The effect of non-uniform inflow on the spatial and temporal distribution of impeller excitation is investigated. The experiments are first conducted to verify the hydraulic performance of the axial ...flow pump and to provide a reference for the accuracy of the numerical simulations. Subsequently, the effect of non-uniform inflow on the spatial and temporal distribution of the flow field and impeller load is investigated. The results indicate that the non-uniform inflow modifies the velocity distribution at the impeller inlet, resulting in alterations in the attack angle and subsequently affecting the radial and circumferential distribution of the impeller load. The extreme difference in the head between the different blades can reach up to 36 % of the total head. Furthermore, velocity pulsation and attack pulsation exhibit more pronounced fluctuations in the low-speed region, and there exists a strong correlation between the amplitude of unsteady forces and the magnitude of the impeller load.
The microstructures and the microwave dielectric properties of (1 − x)Mg(Sn
0.05
Ti
0.95
)O
3
–x(Ca
0.8
Sr
0.2
)TiO
3
−y wt% ZnNb
2
O
6
(x = 0.05–0.08, y = 2–8) ceramics system prepared by ...conventional solid-state route were investigated. The crystalline phases and the microstructures of the ceramics were characterized by means of X-ray diffraction and scanning electron microscopy. Zn
2+
partially replaced Mg
2+
in Mg(Sn
0.05
Ti
0.95
)O
3
and formed the ilmenite-type (Mg
1−δ
Zn
δ
)(Sn
0.05
Ti
0.95
)O
3
phase. Second phase (Mg
1−δ
Zn
δ
)(Sn
0.05
Ti
0.95
)
2
O
5
increased remarkably when excess ZnNb
2
O
6
added. ZnNb
2
O
6
as additives could not only effectively lower the sintering temperature of the ceramics to 1320 °C, but also promote the densification. The microwave dielectric properties of specimens were strongly related to ZnNb
2
O
6
and (Ca
0.8
Sr
0.2
)TiO
3
content. The optimized microwave dielectric properties with
ε
r
~ 22.13, Q × f value ~60,613(at 7 GHz) and
τ
f
value ~0.4 ppm/ °C were achieved for (1 − x)Mg(Sn
0.05
Ti
0.95
)O
3
–x(Ca
0.8
Sr
0.2
)TiO
3
–y wt% ZnNb
2
O
6
(x = 0.07, y = 4) sintered at 1320 °C for 2 h.
The microstructures and the microwave dielectric properties of (1 - x)Mg(Sn^sub 0.05^Ti^sub 0.95^)O3-x(Ca^sub 0.8^Sr^sub 0.2^)TiO3-y wt% ZnNb^sub 2^O^sub 6^ (x = 0.05-0.08, y = 2-8) ceramics system ...prepared by conventional solid-state route were investigated. The crystalline phases and the microstructures of the ceramics were characterized by means of X-ray diffraction and scanning electron microscopy. Zn^sup 2+^ partially replaced Mg^sup 2+^ in Mg(Sn^sub 0.05^Ti^sub 0.95^)O3 and formed the ilmenite-type (Mg^sub 1-δ^Zn^sub δ^)(Sn^sub 0.05^Ti^sub 0.95^)O3 phase. Second phase (Mg^sub 1-δ^Zn^sub δ^)(Sn^sub 0.05^Ti^sub 0.95^)^sub 2^O^sub 5^ increased remarkably when excess ZnNb^sub 2^O^sub 6^ added. ZnNb^sub 2^O^sub 6^ as additives could not only effectively lower the sintering temperature of the ceramics to 1320 °C, but also promote the densification. The microwave dielectric properties of specimens were strongly related to ZnNb^sub 2^O^sub 6^ and (Ca^sub 0.8^Sr^sub 0.2^)TiO3 content. The optimized microwave dielectric properties with straight epsilon ^sub r^ ~ 22.13, Q × f value ~60,613(at 7 GHz) and tau ^sub f^ value ~0.4 ppm/ °C were achieved for (1 - x)Mg(Sn^sub 0.05^Ti^sub 0.95^)O3-x(Ca^sub 0.8^Sr^sub 0.2^)TiO3-y wt% ZnNb^sub 2^O^sub 6^ (x = 0.07, y = 4) sintered at 1320 °C for 2 h.
