Investigations on Diffuser Efficiency in Supersonic Wind Tunnels
Author : Klaus Oswatitsch
Publisher :
Page : 30 pages
File Size : 43,40 MB
Release : 1948
Category : Diffusers
ISBN :
Author : Klaus Oswatitsch
Publisher :
Page : 30 pages
File Size : 43,40 MB
Release : 1948
Category : Diffusers
ISBN :
Author : Rudolf Hermann
Publisher :
Page : 90 pages
File Size : 32,11 MB
Release : 1950
Category : Wind tunnels
ISBN :
In the wind tunnel arrangement under consideration, the air leaves the Laval nozzle as a free jet and is recaptured by the diffuser, which is of the convergent-divergent design. A theoretical analysis of the flow process through this type of supersonic wind tunnel is presented and the diffuser efficiency is calculated for the case of equilibrium between test chamber pressure and pressure in the nozzle exit, assuming one-dimensional, in viscous, steady flow. Using the basic equations of continuity, energy and momentum flux through a bounding surface, an exact solution of the problem is obtained, which is applicable up to Mach number infinite. One of the basic results is, that in the recapturing zone of the diffuser a transition occurs from supersonic to subsonic flow, which is followed by an acceleration in the convergent portion up to sonic velocity at the second throat. The transition is not a normal shock and involves a total pressure loss greater than that of a normal shock at the test section Mach number. A mathematical solution with supersonic velocity after the transition process has no physical existence. A comprehensive comparison of the analytical results with available experiments in supersonic wind tunnels up to Mach number 4.4 regarding diffuser efficiency and second throat area shows good agreement.
Author : John P. Hartin
Publisher :
Page : 72 pages
File Size : 46,25 MB
Release : 1960
Category : Wind tunnels
ISBN :
Author : James Parker Sturrock
Publisher :
Page : 92 pages
File Size : 43,43 MB
Release : 1948
Category : Wind tunnels
ISBN :
Author : Angus Nathaniel MacDonald
Publisher :
Page : 144 pages
File Size : 42,41 MB
Release : 1947
Category :
ISBN :
Author : Heinrich Ramm
Publisher :
Page : 34 pages
File Size : 28,16 MB
Release : 1947
Category : Supersonic diffusers
ISBN :
Author : J. L. Diggins
Publisher :
Page : 22 pages
File Size : 25,1 MB
Release : 1951
Category :
ISBN :
Author : Mancil W. Milligan
Publisher :
Page : 56 pages
File Size : 13,14 MB
Release : 1963
Category : Hypersonic wind tunnels
ISBN :
Author : James J. White (III)
Publisher :
Page : 0 pages
File Size : 34,52 MB
Release : 1967
Category : Aerodynamics, Hypersonic
ISBN :
A fixed-geometry diffuser system was tested in an arc-heated, hypersonic, open-jet wind tunnel facility at Mach numbers between 14 and 18 and Reynolds numbers (based on nozzle exit diameter) between 8,900 and 25,000. Tests were conducted both with an empty test section and with conical models in the flow. Test variables included test section open-jet length, diffuser second-throat length, and diffuser inlet geometry. Diffuser efficiency improved with increased diffuser second-throat length, with increasing Reynolds number, and with the addition of conical models into the flow. Changes in open-jet length and diffuser inlet geometry had no appreciable effect on diffuser efficiency with an empty test section. A streamlined model support strut produced marked improvement in diffuser efficiency over a blunt support strut.
Author : Arthur Kantrowitz
Publisher :
Page : 38 pages
File Size : 13,65 MB
Release : 1945
Category : Aerodynamics, Supersonic
ISBN :
Summary: The deceleration of air from supersonic velocities in channels has been studied. It has become apparent that a normal shock in the diverging part of the diffuser is probably necessary for stable flow, and ways of minimizing the intensity of this shock have been developed. The effect of various geometrical parameters, especially contraction ratio in the entrance region, on the performance of supersonic diffusers has been investigated. By the use of these results, diffusers were designed which, starting without initial boundary layer, recovered 90 percent of the kinetic energy in supersonic air streams up to a Mach number of 1.85.