4 Throat Region

2015 ◽  
pp. 61-72
Keyword(s):  
Throat Region

Steady-State stress distributions in circumferentially notched bars subjected to creep

1982 ◽  
Vol 17 (3) ◽  
pp. 123-132 ◽  
Author(s):  
K D Al-Faddagh ◽  
R T Fenner ◽  
G A Webster
Keyword(s):  
Steady State ◽  
Stress Distribution ◽  
Stress Index ◽  
Stress Distributions ◽  
Computer Solution ◽  
Time Intervals ◽  
Throat Region ◽  
Intermediate Time ◽  
State Stress ◽  
Good Agreement

The paper describes a procedure, based on a finite element method, for calculating directly the steady-state stress distribution in circumferentially notched bars subjected to creep without the need for obtaining solutions at intermediate time intervals. Good agreement is obtained with relevant approximate plasticity solutions and with numerical calculations which approach the steady-state over a period of time from the initial elastic stress distribution. Also, the procedure is equally applicable to primary, secondary, and tertiary creep, provided the variables of stress and time are separable in the creep law. Results obtained for a range of notch geometries and values of the stress index, n, are reported. It is found for each profile that a region of approximately constant effective stress, σ, independent of n, is obtained which can be used to characterise the overall behaviour of the notch throat region when a steady-state is reached sufficiently early in life. An approximate method for estimating the maximum equivalent steady-state stress across the notch throat is also presented which does not require a computer solution.

Transonic flow in the throat region of axisymmetric nozzles

AIAA Journal ◽  
1981 ◽  
Vol 19 (6) ◽  
pp. 801-804 ◽  
Author(s):  
J. C. Dutton ◽  
A. L. Addy
Keyword(s):  
Transonic Flow ◽  
Throat Region

Cooling the throat region of a tank furnace

1975 ◽  
Vol 32 (12) ◽  
pp. 833-834
Author(s):  
V. T. Shevchenko
Keyword(s):  
Tank Furnace ◽  
Throat Region

Integral Axi-Symmetric Nozzle Design

1965 ◽  
Vol 69 (659) ◽  
pp. 795-798
Author(s):  
M. J. Cohen
Keyword(s):  
High Speed ◽  
Design Method ◽  
Space Technology ◽  
Axially Symmetric ◽  
Cross Sectional ◽  
Hypersonic Nozzle ◽  
Low Speed ◽  
Throat Region ◽  
High Enthalpy ◽  
Working Section

SummaryThis is an extension of the design method described in ref. 1 to the compressible flow in integral nozzles comprising both subsonic (contraction) and supersonic (effusor) parts. The nozzles are axially symmetric and will be considered as isentropic convertors of low speed high enthalpy inviscid gas to a high speed, relatively low enthalpy state, heat transfer effects being ignored. The key advantage of the method over existing hybrid design methods(2'3'4'5) is that no assumption is made as to conditions in the “sonic” throat region before expansion in the effusor, the design being integral from low speed inlet to high speed outlet. A slight disadvantage of the method is that of ref 1, namely that a nozzle of an ideally infinite extent has to be truncated both at inlet and outlet. However, for a given nozzle length this limitation can be biased towards the relatively insensitive low subsonic inlet to benefit correspondingly outlet conditions to the extent that it should be possible to make the maximum variation from the mean in the cross-sectional speed at outlet less than 0.01 per cent. The method is being applied to design integral hypersonic nozzle units for the projected small intermittent hypersonic facility in the Department of Aeronautics and Space Technology. This tunnel will have a nominal working-section diameter of 2 in and the flow will be accelerated from low speed (about 20 ft/sec) at inlet to Mach numbers of either 5, 6, or 7 at outlet to the working section using three alternative nozzles.

scholarly journals Qualitative Analysis of Polyethylene Wear in a Bipolar Femoral Prosthesis: A Case Report

2001 ◽  
Vol 9 (2) ◽  
pp. 71-76 ◽  
Author(s):  
Nobuhiro Kaku ◽  
Hiroshi Tsumura ◽  
Takehiko Torisu
Keyword(s):  
Fourier Transform ◽  
Case Report ◽  
Polyethylene Wear ◽  
Femoral Prosthesis ◽  
Bearing Surface ◽  
Throat Region ◽  
Degree Of Oxidation ◽  
Deep Area ◽  
Qualitative Changes

We researched the qualitative changes in the polyethylene of a bipolar head retrieved at revision occurring in vivo using optical microscopy and Fourier transform infrared spectroscopy. The bearing surface of the outer head was smooth with no definable scratches delamination. However, the evidence of delamination of the beveled throat region and cracking at the base of the leaf was noticed. The degree of oxidation was different in each area of the polyethylene in the bearing component and that of the rim was shown to be higher than that of the bearing surface. Comparing the rate of ketone and ester, ketone binding was frequently found around the prosthetic rim rather that at the bearing surface. However, the ratio of ester at the surface was higher than that at the deep area of the same rim. We considered these results showed local environmental effects in vivo play a significant role in dictating the response.

Aerodynamic Throttling of Two-Dimensional Nozzle Flows

1972 ◽  
Vol 23 (1) ◽  
pp. 53-61 ◽  
Author(s):  
R H Nunn ◽  
H Brandt
Keyword(s):  
Control Volume ◽  
Interaction Region ◽  
Experimental Measurements ◽  
Two Dimensional ◽  
Volume Analysis ◽  
Throat Region ◽  
Mainstream Flow ◽  
Nozzle Flows

SummaryThe inviscid interaction resulting from the penetration of a jet of air into the throat region of a bounded mainstream flow is investigated analytically and experimentally. Taking into account the effects of jet shocks, a control volume analysis is used to calculate the mainstream and jet conditions at the boundaries of the interaction region. These results are then used to estimate the shape of the interface separating the jet and mainstream. Particular attention is given to the throttling of the mainstream flow and the analytical predictions show agreement with the experimental measurements.

Numerical simulations for swirlmeter on flow fields and metrological performance

2016 ◽  
Vol 40 (4) ◽  
pp. 1072-1081 ◽  
Author(s):  
Desheng Chen ◽  
Baoling Cui ◽  
Zuchao Zhu
Keyword(s):  
Vortex Core ◽  
Reverse Flow ◽  
Pressure Fluctuations ◽  
Flow Characteristics ◽  
Turbulence Models ◽  
Internal Flow ◽  
Industrial Applications ◽  
Throat Region ◽  
Vortex Precession ◽  
Metrological Performance

Measurements of flow rates of fluids are important in industrial applications. Swirlmeters (vortex precession meters) are widely used in the natural gas industry because of their advantage in having a large measurement range and strong output signal. In this study, using air as a working medium, computational fluid dynamics (CFD) simulations of a swirlmeter were conducted using the Reynolds-averaged Navier–Stokes (RANS) and renormalization group (RNG) k–ε turbulence models. The internal flow characteristics and the influence of the tube structure (geometric parameter of flow passage) on metrological performance were studied, with a particular focus on the meter factor. Calibration experiments were performed to validate the CFD predictions; the results show good agreement with those from simulations. From the streamline distributions, a clear vortex precession is found in the throat region. At the end of throat, the pressure fluctuation reached a maximum accompanied by the largest shift in the vortex core from the centreline. There exists a large reverse flow zone in the vortex core region in the convergent section. To mitigate the influence of reverse flow on vortex precession, a suitable length of throat is required. For a larger convergent angle, the fluid undergoes higher acceleration leading to an increase in velocity that produces more intensive pressure fluctuations. The minor diameter of the throat also produces a higher velocity and larger meter factor. Compared with both divergent angle and throat length, the convergent angle and throat diameter play a more important role in determining precession frequency.

scholarly journals Two Immigrants with Tuberculosis of the Ear, Nose, and Throat Region with Skull Base and Cranial Nerve Involvement

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Renate A. Richardus ◽  
Jeroen C. Jansen ◽  
Stefan C. A. Steens ◽  
Sandra M. Arend
Keyword(s):  
Differential Diagnosis ◽  
Skull Base ◽  
Retropharyngeal Abscess ◽  
Review Of The Literature ◽  
Abducens Palsy ◽  
Cranial Nerve Involvement ◽  
Throat Region ◽  
The Many ◽  
Nose And Throat ◽  
Acid Fast Staining

We report two immigrants with tuberculosis of the skull base and a review of the literature. A Somalian man presented with bilateral otitis media, hearing loss, and facial and abducens palsy. Imaging showed involvement of both mastoid and petrous bones, extending via the skull base to the nasopharynx, suggesting tuberculosis which was confirmed by characteristic histology and positive auramine staining, while Ziehl-Neelsen staining and PCR were negative. A Sudanese man presented with torticollis and deviation of the uvula due to paresis of N. IX and XI. Imaging showed a retropharyngeal abscess and lysis of the clivus. Histology, acid-fast staining, and PCR were negative. Both patients had a positive Quantiferon TB Gold in-tube result and improved rapidly after empiric treatment for tuberculosis. Cultures eventually yieldedM. tuberculosis. These unusual cases exemplify the many faces of tuberculosis and the importance to include tuberculosis in the differential diagnosis of unexplained problems.

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