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24.12.2008 |
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 The centrifugal pump of high specific speed with a diagonal type of impeller flow is studied experimentally and numerically. 2D and 3D numerical methods are used with applying acoustics – vortex equations.
Increasing energetic parameters of centrifugal pumps requires a more complex geometry of the impeller and volute as one need to raise the specific speed of the pump to provide a higher efficiency value. The pump of higher specific speed has an impeller with curved blades and diagonal meridional section. The flow outgoing the impeller has an essential axial component of velocity. Thus the two dimensional approach will not give the accurate prediction of pressure pulsations in the volute casing. This is why the new 3-dimensional method has been elaborated for this task. The 3D computational results of pressure pulsation are compared with those obtained by 2D-computation Measurements show that in the beginning of volute, in the pseudo-sound zone, amplitude of Blade Passing Frequency (BPF) spectral component is higher than that at the pump outlet by an order of magnitude. 3-Dimensional analysis
gives a good agreement with experimental data while 2D prediction underestimates the BPF amplitude in the beginning of volute.
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24.12.2008 |
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 Due to a current trend of increasing rotational speed and power, the problem of tone noise and pressure pulsation in centrifugal ventilators becomes a more urgent issue. Often the level of tones determines noise characteristicsmainly these are blade-passing frequencies (BPF). The broadband noise resulting from small-scale turbulent pressure pulsation and secondary flows is an important problem as well. Numerical studies of pressure pulation in ventilators are undertaken using the method based on a representation of non-stationary motion of a compressible medium as a combination of acoustic and vortex modes.
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24.12.2008 |
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 CFD analysis of two first - stage centrifugal impellers is undertaken with the main goal to obtain additional evaluation data regarding flow characteristics of the old first stage impeller design and in the proposed new cantilever impeller design. The new design is developed to reduce the 1st stage impeller cavitation erosion damage of a multistage centrifugal feed pump. This stage of work comprises computational tests of both impeller models under the same mode of operation, 3000 RPM and volumetric flow rate 0.0503 m3/s. Both impellers are planning to be tested experimentally. The inlet geometry for CFD tests is taken from the test facility draft. The outlet is made like a circular vaneless diffuser. In the old design, a hub developed upstream presents the through shaft...
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26.06.2008 |
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 Oil Leakage Trough a Valve Stem Seal
Capvidia (Belgium), Dana Corporation (USA) |
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| Results 13 - 16 of 16 |
