Biomedical Engineering Reference
In-Depth Information
convergence criteria was specified as 1e-6 for the geometries. From the table,
it could be observed that the pressure coefficient values obtained for the
numerical simulations of two-stage rotor and its modified geometry are very
high compared to other geometries of rotor for half-million, one million and
two million rpm rotational speeds. The pressure coefficient was found to be
almost the same with other geometries of the rotor for five million rpm. Figure
3 shows the variation of pressure coefficient with rotational speed of rotor for
two-stage rotor and its modified geometry.
Table 3 Pressure coefficient values for rotor geometries two-stage rotor
and its modified geometry
Geometry
Half-million
One Million
Two Million
Five Million
Two-Stage Rotor
1.17
1.19
1.20
1.46
Modified Geometry
of Two-Stage Rotor
1.21
1.26
1.35
1.65
Reproduced with permission. Copyright retained by Inderscience Publishers.
From all the geometries discussed above, it can be concluded that for half-
million rpm rotational speed of the rotor, rotor with 90-degree blade angle is
the optimum geometry for rotor and for one million rpm rotating speed of the
rotor, rotor with three inlets inclined at an angle of 45 degrees is the optimum
design compared to other geometries of the rotor. For two million and five
million rpm rotational speed of the rotor, rotor with twelve blades is the
optimum design of rotor for high-speed spindle compared to the other
geometries of the rotor.
3.2. Flow Topology And Pressure Variations
Flow topology and pressure variation of rotor geometries such as rotor
with 90-degree blade angle, rotor three inlets inclined at an angle of 45
degrees, and two-stage rotor are described.
Rotor with 90-Degree Blade Angle
Flow topology and pressure variation of this geometry will be explained
as the pressure coefficient of this geometry was found to be lower than for the
other geometries of rotors. The rotational speed of the rotor was specified as
one million (1,000,000) RPM.
