CN111852879A - A gas-liquid two-phase vane pump and its design method and device - Google Patents

Abstract

The invention discloses a gas-liquid two-phase vane pump and a design method and device thereof, wherein the impeller of the gas-liquid two-phase vane pump comprises: a hub and blades; the blades have a first end and a second end in the extending direction , the first end is connected to the inlet angle, and the second end is connected to the outlet angle. The inlet and outlet angles of the blades are determined by a two-phase design method based on gas holdup prediction. The profile of the blade is determined by the distribution law of the middle placement angle. Therefore, the impeller of the gas-liquid two-phase vane pump can effectively reduce the loss caused by the gas-liquid two-phase interaction under the two-phase working condition, and improve the pump head and efficiency.

Description

A gas-liquid two-phase vane pump and its design method and device

technical field

The invention relates to the technical field of vane pumps, in particular to a gas-liquid two-phase vane pump and a design method and device thereof.

Background technique

In recent years, with the increasing demand for transportation equipment in petroleum, food, chemical and other industries, vane pumps have become more and more widely used in the two-phase mixed transportation industry. Two-phase transportation with vane pump can reduce the application of separation device and pipeline laying, which has the advantages of economical, environmental protection and high efficiency.

At present, when the vane pump is applied in two-phase conditions, the lift and efficiency are far from meeting the design requirements. The main reason is that the design method of the vane pump has always been the design method of the clean water pump. Although various optimization algorithms can improve the performance of the vane pump under two-phase conditions, it requires a lot of resources and lacks theoretical support, so it cannot be promoted.

The traditional gas-liquid two-phase vane pump impeller vane design method generally follows the design experience and design formula of the clean water pump. This design method can realize the working characteristics of the vane under single-phase conditions, but in the actual gas-liquid two-phase mixed transmission application, the gas-liquid two-phase strong interaction at the inlet is very important for the gas-liquid two-phase vane pump. The performance of the pump puts forward great requirements, and the pump designed by the traditional method cannot meet the requirements of operating head and efficiency under gas-containing conditions.

SUMMARY OF THE INVENTION

The present invention aims to solve one of the technical problems in the related art at least to a certain extent.

Therefore, an object of the present invention is to propose a gas-liquid two-phase vane pump, and the impeller of the gas-liquid two-phase vane pump can effectively reduce the loss caused by the gas-liquid two-phase interaction under the two-phase working condition, and improve the Pump head and efficiency.

Another object of the present invention is to propose a gas-liquid two-phase vane design method based on gas content prediction, which can quickly design the vanes of the gas-liquid two-phase vane pump and effectively improve the gas-liquid two-phase vane under two-phase working conditions. Phase vane pump head and efficiency.

Another object of the present invention is to propose a gas-liquid two-phase blade design device based on prediction of gas content.

In order to achieve the above purpose, an embodiment of the present invention proposes a gas-liquid two-phase vane pump, comprising:

The impeller of the gas-liquid two-phase vane pump includes: a hub and a blade;

The blades are arranged on the outer peripheral surface of the hub and spirally extend along the axial direction of the hub;

The blade has a first end and a second end in the extending direction of the blade, and an inlet angle is formed between a tangent of the axial streamline of the first end of the blade and a plane perpendicular to the axis of the hub, and the blade has an inlet angle. An inlet angle is formed between a tangent to the axial streamline of the second end and a plane perpendicular to the hub axis, and the inlet angle and the outlet angle are determined by a two-phase design method based on gas content prediction;

the blade includes a hub side connected to the hub, and a rim side remote from the hub;

The placement angle formed between the tangent of the axial streamline of the blade and the plane perpendicular to the axis of the hub side is the placement angle on the hub side of the blade, and the tangent to the axial streamline of the blade is perpendicular to the rim. The placement angle formed between the planes of the side axes is the placement angle on the rim side of the blade; the distribution law of the placement angle on the hub side of the blade and the placement angle on the rim side of the blade along the relative axial streamline is determined by iteration.

In order to achieve the above object, another embodiment of the present invention proposes a gas-liquid two-phase blade design method based on prediction of gas content, including:

S1, according to the given design flow, head and rotational speed of the impeller of the gas-liquid two-phase vane pump, use the single-phase design method to obtain the initial blade placement angle distribution law;

S2, according to the distribution law of the placement angle of the blades and the given inlet gas content of the gas-liquid two-phase vane pump impeller, use the gas content distribution prediction model to predict the distribution law of the gas content in the impeller along the length of the axial streamline ;

S3, calculate the gas phase velocity and the liquid phase velocity in the impeller according to the distribution law of the gas content along the length of the streamline length of the axial surface, and analyze the influence of the gas-liquid two-phase velocity field by the distribution law of the gas content;

S4, according to the gas phase velocity and the liquid phase velocity, and based on the equivalent head prediction model of the velocity slip to predict the equivalent head under the two-phase working condition;

S5, determine whether the predicted equivalent head under the two-phase working conditions meets the requirements of the design head, and if so, determine the distribution law of the blade inlet placement angle, outlet placement angle and intermediate placement angle that meet the design requirements; if not If it is satisfied, change the distribution law of the placement angle of the blade, and return to S2 for iteration until the requirements of the design head are met.

In order to achieve the above object, another embodiment of the present invention provides a gas-liquid two-phase blade design device based on prediction of gas content, including:

The initialization module is used to obtain the initial blade placement angle distribution law by using the single-phase design method according to the given design flow, head and speed of the impeller of the gas-liquid two-phase vane pump;

The first prediction module is used for predicting the flow of the air content in the impeller along the axial surface by using the air content distribution prediction model according to the distribution law of the placement angle of the blades and the inlet air content of the given gas-liquid two-phase vane pump impeller Line length distribution law;

The calculation module is used to solve the gas phase velocity and the liquid phase velocity in the impeller according to the distribution law of the gas content along the length of the streamline of the axial surface, and analyze the influence of the gas-liquid two-phase velocity field by the distribution law of the gas content;

The second prediction module predicts the equivalent head under two-phase working conditions according to the gas phase velocity and the liquid phase velocity and based on the equivalent head prediction model of velocity slip;

The iterative module judges whether the predicted equivalent head under the two-phase working conditions meets the requirements of the design head, and if so, determines the distribution rules of the blade inlet placement angle, outlet placement angle and intermediate placement angle that meet the design requirements; If not, change the distribution law of the placement angle of the blades, and execute the first prediction module until the requirements of the design lift are met.

The gas-liquid two-phase vane pump and the design method and device thereof according to the embodiments of the present invention have the beneficial effects that the design of the impeller blades of the gas-liquid two-phase vane pump can be completed quickly, and the gas-liquid two-phase vane pump can be effectively improved in the two-phase process. operating head and efficiency.

Additional aspects and advantages of the present invention will be set forth, in part, from the following description, and in part will be apparent from the following description, or may be learned by practice of the invention.

Description of drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily understood from the following description of embodiments taken in conjunction with the accompanying drawings, wherein:

1 is a schematic perspective view of an impeller of a gas-liquid two-phase vane pump according to an embodiment of the present invention;

2 is a flow chart of a method for designing a gas-liquid two-phase blade based on prediction of gas content according to an embodiment of the present invention;

3 is a schematic diagram of the distribution law of the blade placement angle along the length of the axial streamline of the model hub side and the rim side obtained by the traditional design method according to an embodiment of the present invention;

4 is a schematic diagram of the distribution law of the blade placement angle along the length of the axial streamline of the gas-liquid two-phase vane pump impeller optimized design model of the hub side and the rim side according to an embodiment of the present invention;

5 is a schematic structural diagram of a device for designing a gas-liquid two-phase blade based on prediction of gas content according to an embodiment of the present invention.

Reference Signs: Impeller-100, Hub-10, Blade-20, First End-21, Second End-22, Hub Side-23, Rim Side-24, Mounting Angle- _β0 , Mounting Angle _- β1 .

Detailed ways

The following describes in detail the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary, and are intended to explain the present invention and should not be construed as limiting the present invention.

The following describes a gas-liquid two-phase vane pump and a design method and device thereof according to the embodiments of the present invention with reference to the accompanying drawings.

First, a gas-liquid two-phase vane pump according to an embodiment of the present invention will be described with reference to the accompanying drawings.

1 is a schematic perspective view of an impeller of a gas-liquid two-phase vane pump according to an embodiment of the present invention.

As shown in FIG. 1 , the impeller 100 of the gas-liquid two-phase vane pump includes: a hub 10 and a blade 20;

The blades 20 are arranged on the outer peripheral surface of the hub 10 and spirally extend along the axial direction of the hub 10;

The blade 20 has a first end 21 and a second end 22 in the extending direction. The tangent of the axial streamline of the first end of the blade 20 forms an inlet angle with a plane perpendicular to the axis of the hub. The axis of the second end of the blade forms an inlet angle. The inlet angle is formed between the tangent of the surface streamline and the plane perpendicular to the axis of the hub, and the inlet angle and outlet angle are determined by the two-phase design method based on the prediction of gas content;

The blade 20 includes a hub side 23 connected to the hub, and a rim side 24 remote from the hub;

The placement angle formed between the tangent of the axial streamline of the blade and the plane perpendicular to the axis on the hub side is the placement angle on the hub side of the blade. The placement angle is the placement angle on the rim side of the blade; wherein, β ₀ is the placement angle of the axial streamline at the first end 21 , and β ₁ is the placement angle of the axial streamline at the second end 22 . The distribution law of the placement angle on the hub side of the blade and the placement angle on the rim side of the blade along the relative axial streamlines is determined by iteration.

According to the gas-liquid two-phase vane pump proposed in the embodiment of the present invention, the design of the impeller blades of the gas-liquid two-phase vane pump can be quickly completed, and the head and efficiency of the gas-liquid two-phase vane pump operating under two-phase working conditions can be effectively improved.

Next, a method for designing a gas-liquid two-phase blade based on prediction of gas content according to an embodiment of the present invention will be described with reference to the accompanying drawings.

FIG. 2 is a flow chart of a method for designing a gas-liquid two-phase blade based on gas holdup prediction according to an embodiment of the invention.

As shown in Fig. 2, the gas-liquid two-phase blade design method based on gas content prediction includes the following steps:

S1, according to the given design flow, head and rotational speed of the impeller of the gas-liquid two-phase vane pump, use the single-phase design method to obtain the initial blade placement angle distribution law.

First, the design flow, head and rotational speed need to be given, and the initial placement angle distribution law of the blade 20 is obtained by using the traditional single-phase design method, as shown in FIG. 3 .

S2, according to the distribution law of the blade placement angle and the given inlet gas content of the gas-liquid two-phase vane pump impeller, the gas content distribution prediction model is used to predict the distribution law of the gas content in the impeller along the length of the axial streamline.

In the embodiment of the present invention, given the inlet gas content of the gas-liquid two-phase vane pump impeller 100, according to the distribution law of the placement angle of the blades and the inlet gas content of the given gas-liquid two-phase vane pump impeller, use the following The gas content distribution prediction model predicts the distribution law of the gas content in the impeller 100 along the length of the axial streamline:

表示入口质量流量，下标“l”和“g”分别表示液体和气体，A为流道的截面积，β为叶片安放角，r为叶轮的半径，C_d为阻力系数，r_g为气泡半径。Among them, α(s) represents the gas content distribution in the impeller, s is the length of the streamline, ρ represents the density,

Indicates the inlet mass flow, the subscripts "l" and "g" indicate liquid and gas respectively, A is the cross-sectional area of the flow channel, β is the blade placement angle, r is the radius of the impeller, C _d is the resistance coefficient, and r _g is the bubble radius.

S3, calculate the gas velocity and liquid velocity in the impeller according to the distribution law of the gas content along the length of the streamline length of the axial surface, and analyze the influence of the gas-liquid two-phase velocity field by the distribution law of the gas content.

和液相速度

分析气液两相速度场受含气率分布规律的影响。Calculate the gas velocity in the impeller by the distribution law of the gas content along the length of the axial streamline

and liquid phase velocity

It is analyzed that the gas-liquid two-phase velocity field is affected by the distribution law of gas holdup.

S4, according to the gas phase velocity and the liquid phase velocity, and the equivalent head prediction model based on the velocity slip to predict the equivalent head under the two-phase working condition.

According to the obtained gas-liquid two-phase velocity field, calculate the equivalent head considering the velocity slip:

Among them, V is the absolute velocity, u is the circumferential velocity, W is the relative velocity, the subscripts "1" and "2" represent the impeller inlet and the impeller outlet, respectively, x is the inlet gas mass fraction, and g is the gravitational acceleration.

S5, judge whether the predicted equivalent head under the two-phase working condition meets the requirements of the design head, if so, determine the distribution law of the blade inlet placement angle, outlet placement angle and intermediate placement angle that meet the design requirements; if not, Then change the distribution law of blade placement angle, and return to S2 for iteration until the design head requirements are met.

In the embodiment of the present invention, if the equivalent head calculated by the above formula does not meet the design head requirements, change the placement angle distribution law of the impeller 100 and perform iterative calculation, and finally obtain the blade placement angle distribution law that meets the design head requirements. As shown in Figure 4.

Compared with the traditional design method, the hydraulic performance of the impeller of the gas-liquid two-phase vane pump designed by the above-mentioned design method is improved. Compared with the original gas-liquid two-phase vane pump, the nominal head of the impeller designed by the two-phase method is increased by 15.74% compared with the prototype pump; the pressure rise of the entire compression stage is increased by 10.06% from the monitoring of the outlet section; the entire compression stage The efficiency of the blade is increased by 2.2 percentage points, which can prove the feasibility and superiority of the blade two-phase working condition design method based on the gas content prediction.

The gas-liquid two-phase vane design method based on the gas content prediction in the embodiment of the present invention is a design method for the impeller of the gas-liquid two-phase vane pump derived from the theoretical level, which can effectively improve the operation of the gas-liquid two-phase vane pump under two-phase working conditions. important way of performance. The designed gas-liquid two-phase vane pump can quickly complete the design of the impeller blades of the gas-liquid two-phase vane pump, and effectively improve the head and efficiency of the gas-liquid two-phase vane pump operating under two-phase conditions.

The gas-liquid two-phase blade design device based on prediction of gas content according to the embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 5 is a schematic structural diagram of a device for designing a gas-liquid two-phase blade based on gas content prediction according to an embodiment of the invention.

As shown in FIG. 5 , the gas-liquid two-phase blade design device based on gas holdup prediction includes: an initialization module 100 , a first prediction module 200 , a calculation module 300 , a second prediction module 400 and an iteration module 500 .

The initialization module 100 is used to obtain the initial blade placement angle distribution law by using the single-phase design method according to the given design flow, head and rotational speed of the impeller of the gas-liquid two-phase vane pump.

The first prediction module 200 is used for predicting the air content in the impeller along the axial surface streamline by using the air content distribution prediction model according to the distribution law of the placement angle of the blades and the inlet air content of the given gas-liquid two-phase vane pump impeller. length distribution.

The calculation module 300 is used to calculate the gas phase velocity and the liquid phase velocity in the impeller according to the distribution law of the gas content along the length of the streamline of the axial surface, and analyze the influence of the gas-liquid two-phase velocity field by the distribution law of the gas content.

The second prediction module 400 predicts the equivalent head under the two-phase working condition according to the velocity of the gas phase and the velocity of the liquid phase, and based on the equivalent head prediction model of the velocity slip.

The iterative module 500 judges whether the predicted equivalent head under two-phase operating conditions meets the requirements of the design head, and if so, determines the distribution law of the blade inlet placement angle, the outlet placement angle and the intermediate placement angle that meet the design requirements; if not If it is satisfied, change the distribution law of the placement angle of the blade, and execute the first prediction module until the requirements of the design head are met.

Further, in an embodiment of the present invention, the gas content distribution prediction model is:

表示入口质量流量，下标“l”和“g”分别表示液体和气体，A为流道的截面积，β为叶片安放角，r为叶轮的半径，C_d为阻力系数，r_g为气泡半径。Among them, α(s) represents the gas content distribution in the impeller, s is the length of the streamline, ρ represents the density,

Indicates the inlet mass flow, the subscripts "l" and "g" indicate liquid and gas respectively, A is the cross-sectional area of the flow channel, β is the blade placement angle, r is the radius of the impeller, C _d is the resistance coefficient, and r _g is the bubble radius.

Further, in one embodiment of the present invention, the gas phase velocity is:

The liquid phase velocity is:

Further, in an embodiment of the present invention, the equivalent head under the two-phase working condition is:

Among them, V is the absolute velocity, u is the circumferential velocity, W is the relative velocity, the subscripts "1" and "2" represent the impeller inlet and the impeller outlet, respectively, x is the inlet gas mass fraction, and g is the gravitational acceleration.

It should be noted that the foregoing explanations of the method embodiment are also applicable to the apparatus of this embodiment, and details are not repeated here.

The gas-liquid two-phase vane design device based on the prediction of the gas content according to the embodiment of the present invention is a design method for the impeller of the gas-liquid two-phase vane pump derived from the theoretical level, which can effectively improve the gas-liquid two-phase vane pump in the two-phase An important way of operating performance under working conditions. The designed gas-liquid two-phase vane pump can quickly complete the design of the impeller blades of the gas-liquid two-phase vane pump, and effectively improve the head and efficiency of the gas-liquid two-phase vane pump operating under two-phase conditions.

In addition, the terms "first" and "second" are only used for descriptive purposes, and should not be construed as indicating or implying relative importance or implying the number of indicated technical features. Thus, a feature delimited with "first", "second" may expressly or implicitly include at least one of that feature. In the description of the present invention, "plurality" means at least two, such as two, three, etc., unless otherwise expressly and specifically defined.

In the description of this specification, description with reference to the terms "one embodiment," "some embodiments," "example," "specific example," or "some examples", etc., mean specific features described in connection with the embodiment or example , structure, material or feature is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms are not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Furthermore, those skilled in the art may combine and combine the different embodiments or examples described in this specification, as well as the features of the different embodiments or examples, without conflicting each other.

Although the embodiments of the present invention have been shown and described above, it should be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Embodiments are subject to variations, modifications, substitutions and variations.

Claims (9)

1. a gas-liquid two-phase vane pump, is characterized in that, the impeller of described gas-liquid two-phase vane pump comprises: hub and blade; The blades are arranged on the outer peripheral surface of the hub and spirally extend along the axial direction of the hub; The blade has a first end and a second end in the extending direction of the blade, and an inlet angle is formed between a tangent of the axial streamline of the first end of the blade and a plane perpendicular to the axis of the hub, and the blade has an inlet angle. An inlet angle is formed between a tangent to the axial streamline of the second end and a plane perpendicular to the hub axis, and the inlet angle and the outlet angle are determined by a two-phase design method based on gas content prediction; the blade includes a hub side connected to the hub, and a rim side remote from the hub; The placement angle formed between the tangent of the axial streamline of the blade and the plane perpendicular to the axis of the hub side is the placement angle on the hub side of the blade, and the tangent to the axial streamline of the blade is perpendicular to the rim. The placement angle formed between the planes of the side axes is the placement angle on the rim side of the blade; the distribution law of the placement angle on the hub side of the blade and the placement angle on the rim side of the blade along the relative axial streamline is determined by iteration. 2. A gas-liquid two-phase blade design method based on prediction of gas content, is characterized in that, comprises the following steps: S1, according to the given design flow, head and rotational speed of the impeller of the gas-liquid two-phase vane pump, use the single-phase design method to obtain the initial blade placement angle distribution law; S2, according to the distribution law of the placement angle of the blades and the given inlet gas content of the gas-liquid two-phase vane pump impeller, use the gas content distribution prediction model to predict the distribution law of the gas content in the impeller along the length of the axial streamline ; S3, calculate the gas phase velocity and the liquid phase velocity in the impeller according to the distribution law of the gas content along the length of the streamline length of the axial surface, and analyze the influence of the gas-liquid two-phase velocity field by the distribution law of the gas content; S4, according to the gas phase velocity and the liquid phase velocity, and based on the equivalent head prediction model of the velocity slip to predict the equivalent head under the two-phase working condition; S5, determine whether the predicted equivalent head under the two-phase working conditions meets the requirements of the design head, and if so, determine the distribution law of the blade inlet placement angle, outlet placement angle and intermediate placement angle that meet the design requirements; if not If it is satisfied, change the distribution law of the placement angle of the blade, and return to S2 for iteration until the requirements of the design head are met. 3. The method according to claim 2, wherein the gas content distribution prediction model is:

Among them, α(s) represents the gas content distribution in the impeller, s is the length of the streamline, ρ represents the density,

Indicates the inlet mass flow, the subscripts "l" and "g" indicate liquid and gas respectively, A is the cross-sectional area of the flow channel, β is the blade placement angle, r is the radius of the impeller, C _d is the resistance coefficient, and r _g is the bubble radius. 4. The method of claim 3, wherein The gas phase velocity is:

The liquid phase velocity is:

5. The method according to claim 2, wherein the equivalent head under the two-phase working condition is:

Among them, V is the absolute velocity, u is the circumferential velocity, W is the relative velocity, the subscripts "1" and "2" represent the impeller inlet and the impeller outlet, respectively, x is the inlet gas mass fraction, and g is the gravitational acceleration. 6. A gas-liquid two-phase blade design device based on prediction of gas content, characterized in that, comprising: The initialization module is used to obtain the initial blade placement angle distribution law by using the single-phase design method according to the given design flow, head and speed of the impeller of the gas-liquid two-phase vane pump; The first prediction module is used for predicting the flow of the air content in the impeller along the axial surface by using the air content distribution prediction model according to the distribution law of the placement angle of the blades and the inlet air content of the given gas-liquid two-phase vane pump impeller Line length distribution law; The calculation module is used to solve the gas phase velocity and the liquid phase velocity in the impeller according to the distribution law of the gas content along the length of the streamline of the axial surface, and analyze the influence of the gas-liquid two-phase velocity field by the distribution law of the gas content; The second prediction module predicts the equivalent head under two-phase working conditions according to the gas phase velocity and the liquid phase velocity and based on the equivalent head prediction model of velocity slip; The iterative module judges whether the predicted equivalent head under the two-phase working conditions meets the requirements of the design head, and if so, determines the distribution rules of the blade inlet placement angle, outlet placement angle and intermediate placement angle that meet the design requirements; If not, change the distribution law of the placement angle of the blades, and execute the first prediction module until the requirements of the design lift are met. 7. The device according to claim 6, wherein the gas content distribution prediction model is:

Among them, α(s) represents the gas content distribution in the impeller, s is the length of the streamline, ρ represents the density,

Indicates the inlet mass flow, the subscripts "l" and "g" indicate liquid and gas respectively, A is the cross-sectional area of the flow channel, β is the blade placement angle, r is the radius of the impeller, C _d is the resistance coefficient, and r _g is the bubble radius. 8. device according to claim 6, is characterized in that, described gas phase velocity is:

The liquid phase velocity is:

9. The device according to claim 6, wherein the equivalent head under the two-phase working condition is:

Among them, V is the absolute velocity, u is the circumferential velocity, W is the relative velocity, the subscripts "1" and "2" represent the impeller inlet and the impeller outlet, respectively, x is the inlet gas mass fraction, and g is the gravitational acceleration.

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