Pressure Distribution of Pressure and Non-Pressure Sections of a Hydropower Station Spillway Tunnel

2014 ◽  
Vol 716-717 ◽  
pp. 244-247
Author(s):  
Hong Qing Zhang ◽  
Wei Kai Tan ◽  
Yi Long Lou ◽  
Qian Zhao
Keyword(s):  
Pressure Distribution ◽  
Model Experiment ◽  
Hydropower Station ◽  
Maximum Pressure ◽  
Turbulent Model ◽  
Sudden Drop ◽  
Sudden Enlargement ◽  
High Head ◽  
Spillway Tunnel ◽  
Large Discharge

In this paper, we used VOF combining turbulent model to simulate pressure distribution of pressure section and non-pressure section in a hydropower station spillway tunnel with high head and large discharge in China. The results show that in the pressure section of the spillway tunnel, the values of pressure of emergency gate slot, working gate and the pressing slope, getting from physical model experiment and numerical simulation, are all positive. While in the non-pressure section, the No.1、2、3 aerators of the sudden enlargement and sudden drop occur the maximum pressure. And at the back of the No.1、2、3 aerators, where the values of pressure are negative, forms cavity. The conclusions obtained can improve the design of spillway tunnel.

Numerical Simulation of Ventilation Characteristics in a Hydropower Station Spillway Tunnel with High Head and Large Discharge

2014 ◽  
Vol 926-930 ◽  
pp. 3527-3530
Author(s):  
Hong Qing Zhang ◽  
Yi Long Lou ◽  
Wei Ping Xing ◽  
Jun Jun Tan
Keyword(s):  
Wind Speed ◽  
Hydropower Station ◽  
Aerated Flow ◽  
Speed Distribution ◽  
Vof Model ◽  
High Head ◽  
Spillway Tunnel ◽  
The Right ◽  
Ventilation Hole ◽  
Large Discharge

High wind speedandloudnoise usually occur in the hydropower station spillway tunnel, which will impact the producing environment of operators. In this paper, turbulent model and VOF modelwere combinedto simulate wind speed and the volume of ventilated airin ventilation holeandthreeaeratorsin the spillway tunnel on the right bank of a hydropower station in China. The results show thatVOF modelcan well simulate ventilated air induced by water drag, andthe volume of ventilated air in ventilation hole is the largest.Wind speed distribution on the longitudinal sectionof the inlet of ventilation hole is non-uniform,and loud noisewill occurthere. Wind speed on the left side of three aerators is higher than that on the right side. The results of the volume of ventilated airin threeaerators simulated by VOF modelare credible, but we should improve the VOF model to more accurately simulate aerated flow.

Analysis the Response of Aerated Flow Depth to the VOF Model

2014 ◽  
Vol 716-717 ◽  
pp. 767-770
Author(s):  
Hong Qing Zhang ◽  
Yi Long Lou ◽  
Qian Zhao ◽  
Wei Kai Tan
Keyword(s):  
Water Depth ◽  
Empirical Formula ◽  
Maximum Deviation ◽  
Flow Depth ◽  
Turbulent Model ◽  
Aerated Flow ◽  
Vof Model ◽  
High Head ◽  
Spillway Tunnel ◽  
Large Discharge

In order to analysis the response of aerated flow depth to the VOF model, in this paper, we used VOF combining turbulent model to simulate aerated flow depth in a hydropower station spillway tunnel with high head and large discharge in China. The results show that aerated flow depth is slightly larger than the experiment water depth, but the maximum deviation are not greater than 5% (except the pile number 0+605.236 m). So, using empirical formula to converse the calculate value of water depth into aerated flow depth can make up for the defects of the VOF model which cannot directly get aerated flow depth of the cross section inside the spillway tunnel. But the section water depth can’t be obtained by empirical formula calculation value conversion when cavity exists in the spillway tunnel.

Test on the Shape Schemes of Jilintai-I Hydropower Station Flood Discharge System

2012 ◽  
Vol 490-495 ◽  
pp. 2902-2905
Author(s):  
Wen Xin Zheng
Keyword(s):  
Local Structure ◽  
Hydropower Station ◽  
Shape Design ◽  
Test Results ◽  
Bottom Slope ◽  
Discharge System ◽  
Flood Discharge ◽  
Sudden Enlargement ◽  
Original Scheme ◽  
Spillway Tunnel

According to the original scheme, the surface spillway tunnel of the Jilintai-I hydropower station flood discharge system was designed to be arranged separately, but not to be combined with diversion tunnel; the radial gate of the lower level spillway tunnel was designed not to have the vertical drop and lateral sudden enlargement, and the discharge structures at oblique tunnel were designed to be cancelled. In this paper, through the test on the hydraulic model, the analysis on the test results and many advisory demonstrations, multiple modifications and optimizations are made for the shape design of the axis, bottom slope and local structure of bottom slope and local structure, and also an analysis is conducted on the test results of the main shape scheme of surface spillway tunnel, and then the related opinions and suggestions are proposed according to the existing problems. The way of the pressured vertical drop and lateral sudden enlargement was ultimately used in lower level spillway tunnel of the hydropower station flood discharge system. Also, in this paper, the author makes a hydraulic test on the main shape design of lower level spillway tunnel based on the original scheme, and then an analysis is conducted on the test results and a final scheme is proposed according to the actual problems.

Study on Flow Characteristics inside a Spillway Tunnel of Hydropower Station

2014 ◽  
Vol 716-717 ◽  
pp. 219-222
Author(s):  
Hong Qing Zhang ◽  
Bing Cao ◽  
Yi Long Lou ◽  
Wei Kai Tan
Keyword(s):  
Flow Velocity ◽  
High Speed ◽  
Flow Characteristic ◽  
Flow Characteristics ◽  
Hydropower Station ◽  
Turbulent Model ◽  
Cross Sectional ◽  
Vof Model ◽  
Spillway Tunnel ◽  
The Right

VOF model and turbulent model were used in this paper to study on flow characteristic inside a certain spillway tunnel of hydropower station, which includes cross sectional distributions of flow velocity in pressure section and non-pressure section. The results show that flow velocity distribution in the pressure section of the spillway tunnel is basically symmetrical. After turning, flow velocity is well-distributed and move ahead; flow velocity in the right side of non-pressure section in the spillway tunnel is 1m/s faster than that in the left side. When two high-speed water flow come together after passing through the central division pier, flow velocity distributions in the both sides of the spillway tunnel are all uniform. The conclusions obtained can improve the design of the spillway tunnel.

scholarly journals Standard reference values of weight and maximum pressure distribution in healthy adults aged 18–65 years in Germany

2020 ◽  
Vol 39 (1) ◽  
Author(s):  
D. Ohlendorf ◽  
K. Kerth ◽  
W. Osiander ◽  
F. Holzgreve ◽  
L. Fraeulin ◽  
...  
Keyword(s):  
Body Weight ◽  
Pressure Distribution ◽  
Reference Values ◽  
Effect Size ◽  
Weight Distribution ◽  
Age Groups ◽  
Healthy Adults ◽  
The Body ◽  
Maximum Pressure ◽  
Left And Right

Abstract Background The aim of this study was to collect standard reference values of the weight and the maximum pressure distribution in healthy adults aged 18–65 years and to investigate the influence of constitutional parameters on it. Methods A total of 416 healthy subjects (208 male / 208 female) aged between 18 and 65 years (Ø 38.3 ± 14.1 years) participated in this study, conducted 2015–2019 in Heidelberg. The age-specific evaluation is based on 4 age groups (G1, 18–30 years; G2, 31–40 years; G3, 41–50 years; G4, 51–65 years). A pressure measuring plate FDM-S (Zebris/Isny/Germany) was used to collect body weight distribution and maximum pressure distribution of the right and left foot and left and right forefoot/rearfoot, respectively. Results Body weight distribution of the left (50.07%) and right (50.12%) foot was balanced. There was higher load on the rearfoot (left 54.14%; right 55.09%) than on the forefoot (left 45.49%; right 44.26%). The pressure in the rearfoot was higher than in the forefoot (rearfoot left 9.60 N/cm2, rearfoot right 9.51 N/cm2/forefoot left 8.23 N/cm2, forefoot right 8.59 N/cm2). With increasing age, the load in the left foot shifted from the rearfoot to the forefoot as well as the maximum pressure (p ≤ 0.02 and 0.03; poor effect size). With increasing BMI, the body weight shifted to the left and right rearfoot (p ≤ 0.001, poor effect size). As BMI increased, so did the maximum pressure in all areas (p ≤ 0.001 and 0.03, weak to moderate effect size). There were significant differences in weight and maximum pressure distribution in the forefoot and rearfoot in the different age groups, especially between younger (18–40 years) and older (41–65 years) subjects. Discussion Healthy individuals aged from 18 to 65 years were found to have a balanced weight distribution in an aspect ratio, with a 20% greater load of the rearfoot. Age and BMI were found to be influencing factors of the weight and maximum pressure distribution, especially between younger and elder subjects. The collected standard reference values allow comparisons with other studies and can serve as a guideline in clinical practice and scientific studies.

Visualization of Contact-Pressure Distribution between Material and Backing Plate in Friction Stir Processing

2018 ◽  
Vol 765 ◽  
pp. 199-203
Author(s):  
Takahiro Ohashi ◽  
Xin Tong ◽  
Zi Jie Zhao ◽  
Hamed Mofidi Tabatabaei ◽  
Tadashi Nishihara
Keyword(s):  
Pressure Distribution ◽  
Contact Pressure ◽  
Friction Stir Processing ◽  
Maximum Pressure ◽  
Height Distribution ◽  
Contact Pressure Distribution ◽  
Friction Stir ◽  
Backing Plate ◽  
Load Sensor ◽  
Tool Position

In this study, the authors evaluated pressure distribution on a backing plate in friction-stir processing (FSP) utilizing an embedded pressure pin connected to a load sensor. They conducted FSP on aluminum alloy plates repeatedly offsetting the path-lines from the center of the pin and recorded change of forming pressure with tool position, which was compiled from the bearing load of the pin. The authors mapped the results to visualize the two-dimensional contact pressure distribution on a backing plate during FSP. They then compared the height distribution of the wall fabricated by friction-stir forming (FSF) utilizing a die having a groove with the observed distribution of pressure. Consequently, maximum pressure was observed beneath the rim of the tool probe at the retreating side (RS), and the highest points of the wall were observed at the RS.

PRESSURE DISTRIBUTION DUE TO STERN TAB DEFLECTION AT MODEL SCALE

2021 ◽  
Vol 157 (A1) ◽  
Author(s):  
T Arnold ◽  
J Lavroff ◽  
M R Davis
Keyword(s):  
Pressure Distribution ◽  
High Speed ◽  
Lift Force ◽  
Force Measurement ◽  
Maximum Pressure ◽  
Model Scale ◽  
Measure Model ◽  
Overall Resistance ◽  
Hydraulics Laboratory ◽  
The University

Trim tabs form an important part of motion control systems on high-speed watercraft. By altering the pitch angle, significant improvements in propulsion efficiency can be achieved by reducing overall resistance. For a ship in heavy seas, trim tabs can also be used to reduce structural loads by changing the vessel orientation in response to encountered waves. In this study, trials have been conducted in the University of Tasmania hydraulics laboratory using a closed- circuit water tunnel to measure model scale trim tab forces. The model scale system replicates the stern tabs on the full- scale INCAT Tasmania 112 m high-speed wave-piercer catamaran. The model was designed for total lift force measurement and pressure tappings allowed for pressures to be measured at fixed locations on the underside of the hull and tab. This investigation examines the pressures at various flow velocities and tab deflection angles for the case of horizontal vessel trim. A simplified two-dimensional CFD model of the hull and tab has also been analysed using ANSYS CFX software. The results of model tests and CFD indicate that the maximum pressure occurs in the vicinity of the tab hinge and that the pressure distribution is long-tailed in the direction forward of the hinge. This accounts for the location of the resultant lift force, which is found to act forward of the tab hinge.

End Effect Attenuation in Tapered Roller Contacts

2009 ◽  
Author(s):  
Emanuel Diaconescu
Keyword(s):  
Pressure Distribution ◽  
Finite Length ◽  
Contact Length ◽  
Maximum Pressure ◽  
End Effect ◽  
End Effects ◽  
Maximum Value ◽  
Line Contacts ◽  
Tapered Roller

The end effect attenuation in finite length line contacts is mainly approached for cylindrical bodies. Multi-radius crowning may remove end effects in tapered roller contacts. Another method for leveling maximum pressure in these contacts is the use of polynomial generatrix. This paper investigates the effect of this generatrix in tapered roller contacts. An improved pressure distribution is obtained. This has a nearly flat maximum value along most of contact length.

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