The effect of orifice head loss coefficient on the discharge of throttled surge tank

2016 ◽  
pp. 87-92
Author(s):  
S Palikhe ◽  
J Zhou
Keyword(s):  
Head Loss ◽  
Loss Coefficient ◽  
Surge Tank ◽  
Head Loss Coefficient

scholarly journals Holistic Design Approach of a Throttled Surge Tank: The Case of Refurbishment of Gondo High-Head Power Plant in Switzerland

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3440
Author(s):  
Mona Seyfeddine ◽  
Samuel Vorlet ◽  
Nicolas Adam ◽  
Giovanni De Cesare
Keyword(s):  
Power Plant ◽  
Transient Flow ◽  
Holistic Approach ◽  
Head Loss ◽  
Surge Tank ◽  
3D Numerical Modeling ◽  
Head Loss Coefficient ◽  
Loss Coefficients ◽  
High Head ◽  
Modeling Strategy

In order to increase the installed capacity, the refurbishment of Gondo high-head power plant required a modification of the existing surge tank by installing a throttle at its entrance. In a previous study, the geometry of this throttle was optimized by physical modeling to achieve the target loss coefficients as identified by a transient 1D numerical analysis. This study complements previous analyses by means of 3D numerical modeling using the commercial software ANSYS-CFX 19 R1. Results show that: (i) a 3D computational fluid dynamics (CFD) model predicts sufficiently accurate local head loss coefficients that agree closely with the findings of the physical model; (ii) in contrast to a standard surge tank, the presence of an internal gallery in the surge tank proved to be of insignificant effect on a surge tank equipped with a throttle, as the variations in the section of the tank cause negligible local losses compared to the ones induced by the throttle; (iii) CFD investigations of transient flow regimes revealed that the head loss coefficient of the throttle only varies for flow ratios below 20% of the total flow in the system, without significantly affecting the conclusions of the 1D transient analysis with respect to minimum and maximum water level in the surge tank as well as pressure peaks below the surge tank. This study highlights the importance of examining the characteristics of a hydraulic system from a holistic approach involving hybrid modeling (1D, 3D numerical and physical) backed by calibration as well as validation with in-situ measurements. This results in a more rapid and economic design of throttled surge tanks that makes full use of the advantages associated with each modeling strategy.

scholarly journals Head loss coefficient through sharp-edged orifices

2016 ◽  
Vol 49 (6) ◽  
pp. 062009 ◽  
Author(s):  
Nicolas J. Adam ◽  
Giovanni De Cesare ◽  
Anton J. Schleiss ◽  
Sylvain Richard ◽  
Cécile Muench-Alligné
Keyword(s):  
Head Loss ◽  
Loss Coefficient ◽  
Head Loss Coefficient

Study of tunnel outlet head-loss coefficient

2000 ◽  
Vol 27 (6) ◽  
pp. 1306-1310 ◽  
Author(s):  
Minnan Liu ◽  
David Z Zhu
Keyword(s):  
Head Loss ◽  
Loss Coefficient ◽  
Diversion Tunnel ◽  
Head Loss Coefficient

In the design of diversion tunnels, culverts, and pressurized conduits, the outlet head-loss coefficient is generally assumed to be 1.0. However, the head loss can be reduced if a transitional expansion is added to the conduit outlet. This paper studies the reduction in the outlet loss coefficient by using the wingwalls at the tunnel outlet. The best wingwall diffusion angle is found to be 8°, which gives an outlet loss coefficient of 0.62-0.81 with a wingwall length of 2D, with D being the height of the tunnel. A wingwall length of 2D is also found to be suitable, as further increase in length only reduces the outlet loss coefficient marginally. An illustrating example shows that by adding wingwalls of 8° and a length of 2D the headwater level is decreased by 9-22% compared to the case without wingwalls for the same discharge.Key words: outlet, loss coefficient, diversion tunnel, wingwall, diffusion angle.

scholarly journals Experimental Study on Variation Rules of Damping with Influential Factors of Tuned Liquid Column Damper

2017 ◽  
Vol 2017 ◽  
pp. 1-17 ◽  
Author(s):  
Yang Yu ◽  
Lixin Xu ◽  
Liang Zhang
Keyword(s):  
Passive Control ◽  
Uniform Design ◽  
Experimental Studies ◽  
Test System ◽  
Head Loss ◽  
Loss Coefficient ◽  
Liquid Column ◽  
Tuned Liquid Column Damper ◽  
Head Loss Coefficient ◽  
Liquid Column Damper

A tuned liquid column damper (TLCD) is a more effective form of passive control for structural vibration suppression and may be promising for floating platform applications. To achieve good damping effects for a TLCD under actual working conditions, factors that influence the damping characteristics need to be identified. In this study, the relationships between head loss coefficients and other factors such as the total length of the liquid column, opening ratio, Reynolds number, Kc number, and horizontal length of the liquid column were experimentally investigated. By using a hydraulic vibration table, a vibration test system with large-amplitude motion simulation, low-frequency performance, and large stroke force (displacement) control is devised with a simple operation and at low cost. Based on the experimental method of uniform design, a series of experimental studies were conducted to determine the quantitative relationships between the head loss coefficient and other factors. In addition, regression analyses indicated the importance of each factor affecting the head loss coefficient. A rapid design strategy of TLCD head loss coefficient is proposed. This strategy can help people conveniently and efficiently adjust the head loss coefficient to a specified value to effectively suppress vibration.

scholarly journals Iterative calculation of local head loss coefficient of emitters in lateral lines

2021 ◽  
Vol 25 (5) ◽  
pp. 291-296
Author(s):  
Giuliani Prado ◽  
Rafael R. Bruscagin ◽  
Adriano C. Tinos ◽  
Edmilson C. Bortoletto ◽  
Denise Mahl
Keyword(s):  
Lateral Line ◽  
Pressure Head ◽  
Head Loss ◽  
Loss Coefficient ◽  
Inlet Pressure ◽  
Head Loss Coefficient ◽  
Step Procedure ◽  
Total Head ◽  
Lateral Lines ◽  
Rigid Pvc

ABSTRACT This study aimed to iteratively set the local head loss coefficient of the Naan® micro-sprinkler, model 7110 Hadar, installed in a lateral irrigation line. To evaluate the total head loss along the lateral line, tests were performed using a rigid PVC pipe with an inner diameter of 15.8 mm, 12 m in length, and 24 micro-sprinklers inserted along the pipe, regularly spaced 0.5 m. In the tests carried out for four micro-sprinkler nozzle diameters (0.9, 1.0, 1.1, and 1.2 mm) and six inlet pressure head values (5, 10, 15, 20, 25, and 30 m) in the line, the pressure head difference between inlet and outlet in the pipe and the discharge of each emitter along the pipe were measured. The head loss computation was performed by the step-by-step procedure, starting from the downstream end to the upstream end of the line; since varying the local head loss coefficient values iteratively, the total head loss measured in the tests was equal to the calculated. For the different working conditions of the inlet pressure head and the micro-sprinkler nozzle diameter, the local head loss coefficient had values from 0.051 to 0.169. Relating the discharge values measured and estimated along the lateral line, the confidence coefficient of 0.9991 was verified, and the calculation procedure was considered optimal.

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