CN101832292A - Paper pulp pump centrifugal open impeller based on fiber suspension flow design criteria - Google Patents

Abstract

The invention discloses a paper pulp pump centrifugal open impeller based on fiber suspension flow design criteria, which mainly consists of a hub and three blades, wherein the three blades are evenly distributed on the hub along the circumference and is integrated with the hub into a whole. The paper pulp pump centrifugal open impeller is applicable to conveying slurry with medium and low concentration, can better control the slurry to flow in an impeller channel, improves the passing capability of paper pulp, increases the hydraulic efficiency of the impeller, and has the convey efficiency which is obviously superior to the common paper pulp pump which is widely used at present.

Description

Based on the centrifugal unshrouded impeller of the pulp pump of fiber suspension flow design criterion

Technical field

The present invention relates to a kind of impeller of pulp pump, relate in particular to the centrifugal unshrouded impeller of a kind of pulp pump based on the fiber suspension flow design criterion.

Background technique

Pulp pump is one of key equipment of paper-making industry, and it also is important energy consumption equipment, in case can improve efficient, will be very favourable to excavating papermaking flow process energy-saving potential.

The critical component of pulp pump is an impeller, in the various design method of pulp pump impeller, adopts the enlargement discharge method at present, is the clear water design that strengthens with lift rotating speed down-off with the change working of transmitting paper pulp.And be similar to the pulp pump impeller by revising clean waterpump impeller design scheme, and belong to semi-empirical relation, also there is not one group of clear and definite formula of theoretical foundation to finish the calculating of relevant parameter up till now.The selection of parameter and definite degrees of freedom greatly that exists lack sufficient constraint.Second method can adopt similar scaling method, converts to need the prototype of better performances, so its applicable surface is limited.

For overcoming existing problem, the author by fiber orientation in the eddy channel is developed, the additional stress analysis, obtain to a certain degree in, can embody the formula of binding function.At first, the fiber additional stress is the embodiment of fiber to mobilization, and there is the sign near the mobile structure influence of microcosmic it in fiber.Fiber additional stress analytical calculation in the rotary blade runner, we obtain concrete structural parameter computational methods.Thus, set up the formula of structural parameter.

Summary of the invention

The objective of the invention is at the deficiencies in the prior art, provide a kind of pulp pump centrifugal unshrouded impeller based on the fiber suspension flow design criterion.

For achieving the above object, the technical solution adopted in the present invention is as follows: the centrifugal unshrouded impeller of a kind of pulp pump based on the fiber suspension flow design criterion, mainly be made up of wheel hub and three blades, three blades are evenly distributed on the wheel hub by circumference and are integrally formed with wheel hub, the blade exit diameter

Wherein, the peripheral velocity of impeller outlet H is a lift, and n is a wheel speed, K _U2Be impeller outlet peripheral velocity coefficient.Exit width

Wherein, outlet radial velocity

Q is a fluid flow, T _K2Be outlet blade blockage factor: K _R2Be impeller outlet radial velocity coefficient.The blade inlet diameter

Wherein, λ is the speed homogenization coefficient, and ξ is a moderating ratio, T _K1Be inlet vane blockage factor, T _K2Be outlet blade blockage factor,

For revealing coefficient.Impeller inlet diameter D _j=D ₁/ K ₁Wherein, K ₁Be impeller inlet diameter and blade inlet diameter ratio, blade entrance width

β ₁Be inlet blade angle, β ₂Be blade outlet angle, the equivalent diffusance

Further, described impeller outlet peripheral velocity COEFFICIENT K _U2Can be 1.07, outlet radial velocity COEFFICIENT K _R2Desirable 0.05, speed homogenization coefficient λ is desirable 1.05～1.1, and moderating ratio ξ is 0.65 inlet vane blockage factor T _K1Be 0.95, outlet blade blockage factor T _K2Be 0.9, reveal coefficient

Be 1.1, the impeller inlet diameter compares K with the blade inlet diameter ₁Be 0.8, inlet blade angle β ₁Desirable 20～30 °, blade outlet angle β ₂It is 30 °.

The present invention compared with prior art, its beneficial effect is: the slurry of low density was carried during the present invention was applicable to, can control flowing in the impeller passage better, promoted the passing capacity of paper pulp, improve the hydraulic efficiency of impeller, its transfer efficiency obviously is better than the current common paper stock pump that widely uses.

Embodiment

The present invention is based on the centrifugal unshrouded impeller of pulp pump of fiber suspension flow design criterion, mainly be made up of wheel hub and three blades, three blades are evenly distributed on the wheel hub by circumference and are integrally formed with wheel hub.

According to design fluid flow Q, lift H, wheel speed n, impeller outlet diameter D ₂With impeller outlet width b ₂Be calculated as follows:

$D_2=\frac{60U_2}{\mathrm{\πn}}$

Wherein, the peripheral velocity of impeller outlet H is a lift, and n is a rotating speed

Because the flow losses that the effect of the additional shearing stress of fiber causes, the theoretical head of pulp pump will suitably strengthen, therefore, and impeller outlet peripheral velocity COEFFICIENT K _U2Desirable 1.07.

Impeller outlet width $b_2=\frac{Q}{\mathrm{\π}{D}_2{T}_{K2}{V}_{r2}}$

Wherein, impeller outlet radial velocity

Q is a flow, T _K2Be outlet blade blockage factor:

Be the passing capacity of raising paper pulp, and reduce the fiber adjection that the liquid speed shearing causes, exit width should be got higher value, like this, and impeller outlet radial velocity COEFFICIENT K _R2Desirable 0.05, or smaller.

In the fiber suspension flow theory, the principle that the fiber additional stress is relevant with the flowing velocity gradient, import is sheared more little, and the obstruction that fiber causes flowing is low more, then helps the performance of passing through of fiber suspension flow.A requirement is a homogenization degree height, and another is that the inlet velocity value is little.

For the pulp pump impeller, for the pulp pump impeller that with the high efficiency is target, the import relative velocity should control to minimum, introduces first constraint conditio: import is slowed down and is retrained, and formula is:

The blade inlet diameter meets:

Wherein,

Speed homogenization coefficient: λ is desirable 1.05～1.1,

Moderating ratio: ξ=0.65

Inlet vane blockage factor: T _K1=0.95

Outlet blade blockage factor: T _K2=o.9

Reveal coefficient:

In the formula, 24 ° is the best average inlet angle of blade.

Impeller inlet diameter: D _j=D ₁/ K ₁

Wherein, impeller inlet diameter and blade inlet diameter ratio: K ₁=0.8

The blade entrance width: $b_1=\frac{D_1}{4\mathrm{\ξ}{T}_{k1}{K}_1^2}$

Inlet blade angle β ₁: desirable 20～30 °

Blade outlet angle: β ₂=30.0 °

Second constraint conditio:

The equivalent diffusance $\tan \frac{{\mathrm{\θ}}_{\mathrm{eq}}}{2}=\frac{\sqrt{D_2{b}_2{T}_{k2}\sin {\mathrm{\β}}_2}-\sqrt{D_1{b}_1{T}_{k1}\sin {\mathrm{\β}}_1}}{0.75(D_2-D_1)\sqrt{3}}$

Equivalent divergent angle θ _EqBe controlled between 6.5 ° to 8 °.

Subtended angle of blade is got 155 °.

According to specific embodiment, it is more obvious that purpose of the present invention and effect will become below.

Embodiment

Operating mode: flow Q=100 (m ³/ h), lift H=20 (m), rotation speed n=1450 (rev/min).

The substitution formula calculates concrete parameter:

Outlet diameter: D ₂=280 (mm)

Exit width: b ₂=35 (mm)

Blade entrance width: b ₁=61.4 (mm)

Blade inlet diameter D ₁=97.0 (mm)

Impeller inlet diameter D _j=121 (mm)

Inlet blade angle is respectively at shroud streamline, center line of flow path and hub disk streamline place: 22 °, 26.4 ° and 30 °.Blade outlet angle is 30 °.

Compare outstanding feature from additional stress at the bend middle part, requiring constraint to stride the passage relative velocity distributes smooth, then we keep blade loading to distribute gently for good, be proper extension blade path length, the structural parameter that this constraint is related to are subtended angle of blade and equivalent divergent angle, and cornerite is got 155 ° here.

Equivalent divergent angle:

According to above parameter, draw the impeller form drawing.

Evidence: this pump efficiency has improved 5% on the basis of existing pump efficient 67%, reached 73%.Show that the present invention meets the feature of pulp flow, to control paper pulp flowing in impeller channel, especially the loss that effect causes to minimizing fiber additional stress has obvious improvement.

The foregoing description is used for the present invention that explains, rather than limits the invention, and in the protection domain of spirit of the present invention and claim, any modification and change to the present invention makes all fall into protection scope of the present invention.

Claims (2)

1. the centrifugal unshrouded impeller of the pulp pump based on the fiber suspension flow design criterion mainly is made up of wheel hub and three blades, and three blades are evenly distributed on the wheel hub by circumference and are integrally formed with wheel hub.It is characterized in that the blade exit diameter

Wherein, the peripheral velocity of impeller outlet

H is a lift, and n is a wheel speed, K _U2Be impeller outlet peripheral velocity coefficient.Exit width

Wherein, outlet radial velocity Q is a fluid flow, T _K2Be outlet blade blockage factor, K _R2Be impeller outlet radial velocity coefficient.The blade inlet diameter

Wherein, λ is the speed homogenization coefficient, and ξ is a moderating ratio, T _K1Be inlet vane blockage factor, T _K2Be outlet blade blockage factor,

For revealing coefficient.Impeller inlet diameter D _j=D ₁/ K ₁, wherein, K ₁Be impeller inlet diameter and blade inlet diameter ratio, blade entrance width β ₁Be inlet blade angle, β ₂Be blade outlet angle, the equivalent diffusance

Subtended angle of blade is 155 °.

2. according to the centrifugal unshrouded impeller of the described pulp pump of claim 1, it is characterized in that described impeller outlet peripheral velocity COEFFICIENT K based on the fiber suspension flow design criterion _U2Can be 1.07, outlet radial velocity COEFFICIENT K _R2Desirable 0.05, speed homogenization coefficient λ is desirable 1.05～1.1, and moderating ratio ξ is 0.65 inlet vane blockage factor T _K1Be 0.95, outlet blade blockage factor T _K2Be 0.9, reveal coefficient

Be 1.1, the impeller inlet diameter compares K with the blade inlet diameter ₁Be 0.8, inlet blade angle β ₁Desirable 20～30 °, blade outlet angle β ₂It is 30 °.