The present paper demonstrates a proof-of-concept by introducing variable guide vane system in the draft tube of high-head Francis model turbine. aim is to examine hydraulic performance turbine while mitigating pressure pulsations tube. vanes can rotate about an axis up ±45°. mitigation studies were performed at lower- and upper-part loads. was examined all operating ranges within head. There s...

A solar chimney is designed and tested to pump outside air through an underground cooling tube during summer for building cooling. Both theoretical analysis and experimental results show that the solar chimney can be used to power the underground cooling system during daytime without use of electricity. This paper presents the theoretical design principals of the solar chimney, detailed experim...

Staphylococcus epidermidis strain ET-024 was isolated from a biofilm on an endotracheal tube of a mechanically ventilated patient. This strain is resistant to methicillin, and the draft genome sequence shares some characteristics with other nosocomial S. epidermidis strains (such as S. epidermidis RP62A).

With economical energy market strategies based on instantaneous pricings of electricity as function of the demand or the predictions, operators harness more hydroelectric facilities to off-design operating points to cover the variations of the electricity production. Under these operating conditions, Francis turbines develop a cavitating swirling flow at the runner outlet which induces pressure...

Hydraulic turbines are usually operating at high efficiencies around 90%. It is possible to increase the efficiency by preventing flow characteristics such as failure, cavitation and vortex rope in draft tube. In some cases, partial loads or overloads, pressure pulsations would occur These undesired events damage components of turbine that also causes decrease. To eliminate these artifacts, it ...

In order to study the influence of change guide vane airfoil on flow characteristics in draft tube a reversible hydraulic turbine, turbine was used as object study, and effect pattern, energy loss, pressure pulsation area studied based SST k-ω turbulence model. The results show that under low conditions, modified movable directly affects direction speed water entering tube, reduces density vort...