Measurements of the boundary layer growth in annular diffusers

Stevens, S. J.; Fry, P.R.

doi:10.2514/6.1972-86

Cited by 3 publications

(3 citation statements)

References 6 publications

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“…The performance parameters of the prediffuser section (1-2 in Fig. 2) were taken from the experimental investigation (3) and added to the predicted behaviour for section (2)(3)(4) so that the overall performance (1-4) could be evaluated and compared with measurements. The range of investigated cases is given in Table 1.…”

Section: Flow Configuration Chosen For the Numerical Investigationmentioning

confidence: 99%

Numerical Calculations of the Flow in Annular Combustor Dump Diffuser Geometries

Koutmos

McGuirk

1989

Proceedings of the Institution of Mechanical Engineers, Part C:

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A method for calculating the turbulent isothermal flow in axisymmetric annular dump difluser geometries is described and appraised. The calculation method is based on the numerical solution of the time-averaged transport equations for momentum, continuity, turbulence kinetic energy and energy dissipation, using a jinite diyerence formulation. A boundary-jitted curvilinear orthogonal grid obtained from a solution of the inverse Laplace equations is used to represent the curved combustor head accurately and reduce numerical diffusion errors due to better alignment of the flow streamlines with the grid lines. Comparison between predicted results and measurements indicates that variations in ( a ) the overall pressure recovery and ( b ) the loss coeflcient performance of the dump diffuser system, with changes in diffuser design features (for example innerfouter annulus mass flow split or dump gap), can be predicted to within 7 per cent of the inlet dynamic head without adopting a more refined turbulence closure. The method is therefore demonstrated to be a usejiil design tool for dump diyuser geometries. NOTATION Roman charactersA cross-section area AR area ratio c,, c , , c2constants in k--E turbulence model k 11, 1, and 1, ui uj U U1 and U 2 *, Y static pressure coefficient dump gap annulus height turbulence kinetic energy metric coefficients relating to curvilinear system of coordinates mass flowrate total pressure static pressure radius mass flow split between outer and inner annulus source term in the transformed conservation equation Reynolds stress tensor mean axial velocity mean velocities in curvilinear coordinate directions 1 and 2 Cartesian coordinates dk, c~ constants in k-E turbulence model dependent variable ( = U , V , P, k, E ) in transformed conservation equation 4

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Section: Flow Configuration Chosen For the Numerical Investigationmentioning

confidence: 99%

Numerical Calculations of the Flow in Annular Combustor Dump Diffuser Geometries

Koutmos

McGuirk

1989

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…Critically distorted asymmetric inlet velocity profiles produce a severe drop in pressure recovery. Stevens and Fry [9] worked on two optimum straight-walled annular diffusers. One diffuser had a uniform diameter center body, the other had an expanding diameter center body (divergence angle 40°).…”

Section: Introductionmentioning

confidence: 99%

Effects of casing angle on the performance of parallel hub axial annular diffuser

Singh

Arora

2020

International Journal of Turbo &Amp; Jet-Engines

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In this paper, the effects of non-swirling and swirling flow on the performance of parallel hub axial annular diffuser has been investigated. The study was conducted on a fully developed swirling flow and non-swirling flow to predict the separation of the flow from the wall. Three different annular diffusers were used with casing wall angles of 3°, 6°, and 9°. Furthermore, various swirl angles (0–25°) at the inlet of diffusers have been investigated to analyze the performance across the length. It was found that parallel hub axial annular diffuser performance increases up to a certain length as the inlet swirl angle increases. However, the performance also improves as the diffuser area ratio (AR) increases. The performance is evaluated based on the static pressure recovery coefficient (Cp) and the total pressure loss coefficient (CTL). The highest possible pressure recovery is achieved by the 12° swirl angle with a casing angle of 6°.

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“…Similarly, Birk and Davis [13] proposed a curved exhaust passage with the objective of reducing or eliminating high radiance sources. Numerous experi ments have also been completed on annular diffusers with curva ture [15][16][17][18], The degree of difficulty in determining the flow distribution is increased because radial pressure gradients relating to the geometry are present. Numerous experi ments have also been completed on annular diffusers with curva ture [15][16][17][18], The degree of difficulty in determining the flow distribution is increased because radial pressure gradients relating to the geometry are present.…”

Section: Introductionmentioning

confidence: 99%

Experimental Validation of Numerically Optimized Short Annular Diffusers

Cerantola

Birk

2015

Journal of Engineering for Gas Turbines and Power

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Short annular diffusers with negative wall angles were evaluated numerically and experi mentally with up to 40 deg inlet swirl at an inlet Reynolds number of Re, « 1.4 x 10s and Mach number ofM, » 0.16. The 80% experimental effectiveness of the 1.61 and 1.91 area ratio (AR) diffusers with 0-20 deg inlet swirl were on par with unswirled maximums reported in literature and computational fluid dynamics (CFD) predicted reasonable outlet axial velocity profiles and wall pressure distributions. The AR = 2.73 diffuser's effective ness without swirl was 13% below the maximum for the given AR and larger discrepancies occurred in the CFD results due to the incorrect prediction of the recirculation zone strength. Preference was given to the realizable k-& model on coarse grids with wall func tions that predicted performance of all cases with at least 20 deg inlet swirl to within 20%.

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Measurements of the boundary layer growth in annular diffusers

Cited by 3 publications

References 6 publications

Numerical Calculations of the Flow in Annular Combustor Dump Diffuser Geometries

Numerical Calculations of the Flow in Annular Combustor Dump Diffuser Geometries

Effects of casing angle on the performance of parallel hub axial annular diffuser

Experimental Validation of Numerically Optimized Short Annular Diffusers

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