Surge wave characteristics for hydropower plant with upstream double surge tanks connected in series under small load disturbance

2022 ◽  
Author(s):  
Yi Liu ◽  
Jian Zhang ◽  
Zhe Liu ◽  
Long Chen ◽  
Xiaodong Yu
Keyword(s):  
Hydropower Plant ◽  
Wave Characteristics ◽  
Load Disturbance ◽  
Small Load ◽  
In Series

Operational Stability of a Hydropower Plant with a Pipe-Shaped Air-Cushion Surge Chamber

2020 ◽  
Author(s):  
Tingyu Xu ◽  
Jian Zhang ◽  
Sheng Chen ◽  
Wei He ◽  
xiaodong Yu ◽  
...  
Keyword(s):  
Volume Ratio ◽  
Operational Stability ◽  
Hydropower Plant ◽  
Water Volume ◽  
Stable Operation ◽  
Initial Water ◽  
Hydropower Plants ◽  
Small Load ◽  
Air Cushion ◽  
Horizontal Area

Abstract This paper theoretically analyzed the design and operating parameters of a pipe-shaped air-cushion surge chamber (PS-ACSC). A mathematical model for a small load disturbance in a hydropower plant containing the PS-ACSC was established to analyze the effects of the sensitivity of its initial horizontal area and the air-water volume ratio on the operational stability of the plant. The results showed that the PS-ACSC should occupy a critical horizontal area, and its initial water level and the initial air-water volume ratio should be within a certain range to ensure its own stable operation as well as that of the turbine units. The results of a case study showed that a hydropower plant containing the PS-ACSC is most stable when the initial air-water volume ratio ranges from 2.90:1 to 6.68:1. In addition, a hydropower plant containing the PS-ACSC delivers better performance than a horseshoe-shaped air-cushion surge chamber under the same conditions. This study contributes to the design and operational control of hydropower plants containing the PS-ACSC.

The Shikani HME: A New Tracheostomy Heat and Moisture Exchanger

2020 ◽  
Vol 63 (9) ◽  
pp. 2921-2929
Author(s):  
Alan H. Shikani ◽  
Elamin M. Elamin ◽  
Andrew C. Miller
Keyword(s):  
Ex Vivo ◽  
Moisture Loss ◽  
Speaking Valve ◽  
Time Zero ◽  
In Series ◽  
Turbulent Airflow ◽  
The Difference ◽  
Loss Efficiency ◽  
Heat And Moisture ◽  
Lung Simulation

Purpose Tracheostomy patients face many adversities including loss of phonation and essential airway functions including air filtering, warming, and humidification. Heat and moisture exchangers (HMEs) facilitate humidification and filtering of inspired air. The Shikani HME (S-HME) is a novel turbulent airflow HME that may be used in-line with the Shikani Speaking Valve (SSV), allowing for uniquely preserved phonation during humidification. The aims of this study were to (a) compare the airflow resistance ( R airflow ) and humidification efficiency of the S-HME and the Mallinckrodt Tracheolife II tracheostomy HME (M-HME) when dry (time zero) and wet (after 24 hr) and (b) determine if in-line application of the S-HME with a tracheostomy speaking valve significantly increases R airflow over a tracheostomy speaking valve alone (whether SSV or Passy Muir Valve [PMV]). Method A prospective observational ex vivo study was conducted using a pneumotachometer lung simulation unit to measure airflow ( Q ) amplitude and R airflow , as indicated by a pressure drop ( P Drop ) across the device (S-HME, M-HME, SSV + S-HME, and PMV). Additionally, P Drop was studied for the S-HME and M-HME when dry at time zero (T 0 ) and after 24 hr of moisture testing (T 24 ) at Q of 0.5, 1, and 1.5 L/s. Results R airflow was significantly less for the S-HME than M-HME (T 0 and T 24 ). R airflow of the SSV + S-HME in series did not significant increase R airflow over the SSV or PMV alone. Moisture loss efficiency trended toward greater efficiency for the S-HME; however, the difference was not statistically significant. Conclusions The turbulent flow S-HME provides heat and moisture exchange with similar or greater efficacy than the widely used laminar airflow M-HME, but with significantly lower resistance. The S-HME also allows the innovative advantage of in-line use with the SSV, hence allowing concurrent humidification and phonation during application, without having to manipulate either device.

Refurbishment and upgrading of Chancy-Pougny hydropower plant

2016 ◽  
pp. 40-49 ◽  
Author(s):  
Emmanuel Maginot ◽  
Lionel Orcel ◽  
Didier Jimenez
Keyword(s):  
Hydropower Plant

Status of nondestructive control of transport function metal products at JSC EVRAZ NTMK

2020 ◽  
Vol 76 (6) ◽  
pp. 586-590
Author(s):  
S. P. Bersenev ◽  
E. M. Slobtsova
Keyword(s):  
Crack Detection ◽  
Middle Part ◽  
Control Line ◽  
Magnetic Powder ◽  
Nondestructive Control ◽  
Automated Control ◽  
Ultrasonic Control ◽  
Acoustic Contact ◽  
In Series

Achievements in the area of automated ultrasonic control of quality of rails, solid-rolled wheels and tyres, wheels magnetic powder crack detection, carried out at JSC EVRAZ NTMK. The 100% nondestructive control is accomplished by automated control in series at two ultrasonic facilities RWI-01 and four facilities УМКК-1 of magnetic powder control, installed into the exit control line in the wheel-tyre shop. Diagram of location, converters displacement and control operations in the process of control at the facility RWI-01 presented, as well as the structural diagram of the facility УМКК-1. The automated ultrasonic control of rough tyres is made in the tyres control line of the wheel-tyre shop at the facility УКБ-1Д. The facility enables to control internal defects of tyres in radial, axis and circular directions of radiation. Possibilities of the facility УКБ-1Д software were shown. Nondestructive control of railway rails is made at two facilities, comprising the automated control line of the rail and structural shop. The УКР-64Э facility of automated ultrasonic rails control is intended to reveal defects in the area of head, web and middle part of rail foot by pulse echo-method with a immersion acoustic contact. The diagram of rail P65 at the facility УКР-64Э control presented. To reveal defects of the macrostructure in the area of rail head and web by mirror-shadow method, an ultrasonic noncontact electromagnetic-acoustic facility is used. It was noted, that implementation of the 100% nondestructive control into the technology of rolled stuff production enabled to increase the quality of products supplied to customers and to increase their competiveness.

Dimensions of plane and solid angles and their units in the International System of Units (SI)

2020 ◽  
pp. 26-32
Author(s):  
M. I. Kalinin ◽  
L. K. Isaev ◽  
F. V. Bulygin
Keyword(s):  
Solid Angle ◽  
International System ◽  
International Committee ◽  
Plane Angle ◽  
Arc Length ◽  
Weights And Measures ◽  
International System Of Units ◽  
System Of Units ◽  
In Series ◽  
Solid Angles

The situation that has developed in the International System of Units (SI) as a result of adopting the recommendation of the International Committee of Weights and Measures (CIPM) in 1980, which proposed to consider plane and solid angles as dimensionless derived quantities, is analyzed. It is shown that the basis for such a solution was a misunderstanding of the mathematical formula relating the arc length of a circle with its radius and corresponding central angle, as well as of the expansions of trigonometric functions in series. From the analysis presented in the article, it follows that a plane angle does not depend on any of the SI quantities and should be assigned to the base quantities, and its unit, the radian, should be added to the base SI units. A solid angle, in this case, turns out to be a derived quantity of a plane angle. Its unit, the steradian, is a coherent derived unit equal to the square radian.

Solar Power Conditioners Using Bidirectional Chopper Circuits Connected in Series

2012 ◽  
Vol 132 (1) ◽  
pp. 50-57 ◽  
Author(s):  
Hideaki Fujita ◽  
Masao Mabuchi ◽  
Yasuhiro Tsubota ◽  
Takao Mizogami
Keyword(s):  
Solar Power ◽  
In Series

GENERATION AND SHOCK WAVE CHARACTERISTICS OF UNSTEADY PULSED SUPERSONIC LIQUID JETS

2003 ◽  
Vol 13 (5-6) ◽  
pp. 475-498 ◽  
Author(s):  
K. Pianthong ◽  
B. E. Milton ◽  
M. Behnia
Keyword(s):  
Shock Wave ◽  
Liquid Jets ◽  
Wave Characteristics
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