Effects of the time-variant flow in a single-blade pump are investigated by numerical and experimental methods. For a numerical approach the three-dimensional, viscous, unsteady flow field in the pump has been achieved by solving the unsteady Navier-Stokes equations (URANS) with a commercial solver. From the obtained periodic flow field the time-variant forces acting at the wetted impeller surf...

In oil field applications it is often required to pump oil, gas, and water as mixtures rather than separating the fluid. Although the performance prediction of twin-screw pumps on liquids is well established, the prediction of performance of these pumps on multiphase mixtures presents a challenge. Test data of twin-screw rotary pumps are compared with predictions of performance over ranges of f...

Large-eddy simulation is performed to study the turbulence statistics and flow structures of water past a rotating axial-flow pump under different flow-rate working conditions. A novel sharp-interface level-set based immersed boundary method applied capture complex geometry pump. An unstructured triangular mesh used discretize surface pump, ray-tracing employed classify computational domain int...

the non-uniformity factor is used for correction of the formulas obtained from the one-dimentional fluid flow method in a centrifugal impeller pump. the variations of radial velocity at the outlet of five centrifugal impellers with the specific speed of about ns =50 are calculated at design point by using two-dimentional potentional flow method for an invisid fluid. on the other hand~ the varia...

We present a programmable acoustofluidic pump that utilizes the acoustic streaming effects generated by the oscillation of tilted sharp-edge structures. This sharp-edge-based acoustofluidic pump is capable of generating stable flow rates as high as 8 μL min(-1) (~76 Pa of pumping pressure), and it can tune flow rates across a wide range (nanoliters to microliters per minute). Along with its abi...

A study of a small centrifugal blood pump has been made to address the effectiveness of traditional pump affinity laws and the influence that viscous effects, as characterized by the Reynolds number, have on the pump performance. This was investigated both experimentally and numerically on models of a small implantable centrifugal blood pump, which has an impeller diameter of 46 mm with a log s...

Sewage water pumps very often are equipped with impellers featuring a small number of blades which therefore provide big cross sections of the flow channel. Single-blade impellers comprise the smallest possible number of blades and are known as non-clogging pumps. But severe disadvantages occur during operation, because the timevariant flow in such pumps results in periodic unsteady flow forces...

A computational fluid dynamics model is used to predict the oscillatory flow through tapered cylindrical tube sections (jet pumps). The asymmetric shape of jet pumps results in a time-averaged pressure drop that can be used to suppress Gedeon streaming in closed-loop thermoacoustic devices. However, previous work has shown that flow separation in the diverging flow direction counteracts the tim...

Controller algorithms are an important feature for assessment of ventricular assist device performance. Flow estimation is one algorithm implemented in the HeartWare continuous-flow ventricular assist device pump system. This parameter estimates flow passing through the pump and is calculated using speed, current, and hematocrit. In vitro and in vivo studies were conducted to assess the algorit...

After implanting a permanent Jarvik 2000 Heart (Jarvik Heart, Inc) in a patient with end-stage heart failure (Figure 1), we simultaneously recorded ECG and Doppler flow velocity in the vascular graft that connects the blood pump and descending aorta. With the pump temporarily switched off, the graft blood flow reversed, passing from the descending aorta through the device to the left ventricle....