A Method of Estimating Basic Parameters of Francis Turbine

Abstract

The invention relates to a water turbine, provides a method for estimating basic parameters of a mixed-flow type water turbine, and aims to estimate the basic parameters of the mixed-flow type water turbine. The basic parameters to be estimated of the water turbine comprise a specific speed ns, a unit speed n11 and unit flow Q11. The method comprises the following steps: determining the specific speed of the mixed-flow type water turbine to be estimated, and recording the specific speed as ns; determining the maximum application water head of the mixed-flow type water turbine to be estimated, recording the maximum application water head as Hmax, and judging a range where the Hmax falls; estimating the basic parameters according to estimation formulas of the corresponding ranges of Hmax, wherein the formulas are as follows: when Hmax is less than or equal to 100 m, ns=374.05e<-0.0053Hr>, n11=45.395e<0.0022ns> and Q11=5.9 x 10<-3> x ns<0.9516>; when Hmax is greater than 100 m and less than or equal to 200 m, ns=2191.5Hr<-0.5007>, n11=48.289e<0.002ns> and Q11=1.0642Ln(ns)-4.7812; when Hmax is greater than 200 m and less than or equal to 300 m, ns=343.12e<-0.0042Hr>, n11=1.2874ns<0.7878> and Q11=0.7821Ln(ns)-3.3718; when Hmax is greater than 300 m, ns=3609.2Hr<-0.6189>,n11=37.207ns<0.1186> and Q11=0.3652Ln(ns)-1.4009. The method is applicable to the mixed-flow type water turbine and can better meet new hydropower engineering requirements.

Description

technical field [0001] The invention relates to water turbines, in particular to a method for estimating basic parameters of Francis water turbines. Background technique [0002] A hydro turbine is a machine in a hydropower station that converts the mechanical energy of the water flow into the mechanical energy of the runner, so that the runner and the main shaft can run continuously against various resistances. It is called the "heart" of the hydropower station. The initial investment and the economic benefit of the power plant after it is put into operation play a very important role and are an important content of hydropower engineering design. [0003] Turbine specific speed n s It is a comprehensive index to measure the energy characteristics, cavitation characteristics, operation stability, economy and advanced nature of the turbine. Increasing the specific speed is of great significance to improve the energy characteristics of the turbine, reduce the cost of the uni...

AI Technical Summary

Problems solved by technology

Because this method is to estimate the basic parameters of the turbine according to the statistical formula, there are many such statistical formulas at present, because the sample data of the turbine parameters on which each statistical formula is based is before the 1970s and 1980s or at a certain water head section or For a certain output range, there are certain limitations. The results calculated by different statistical formulas for the same hydropower project are different, and some even have large differences, so it cannot be selected correctly.

Therefore, methods 1 and 2 cannot meet the requirements of hydropower engineering for the continuous development of new technologies, new materials, new processes, and new structures. The calculated specific speed n of the turbine is s , unit speed n 11 and unit flow Q 11 Generally, it is also difficult to meet the new hydropower engineering requirements

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