Experimental Investigation on Aerodynamic Characteristics of a Variable Area Nozzleless Volute

1985 ◽  
Author(s):  
Feng Zhenping ◽  
Shen Zuda ◽  
Xiang Yimin
Keyword(s):  
Experimental Investigation ◽  
Aerodynamic Characteristics ◽  
Sectional Area ◽  
Cross Sectional ◽  
Flow Angle ◽  
Rate Range ◽  
Flow Parameters ◽  
Outlet Flow ◽  
Flow Rate Range ◽  
Aerodynamic Parameters

The aerodynamic characteristics of a variable area nozzleless volute (VAV) for small radial inflow turbines are studied with the aid of cold air tests in which flow parameters inside the volute channel and at the outlet of the nozzleless ring are measured for cases of various cross-sectional areas. The experimental investigation shows that the desired aerodynamic parameters, especially the outlet flow angle α1 as well as the mass flow rate range can be obtained by varying the croes-sectional area of the VAV. A reasonable approximate method for calculating the average outlet flow angle α1 is presented in which the variation of the circulation in the flow is taken into account.

scholarly journals Experimental Investigation on Behavior of Rectangular Concrete-Filled Tubular Columns Considering Diaphragms

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4412
Author(s):  
Sang-Lyul Cha ◽  
Jung-Soo Lee ◽  
Chan-Kyu Park ◽  
Jin-Keun Kim ◽  
Seung-Hee Kwon
Keyword(s):  
Experimental Investigation ◽  
High Strength ◽  
Failure Behavior ◽  
High Ductility ◽  
Inelastic Behavior ◽  
Structural Members ◽  
Sectional Area ◽  
Cross Sectional ◽  
Tubular Columns ◽  
Energy Dissipation Capacity

Concrete-filled tubular (CFT) columns have been widely used as structural members because CFT columns synergize the advantages of steel and concrete resulting in high strength, high ductility, and large energy dissipation capacity. Numerous studies have been performed to understand the behavior of CFT columns. However, the behavior of CFT columns remains uncertain due to their inelastic behavior and uncertain confinement effects, especially when failure occurs. In addition, diaphragms, which are generally installed, make it more complicated to understand the behavior of CFT columns. The purpose of this study is to investigate the effects of the diaphragms on the failure behavior of the CFT columns. To this end, eighteen rectangular CFT columns were tested with five different loading cases. The experimental results suggest that the size of the diaphragm has significant effects on the compressive strength and toughness of the CFT columns. In order to facilitate the proper composite actions of steel and concrete, the size of a diaphragm has to be at least three-quarters of the cross-sectional area.

scholarly journals Influence of the volute cross-sectional shape on mixed inflow turbine performances

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401770817 ◽  
Author(s):  
Mohamed Amine Meghnine ◽  
Mohammad Kamal Hamidou ◽  
Mohammed Hamel
Keyword(s):  
Cross Sections ◽  
Radial Direction ◽  
Essential Element ◽  
Sectional Area ◽  
Cross Sectional ◽  
Flow Angle ◽  
Absolute Flow ◽  
Subsonic Regime ◽  
Simulation Results ◽  
Sectional Shape

The volute is an essential element in the centrifugal machines. Improving its performance is an effective way to improve the total performance of the turbine. The purpose of this study is to replace the accelerating and guiding nozzle vanes by exploring different design possibilities on the cross-sectional area convergence of the volute, since a decreasing area is then associated with expansion in the subsonic regime. The work is extended to a mixed inflow turbine using the new volute cross sections under pulsating regimes for turbocharging. The numerical simulation results show larger accelerations [Formula: see text] and lesser losses in the case of sections with flatter area in the radial direction and without vaneless space between the volute and the rotor; but this combination has an effect on the exit absolute flow angle which is less uniform.

An Experimental Investigation of the Three-Dimensional Flow Within Large Scale Turbine Cascades

1986 ◽  
Author(s):  
Jaromír Jílek
Keyword(s):  
Experimental Investigation ◽  
Large Scale ◽  
Three Dimensional ◽  
Side Wall ◽  
Aerodynamic Characteristics ◽  
Flow Measurements ◽  
Wall Boundary Layer ◽  
Flow Parameters ◽  
Side Walls ◽  
Turbine Cascades

A detailed experimental investigation of the three-dimensional subsonic flow was carried out in a typical nozzle and impulse configuration of plane turbine cascades with a chord length 0.5 m. Flow parameters were measured within the passage and behind the cascade using a five-hole probe. Pressure distribution measurements and flow visualization were made on blade surfaces and side walls. Flow measurements were taken in endwall and airfoil boundary layers for both types of cascades. The influence of the aspect ratio, the inlet side wall boundary layer and the position of traversing planes on aerodynamic characteristics and losses is discussed.

An Experimental Investigation of the Capillary Performance of Triangular Versus Sinusoidal Channels

1997 ◽  
Vol 119 (4) ◽  
pp. 851-853 ◽  
Author(s):  
G. R. Stroes ◽  
I. Catton
Keyword(s):  
Heat Flux ◽  
Experimental Investigation ◽  
Heat Input ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Average Heat ◽  
Wetted Area

This paper discusses an experimental investigation of the performance of capillary channels with sinusoidal versus triangular geometry. Results indicate that for equivalent cross-sectional area, angle of inclination, and heat input from below, a triangular groove geometry sustains a larger wetted area while a sinusoidal groove geometry supports a greater average heat flux.

scholarly journals Quantification of Arterial, Venous, and Cerebrospinal Fluid Flow Dynamics by Magnetic Resonance Imaging Under Simulated Micro-Gravity Conditions: A Prospective Cohort Study

2020 ◽  
Author(s):  
Arslan Zahid ◽  
Bryn Martin ◽  
Stephanie Collins ◽  
John N. Oshinski ◽  
Christopher Ross Ethier
Keyword(s):  
Cerebrospinal Fluid ◽  
Peak Flow ◽  
Pulse Amplitude ◽  
Flow Dynamics ◽  
Venous Congestion ◽  
Sectional Area ◽  
Csf Flow ◽  
Cross Sectional ◽  
Flow Parameters ◽  
Microgravity Conditions

Abstract Background: Astronauts undergoing long-duration spaceflight are exposed to numerous health risks, including Spaceflight-Associated Neuro-Ocular Syndrome (SANS), a spectrum of ophthalmic changes that can result in permanent loss of visual acuity. The etiology of SANS is not well understood but is thought to involve changes in cerebrovascular flow dynamics in response to microgravity. There is a paucity of knowledge in this area; in particular, cerebrospinal fluid (CSF) flow dynamics have not been well characterized under microgravity conditions. Our study was designed to determine the effect of simulated microgravity (head-down tilt [HDT]) on cerebrovascular flow dynamics. We hypothesized that under microgravity conditions simulated by HDT, increased pressure in the intracranial space would alter intracranial CSF and venous flow dynamics by causing: 1) venous congestion reflected by increased venous cross-sectional area; and 2) a decrease in cardiac-related CSF flow oscillations. Methods: In a prospective cohort study, we measured flow in major cerebral arteries, veins, and CSF spaces in fifteen healthy volunteers using phase contrast magnetic resonance (PCMR) before and during 15° HDT. Results: We found a significant increase in venous cross-sectional area with HDT (p=0.005), indicating venous congestion, along with a decrease in all CSF flow parameters [systolic peak flow (p=0.009), peak-to-peak pulse amplitude (p=0.001), and stroke volume (p=0.10)]. Arterial average flow (p=0.04), systolic peak flow (p=0.04), and peak-to-peak pulse amplitude (p=0.02) all also significantly decreased. Conclusions: These results collectively demonstrate that acute application of 15° HDT caused a reduction in CSF flow parameters (systolic peak flow and peak-to-peak pulse amplitude), coupled with an increase in venous CSA suggesting increased venous congestion with HDT.

scholarly journals An experimental investigation to model wheezing in lungs

2021 ◽  
Vol 8 (2) ◽  
Author(s):  
A. L. Gregory ◽  
A. Agarwal ◽  
J. Lasenby
Keyword(s):  
Experimental Investigation ◽  
Lung Diseases ◽  
Necessary Conditions ◽  
Quantitative Model ◽  
Sectional Area ◽  
Predictive Tool ◽  
Cross Sectional ◽  
Physical Mechanisms ◽  
Elastic Tubes ◽  
Deformed State

A quarter of the world's population experience wheezing. These sounds have been used for diagnosis since the time of the Ebers Papyrus ( ca 1500 BC). We know that wheezing is a result of the oscillations of the airways that make up the lung. However, the physical mechanisms for the onset of wheezing remain poorly understood, and we do not have a quantitative model to predict when wheezing occurs. We address these issues in this paper. We model the airways of the lungs by a modified Starling resistor in which airflow is driven through thin, stretched elastic tubes. By completing systematic experiments, we find a generalized ‘tube law’ that describes how the cross-sectional area of the tubes change in response to the transmural pressure difference across them. We find the necessary conditions for the onset of oscillations that represent wheezing and propose a flutter-like instability model for it about a heavily deformed state of the tube. Our findings allow for a predictive tool for wheezing in lungs, which could lead to better diagnosis and treatment of lung diseases.

Pelvic Canal Narrowing Caused by Triple Pelvic Osteotomy in the Dog

1994 ◽  
Vol 07 (03) ◽  
pp. 110-113 ◽  
Author(s):  
D. L. Holmberg ◽  
M. B. Hurtig ◽  
H. R. Sukhiani
Keyword(s):  
Postoperative Complications ◽  
Pelvic Osteotomy ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Cross Sectional ◽  
Canal Width ◽  
Operative Complications ◽  
Post Operative Complications

SummaryDuring a triple pelvic osteotomy, rotation of the free acetabular segment causes the pubic remnant on the acetabulum to rotate into the pelvic canal. The resulting narrowing may cause complications by impingement on the organs within the pelvic canal. Triple pelvic osteotomies were performed on ten cadaver pelves with pubic remnants equal to 0, 25, and 50% of the hemi-pubic length and angles of acetabular rotation of 20, 30, and 40 degrees. All combinations of pubic remnant lengths and angles of acetabular rotation caused a significant reduction in pelvic canal-width and cross-sectional area, when compared to the inact pelvis. Zero, 25, and 50% pubic remnants result in 15, 35, and 50% reductions in pelvic canal width respectively. Overrotation of the acetabulum should be avoided and the pubic remnant on the acetabular segment should be minimized to reduce postoperative complications due to pelvic canal narrowing.When performing triple pelvic osteotomies, the length of the pubic remnant on the acetabular segment and the angle of acetabular rotation both significantly narrow the pelvic canal. To reduce post-operative complications, due to narrowing of the pelvic canal, overrotation of the acetabulum should be avoided and the length of the pubic remnant should be minimized.

NUMERICAL AND EXPERIMENTAL INVESTIGATION OF AERODYNAMIC CHARACTERISTICS OF THE HYPERSONIC AIRCRAFT MODEL OF INTEGRATED CONFIGURATION

2013 ◽  
Vol 44 (1) ◽  
pp. 111-127
Author(s):  
Sergey Mikhailovich Zadonsky ◽  
Alexander Petrovich Kosykh ◽  
Garry Grantovich Nersesov ◽  
Iraida Fedorovna Chelysheva ◽  
Sergey Valer'evich Chernov ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
Aerodynamic Characteristics ◽  
Aircraft Model ◽  
Hypersonic Aircraft
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