The mechanical arrangement may be a ducted propeller (axial-flow pump
), a centrifugal pump, or a mixed flow pump which is a combination of both centrifugal and axial designs.
The 3D model of the axial-flow pump impeller is shown in the Fig.
11-14 show the distributions of relative velocity of the liquid phase (water) near the surface of the axial-flow pump blades (hereinafter referred to as blade surface).
Keywords: axial-flow pump; impeller; solid-liquid two-Phased; CFD numerical simulation; prediction analysis.
Mehra, M.D., from the Brigham and Women's Hospital in Boston, and colleagues conducted a randomized noninferiority and superiority trial comparing the centrifugal-flow pump (190 patients) with the axial-flow pump (176 patients) in patients with advanced heart failure.
The researchers found that the primary end point (composite of survival at two years free of disabling stroke or survival free of reoperation to replace or remove a malfunctioning device) occurred in 79.5 and 60.2 percent of the centrifugal-flow and axial-flow pump groups, respectively (absolute difference, 19.2 percentage points; 95 percent lower confidence boundary, 9.8 percentage points [P < 0.001 for noninferiority]; hazard ratio, 0.46; 95 percent confidence interval, 0.31 to 0.69 [P < 0.001 for superiority]).
"In patients with advanced heart failure, a fully magnetically levitated centrifugal-flow pump was superior to a mechanical-bearing axial-flow pump with regard to survival free of disabling stroke or reoperation to replace or remove a malfunctioning device," the authors write.
With the increasing application of an axial-flow pump, the improvement of its efficiency continues to become more and more important.
The numerical model and method for simulating the flow field in the axial-flow pump can be found in previous work by Yang and Liu  and Jafarzadeh et al.
Figure 1 shows 3D geometry of axial-flow pump model, with the specific speed [n.sub.s] of 1200 and impeller diameter of 300 mm, which is used to simulate and measure its entire flow field.
The grid quality in the impeller and guide vane will affect the accuracy of axial-flow pump simulation.
where [K.sub.H] is head coefficient, H is the head of the axial-flow pump, n is rotation speed, and D is the impeller diameter.