High Pressure Vertical Axis Wind Pump

2021 ◽  
Vol 143 (5) ◽  
Author(s):  
D. Keisar ◽  
B. Eilan ◽  
D. Greenblatt
Keyword(s):  
High Pressure ◽  
Vertical Axis ◽  
Cross Sectional Area ◽  
Liquid Volume ◽  
Medium Size ◽  
Small Scale ◽  
Sectional Area ◽  
Peak Efficiency ◽  
Cross Sectional ◽  
Positive Displacement

Abstract A novel positive displacement, high pressure, vertical axis wind pump (HP-VAWP) was evaluated for the application of stand-alone high-pressure reverse-osmosis desalination and drip irrigation systems. The direct interface between a vertical axis wind turbine (VAWT) and a positive displacement pump that delivers a constant liquid volume per revolution has never been studied before. Understanding the interaction between turbine and pump efficiencies, where delivery pressure is determined by back-pressure alone, is critical for efficient design. Wind tunnel experiments were conducted on a small-scale two-bladed turbine (0.4 m2 cross-sectional area) that operated on a dynamic stall principle. At these small laboratory scales, the turbine and pump peak efficiencies were relatively low (15% and 28%, respectively); nevertheless, the system produced nearly constant pressures in excess of 1.5 bar for a broad operational range. Moreover, the system exhibited a basic self-priming capability, and the turbine could easily be braked by overloading the pump. A conservative field-scale analysis of an HP-VAWP system indicated that a medium-size turbine (12.5 m2 cross-sectional area) could attain a peak efficiency of 12.9%. Realistic efficiencies greater than 20% are attainable, significantly exceeding the 4%–8% typical peak efficiency of the widely used American multibladed wind pumps. Indeed, our research indicates that an HP-VAWP system is viable and requires further development. The benefits of zero carbon emissions during operation, high relative efficiency, and easy manufacturing and maintenance render the HP-VAWP ideal for stand-alone or off-grid environments.

Effect of Hub Configuration on the Performance of Mixed Flow Turbine for Micro Hydropower in Pipes

2021 ◽  
Author(s):  
Seungsoo Jang ◽  
Ji-Hun Song ◽  
Youn-Jea Kim
Keyword(s):  
Numerical Analysis ◽  
Design Of Experiments ◽  
Guide Vane ◽  
Environmental Issues ◽  
Cross Sectional Area ◽  
Small Scale ◽  
Sectional Area ◽  
Mixed Flow ◽  
Cross Sectional ◽  
Waste Energy

Abstract As environmental issues have been on the rise recently, the demand for hydropower is increasing. Micro hydropower in pipes is highly safe, sustainable, and easy to introduce. In this study, a mixed flow turbine is introduced to collect waste energy in pipes, and numerical analysis was conducted to estimate the performance. Efficiency was adopted as an indicator to evaluate the performance, and the performance of three different hub configurations, which are conical, convex, and concave, was investigated. The hydroturbine used in this study was modeled except for the guide vane due to the small scale, and the blade was designed using design of experiments. As a result, three different hub configurations have the best efficiency point between rotational speeds of 3000 rpm and 3200 rpm. The convex hub showed the highest efficiency, which was 1.60% and 3.63% higher than the conical and concave hub, respectively. It is related to the variation in the cross-sectional area of the flow path of the runner depending on the hub configuration. Consequently, the convex hub configuration showed the best performance.

scholarly journals Ice discharge error estimates using different cross-sectional area approaches: a case study for the Canadian High Arctic, 2016/17

2018 ◽  
Vol 64 (246) ◽  
pp. 595-608 ◽  
Author(s):  
PABLO SÁNCHEZ-GÁMEZ ◽  
FRANCISCO J. NAVARRO
Keyword(s):  
Cross Sections ◽  
High Arctic ◽  
Thickness Measurement ◽  
Cross Sectional Area ◽  
Medium Size ◽  
Ice Thickness ◽  
Sectional Area ◽  
Canadian High Arctic ◽  
Cross Sectional ◽  
Ice Cap

ABSTRACTWe analyse the various error sources in the estimation of ice discharge through flux gates, distinguishing the cases with ice-thickness data available for glacier cross-sections or only along the centreline. For the latter, we analyse the performance of three U-shaped cross-sectional approaches. We apply this methodology to glaciers of the Canadian High Arctic. The velocity field is the main error source for small and medium-size glaciers (discharge <100 Mt a−1) with low velocities (<100 m a−1), while for large glaciers (discharge >100 Mt a−1) with high velocities (>100 m a−1) the error in cross-sectional area dominates. Thinning/thickening between ice-thickness and velocity measurements should be considered, as it implies systematic errors up to 8% in our study. The U-shaped parabolic approach, which allows for an adjusted estimation when the ice-thickness measurement point is displaced from the glacier centreline, performs best, with small bias and admissible standard error. We observe an increase of ice discharge from the main glaciers (Trinity and Wykeham) of the Prince of Wales Icefield from 2015 to 2016, by 5 and 20%, respectively, followed by a decrease in 2017, by 10 and 15%, respectively. Belcher Glacier, of the Devon Ice Cap, maintains similar discharges during 2015–17.

Detecting Blockages and Valve Status in Natural Gas Pipelines

2010 ◽  
Author(s):  
Xuesong Wang ◽  
Barry Lennox ◽  
Gordon Short ◽  
John Turner ◽  
Keith Lewis ◽  
...  
Keyword(s):  
High Pressure ◽  
Field Trials ◽  
Cross Sectional Area ◽  
Sectional Area ◽  
Gas Pipelines ◽  
Cross Sectional ◽  
Natural Gas Pipelines ◽  
Non Invasive ◽  
Offshore Pipeline ◽  
Signal Processing Methods

This paper will provide an overview of a novel acoustic reflectometry method that has been developed to detect features, such as blockages and leakages in industrial gas-filled pipelines. The basic concept of the technique is to inject a pulse of sound into a pipeline and then measure the reflections produced as this signal travels along the length of the pipe. Wherever the internal cross sectional area of the pipeline changes then there will be a refection produced. With knowledge of the speed of sound in the gas, the time of flight can be determined and the location of the change in cross sectional area can be identified. The technique is non-invasive and can be used to accurately detect many pipeline features, such as holes, blockages and other objects including valves and even welding joints. The paper will present the results from laboratory tests and field trials which will show the accuracy of the technique in detecting and locating blockages and valve status in industrial pipelines with lengths exceeding 10km and containing high pressure gas. In particular, details of a test where the method was used to identify valve status in a live offshore pipeline, containing high pressure gas will be provided. The difficulties associated with detecting abnormalities in pipelines containing flowing gas will be discussed and suitable signal processing methods will be described which should enable the technique to be applied as a continuous monitoring tool for offshore gas pipelines.

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.

DETERMINATION OF THE FUNCTION OF THE ROD’S CROSS-SECTIONAL AREA USING VIBRATION EIGENFREQUENCIES

2020 ◽  
Vol 0 (4) ◽  
pp. 19-24
Author(s):  
I.M. UTYASHEV ◽  
◽  
A.A. AITBAEVA ◽  
A.A. YULMUKHAMETOV ◽  
◽  
...  
Keyword(s):  
Cross Sectional Area ◽  
Variable Cross ◽  
Sectional Area ◽  
Longitudinal Vibrations ◽  
Cross Sectional ◽  
Method Error ◽  
Various Boundary Conditions ◽  
Elastic Fixation ◽  
Crosssectional Area

The paper presents solutions to the direct and inverse problems on longitudinal vibrations of a rod with a variable cross-sectional area. The law of variation of the cross-sectional area is modeled as an exponential function of a polynomial of degree n . The method for reconstructing this function is based on representing the fundamental system of solutions of the direct problem in the form of a Maclaurin series in the variables x and λ. Examples of solutions for various section functions and various boundary conditions are given. It is shown that to recover n unknown coefficients of a polynomial, n eigenvalues are required, and the solution is dual. An unambiguous solution was obtained only for the case of elastic fixation at one of the rod’s ends. The numerical estimation of the method error was made using input data noise. It is shown that the error in finding the variable crosssectional area is less than 1% with the error in the eigenvalues of longitudinal vibrations not exceeding 0.0001.

Changes in the parameters of nasal breathing and parameters of the upper respiratory tract during orthognathic operations in patients with II and III skeletal class of jaw anomalies

2020 ◽  
pp. 22-27
Author(s):  
S.Sh. Gammadaeva ◽  
M.I. Misirkhanova ◽  
A.Yu. Drobyshev
Keyword(s):  
Respiratory Tract ◽  
Nasal Cavity ◽  
Nasal Septum ◽  
Cross Sectional Area ◽  
Upper Respiratory Tract ◽  
Sectional Area ◽  
Nasal Breathing ◽  
Cross Sectional ◽  
Skeletal Class ◽  
Upper Respiratory

The study analyzed the functional parameters of nasal breathing, linear parameters of the nasal aperture, nasal cavity and nasopharynx, volumetric parameters of the upper airways in patients with II and III skeletal class of jaw anomalies before and after orthognathic surgery. The respiratory function of the nose was assessed using a rhinomanometric complex. According to rhinoresistometry data, nasal resistance and hydraulic diameter were assessed. According to the data of acoustic rhinometry, the minimum cross-sectional area along the internal valve, the minimum cross-sectional area on the head of the inferior turbinate and nasal septum and related parameters were estimated. According to the CBCT data, the state of the nasal septum, the inferior turbinates, the nasal aperture, the state of the nasal cavity, and the linear values of the upper respiratory tract (nasopharynx) were analyzed. The patients were divided into 4 groups according to the classification of the patency of the nasal passages by

Unequal Probability Scheme for Fruit Count in a Guava Tree

2016 ◽  
Vol 3 (4) ◽  
Author(s):  
R. C. BHARATI
Keyword(s):  
Cross Sectional Area ◽  
Equal Probability ◽  
Sampling Scheme ◽  
Research Station ◽  
Sectional Area ◽  
Cross Sectional ◽  
Unequal Probability ◽  
Selection Probabilities ◽  
Horticultural Research ◽  
Number Of Branches

Data on fruit count corresponding to primary, secondary and tertiary branches of a randomly selected guava CV. Allahabad Safeda were recorded from the guava orchard of Horticultural Research Station, Birauli. The proposed sampling scheme in which the selection probabilities are based on length of braches between two forking points was compared with equal probability(PE), probability proportional to the number of branches(PPN), probability proportional to the cross sectional area (PPA) and probability proportional to volume (PPV) method of sampling and found to be more efficient.

Sign in / Sign up

Export Citation Format

Share Document