CN103104543A - Multi-operating-point design method of nuclear main pump omni-characteristic impeller - Google Patents

Abstract

The invention relates to a multi-operating-point design method of a nuclear main pump omni-characteristic impeller. The method is characterized in that when the nuclear main pump impeller is designed, geometric parameters of the nuclear main pump impeller and omni-characteristics of a pump are associated together; and a method of combining pump operating conditions and turbine operating conditions as well as multiple operating condition design method is adopted for the hydraulic design of the nuclear main pump, thus achieving the requirement that the nuclear main pump can operate safely and stably under accident operating conditions. The impeller designed by adopting the method has the beneficial effect that the geometric parameters of the impeller can be adjusted, thus achieving the aim that the performance of the nuclear main pump meets the requirement of various normal operating conditions and transient operation condition, and the method is particularly applicable to designs of main pump impellers having stick requirement on multiple operating points.

Description

The multi-operating mode point design method of core main pump total external characteristic impeller

Technical field

The present invention relates to a kind of multi-operating mode point design method of core main pump total external characteristic impeller, can use when the various nominal situations of core main pump and transient working condition design impeller, also can use when the low specific speed operating mode of core main pump and higher specific speed design impeller, when being particularly useful for loss of-coolant accident (LOCA), the strict situation of core main pump performance parameter is used.

Background technique

The nuclear reactor coolant main circulating pump is called for short the core main pump, is the most critical power equipment of guaranteeing nuclear plant safety and reliable operation, belongs to core I level pump, is unique rotating equipment in nuclear island, is also one of the pressure boundary in a loop.Core main pump long-term stability is moved safely cooling reactor core and is prevented that the generation of nuclear power plant accident is particularly important, so the core main pump often is called the heart of nuclear power station.Nuclear reactor moves in the full power situation, and core main pump inducer ooling channel breaks suddenly and causes the generation of loss of-coolant accident (LOCA) (LOCA) and cause that Main Coolant runs off, and makes the whole decline of whole reactor coolant loop pressure.Loss of-coolant accident (LOCA) refers to a circuit pressure border generation cut or breaks, the accident that a part of or most of freezing mixture is revealed.In the heat pipe section, and break size is when continue increasing when cut, and the core main pump will occur to follow simultaneously flow progressively to reduce by the transition transient process of pump operating mode to damped condition at short notice.At cold leg, and break size is when continue increasing when cut, and the transition transient process that flow is uprushed will occur the core main pump at short notice.

At present, except minority core main pump adopted receded disk impeller or aial flow impeller, most of core main pumps all adopted mixed-flow impeller, because this impeller can in large flow, reach higher lift.The core main pump has the performance curve that suddenly falls, and this specific character has an advantage: during lower than calculated value, the changes in flow rate of main pump is less when the main coolant system resistance of reality.Mixed flow pump structure and performance between axial-flow pump and centrifugal pump, are a kind of absorption centrifugal pump and axial-flow pump advantage, the ideal model of compensation two aspect shortcomings.The normal velocity coefficient method that adopts of known mixed-flow pump impeller design, but when accident conditions, the runnability of core main pump is very complicated, causes core main pump actual operating mode skew, so single can not satisfy nuclear plant safety stable operation requirement with pump operating condition parameter designing core main pump impeller.

In order to make the core main pump guarantee nuclear power station safe and stable operation under accident conditions at various nominal situations and transient running, the multi-operating mode point design method that proposes a kind of core main pump total external characteristic impeller is very necessary.

Summary of the invention

In order to make the core main pump at various nominal situations and transient running, the invention provides a kind of multi-operating mode point design method of core main pump total external characteristic impeller.Not only satisfy the service condition of pump operating condition with the impeller geometric parameter of the present invention's design, satisfy simultaneously the turbinging requirement, also can use the total external characteristic requirement of core main pump when being particularly useful for loss of-coolant accident (LOCA) when the low specific speed operating mode of core main pump and higher specific speed design impeller.

Technological scheme of the present invention is:

Pump operating condition plays a decisive role to the selection of core main pump, and the design process of all core main pump impeller and conventional water pump are very close, but accident at present the core main pump will be in complicated transient working condition, need to consider that the water turbine operating mode is on the impact of core main pump safe operation.when design core main pump impeller, according to the flow QBEP of pump to the optimum efficiency operating point, the lift HBEP of optimum efficiency operating point, wheel speed n, the specific speed nsBEP of optimum efficiency operating point, i operating point flow Qi, the requirement of i operating point lift Hi comes the geometric parameter of designing and calculating impeller blade, it is characterized in that: adopt velocity coefficient method design core main pump impeller will obtain the representation of Q-H performance curve, obtain simultaneously the geometric parameter of core main pump impeller, utilize this representation can calculate the poor Δ Hi of lift between each operating point and Q-H performance curve, on this basis, rebulid the relation between Δ Hi and geometric parameter, obtain the relation between each operating point performance and core main pump impeller geometric parameter, and the requirement of turbinging to core main pump impeller performance when considering accident, the geometric parameter of core main pump impeller is linked together from the performance parameter of different operating points, make the actual motion performance curve of core main pump consistent with the requirement performance curve.

Basic design parameters:

Optimum efficiency operating point flow Q _BEP(m ³/ s)

Optimum efficiency operating point lift H _BEP(m)

Rated speed n (r/min)

1. specific speed n _s

$n_s=\frac{3.65n\sqrt{Q}}{H^{0.75}}---\left(1\right)$

2. impeller inlet diameter D ₀

$D_0=K_0\sqrt[3]{\frac{Q}{n}}---\left(2\right)$

K ₀-pump inlet Size factor, guaranteed efficiency is got K ₀=4～4.25, get K when considering efficiency and cavitation ₀=4.25～4.5, get K when guaranteeing cavitation performance ₀=4.5～5.5.

3. impeller outlet average diameter D ₂

If the impeller outlet diameter is the arithmetic mean value of impeller front and rear cover plate diameter, as shown in Figure 1.

${\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HSA00000861201600011.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=5.9709n^{-0.6586}{Q}_{\mathrm{BEP}}^{0.6707}{H}_{\mathrm{BEP}}^{1.5914}{b}_2^{-1}{\left(\tan {\mathrm{\&beta;}}_2\right)}^{-0.252}{(1+\frac{H}{H_{\mathrm{BEP}}})}^{0.45}---\left(3\right)$

${\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HSA00000861201600011.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=\frac{D_{20}+D_{2h}}{2}---\left(4\right)$

ΔH＝max{ΔH ₁，ΔH ₂….，ΔH _i-1，ΔH _i，ΔH _i+1，…，ΔH _n-1，ΔH _n}

(5)

H _i＝H-H _i′ (6)

$H_i^{\&prime;}=H_{\mathrm{BEP}}[0.177n_{\mathrm{sBEP}}^{0.4638}-(0.0076n_{\mathrm{sBEP}}+1.0425)\left(\frac{Q_i}{Q_{\mathrm{BEP}}}\right)-\left(1.5n_{\mathrm{sBEP}}^{-0.161}\right){\left(\frac{Q_i}{Q_{\mathrm{BEP}}}\right)}^2---\left(7\right)$

N in formula _SBEPOne optimum efficiency point specific speed;

D _2BEPOne presses the optimum efficiency operating point impeller blade outside diameter of velocity coefficient method design, rice;

Q _iThe flow of one i operating point, rice ³/ second;

H _iThe lift of the i operating point of ' one traditional design method, rice;

Δ H _iThe difference that requires lift and traditional design lift of one i operating point, rice.

4. relative diameter D _s

D _s＝D ₀/D ₂ (8)

Due to core main pump impeller boundary dimension and its leaf characteristic all closer to conventional water pump, therefore relative diameter D _sSpan is 0.72～0.95.

5. exit width b ₂

${\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HSA00000861201600011.png"\; state="\{\{state\}\}">b</figure-callout>}}_2=0.0809n^{0.3212}{Q}_{\mathrm{BEP}}^{0.6606}{H}_{\mathrm{BEP}}^{-0.4909}{\left(\frac{D_2}{{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HSA00000861201600011.png"\; state="\{\{state\}\}">D</figure-callout>}}_{2\mathrm{BEP}}}\right)}^{-0.496}---\left(9\right)$

6. relative width B _s

B _s＝b ₂/D ₂ (10)

In conventional Centrifugal Pump Design, the blade exit width is trended towards selecting than fractional value, purpose is to avoid when small flow that in runner, too early appearance current break away from.But water turbine for reducing inlet velocity, is reduced to clash into loss, require entrance width to obtain larger.The width of blade that the present invention adopts is between water pump and water turbine requirement, so relative width B _sSpan be 0.25～0.34.

7. blade import laying angle β ₁

β ₁＝β ₁′+Δβ (11)

In formula, Δ β is the angle of attack, and according to the Centrifugal Pump Design experience, it is favourable to Cavitation Characteristics that blade water inlet limit has a certain amount of high incidence, because the specific speed of core main pump is high, generally gets 8 °～12 °, and the angle of attack also should not be obtained excessive, otherwise is unfavorable for the pump operating condition operation.

8. blade exit laying angle β ₂

Blade exit laying angle β ₂=15 °～25 °, specific speed gets the small value greatly, for guaranteeing the flow stability of water turbine operating mode when low water head or the little load, selects little β as far as possible ₂

9. subtended angle of blade

Can form long runner and make water flow stationary with large cornerite, but following and have a larger frictional loss.Subtended angle of blade and the number of blade can require to select to determine according to casting technique.

Description of drawings

The present invention is further described below in conjunction with drawings and Examples.

Fig. 1 is an embodiment's of patent of the present invention impeller axial plane sectional view.

Fig. 2 is same embodiment's impeller blade figure (throwing off the paddle wheel plane sectional view of seeing from front shroud of impeller towards back shroud of impeller after front shroud of impeller).

In figure: 1. front shroud of impeller, 2. back shroud of impeller, 3. impeller blade entrance width, 4. impeller blade exit width b ₂, 5. impeller outlet average diameter D ₂, 6. front shroud of impeller diameter D ₂₀, 7. back shroud of impeller diameter D _2h, 8. impeller inlet diameter D ₀, 9. blade import laying angle β ₁, 10. blade exit laying angle β ₂, 11. subtended angle of blades

12. blade, 13. front side of vanes, 14. vacuum side of blades.

Embodiment

Fig. 1 and Fig. 2 have determined this embodiment's impeller shape jointly.It is the same with most of centrifugal pump impellers, has front shroud of impeller (1) and back shroud of impeller (2), is a kind of double shrouded wheel.In the drawings, the convex surface of blade (12) is front side of vane (13), and the concave surface of blade is front side of vane (14).The present invention adjusts the impeller geometric parameter by following relation, impeller blade exit width b ₂(4), the outside diameter D of impeller blade ₂(5), impeller inlet diameter D ₀(8), blade import laying angle β ₁(9), blade exit laying angle β ₂(10), subtended angle of blade

Make this embodiment's core main pump performance satisfy the flow Q of optimum efficiency operating point _BEP, the optimum efficiency operating point Yang Chengshi H _BEP, wheel speed n requirement.Carry out the design of core main pump hydraulic by the turbinging condition simultaneously, can guarantee core main pump safe and stable operation under accident conditions.

$D_0=K_0\sqrt[3]{\frac{Q}{n}}$

$H_i^{\&prime;}=H_{\mathrm{BEP}}[0.177n_{\mathrm{sBEP}}^{0.4638}-(0.0076n_{\mathrm{sBEP}}+1.0425)\left(\frac{Q_i}{Q_{\mathrm{BEP}}}\right)-\left(1.5n_{\mathrm{sBEP}}^{-0.161}\right){\left(\frac{Q_i}{Q_{\mathrm{BEP}}}\right)}^2]$

H _i＝H-H _i′

□H＝max{□H ₁，□H ₂，…，□H _i-1，□H _i，□H _i+1，…，□H _n-1，□H _n}

${\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HSA00000861201600011.png"\; state="\{\{state\}\}">D</figure-callout>}}_2=5.9709n^{-0.6586}{Q}_{\mathrm{BEP}}^{0.6707}{H}_{\mathrm{BEP}}^{1.5914}{b}_2^{-1}{\left(\tan {\mathrm{\&beta;}}_2\right)}^{-0.252}{(1+\frac{H}{H_{\mathrm{BEP}}})}^{0.45}$

D _s＝D ₀/D ₂＝0.72～0.95

${\mathrm{<figure-callout\; id="2"\; label="b"\; filenames="HSA00000861201600011.png"\; state="\{\{state\}\}">b</figure-callout>}}_2=0.0809n^{0.3212}{Q}_{\mathrm{BEP}}^{0.6606}{H}_{\mathrm{BEP}}^{-0.4909}{\left(\frac{D_2}{{\mathrm{<figure-callout\; id="2"\; label="D"\; filenames="HSA00000861201600011.png"\; state="\{\{state\}\}">D</figure-callout>}}_{2\mathrm{BEP}}}\right)}^{-0.496}$

B _s＝b ₂/D ₂＝0.25～0.34

β ₁＝β ₁′+Δβ

K ₀-pump inlet Size factor, guaranteed efficiency is got K ₀=4～4.25, get K when considering efficiency and cavitation ₀=4.25～4.5, get K when guaranteeing cavitation performance ₀=4.5～5.5.

According to the Centrifugal Pump Design experience, it is favourable to Cavitation Characteristics that blade water inlet limit has a certain amount of high incidence, because the specific speed of core main pump is high, generally gets Δ β=8 °～12 °, and the angle of attack also should not be obtained excessive, otherwise is unfavorable for the pump operating condition operation.

Blade exit laying angle β ₂=15 °～25 °, specific speed gets the small value greatly, for guaranteeing the flow stability of water turbine operating mode when low water head or the little load, selects little β as far as possible ₂

Subtended angle of blade

Can form long runner and make water flow stationary with large cornerite, but following and have a larger frictional loss.Subtended angle of blade and the number of blade can require to select to determine according to casting technique.

Claims (6)

1. the multi-operating mode point design method of core main pump total external characteristic impeller is according to core main pump performance being satisfied the flow Q of optimum efficiency operating point _BEP, the optimum efficiency operating point Yang Chengshi H _BEP, wheel speed n requirement.Impeller blade exit width b ₂, impeller outer circular diameter D ₂, impeller inlet diameter D ₀, blade import laying angle β ₁, blade exit laying angle β ₂, subtended angle of blade

Carry out the design of core main pump hydraulic in conjunction with pump operating condition and turbinging condition and multi-operating mode design method, guarantee core main pump safe and stable operation under accident conditions.It is characterized in that: be fit to following relation between impeller geometric parameter and pump operating point for design performance parameter:

$D_0=K_0\sqrt[3]{\frac{Q}{n}}$

$H_i^{\&prime;}=H_{\mathrm{BEP}}[0.177n_{\mathrm{sBEP}}^{0.4638}-(0.0076n_{\mathrm{sBEP}}+1.0425)\left(\frac{Q_i}{Q_{\mathrm{BEP}}}\right)-\left(1.5n_{\mathrm{sBEP}}^{-0.161}\right){\left(\frac{Q_i}{Q_{\mathrm{BEP}}}\right)}^2]$

ΔH _i＝H-H _i′

ΔH＝max{ΔH ₁，ΔH ₂，…，ΔH _i-1，ΔH _i，ΔH _i+1，…，ΔH _n-1，ΔH _n}

$D_2=5.9709n^{-0.6586}{Q}_{\mathrm{BEP}}^{0.6707}{H}_{\mathrm{BEP}}^{1.5914}{b}_2^{-1}{\left(\tan {\mathrm{\&beta;}}_2\right)}^{-0.252}{(1+\frac{H}{H_{\mathrm{BEP}}})}^{0.45}$

D _s＝D ₀/D ₂＝0.72～0.95

$b_2=0.0809n^{0.3212}{Q}_{\mathrm{BEP}}^{0.6606}{H}_{\mathrm{BEP}}^{-0.4909}{\left(\frac{D_2}{D_{2\mathrm{BEP}}}\right)}^{-0.496}$

B _s＝b ₂/D ₂＝0.25～0.34

β ₁＝β ₁′+Δβ

2. core main pump impeller boundary dimension and its leaf characteristic be all closer to conventional water pump, relative diameter D _sSpan is 0.72～0.95.

3. for avoiding when small flow appearance current too early in runner to break away from, and for reducing inlet velocity, reduce to clash into loss, require entrance width to obtain larger.The width of blade that the present invention adopts between water pump and water turbine require, relative width B _sSpan be 0.25～0.34.

4. according to the Centrifugal Pump Design experience, it is favourable to Cavitation Characteristics that blade water inlet limit has a certain amount of high incidence, because the specific speed of core main pump is high, generally gets Δ β=8 °～12 °, and the angle of attack also should not be obtained excessive, otherwise is unfavorable for the pump operating condition operation.

5. blade exit laying angle β ₂=15 °～25 °, specific speed gets the small value greatly, for guaranteeing the flow stability of water turbine operating mode when low water head or the little load, selects little β as far as possible ₂

6. subtended angle of blade

Can form long runner and make water flow stationary with large cornerite, but following and have a larger frictional loss.Subtended angle of blade and the number of blade can require to select to determine according to casting technique.

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