CN102979759A - Design method for impeller of multiphase mixed transportation pump - Google Patents

Abstract

The invention relates to a design method for an impeller of a multiphase mixed transportation pump. With the adoption of the design method, hydraulic performance of the mixed transportation pump is improved, and the influences of gas content on the performances of the mixed transportation pump are reduced through controlling main geometrical parameters such as an inlet diameter, an impeller outlet diameter, an outlet width of each impeller blade; the thickness of a front cover plate side of each impeller blade is 25% less than the thickness of a rear cover plate side; the thickness of each blade is uniformly increased from the front cover plate side to the rear cover plate side according to linearity; the thickness of each blade is gradually increased along a filament line direction from an inlet edge to an outlet edge; the thickness of each inlet edge is about 40% of the thickness of the corresponding outlet edge; and the number of the blades of the impeller is 3 to 6.

Description

A kind of design method of multi-phase mixed delivering pump impeller

Technical field

The present invention relates to fluid machinery, particularly a kind of design method of multi-phase mixed delivering pump impeller.

Background technique

It is the most extensive that multiphase mixing transmission pump uses in oilfield exploitation, and at present, what domestic use was more is screw rod mixing delivery pump, mainly is to reduce wellhead back pressure and improve the production fluid amount.But the allowance of the solid phase impurity of screw rod mixing delivery pump is generally less, and is subjected to the restriction of pump physical dimension, and its discharge capacity is also less, so screw rod mixing delivery pump is not easy to the heterogeneous conveying of the oil gas of large discharge capacity.And the blade mixing pump is simple in structure, and discharge capacity is large, and reliability is stronger, and is better to the adaptability of solid phase impurity, can satisfy the needs of the heterogeneous conveying of large discharge capacity oil gas.When pump during in heterogeneous lower work such as oil gas, because there is velocity-slip in the existence of gas between liquid and gas, and can make lift of pump, flow that to a certain degree decline is arranged, along with the rising of air content, this phenomenon can be more and more obvious, and then the pump transfer efficiency is reduced, affect pump performance.In order to address this problem to a certain extent, the present invention proposes a kind of design method for the multi-phase mixed delivering pump impeller.

Summary of the invention

The invention provides a kind of design method of multi-phase mixed delivering pump impeller.By the design method of the several important design parameter of control impeller, realize improving the hydraulic performance of mixing pump and reduce gas content to the impact of mixing pump performance.

Realize that the technological scheme that above-mentioned purpose adopts is:

(1) revolution of raising pump

The revolution that improves pump can make the medium of high air content obtain the pressure head compensation, but too high supercharging will increase again two possibilities that are separated in the pump.Suggestion revolution n turns above at 1750r/min, is aided with the frequency variator realization to the needs of different revolutions.

(2) selection of specific speed

Specific speed n _sLess, the pressure head that the medium of the identical physical property of pumping and discharge capacity increases is just higher, but the segregation phenomenon of gas-liquid two-phase will be more serious.Specific speed n _sAlso unsuitable too high, otherwise will not reach the purpose of pumping mixture, and might reduce the rigidity of pump shaft, increase the wearing and tearing probability of pump.Therefore should reasonably select the specific speed n of pump _sWith reference to the specific speed of outstanding model pump, carried out certain limit on its basis reduction, suggestion n _sBetween 210～270, select.

(3) impeller inlet diameter D _j

$D_j=(3.5+\frac{n_s}{500})\·\sqrt[3]{\frac{Q}{n}}$

In the formula: D _j-impeller inlet diameter, rice;

The flow of Q-design conditions, cube meter per second;

The n-wheel speed, rev/min;

n _s-specific speed.

(2) impeller outlet diameter D ₂

$D_2=(9.31~9.75){\left(\frac{n_s}{100}\right)}^{-1/2}\·\sqrt[3]{\frac{Q}{n}}$

In the formula:

The flow of Q-design conditions, cube meter per second;

The n-wheel speed, rev/min;

n _s-specific speed.

The number of the large formula of specific speed the inside is got large value

(4) exit width b ₂

$b_2=(1.05-\frac{n_s-200}{1263})\·(1-2.12\·\frac{n_s-135}{10000})\·\sqrt[3]{\frac{Q}{n}}$

In the formula: b ₂-impeller blade exit width, rice;

The flow of Q-design conditions, cube meter per second;

The n-wheel speed, rev/min;

n _s-specific speed.

A kind of impeller of multiphase mixing transmission pump, its structure comprises: impeller cover, blade, wheel hub etc.The inlet diameter of impeller, outlet diameter, blade exit width adopt above-mentioned design method to determine.The blade front shroud side Thickness Ratio back shroud side thickness of impeller is little by 25%, and vane thickness from front shroud side direction back shroud side according to linear uniform thickened; Blade increases gradually from inlet side along grain direction to the thickness of outlet, and wherein inlet side thickness is about 40% of Exit-edge thickness.The number of blade of impeller is 3 to 6.

The invention has the beneficial effects as follows: the impeller of the design's method design has outstanding hydraulic performance, can make pump keep higher efficient when carrying multiphase flow, and its gas content that general pump is compared in the impact of this pump is less.

Description of drawings

Fig. 1 is the impeller axis projection of one embodiment of the invention

Fig. 2 is same embodiment's impeller blade figure

Among the figure: 1. front shroud of impeller, 2. impeller inlet diameter D _j, 3. impeller outlet diameter D ₂, 4. back shroud of impeller, 5. impeller blade exit width b ₂, 6. blade, 7. wheel hub.

Embodiment

Fig. 1 and Fig. 2 have determined this embodiment's impeller shape jointly.It has impeller cover (1), and front shroud and back shroud are arranged respectively, is a kind of double shrouded wheel, and the number of blade 3≤z≤6, can improve mobility status, and the hydraulic performance of raising mixing pump and anti-gas are on the impact of its conveying capacity.The present invention determines impeller inlet diameter (2) D by following relation _j, impeller outlet diameter (3) D ₂, impeller blade exit width (5) b ₂

$D_j=(3.5+\frac{n_s}{500})\·\sqrt[3]{\frac{Q}{n}};$

$D_2=(9.31~9.75){\left(\frac{n_s}{100}\right)}^{-1/2}\·\sqrt[3]{\frac{Q}{n}};$

$b_2=(1.05-\frac{n_s-200}{1263})\·(1-2.12\·\frac{n_s-135}{10000})\·\sqrt[3]{\frac{Q}{n}}.$

The blade front shroud side Thickness Ratio back shroud side thickness of impeller is little by 25%, and vane thickness from front shroud side direction back shroud side according to linear uniform thickened; Blade increases gradually from inlet side along grain direction to the thickness of outlet, and wherein inlet side thickness is about 40% of Exit-edge thickness.The number of blade of impeller is 3 to 6.

Claims (2)

1. a multiphase mixing transmission pump method for designing impeller comprises impeller main geometric parameters inlet diameter D _j, impeller outlet diameter D ₂, impeller blade exit width b ₂Design formula and the number of blade of impeller be 3 to 6, rotating speed is more than 1750r/min, specific speed is between 210～270.It is characterized in that: be fit to following relation between impeller geometric parameter and the pump operating point for design performance parameter:

In the formula: the lift of Q-design conditions, rice;

D ₂-impeller outlet diameter, rice;

b ₂-impeller blade exit width, rice

The n-wheel speed, rev/min;

n _s-specific speed, rev/min;

D _j-impeller inlet diameter, rice.

2. a kind of multiphase mixing transmission pump method for designing impeller according to claim 1, it is characterized in that: the multiphase mixing transmission pump blade wheel structure comprises: front shroud of impeller (1), back shroud of impeller (4), blade (6), wheel hub (7).The inlet diameter D of impeller _j, outlet diameter D ₂, blade exit width b ₂Adopt above-mentioned design method to determine.The blade front shroud side Thickness Ratio back shroud side thickness of impeller is little by 25%, and vane thickness from front shroud side direction back shroud side according to linear uniform thickened; Blade increases gradually from inlet side along grain direction to the thickness of outlet, and wherein inlet side thickness is about 40% of Exit-edge thickness.

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