurring in combining flow through several sharp-edged three-leg junctions has been made. Experimental results covering a wide speed range up to choking are presented for three flow geometries of a lateral branch off a straight duct using dry air as the working fluid. A new theoretical flow model provided results in fairly good agreement with the experimental data obtained. Flow visualisation of the high speed flow using the Schlieren method revealed the presence of normal shock waves in the combined flow about one duct diameter downstream of the junction. The highest attainable Mach number (M3) of the averaged downstream (combined) flow was 0.66 for several of the flow geometries. This value of M3 appears to be the maximum possible and is the result of a combination of flow separation and local flow choking.

High Speed Flow through Perforated Plates

1960 ◽  
Vol 64 (590) ◽  
pp. 103-105
Author(s):  
P. G. Morgan
Keyword(s):  
Pressure Drop ◽  
High Speed ◽  
Perforated Plate ◽  
Wire Mesh ◽  
Flow Conditions ◽  
High Speed Flow ◽  
Perforated Plates ◽  
Speed Flow ◽  
Flow Through ◽  
Points Of View

The flow through porous screens has been widely studied from both the theoretical and experimental points of view. The most widely used types of screen are the wire mesh and the perforated plate, and the majority of the literature has been concerned with the former. Several attempts have been made to correlate the parameters governing the flow through such screens, i.e. the pressure drop, the flow conditions and the geometry of the mesh.

High Speed Flow Through Wire Gauzes

1959 ◽  
Vol 63 (584) ◽  
pp. 474-475 ◽  
Author(s):  
P. G. Morgan
Keyword(s):  
Pressure Drop ◽  
Pressure Loss ◽  
High Speed ◽  
Static Pressure ◽  
Flow Conditions ◽  
High Speed Flow ◽  
Speed Flow ◽  
Wire Gauze ◽  
Flow Through

The Flow of Fluids through screens has been widely studied with particular importance being attached to the measurement of the pressure drop caused by a screen and its relation to the screen geometry and the flow conditions. The majority of the investigations have been carried out on wire gauze screens mounted in ducts with air passing through them, the static pressure being measured on either side of the gauze. Attempts have been made by Weighardt Annand and Grootenhuisto correlate the gauze geometry with the pressure drop and to enable the pressure loss over a given screen and with given flow conditions to be predicted.

High-Speed Aerosol Flow Through Micro-Nozzles for Direct-Write Processes

2013 ◽  
Author(s):  
Justin M. Hoey ◽  
Sourin Bhattacharya ◽  
Artur Lutfurakhmanov ◽  
Michael Robinson ◽  
Orven F. Swenson ◽  
...  
Keyword(s):  
High Speed ◽  
Aerosol Particles ◽  
Particle Interaction ◽  
Direct Write ◽  
Particle Rotation ◽  
High Speed Flow ◽  
Magnus Force ◽  
Aerosol Flow ◽  
Speed Flow ◽  
Flow Through

Aerosol direct-write printing for mesoscale features has been commercially available since around 2002 from Optomec®. We have developed variances to this process first in Collimated Aerosol Beam-Direct Write (CAB-DW) for printing sub-10 μm features and in Micro Cold Spray for printing with solid metallic aerosols. These deposition tools offer extensive uses, but are still limited in certain applications by either line widths or the amount of overspray. Modeling of aerosol flow through micro-nozzles used in these applications yields a greater understanding of the focusing of these aerosol particles, and may provide a vehicle for new nozzle designs which will further enhance these tools. Recent modeling applied both Stokes and Saffman force to the aerosol particles. Under certain conditions particle rotation and Magnus force may also be necessary to accurately predict the aerosol particles. In this paper we will present our recent results of high-speed flow of 1–10 μm diameter aerosol particles through micro-nozzles in which the model includes all three forces (Stokes, Saffman, Magnus) of fluid-particle interaction, and a comparison of these results to experiments.

Energy Losses at Tees With Large Area Ratios

2005 ◽  
Vol 127 (1) ◽  
pp. 110-116 ◽  
Author(s):  
Kenji Oka ◽  
Hidesato Ito¯
Keyword(s):  
Branch Pipe ◽  
Circular Cross Section ◽  
Correction Factors ◽  
Large Area ◽  
Combined Flow ◽  
Flow Through ◽  
Loss Coefficients ◽  
Energy And Momentum ◽  
Good Agreement

The loss coefficients for smooth, sharp-edged tees of circular cross-section with the area ratio of 11.44 were determined experimentally for five branch angles which ranged from 45 deg to 135 deg giving special consideration to all configurations of flow through the tees. The Reynolds number, in the leg carrying the combined flow, was kept to a constant value, i.e., 105 for the branch pipe and 3×104 for the main pipe, respectively. The equations for loss coefficients developed from the continuity, energy, and momentum principles give good agreement with the experimental results for tees with large area ratios provided that correction factors are introduced. The correction factors were determined by the analysis of the experimental data with the relative uncertainties from 0.9 to 3.3% according to the configurations of flow. The results constitute a useful guide to the determination of the loss coefficients for tees with large area ratios.

Condensation Phenomena in High Speed Flow of Steam

1970 ◽  
Vol 185 (1) ◽  
pp. 395-405 ◽  
Author(s):  
B. A. Campbell ◽  
F. Bakhtar
Keyword(s):  
Surface Tension ◽  
High Speed ◽  
Nucleation Theory ◽  
Condensation Coefficient ◽  
High Speed Flow ◽  
Friction Factors ◽  
Speed Flow ◽  
Condensation Shock ◽  
Droplet Sizes ◽  
Good Agreement

This paper, starting from the nucleation theory, treats numerically the condensing flow of steam in a nozzle and compares the results with existing experimental observations. It is shown that the location of the condensation shock in the theoretical solutions is sensitive to the values adopted for the friction factor, condensation coefficient and variations in surface tension at small droplet sizes. By using friction factors reported in the literature, good agreement between theoretical and experimental results is obtained when the condensation coefficient is taken as 0036 and the surface tension is taken to vary in accordance with Benson and Shuttleworth's model.

High Speed Transient Flow in Manifolds

2019 ◽  
Author(s):  
Nicholas Findanis
Keyword(s):  
Aspect Ratio ◽  
Flow Field ◽  
High Speed ◽  
Transient Flow ◽  
Flow Distribution ◽  
Ideal Gas ◽  
Working Fluid ◽  
High Speed Flow ◽  
Speed Flow ◽  
High Speed Flows

Abstract Flows in manifolds is a ubiquitous and important area to implement flow improvements. In almost all applications of industrial pipe flows, there is the requirement to distribute the flow of fluid. There is a deficiency of studies in the area of flow distribution in manifolds with high speed flows. The present work is aimed at providing a further understanding of transient high speed flow distribution in manifolds. The different manifold configurations were analysed computationally. A comparison was focused between through the different aspect ratio manifolds. The velocity field and the eddy viscosity parameters where compared between the simulated flow models to ascertain the key features in the distributed flow field and especially, to determine the areas that showed greater flow recirculation or flow eddies and the separated flow regions. The CFD study was conducted as a high speed flow/ compressible flow regime accounting for the ideal gas dynamic model being air as the working fluid. The study showed that the transient behaviour of flow field can significantly affect distribution of the flow depending on the aspect ratio and number of branches on the manifold. Efficiency gains can be achieved in high speed flows that can be of benefit in industrial and other engineered flow applications.

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