The back-flow of an aortic valvo-pump will reduce the pumping flow rate but can wash out the gap between the rotor and the stator, and thus can improve the antithrombogenicity of the device. To investigate the regurgitation of a 23mm OD aortic valvo-pump, its closed impeller was replaced by a cylinder and hereby the valvopump had lost its pumping function. The pressure head crossing the aortic ...

Pump cavitation is the formation and subsequent collapse or implosion of vapor bubbles in a pump. It occurs when the absolute pressure on the liquid falls below the liquid’s vapor pressure. This paper describes the validation of cavitation inception on a radial flow pump which develops 21m of head at 26lps of discharge at its best efficiency point (BEP) of discharge while operating at a speed o...

This paper concentrates on cavitation detection using discrete wavelet transform by classifying the pump vibration signal. Vibration signal acquired from centrifugal pump cavitation test rig carry more information about the cavitation classes. In this paper two classes has been defined namely, no cavitation class and developed cavitation class. This method uses the deviation from zero mean valu...

Traditional commercial centrifugal pump designs have specific speeds (Ns) greater than 500 because low values of Ns are usually associated with low efficiency, pulsation, and a drooping head characteristic. In this instance, acceptable hydraulic performance is achieved with a unique impeller design coupled with direct current (DC) motor characteristics. When the specific speed of a centrifugal ...

Silicone based oil is heated in the boiler of the diffusion pump and the vaporized oil rises in the central tower and streams out of directional flutes directed downward in the pump throat. This allows air molecules to dissolve in the gaseous oil (gas dissolved in gas). As the oil-air mixture cools (due to water cooling coils wrapped around the pump throat) the oil condenses and returns to liqu...

In contrast to conventional generators, self-excited induction generators are found to be most suitable machines for wind energy conversion in remote and windy areas due to many advantages over grid connected machines. This papers presents a Self-Excited Induction Generator (SEIG) driven by wind turbine and supplying an induction motor which is coupled to a centrifugal pump. A method to describ...

The flow in centrifugal pumps is exceedingly complex, involving curvature, system rotation, separation, turbulence, and secondary flows. Moreover, the geometry is often asymmetric due to the volute shape. As a result, the relative motion between impeller and volute generates an unstableness which affects not only the overall pump performance, but is also responsible for pressure fluctuations, h...

Centrifugal heat pump has to be coupled with gas boiler to supply high temperature water in radiator heating system. Regarding to hybrid heating system (HHS), operation strategy has significant impact on its annual energy consumption and cost. In this paper, the optimal operation strategy of the HHS composed of sewage-source centrifugal heat pumps and gas boilers was analyzed. Firstly, the perf...

In this study, the effects of the volute tongue geometry variation on the head, efficiency, velocity distribution and cavitation structure of a centrifugal pump in the steady flow behavior under off-design conditions have been investigated. Numerical simulation modeling based on the  turbulence model with a hybrid grid is used to simulate the flow within the modeled pump. The flow is simulated ...

This paper presents a ‘Lexicographic’ Goal Programming (LGP) approach to define the best strategies for the maintenance of critical centrifugal pumps in an oil refinery. For each pump failure mode, the model allows to take into account the maintenance policy burden in terms of inspection or repair and in terms of the manpower involved, linking them to efficiency-risk aspects quantified as in FM...