<< Click to Display Table of Contents >>

Navigation:  Impeller > Main dimensions >


Previous pageReturn to chapter overviewNext page

The Balje diagram is based on the work of O. E. Balje. For given specific speed and diameter coefficient as well as degree of reaction the diagram delivers suggestions for:

Width ratio h/dS = f(nq, δ),

Isentropic velocity ratio total-static u/c0 = f(nq, δ, h/d),

Absolute flow angle α*1 =  f(δ, h/d, γ),

Relative flow angle β*1 =  f(nq, δ, h/d, α*1),

Rotor velocity ratio ψR = w2/w2id =  f(nq, δ, h/d, α*1, β*1),

Efficiency total-static ηts =  f(nq, δ, h/d, γ, β*1, ψR).

The density ratio γ = ρ12 is determined by the solution of a set of equations (Euler, continuity, etc.). Balje's angle notation is displayed in the following image:

The Balje diagram is displayed in the Main dimensions. If Energy transmission = total pressure ratio πtt, see Global setup, the diagram is only for information and diagram parameters can be defined on top of the diagram (left image).

If Energy transmission = total-to-static pressure πtst, the diagram is used to make proposals for u/c0, h/d and ηts, which are design parameters. On the second tab parameters derived from the Balje diagram in the design point (by specific speed, diameter coefficient and degree of reaction) are displayed for information.