Method for building turbulence model of S-shaped feature of low water head generator

A technology of turbulence model and construction method, which is applied in the direction of internal combustion engine testing, etc., can solve problems such as low water head no-load operation instability, failure to successfully connect to the grid, etc., achieve important engineering significance and application value, small structure size, and high sensitivity.

Inactive Publication Date: 2013-03-13

河南国网宝泉抽水蓄能有限公司

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AI-Extracted Technical Summary

Problems solved by technology

[0004] A pumped-storage power station in my country is a high-head power station with a water head section of 600m. During the dynamic commissioning process of unit 1, because the unit entered the anti-water pump area duri...

Abstract

The invention relates to a method for building a turbulence model of an S-shaped feature of a low water head generator. The method comprises the following steps of: firstly, carrying out site test on the idle running parameter of the low water head generator of a water turbine of a unit, then, carrying out three-dimensional CFD (Computational Fluid Dynamics) computation on a fluid in the idle running process of the low water head generator and analyzing the mechanism for forming instability under such a working condition; and finally, comprehensively analyzing the running instability under the working condition according to site test and fluid computation and analysis results, and then, proposing a proposed project for solving the problem in a pumped storage power station. The idle running stability of the low water head of the water turbine of a pumped storage unit is researched by using a site test and CFD computation combination method, so that the method has important engineering significance and application values.

Application Domain

Internal-combustion engine testing

Technology Topic

InstabilityPower station +5

Examples

Experimental program(1)

Example Embodiment

[0017] Example 1: The power station hub is composed of upper reservoir, lower reservoir, water delivery system, underground powerhouse, and ground 500kV switch station.

[0018] The diversion tunnel in the water delivery system is arranged with two holes and four machines. The center distance between the two water delivery channels is 41.35m and the tunnel diameter is 6.5m. The reinforced concrete bifurcated pipe divides the main pipe into two branch pipes with a branch pipe diameter of 3.5m-2.3m and bifurcation. The last four high-pressure steel branch pipes are about 98.79m-121.37m long.

[0019] The tailrace system is arranged in a tunnel with two engines combined. Two reinforced concrete bifurcation pipes are arranged at 145.757m downstream of the center line of the unit. The four tailwater branch pipes are merged into two tailwater tunnels. The inner diameter of the tailwater branch pipe is 4.4m, and the tailwater tunnel The inner diameter is 8.2m.

[0020] The method for constructing a turbulence model with the "S" shape feature of a low-head generator is characterized by including the following steps:

[0021] (1) Conduct on-site testing of the low-water head electric no-load operating parameters of a unit.

[0022] a. Swing measurement, using eddy current sensor: it is a displacement sensor that relies on the high-frequency electromagnetic field generated by the probe coil to induce eddy current on the measured surface and the change in coil impedance caused by it to reflect the probe and the measured surface the distance between. Compared with other types of displacement sensors, eddy current sensors have many advantages such as non-contact measurement, high sensitivity, large linear range, wide frequency range, small structure size, and strong anti-interference ability. They are especially suitable for vibration monitoring of rotating machinery and shafts. Displacement monitoring and axis track monitoring, etc.

[0023] b. Setting the key phase sensor: Due to the large range, the key phase sensor is a non-standard product and needs to be customized.

[0024] c. Vibration measurement, using speed sensor: In the vibration test of machinery and equipment, the speed sensor is widely used, and it is mainly used to measure the vibration of the shell. The commonly used speed sensor is a magnetoelectric sensor with a spring-mass system, which measures the absolute movement of the component relative to the ground, so it is also called an inertial sensor.

[0025] d. Pressure pulsation sensor: Pressure measurement uses the piezoelectric effect of certain materials to convert pressure into electrical signals. In theory, the average value of the output of the same sensor is pressure, and the AC value is pulsation. But from the perspective of analysis and diagnosis, the sensors used to measure pressure and pulsation are different. The pressure pulsation sensor requires that the dynamic response time is not more than 1ms, and can analyze the pulsation frequency above 200Hz. In this field test, the pressure pulsation was measured using the AK-4 pressure pulsation sensor produced by China Aerospace Science and Industry Corporation.

[0026] (2) Carry out three-dimensional CFD calculation on the fluid of low-water head electric no-load operation, analyze the mechanism of unstable operation under this condition; at the same time, carry out the flow pattern of the water flow after installing the guide vane asynchronous pre-opening device (MGV) Three-dimensional analysis.

[0027] Turbulence is an irregular pulsation that appears over time and space, and is composed of many vortices of different sizes. Those large vortices have a relatively obvious impact on the average flow, while those small vortices have an impact on large-scale motions through nonlinear effects. A large amount of mass, momentum, heat and energy exchange are realized through large vortices, and the effects of small vortices Appears as dissipation. The motion characteristics of turbulence can be described by continuity equation and momentum equation. By solving them simultaneously, the flow velocity and pressure information can be calculated everywhere.

[0028] (3) According to the results of field test and flow pattern calculation and analysis, a comprehensive analysis of the unstable operation of this working condition is carried out, and a proposal to solve this problem of the pumped storage power station is proposed.

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Classification and recommendation of technical efficacy words

high sensitivity
Large linear range

Fluorescence immunochromatographic assay and kit for quantitative detection of troponin I/creatine kinase isoenzyme/myohemoglobin

ActiveCN102520192Ahigh sensitivityHigh detection sensitivity

Owner:SHENZHEN KANGMEI BIOTECH

Method for building turbulence model of S-shaped feature of low water head generator

AI-Extracted Technical Summary

Problems solved by technology

Abstract

Examples

Example Embodiment

PUM

Description & Claims & Application Information

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