scholarly journals The effect of guide vane type on performance of multistage energy recovery hydraulic turbine (MERHT)

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 352-364
Author(s):  
Yabin Tian ◽  
Anjie Hu ◽  
Qi Zheng
Keyword(s):  
Energy Recovery ◽  
Guide Vane ◽  
Hydraulic Turbine ◽  
Outlet Section ◽  
External Diameter ◽  
Flow State ◽  
Hydraulic Efficiency ◽  
Factors Affecting ◽  
Factors Affecting Performance ◽  
Determining Factor

AbstractIn this work, we theoretically analyzed the main factors affecting performance of multistage energy recovery hydraulic turbine (MERHT), and found that the arc radius (r) of the edge at the outlet section of the runner guide vane is the determining factor of the hydraulic efficiency of hydraulic turbines. To further improve the performance of the MERHT, a numerical model is then proposed to optimize the arc radius. The MERHT-type DCSGT250-175 × 9 was taken in the simulation. The hydraulic efficiency ηh and the corresponding distributions of pressure and velocity were numerically studied with four different values of r ranging from 133.5 to 138 mm. It is found that the flow state and the flow field distribution were the best when r equals to 134 mm. With the optimum r, the external diameter of the runner guide vane (D) was further adjusted, which can lead to 3.9% increase of average efficiency according to the simulation results.

scholarly journals Factors Affecting Performance of Web Flows in Cellular Networks

2018 ◽  
Author(s):  
Ermias Andargie Walelgne ◽  
Setala Kim ◽  
Vaibhav Bajpai ◽  
Stefan Neumeier ◽  
Jukka Manner ◽  
...  
Keyword(s):  
Cellular Networks ◽  
Factors Affecting ◽  
Factors Affecting Performance

Hydraulic Design of Inlet Guide Vane and its Full Flow Passage Numerical Simulation on Centrifugal Pump

2014 ◽  
Author(s):  
Hucan Hou ◽  
Yongxue Zhang ◽  
Zhenlin Li ◽  
Xin Zhou ◽  
Zizhe Wang
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
Guide Vane ◽  
Hydraulic Performance ◽  
Design Flow ◽  
Inlet Guide Vane ◽  
Hydraulic Efficiency ◽  
Flow Passage ◽  
Setting Angle ◽  
Hydraulic Design

In order to effectively improve hydraulic performance of centrifugal pump on off-conditions, the hydraulic design of inlet guide vane (IGV) was completed by adopting two dimensional theory in-house code based on one kind of IS series of centrifugal pump, which can achieve pre-whirl regulation of centrifugal pump. During design process the trailing edge of vane is assumed as equal velocity moment condition, and the distribution of vane setting angle along meridional streamline is also given as a quartic function firstly, the camber line is then drawn by point-by-point integration method and thickened at both sides along circumferential direction. With local vortex dynamics diagnosis theory, the optimal improvement of vane space shape can be finished by adjusting the design parameters of vane setting angle distribution coefficient ap. The full flow passage numerical simulations of centrifugal pump with IGV device are completed to analyze the influence of pre-whirl regulation on hydraulic performance of centrifugal pump under various pre-whirl angles. The results show that the pre-whirl regulation can improve the hydraulic performance of centrifugal pump on off-conditions. Under the positive pre-whirl regulation conditions, the best efficient point shift to small flow rate zone, and under the negative pre-whirl regulation conditions it moves to large flow rate zone. Compared with the pump without IGV device at the same flow rate condition of 0.8Q (Q the design flow rate), the hydraulic efficiency of centrifugal pump with IGV device improves obviously and reaches up to 1.43%. Meanwhile compared with that installed with the straight vanes designed based on the traditional theory, the inner flow field of centrifugal pump with the designed vanes improves and the overall hydraulic efficiency of centrifugal pump is somewhat increased.

scholarly journals Physiological factors affecting performance in elite distance runners

2016 ◽  
Vol 22 ◽  
pp. 7 ◽  
Author(s):  
Leif Inge Tjelta ◽  
Shaher A. I. Shalfawi
Keyword(s):  
Oxygen Uptake ◽  
Energy System ◽  
Running Economy ◽  
Distance Runners ◽  
Energy Contribution ◽  
Physiological Factors ◽  
Factors Affecting ◽  
Air Resistance ◽  
Factors Affecting Performance ◽  
Response To Exercise

Running distances from 3000 m to the marathon (42 195 m) are events dominated by energy contribution of the aerobic energy system. The physiological factors that underlie success in these running events are maximal oxygen uptake (VO2max), running economy (RE), the utilization of the maximum oxygen uptake (%VO2max) and velocity at the anaerobic threshold (vAT). VO2max for distance runners competing on an international level has been between 70 and 87 ml/kg/min in men, and between 60 and 78.7 ml/kg/min in women, respectively. Due to lack of air resistance, laboratory testing of RE and vAT are recommended to be conducted on treadmill with 1% slope. %VO2max are in most studies expressed as the average fractional utilization of VO2max at vAT. Much of the current understanding regarding the response to exercise is based on studies of untrained and moderately trained individuals. To use this knowledge to give training recommendations to elite runners is hardly valid. Researchers should therefore exercise caution when giving training recommendations to coaches and elite distance runners based on limited available research.

scholarly journals Factors Affecting Performance of Holsteins in Subtropical Regions of Mexico

1976 ◽  
Vol 59 (4) ◽  
pp. 722-729 ◽  
Author(s):  
R.E. McDowell ◽  
J.K. Camoens ◽  
L.D. Van Vleck ◽  
E. Christensen ◽  
E. Cabello Frias
Keyword(s):  
Factors Affecting ◽  
Factors Affecting Performance

scholarly journals Simulation and Experimental Investigation of the Stay Vane Channel Flow in a Reversible Pump Turbine at Off-Design Conditions

2017 ◽  
Vol 61 (2) ◽  
pp. 94 ◽  
Author(s):  
Sandro Erne ◽  
Gernot Edinger ◽  
Anton Maly ◽  
Christian Bauer
Keyword(s):  
Transient Flow ◽  
Guide Vane ◽  
Low Frequency ◽  
Rotating Stall ◽  
Design Flow ◽  
Flow State ◽  
Mean Flow ◽  
Load Range ◽  
Pump Turbine ◽  
Stall Inception

This work presents the assessment of the mean flow field and low frequency disturbances in the stay vane channel of a model pump turbine using transient numerical simulations and LDV-based measurements. The focus is laid on transient CFD simulations of characteristic flow states in the stay vane channel when operating at off-design conditions in pump mode. Experimental and numerical investigations obtained a shifting velocity distribution between the shroud and hub of the distributor when continuously increasing the discharge in the part-load range. Simulations captured the occurrence of this changing flow state in the stay vane channel reasonably well. A further increase of the discharge showed a uniformly redistributed mean flow of both hub and shroud side. Monitoring points and integral quantities from measurements and transient simulations were used to interpret the development of transient flow patterns in the stay vane channel at the operating point of strongest asymmetrical flow. During simulation and measurement, a dominant rotating stall inception was observed near the design flow of the pump turbine. At this point where the stall becomes severe, a high level of correlation between the signals of the upper and lower stalled flow in the stay vane channel was calculated. Further simulations for different guide vane positions predicted a strong influence of the guide vane position on the structure of rotating stall.

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