Rotating stalls are generally the first instability met in turbomachinery, before surges. This 3D phenomenon is characterized by one or more stalled flow cells which rotate at a fraction of the impeller speed. The goal of the present work is to shed some light on the entropy generation in a centrifugal fan under rotating stall conditions. A numerical simulation of entropy generation is carried ...

OBJECTIVE Ventricular assist device (VAD) miniaturization is one design trend that may result in less-invasive implantation techniques and more versatility with patient selection. The MVAD System is a miniature, continuous-flow device implanted in the ventricle. The pump is capable of delivering between 0 and 7 L/min of flow at a mean arterial pressure of 75 mm Hg. The impeller was optimized fr...

The results of a series of numerical simulations for the NASA low-speed centrifugal compressor are presented. Large-eddy simulation (LES) is carried out together with the most commonly used Reynoldsaveraged Navier–Stokes (RANS) models, including the mixing length, k– and k– models. Predictions are compared with the available experimental data. It is seen that quantitative predictions of LES are...

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 ...

The presence of unstable flow phenomena may significantly alter the flow pattern and characteristics of centrifugal pumps; that is, the unstable flows may seriously deteriorate the pumps performance. In this paper, considering the high cost of running license fees and not available with all the computing resources, a high quality Open Source CFD simulation platform like OpenFOAM instead of comm...

Computational fluid dynamic (CFD) simulation is an effective research approach for understanding velocity fields used in process and equipment intensification. It was found that mixer-settler used in rare earth metal extraction process was unsatisfying in large amount of liquid backlogged, high energy consumption and longtime settling process. In this paper, CFD simulations and experiment valid...

This thesis addresses modeling and active surge control of a simple compression system, using only the drive system of the compressor for actuation. Theoretical results are validated by experiments on a test rig that was built as a part of this work. Control laws are derived in two stages. First all system states, such as pressure mass ‡ow and impeller speed, are assumed as available signals. A...

The inducer is often used to prevent cavitation in a centrifugal pump. However, it may lead deterioration of the performance pump when poorly matched with impeller. Numerical simulations are employed study effects matching, specifically, axial space and circumferential deflection between impeller, on performance. results show that destroys rotational symmetry velocity distribution at inlet resu...

Fluid dynamics simulations were applied for evaluating the suspension of particles in stirred vessels. The spatial distribution of particles throughout the vessel was characterized by a single parameter, here called the suspension quality (σ). Based on simulation results, a semi-empirical correlation was developed that correlated the suspension quality with the vessel geometry and solid and flu...

Due to growth of mechanisation and automation, today’s industrial systems are becoming more complex. A small breakdown of any non-redundant machine component affects the operation of the entire system. To increase the availability and reliability, automated health monitoring and self-diagnostic capability (SDC) becoming essential to many industrial machineries like pumps, motors, etc. Condition...