Irregular-pitch regenerative blower and optimization design method for same

A regenerative blower comprising an impeller including a plurality of blades arranged in a circumferential direction to be spaced part from each other,

• wherein the plurality of blades are arranged such that angles therebetween are incremental angles ΔΘi satisfying the formula:
• Δ
• ⁢
• ⁢
• θ
• i
• =
• (
• 360
• N
• )
• +
• (
• -
• 1
• )
• i
• ×
• Am
• ×
• Sin
• ⁡
• (
• P
• i
• ×
• 360
• N
• ×
• i
• )
• ×
• Cos
• ⁡
• (
• P
• 2
• ×
• 360
• N
• ×
• i
• )
• ,
• wherein
• Am, P1, and P2 satisfy both relationships 27≤η≤32 and 77 dB(A)≤SPL≤83.7 dB(A),
• wherein
• η=(Pout−Pin)Q/σω, and
• SPL=10 log10(P/Pref)2,
• where η is efficiency, SPL is a sound pressure level (SPL), (Pout−Pin) is a total pressure, Q is a volumetric flow, σ is a torque, ω is an angular velocity, P is a sound pressure, and Pref is a reference pressure (2×10−5 Pa),
• wherein
• N is a total number of the plurality of blades, where N is a natural number greater than 2,
• Am is a distribution size of distances between the plurality of blades, the plurality of blades being spaced at equal angles, where 0°<Am<360°/N,
• i is a sequence of the plurality of blades, where i=1, 2, 3, 4, . . . , and N, and
• P1 and P2 are factors having an effect on a period, where 0≤P1≤N, and 0≤P2≤N, P1 and P2 being real numbers.