Effect of Blade Outlet Angle on Radial Force of Marine Magnetic Drive Pump

Abstract

To research the effects of the blade outlet angle on the performance and the radial force of the marine pump, the unsteady numerical simulation of the four different models is carried out. The radial forces on the impeller and the blades are obtained under different flow rate conditions. The time and frequency domain characteristics of radial resultant force on the impeller and the blades are analyzed and those of the impeller torque are researched. The results show that the radial forces of the impeller and the blades increase with the increase of the blade outlet angle at the same flow rate. With the same blade outlet angle, the radial forces decrease with the increase of the flow rate. The roundness of radial force vector diagram becomes more obvious with the decrease of the blade outlet angle. The root mean square (RMS) of radial force on the blades is about 30% of that on the impeller. The main frequency of radial force on the impeller and the blades is the axial passing frequency (APF), and that of impeller torque is the blade passing frequency (BPF), and there are peaks at the blade frequency multiplier. At the same flow rate, the main frequency and maximum fluctuation amplitudes on the impeller and the blades increase with the increase of the blade outlet angle. Meanwhile, the impeller torque increases with the increase of the blade outlet angle. With the same blade outlet angle, the main frequency, maximum fluctuation amplitudes, and the impeller torque decrease with the increase of the flow rate. The amplitude difference decreases with the increase of the flow rate. The blade outlet angle has an obvious greater influence on the radial forces and fluctuation at the small flow rate. The vibration test shows that the vibration intensities of model 25 and model 35 are less than 2.5 mm/s, and the vibration intensity of model 25 is about 0.2 mm/s less than that of model 35.

Calculation of field and force of Halbach arrays: Improved magnetic charge method for irregular magnetized magnets

“…According to the unique profile of each surface, the integral forms are different. Equation ( 6) represents the magnetic flux density generated by magnetic charges on the cambered surface (as surface 1 and 2 shown in Figure 2), while (7) represents the magnetic flux density generated by magnetic charges on the plane (as surface 3 and 4 shown in Figure 2). sða, b, c, d, e, f , g,…”

“…In (7), p is the function of input variables a, b, c, d, e, f, g, h, and σ 1 ' , where the input parameter a represents the height of this plane, parameter b represents corresponding angle of this plane, parameter c represents inner radius, parameter d, e, f represent the coordinates of point Q (r, θ, z), and g represents the rotary angle α of the coordinate system, and h represents outer radius. Additionally, parameter σ 1 ' represents the equivalent magnetic charge on this plane, and there are…”

“…Equations ( 15)-( 17) should be multiplied with the integrand in (7) when computing the components of the magnetic flux density in each orthogonal direction z, r, and θ.…”

“…Magnetic drive is widely utilized in many electrical devices and engineering applications due to its advantages, such as non-contact actuation, less friction, no medium limitation, and simple structure. Many magnetic machines such as magnetic bearings, [1][2][3][4] magnetic pumps, [5][6][7] magnetic valves, 8,9 magnetic springs [10][11][12] magnetic couplings, 13,14 magnetic gears, 15,16 etc. rely on permanent magnets (PMs) to transfer force and torque.…”

Effects of the Centrifugal Pump Outlet Blade Angle on Its Internal Flow Field Characteristics under Cavitation Condition

“…Shojaeefard et al (2012) evaluated the role of the outlet blade angle in governing the variations in the centrifugal pump head and efficiency; both of these parameters improved at an outlet blade angle of 30° compared with 32.5° of angles <27.5°. Zhang et al (2020) analyzed the radial force variations of impellers with different outlet blade angles. The force increased as the outlet blade angle increased under constant flow rate conditions.…”