Impact of expansion level on flow field of a circular duct at high Mach numbers

This article focuses on the flow development and the static wall pressure distribution along the circular duct from the convergent-divergent (CD) nozzle. The study aims to examine the quality of the stream in the conduit when the control is employed. The microjets are activated at the base at (PCD) of 13 mm, and the diameter of the microjets is 1 mm. Mach numbers of the investigation are 1.3, 1.9, and 2.4. The length of the duct considered was from L = 10D to 1D. The diameter of the enlarged tube was 16 mm. The experiments were conducted for NPRs from 3 to 11. The results revealed that the lowest duct length mandatory for the flow continued to attach with the circular duct wall are L/D = 1, 2, and 3 for Mach numbers 1.3, 1.9, and 2.4, respectively. The investigation outcome indicates that there are mild oscillations in the flow-field for correctly expanded flows. The oscillatory trend has a pronounced impact on the duct's flow when the jets are operated at higher NPRs. The control does not adversely affect the flow field, and the magnitude of wall pressure is nearly similar.

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The aerodynamic resistance to a sphere rotating at high Mach numbers in the rarefied transition régime

Proceedings of the Royal Society of London Series A - Mathematical and Physical Sciences ◽

10.1098/rspa.1966.0164 ◽

1966 ◽

Vol 293 (1433) ◽

pp. 156-168 ◽

Cited By ~ 4

Keyword(s):

Experimental Study ◽

Aerodynamic Resistance ◽

Pressure Gauge ◽

Transition Regime ◽

Drag Torque ◽

Free Molecule ◽

Rotating Sphere ◽

Mach Numbers ◽

High Mach ◽

Molecule Flow

An experimental study has been made of the gaseous drag torque on an isolated sphere rotating at high Mach numbers. The sphere was suspended electromagnetically and spun by induction. The drag torque has been measured through the transition régime from continuum to free molecule flow at Mach numbers (based on equatorial speed) of up to about five. These high Mach numbers were achieved in heavy vapours (diiodomethane, germanium tetrabromide and stannic bromide) with sonic speed as little as a quarter of that in air. To measure the pressure in the vapour a second (smaller) rotating sphere was used as a pressure gauge. The results agree well with those previously obtained and show an unexpected Mach number dependence in the transition régime.

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The Effect of a Downstream Rotor on the Measured Performance of a Transonic Turbine Nozzle

Journal of Turbomachinery ◽

10.1115/1.3262047 ◽

1986 ◽

Vol 108 (2) ◽

pp. 269-274

Author(s):

R. G. Williamson ◽

S. H. Moustapha ◽

J. P. Huot

Keyword(s):

Performance Evaluation ◽

Aspect Ratio ◽

Flow Field ◽

Large Scale ◽

Outer Wall ◽

Nozzle Flow ◽

Turning Angle ◽

Low Aspect Ratio ◽

Transonic Turbine ◽

Mach Numbers

Two nozzle designs, involving the same low aspect ratio, high turning angle vanes, and differing in outer wall contour, were tested over a range of exit Mach numbers up to supersonic values. The experiments were conducted on a large-scale, full annular configuration with and without a representative rotor downstream. Nozzle performance was found to be significantly affected by rotor operation, the influence depending on the detailed characteristics of the nozzle flow field, as well as on the design and operation of the rotor itself. It is suggested that performance evaluation of low aspect ratio nozzles of high turning angle may require appropriate testing with a rotor.

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