阅读说明：本技术 一种转桨式水轮机变转速运行的桨叶协联方法 (Paddle joint method for variable-speed operation of Kaplan turbine ) 是由 门闯社 南海鹏 李国凤 张松松 罗兴锜 冯建军 于 2019-10-15 设计创作，主要内容包括：本发明公开一种转桨式水轮机变转速运行的桨叶协联方法,首先根据转浆式水轮机综合特性曲线绘制各工况点等单位出力曲线,再根据等单位出力曲线绘制转桨式水轮机变转速运行最优特性曲线,最后在转桨式水轮机变转速运行最优特性曲线上读取各工况点导叶开度α与桨叶开度<Image he="50" wi="67" file="DDA0002234499250000011.GIF" imgContent="drawing" imgFormat="GIF" orientation="portrait" inline="no"></Image>即为转桨式水轮机变转速运行的桨叶协联关系。解决了现有技术中将定转速时的协联方法应用在变转速运行时所存在的测量量多、插值复杂、可靠性与精度低的问题。(The invention discloses a method for cooperating blades of a Kaplan turbine in variable-speed operation, which comprises the steps of firstly drawing an equal unit output curve of each working condition point according to a comprehensive characteristic curve of the Kaplan turbine, then drawing an optimal characteristic curve of the Kaplan turbine in variable-speed operation according to the equal unit output curve, and finally reading guide vane opening α and blade opening α of each working condition point on the optimal characteristic curve of the Kaplan turbine in variable-speed operation Namely the cooperative relation of the blades of the Kaplan turbine running at variable rotating speed. The method solves the problems of more measurement quantity, complex interpolation and low reliability and precision when the cooperative method at the fixed rotating speed is applied to the variable rotating speed operation in the prior art.)

1. A method for linking the blades of a Kaplan turbine in variable-speed operation includes such steps as drawing the uniform output curve of each working point according to the comprehensive characteristic curve of Kaplan turbine, and drawing the optimal characteristic curve of Kaplan turbine in variable-speed operation according to the uniform output curveFinally, the guide vane opening α and the blade opening of each working condition point are read on the optimum characteristic curve of the variable-speed operation of the Kaplan turbine

2. A method for cooperating blades of a Kaplan turbine running at variable rotating speed is characterized by comprising the following steps:

step 1, according to the unit flow rate Q₁₁Is abscissa, unit rotation speed n₁₁Unit flow rate Q at each operating point on comprehensive characteristic curve of Kaplan turbine as ordinate₁₁And operating point efficiency η, calculating unit output P at each operating point₁₁Drawing an equal unit output curve of each working condition point;

step 2, finding out the unit flow Q in the unit output curve of each working condition point drawn in the step 1₁₁Minimum working condition point, and unit flow rate Q in unit output curve of each working condition point₁₁The minimum working condition points are connected in sequence to obtain an optimal characteristic curve of the variable-speed operation of the Kaplan turbine;

step 3, reading guide vane opening α and blade opening at each working point on the optimum characteristic curve of variable-speed operation of the Kaplan turbine obtained in the step 2

3. The method for cooperating the blades of a Kaplan turbine operated at variable rotation speed according to claim 2, wherein in the step 1, the unit output P at each operating point is calculated₁₁The expression of (a) is:

P₁₁＝gηQ₁₁(1)

in the formula (1), P₁₁Is unit output of a working condition point, kW; g is the local gravitational acceleration, m/s²η operating Point efficiency, Q₁₁Is unit flow rate of operating point, m³/s。

4. The method as claimed in claim 2, wherein in step 2, the unit flow rate Q is determined on the curve of the unit output of the operating points₁₁The minimum operating point is the efficiency η maximum operating point.

Technical Field

The invention belongs to the technical field of water turbine adjusting methods, and particularly relates to a blade linkage method for variable-speed operation of a Kaplan turbine.

Background

The Kaplan turbine usually operates at a constant synchronous speed, and in order to improve the operating efficiency, the opening of the blades is in tandem with the opening of the guide vanes and the water head, and the two-dimensional interpolation calculation is carried out by the speed regulator during the operation according to the measured water head and the opening of the guide vanes and the tandem relation preset in the speed regulator to obtain the opening of the blades. At present, reports on how to establish a tandem relationship in variable-speed operation and variable-speed operation of a Kaplan turbine are not seen, and the blade tandem method for the Kaplan turbine to operate at a constant rotating speed has the defects of large measurement quantity, complex interpolation, low reliability and precision and the like when being applied to the variable-speed operation.

Disclosure of Invention

The invention aims to provide a blade joint method for variable-speed operation of a Kaplan turbine, which solves the problems of more measurement quantity, complex interpolation, low reliability and low precision existing in the prior art when the joint method at fixed speed is applied to variable-speed operation.

The invention adopts the technical scheme that a method for linking blades of a Kaplan turbine in variable-speed operation comprises the steps of firstly drawing an equal unit output curve of each working condition point according to a comprehensive characteristic curve of the Kaplan turbine, then drawing an optimal characteristic curve of the Kaplan turbine in variable-speed operation according to the equal unit output curve, and finally reading guide vane opening α and blade opening of each working condition point on the optimal characteristic curve of the Kaplan turbine in variable-speed operation

Namely the cooperative relation of the blades of the Kaplan turbine running at variable rotating speed.

The present invention is also characterized in that,

the method is implemented according to the following steps:

step 1, according to the unit flow rate Q₁₁Is abscissa, unit rotation speed n₁₁Unit flow rate Q at each operating point on comprehensive characteristic curve of Kaplan turbine as ordinate₁₁And operating point efficiency η, calculating unit output P at each operating point₁₁Drawing an equal unit output curve of each working condition point;

step (ii) of2, finding out the unit flow rate Q in the unit output curve of each working condition point drawn in the step 1₁₁Minimum working condition point, and unit flow rate Q in unit output curve of each working condition point₁₁The minimum working condition points are connected in sequence to obtain an optimal characteristic curve of the variable-speed operation of the Kaplan turbine;

step 3, reading guide vane opening α and blade opening at each working point on the optimum characteristic curve of variable-speed operation of the Kaplan turbine obtained in the step 2

Drawing guide vane opening α and blade opening under optimal characteristics

By the guide vane opening α and the blade opening under the optimal characteristic

The relationship between the blade pitch and the blade pitch of the variable-speed running of the Kaplan turbine is obtained according to the relationship curve.

In step 1, calculating unit output P at each working point₁₁The expression of (a) is:

P₁₁＝gηQ₁₁(1)

in the formula (1), P₁₁Is unit output of a working condition point, kW; g is the local gravitational acceleration, m/s²η operating Point efficiency, Q₁₁Is unit flow rate of operating point, m³/s。

In step 2, the unit flow Q on the unit output curve of each working condition point and the like₁₁The minimum operating point is the efficiency η maximum operating point.

The invention has the beneficial effects that: the invention discloses a method for establishing a variable-rotating-speed running blade joint relation of a Kaplan turbine, and provides a method for establishing a variable-rotating-speed running blade joint relation of the Kaplan turbine.

Drawings

FIG. 1 is a schematic view of the turbine comprehensive characteristic curve of the blade-coupled method for variable-speed operation of a Kaplan turbine according to the present invention;

fig. 2 is a blade joint relation curve of variable-speed operation of the Kaplan turbine according to the blade joint method of variable-speed operation of the Kaplan turbine.

The equivalent rate curve is 1, the equal guide vane opening curve is 2, the coordinated blade opening curve is 3, the equal unit output curve is 4, and the optimal characteristic curve for variable-speed operation of the Kaplan turbine is 5.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

The invention relates to a method for cooperating blades of a Kaplan turbine in variable-speed operation, which comprises the steps of firstly drawing an equal unit output curve of each working condition point according to a comprehensive characteristic curve of the Kaplan turbine, then drawing an optimal characteristic curve of the Kaplan turbine in variable-speed operation according to the equal unit output curve, and finally reading guide vane opening α and blade opening α of each working condition point on the optimal characteristic curve of the Kaplan turbine in variable-speed operation

Namely the cooperative relation of the blades of the Kaplan turbine running at variable rotating speed.

The method is implemented according to the following steps:

step 1, according to the unit flow rate Q₁₁Is abscissa, unit rotation speed n₁₁Unit flow rate Q at each operating point on comprehensive characteristic curve of Kaplan turbine as ordinate₁₁And operating point efficiency η, calculating unit output P at each operating point₁₁And drawing an equal unit output curve of each working condition point, wherein an equal efficiency curve 1, an equal guide vane opening curve 2 and a tandem paddle opening curve 3 are drawn on the comprehensive characteristic curve of the Kaplan turbine as shown by a curve 4 in figure 1;

calculating the unit output P at each working point₁₁The expression of (a) is:

P₁₁＝gηQ₁₁(1)

in the formula (1), P₁₁At operating pointUnit output, kW; g is the local gravitational acceleration, m/s²η operating Point efficiency, Q₁₁Is unit flow rate of operating point, m³/s。

The stable working point of the rotor type water turbine set is the highest efficiency point under the current water head and the output when the variable-speed running of the rotor type water turbine set is carried out, and the unit output P of the rotor type water turbine set can be calculated under the condition that the working water head and the working point power of the water turbine are determined₁₁：

In the formula, P is the output of a water turbine, kW; d₁Is the nominal diameter of the turbine, m; h is the working water head of the water turbine, m;

the joint type (1) and the formula (2) can obtain:

from the equation (3), it can be seen that the unit flow Q is determined by the turbine power P and the turbine operating head H₁₁The smaller the turbine efficiency η, the higher the unit flow rate Q₁₁Inversely proportional to turbine efficiency η, i.e. equal unit output (P)₁₁) Unit flow Q on the curve₁₁The minimum operating point is the maximum operating point of turbine efficiency η.

Step 2, finding out the unit flow Q in the unit output curve of each working condition point drawn in the step 1₁₁Minimum working condition point, and unit flow rate Q in unit output curve of each working condition point₁₁The minimum working points are connected in sequence to obtain an optimal characteristic curve 5 for variable-speed operation of the Kaplan turbine, and the steady-state working point of the Kaplan turbine falls on the optimal characteristic curve 5 when the Kaplan turbine operates at variable speed;

step 3, reading guide vane opening α and blade opening at each working point on the optimum characteristic curve of variable-speed operation of the Kaplan turbine obtained in the step 2

Rendering optimal characteristicsOpening α of lower guide vane and opening of blade

By the guide vane opening α and the blade opening under the optimal characteristic

The relationship between the blade pitch and the blade pitch of the variable-speed running of the Kaplan turbine is obtained according to the relationship curve.

As can be seen from the optimal characteristic curve 5 in fig. 1, the guide vane opening α and the blade opening

The blade opening degree can be inquired and obtained only by the guide vane opening degree α when the operation condition of the water turbine falls on the optimal characteristic curve 5

Therefore, the opening degree of the blades of the water turbine can be obtained

The relation curve with the guide vane opening α is shown in fig. 2, so that the speed regulator obtains the blade opening by measuring the guide vane opening α and inquiring according to the relation curve of fig. 2 which is arranged in the speed regulator in advance during the operation of the rotary-propeller turbine set

Through the mode, the blade joint method for variable-speed operation of the Kaplan turbine changes the joint relation of the Kaplan turbine from two dimensions to one dimension, and is simple, less in measured data, simple to operate, high in reliability and high in precision.