Numerical Analysis of the Flow Through in Centrifugal Pumps
In order to investigate the flow structure in centrifugal pump, a numerical model based on three dimensional (3D) incompressible Reynolds-Averaged Navier-Stokes equations has been developed. The turbulence viscosity is computed using the SST model (Shear Stress Transport). These transport equations associated with the appropriate boundaries conditions are solved by the CFX-13 finite-volume code. The computational domain composed by a single stator and rotor blade passages is discretized by a structured multi-block meshes. It describes in detail the numerical approach, based on an approach URANS (Unsteady Reynolds Average Navier Stokes) to predict the pressure fluctuations. On the other hand, simulations digital steady are made to construct the performance for centrifugal pump ( NS32). The unsteady simulations have allowed access to the temporal behavior of internal flow and compare the influence of two parameters in particular: mesh and conditions limits finding it difficult to model the pressure fluctuation The velocity and pressure fields show a radial thrust. Conformed to experimental visualization.
NUMERICAL FLOW SIMULATION IN A CENTRIFUGAL PUMP WITH IMPELLER - VOLUTE INTERACTION
This paper shows a numerical simulation of the tree-dimensional fluid flow inside a centrifugal pump. The pump is a commercial centrifugal water pump with a 190 mm outlet impeller diameter, backward curved blades, nominal flow of 0.013 m3/s and 11 m of head. This simulation has been made with an unsteady calculation and using the sliding mesh technique to take into account the impeller-volute interaction. With them, it is possible to simulate correctly the blade passage in front of the tongue and the flow and pressure fluctuations induced. The numerical results are compared with the experimental characteristic curve and pressure fluctuations measured in the volute. The data obtained allow the analysis of the main phenomena existent in these pumps, such as: the pressure changes in the volute for different flow rates; the incidence at the leading edge of the blade with different flow conditions; and the secondary flow generated in the volute due to the width change between the impeller and the volute.
Laminar heat or mass transfer in rectangular channels and in cylindrical tubes for fully developed flow: comparison of solutions obtained for various boundary conditions
Abstract A comparison is made of results obtained with various boundary conditions at the wall of the channels. By comparing blood Sherwood numbers for finite wall resistance with those for constant concentration boundary condition only a small variation is found for various points along the blood channel.