CN203629870U - Surge-chamber resistance coefficient measurement system used for model debugging - Google Patents

Abstract

The utility model discloses an impedance coefficient measuring system of a surge chamber for model tests. A flowmeter and a first pressure sensor are arranged in the inlet pipeline of the surge chamber. The flowmeter is used to measure the flow in the inlet pipeline of the surge chamber. The first The pressure sensor is used to measure the water pressure at the measuring point in the inlet pipe of the surge chamber; the second pressure sensor is installed in the surge chamber to measure the water pressure at the measuring point in the surge chamber, and the top of the surge chamber is also equipped with a water level measurement The device is used to measure the change of the distance from the fluctuating water surface in the surge chamber to the top of the surge chamber over time, so as to indirectly obtain the flow in and out of the surge chamber. The system of the utility model can dynamically obtain the impedance coefficient of the surge chamber and its change with time in the model test of the hydropower station.

Description

For the Hydraulic Resistance Coefficient of Surge Tanks measuring system of model test

Technical field

The utility model relates to a kind of power station simulation test device, relates in particular to a kind of Hydraulic Resistance Coefficient of Surge Tanks measuring system for model test.

Background technology

Hydraulic Resistance Coefficient of Surge Tanks refers to that current flow to or flow out the loss of flood peak coefficient of front and back, pressure balance chamber impedance hole.Hydraulic Resistance Coefficient of Surge Tanks is the important parameter in hydroelectric station design process, and the value of impedance factor is not only related to the height that Surge in Surge Chamber calculates, and affects the accuracy of other tune guarantor calculation of parameter.The Hydraulic Resistance Coefficient of Surge Tanks in the past adopting in numerical evaluation, major part is that rule of thumb formula valuation obtains, and impedance factor during steady flow is for the computation process of unsteady flow.In fact, no matter Hydropower Plant is under any working condition, as long as pressure balance chamber water level has fluctuation, the flow of inflow and outflow pressure balance chamber is not all fixed value, but time dependent.

Hydraulic Resistance Coefficient of Surge Tanks can not directly measure, because impedance factor size and flow, head are related, therefore need to flowmeter and pressure transducer be set in different locating.But for the flow of inflow and outflow pressure balance chamber, because pressure balance chamber is vertical columnar structured, it is directly connected with pipeline, and cross-sectional area is generally larger, the mode by flowmeter is set of being difficult to is measured the flow of inflow and outflow pressure balance chamber.But can calculate by measuring the fluctuating procession of the water level of pressure balance chamber the discharge process of pressure balance chamber, and the measurement of pressure balance chamber the fluctuating procession of the water level is relatively easy.

Model test is all carried out in domestic a lot of power stations at present, if measure simulation Hydraulic Resistance Coefficient of Surge Tanks value and law thereof by model test, will have very large directive significance for Hydraulic Resistance Coefficient of Surge Tanks value in engineering.

Utility model content

The purpose of this utility model is to provide a kind of Hydraulic Resistance Coefficient of Surge Tanks measuring system for model test, and this system capacity is surveyed impedance factor and the Changing Pattern thereof in pressure balance chamber water flow dynamic process.

For achieving the above object, the technical solution of the utility model is:

For the Hydraulic Resistance Coefficient of Surge Tanks measuring system of model test, in pressure balance chamber inlet pipeline, be provided with flowmeter and the first pressure transducer, flowmeter is used for measuring the flow in pressure balance chamber inlet pipeline, and the first pressure transducer is used for measuring the hydraulic pressure at measuring point place in pressure balance chamber inlet pipeline; In pressure balance chamber, be provided with the second pressure transducer, be used for measuring the hydraulic pressure at measuring point place in pressure balance chamber, pressure balance chamber top is also provided with level measurement device, is used for measuring the fluctuation water surface in pressure balance chamber to the distance at pressure balance chamber top over time, thereby indirectly obtains the flow that flows to outflow pressure balance chamber.

Above-mentioned flow is counted electromagnetic flowmeter.

Above-mentioned level measurement device is ultrasonic distance measuring apparatus.

Above-mentioned the first pressure transducer is arranged at pressure balance chamber inlet pipeline inwall, and guarantees that it is in water.

Above-mentioned the second pressure transducer is arranged on pressure balance chamber madial wall and is positioned at pressure balance chamber base plate vicinity, and guarantees that it is in water.

The pressure transducer that the utility model adopts can be monitored measuring point hydraulic pressure continuously, and has anti-hydraulic shock performance.Ultrasonic distance measuring apparatus measuring distance has untouchable, does not need to contact with water to measure the distance of the water surface apart from measuring point.Ultrasonic distance measuring apparatus is made up of ultrasonic sensor, can monitor continuously the distance of the pressure balance chamber water surface to ultrasonic sensor, measuring accuracy be 1mm and more than, and water-reflected is had to higher susceptibility.

Compared with prior art, the utlity model has following beneficial effect:

The utility model arranges respectively pressure transducer in pressure balance chamber inlet pipeline and pressure balance chamber, measures the head of corresponding measuring point and over time; Flow and over time in inlet pipeline is installed flowmeter survey inlet pipeline; Level measurement device is set at pressure balance chamber top and measures in pressure balance chamber water level and over time, can calculate fluctuations in discharge in pressure balance chamber according to SEA LEVEL VARIATION in pressure balance chamber.Flow rate calculation Hydraulic Resistance Coefficient of Surge Tanks value in head difference and the inlet pipeline, pressure balance chamber of measuring according to pressure transducer measuring point and over time.

Adopt the utility model system, the water level that utilizes level measurement device to measure can obtain flow in pressure balance chamber indirectly, without adopting flowmeter survey pressure balance chamber flow.Obtain Hydraulic Resistance Coefficient of Surge Tanks and over time for power station model test capable of dynamic.

Accompanying drawing explanation

Fig. 1 is the structural representation of the utility model system.

In figure, 1-pressure balance chamber; 2-inlet pipeline; 3-flowmeter; 4,6-pressure transducer; 5-outlet conduit; 7-pressure balance chamber base plate; 8-ultrasonic range finder; 9-pressure balance chamber top; 10-impedance hole; 11-pipe centerline.

Embodiment

Further illustrate embodiment of the present utility model below in conjunction with Fig. 1.

See Fig. 1, pressure balance chamber 1 comprises sidewall and base plate 7, and bottom 7 is provided with impedance hole 10, and inlet pipeline 2 and outlet conduit 5 are communicated with pressure balance chamber 1 by impedance hole 10.In inlet pipeline 2, be provided with electromagnetic flowmeter 3, be used for measuring the interior flow of inlet pipeline 2 and over time, 3 measurement of discharges of electromagnetic flowmeter are designated as Q ₁(t) (unit: m ³/ s), t represents the moment.Inlet pipeline 2 inwalls are provided with pressure transducer 4, are used for measuring the pressure of measuring point and over time, and 4 measuring pressures of pressure transducer are designated as P ₁(t) (unit: Pa) t represents the moment.Pressure balance chamber base plate is provided with pressure transducer 6 near 7 inner sides, is used for measuring near pressure pressure balance chamber base plate 7 inner sides and over time, and pressure transducer 6 measuring point elevations are Z ₂(unit: m), 6 measuring pressures of pressure transducer are designated as P ₂(t) (unit: Pa), t represents the moment.Pressure balance chamber top 9 is provided with ultrasonic range finder 8, is used for measuring the surge chamber fluctuation water surface to the distance at pressure balance chamber top 9 and over time, ultrasonic range finder 8 range findings are from being designated as L (t) (unit: m), t represents the moment.

Take pressure balance chamber pipe centerline 11 as benchmark elevation, be designated as pipeline center line, benchmark elevation is Z ₁(unit: m), pressure balance chamber top 9 is M to the distance of benchmark elevation, in any time pressure balance chamber, the fluctuation water surface is N (t)=M-L (t) to the distance of benchmark elevation.Note pressure balance chamber cross-sectional area is A ₂(unit: m ²), the flow that flows to pressure balance chamber is Q ₂(t) (unit: m ³/ s), the relation according between water level and flow:

${\∫}_{t1}^{t2}{Q}_2\left(t\right)\mathrm{dt}=A_2(N\left(t2\right)-N\left(t1\right))---\left(1\right)$

Have: $Q_2\left(t\right)=\frac{N^{\′}\left(t\right)}{A_2}=\frac{-L^{\′}\left(t\right)}{A_2}---\left(2\right)$

Because L (t) is given value, therefore can this calculate the interior flow Q of pressure balance chamber according to formula (2) ₂(t).

According to overall energy balance principle before and after impedance:

$Z_1+\frac{P_1\left(t\right)}{r}+\frac{{Q^2}_1\left(t\right)}{2g{A}_1^2}=Z_2+\frac{P_2\left(t\right)}{r}+\frac{{Q^2}_2\left(t\right)}{2g{A}_2^2}+\mathrm{\ϵ}\left(t\right)\frac{{Q^2}_2\left(t\right)}{2g{A}_2^2}---\left(3\right)$

In formula (3):

Z ₁for benchmark elevation, unit: m;

Z ₂for the elevation of pressure transducer 6 mounting points, unit: m;

R is water level unit weight, determines according to pressure balance chamber volume, and in this concrete enforcement, r is 9810N/m ³;

ε (t) is Hydraulic Resistance Coefficient of Surge Tanks;

A ₁for inlet pipeline 2 cross sectional areas, unit: m ²;

A ₂for pressure balance chamber cross-sectional area, unit: m ²;

G is acceleration of gravity.

Can obtain Hydraulic Resistance Coefficient of Surge Tanks ε (t) and over time according to formula (3), that is:

$\mathrm{\ϵ}\left(t\right)=\frac{Z_1-Z_2+\frac{P_1\left(t\right)}{r}-\frac{P_2\left(t\right)}{r}+\frac{{Q^2}_1\left(t\right)}{2g{A}_1^2}-\frac{{Q^2}_2\left(t\right)}{2g{A}_2^2}}{\frac{{Q^2}_2\left(t\right)}{{2\mathrm{gA}}_2^2}}---\left(4\right).$

Claims (5)

1. for the Hydraulic Resistance Coefficient of Surge Tanks measuring system of model test, it is characterized in that:

In pressure balance chamber inlet pipeline, be provided with flowmeter and the first pressure transducer, flowmeter is used for measuring the flow in pressure balance chamber inlet pipeline, and the first pressure transducer is used for measuring the hydraulic pressure at measuring point place in pressure balance chamber inlet pipeline; In pressure balance chamber, be provided with the second pressure transducer, be used for measuring the hydraulic pressure at measuring point place in pressure balance chamber, pressure balance chamber top is also provided with level measurement device, is used for measuring the fluctuation water surface in pressure balance chamber to the distance at pressure balance chamber top over time, thereby indirectly obtains the flow that flows to outflow pressure balance chamber.

2. the Hydraulic Resistance Coefficient of Surge Tanks measuring system for model test as claimed in claim 1, is characterized in that:

Described flow is counted electromagnetic flowmeter.

3. the Hydraulic Resistance Coefficient of Surge Tanks measuring system for model test as claimed in claim 1, is characterized in that:

Described level measurement device is ultrasonic distance measuring apparatus.

4. the Hydraulic Resistance Coefficient of Surge Tanks measuring system for model test as claimed in claim 1, is characterized in that:

The first described pressure transducer is arranged at pressure balance chamber inlet pipeline inwall, and guarantees that it is in water.

5. the Hydraulic Resistance Coefficient of Surge Tanks measuring system for model test as claimed in claim 1, is characterized in that:

The second described pressure transducer is arranged on pressure balance chamber madial wall, and guarantees that it is in water.

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