An open-loop control method suitable for a water pump and valve joint control water filling system

Abstract

The application discloses an open-loop control method suitable for a water pump and valve joint control water filling system. The method comprises the following steps: setting initial parameters of the water pump and valve joint control water filling system; acquiring basic parameters of the water pump and valve joint control water filling system; setting initial boundary conditions of the water pump and valve joint control water filling system; and calculating a flow regulating valve opening degree action curve, a water level process change curve of a water filling object, a flow change curve of the water pump and valve joint control water filling system and a motion trajectory of a water pump working point in a water filling process of the water pump and valve joint control water filling system according to the initial parameters, the basic parameters and the initial boundary conditions of the water pump and valve joint control water filling system, so as to realize open-loop control of the water pump and valve joint control water filling system. The application realizes better matching of the water pump and the valve in the water pump and valve joint control water filling system, and realizes safe, stable, efficient and rapid water filling for the water filling object.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of water conservancy and hydropower engineering, and particularly relates to an open-loop control method suitable for a water pump and valve joint control water filling system. BACKGROUND

[0002] In the process of filling water in a reservoir or a large water tank, filling water in a long-distance water pipe network, and filling water in a water-lifting main pipe before the initial start of a large pump station water pump, a water pump needs to be used for filling water. Since the water filling process changes with the water level of the water filling object, the flow and lift of the water pump will change: (1) in the initial stage of water filling, the water level of the water filling object is low, the water filling flow of the water pump is large, and the lift is low. On the one hand, the cavitation performance of the water pump deteriorates, vibration and noise are generated, which threatens the safe operation of the water filling system. On the other hand, the water filling flow is too large, which has an adverse effect on the water filling object: threatens the safety of the reservoir slope, causes the long-distance water pipe network and poor exhaust, and induces pipe explosion, and affects the flow state disorder in the water-lifting main pipe of the large pump station to generate vortexes; (2) in the later stage of water filling, the water level of the water filling object is high, the water filling flow of the water pump is small, and the lift is high. On the one hand, the water pump may enter the hump area and be difficult to operate stably. On the other hand, the water filling flow of the water filling object is too small, which leads to a long water filling time and is not conducive to operation and dispatching management.

[0003] In order to safely, stably, efficiently and quickly fill water, the engineering field prefers to use a water pump and valve joint control water filling system, that is, a flow regulating valve is installed at the outlet of the water pump. Although the joint control of the valve and the water pump can improve the above problems in the process of water filling, since the water filling system is a temporary measure, its use frequency is extremely low, and it does not attract much attention. For a long time, there is a lack of an effective, scientific, efficient and guiding system control method. In the actual operation process, the water pump and the valve are difficult to match well, and a large amount of debugging and testing work is often required. Not only are the stability, safety, rapidity and other problems of the water filling system not completely solved, but the work difficulty of the on-site operation and maintenance unit is also greatly increased, a large amount of human resource cost is wasted, and the function of the water pump and valve joint control water filling system is greatly limited. SUMMARY

[0004] The purpose of the present application is to solve the problems in the background art and provide an open-loop control method suitable for a water pump and valve joint control water filling system.

[0005] The technical scheme adopted by the present application is as follows: an open-loop control method suitable for a water pump and valve joint control water filling system, the water pump and valve joint control water filling system comprising a water inlet pool, a water pump and a water filling object connected in sequence, and a flow regulating valve arranged on a pipeline system between the water pump and the water filling object.

[0006] The open-loop control method suitable for the water pump and valve joint control water filling system comprises the following steps:

[0007] S1: setting initial parameters of the water pump-valve joint control water filling system;

[0008] S2: acquiring basic parameters of the water pump-valve joint control water filling system, the basic parameters including a water pump characteristic curve, a flow regulating valve flow resistance opening degree curve, a pipe network characteristic curve, and water level variation rules of a water filling object and flow control requirements of the water filling object, water level control requirements of the water filling object;

[0009] S3: setting initial boundary conditions of the water pump-valve joint control water filling system;

[0010] S4: according to the initial parameters, the basic parameters, and the initial boundary conditions of the water pump-valve joint control water filling system, calculating a flow regulating valve opening degree action curve, a water filling object water level process variation curve, a water pump-valve joint control water filling system flow variation curve, and a water pump working point motion trajectory in a water filling process of the water pump-valve joint control water filling system for open loop control of the water pump-valve joint control water filling system.

[0011] In the above step S1, the initial parameters include:

[0012] Q—pump and pipe network flow;

[0013] H—pump lift;

[0014] ξ—flow resistance coefficient of the flow regulating valve;

[0015] α—opening degree of the flow regulating valve;

[0016] z—water level of the water filling object;

[0017] Z0—initial value of the front pool water level;

[0018] S—horizontal cross-sectional area of the water filling object;

[0019] h—hydraulic loss of the water conveying pipe network;

[0020] λ—hydraulic loss coefficient of the water conveying pipe network;

[0021] Q * —control flow of the water filling object and the water filling system;

[0022] V * —water filling control flow velocity of the water filling object;

[0023] Z * —water filling water level target value of the water filling object;

[0024] i—time period number, i=0, 1, 2, 3, 4, …;

[0025] △τ—calculation time step;

[0026] t—time;

[0027] T y — the time of full opening or full closing of the flow regulating valve;

[0028] Q i — the flow of the water pump and the pipe network at the i-th moment;

[0029] H i — the head of the water pump at the i-th moment;

[0030] ξ i — the flow resistance coefficient of the flow regulating valve at the i-th moment;

[0031] α i — the opening of the flow regulating valve at the i-th moment;

[0032] z i — the water level of the water-filled object at the i-th moment;

[0033] S i — the horizontal cross-sectional area of the water-filled object at the i-th moment;

[0034] h i — the hydraulic loss of the water delivery pipe network at the i-th moment;

[0035] t i — the time at the i-th moment.

[0036] In the above step S2,

[0037] the calculation formula of the water pump characteristic curve is H = f(Q);

[0038] the calculation formula of the flow resistance opening curve of the flow regulating valve is ξ = ξ(α);

[0039] the calculation formula of the pipe network characteristic curve is h = λ·Q 2 + (z-Z0);

[0040] the calculation formula of the water level change law of the water-filled object is S = S(z);

[0041] the calculation formula of the flow control requirement of the water-filled object is Q ≤ Q * , and Q * = S × V * ;

[0042] the calculation formula of the water level control requirement of the water-filled object is z ≤ Z * .

[0043] In the above step S3, the initial boundary conditions include:

[0044] assuming that T y is much smaller than △τ, the influence of the flow regulating valve action process on the water-filled system in each time period is not considered;

[0045] At the initial moment (i=0), t=0s, z0=Z0, S0=S(z0).

[0046] The process of calculating the flow regulating valve opening action curve of the water pump valve joint control water filling system, the water filling object water level process change curve, the water pump valve joint control water filling system flow change curve and the water pump working point motion trajectory in the water filling process in step S4 includes:

[0047] At any i period, the following equations are solved simultaneously:

[0048] Q * i =S i ×V * ,

[0049] ξ i =ξ(α i ),

[0050] h i =λ·Q i 2 +(z i -Z0),

[0051] f(Q i )=h i +ξ i Q i 2 ,

[0052] Q i =Q * i ,

[0053] t i =i△τ,

[0054] Solving obtains ξ i , α i , Q i , H i , z i , S i , h i , t i ;

[0055] Equation loop iteration and its criterion condition:

[0056] At the end of any i period, the water level of the water filling object is z i+1 =z i +Q i △τ / S i ;

[0057] If z i+1 <Z * , then enter the calculation of the next period (i+1), ti+1 = t i + Δτ

[0058] If z i+1 ≥ Z * , the calculation is ended, and the calculation result is output.

[0059] In the above step S4, the calculation result includes:

[0060] Flow regulating valve opening operation curve: alpha = alpha (t) ;

[0061] Water filling object water level process change curve: z = z (t) ;

[0062] Water pump valve joint control water filling system flow change curve: Q = Q (t) ;

[0063] Water pump working point motion trajectory: f (Q, H, i).

[0064] In the above step S4, the flow regulating valve does not need to feed back pressure, flow, and valve front and back pressure difference signals until the water filling object is filled with water.

[0065] The present application is suitable for water reservoir or large water tank water filling, long distance water pipe network water filling, large pump station water pump initial start before water lifting main water filling, etc.

[0066] The beneficial effects of the present application are as follows:

[0067] (1) The present application makes the water pump and valve of the water pump valve joint control water filling system better match, and safely, stably, efficiently and quickly fills the water filling object with water.

[0068] (2) The present application can be used to guide the water filling of the water filling object on the construction site, has strong operability, greatly reduces the difficulty of on-site debugging and testing, improves the work efficiency of the operation and maintenance unit, and saves human resource cost.

[0069] (3) The present application can simulate the changes of various control parameters such as water pump working point motion trajectory, valve opening, pipe network water filling flow, and water filling object water level during water filling, can comprehensively analyze and judge the effect of the water filling system, and provide reference for the selection and optimization design of the water pump, valve, and pipe system of the water pump valve joint control water filling system. BRIEF DESCRIPTION OF DRAWINGS

[0070] Figure 1 is a schematic diagram of the water pump valve joint control water filling system to which the present application is applied;

[0071] Figure 2 is a logic diagram of an open loop control method of the water pump valve joint control water filling system according to the present application.

[0072] In the figure, 1 - water pool, 2 - water pump, 3 - water filling object, 4 - pipeline system, 5 - flow regulating valve. DETAILED DESCRIPTION

[0073] The application will be further described in conjunction with the accompanying drawings and specific embodiments, so as to clearly understand the application, but they do not constitute limitations to the application.

[0074] Referring to Figure 1 The open-loop control method of the water pump and valve joint control water filling system comprises a water pool 1, a water pump 2 and a water filling object 3 connected in sequence, and a flow regulating valve 5 arranged on the pipeline system 4 between the water pump 2 and the water filling object 3.

[0075] Referring to Figure 2 The logic diagram of the open-loop control method of the water pump and valve joint control water filling system, the specific implementation steps of the application are as follows:

[0076] (1) Initial parameter definition

[0077] Q - water pump and pipeline flow;

[0078] H - water pump lift;

[0079] ξ - flow resistance coefficient of the flow regulating valve;

[0080] α - opening of the flow regulating valve;

[0081] z - water level of the water filling object;

[0082] Z0 - initial value of the water level of the front pool;

[0083] S - horizontal cross-sectional area of the water filling object;

[0084] h - water power loss of the water conveying pipeline;

[0085] λ - water power loss coefficient of the water conveying pipeline;

[0086] Q * - control flow of the water filling object and the water filling system;

[0087] V * - water filling control flow rate of the water filling object;

[0088] Z * - water level target value of the water filling object;

[0089] i - time period number, i = 0, 1, 2, 3, 4, …;

[0090] △τ - calculation time step;

[0091] t - time;

[0092] T y — the time of full opening or full closing of the flow regulating valve;

[0093] Q i — the flow of the water pump and the pipe network at the i-th moment;

[0094] H i — the head of the water pump at the i-th moment;

[0095] ξ i — the flow resistance coefficient of the flow regulating valve at the i-th moment;

[0096] α i — the opening of the flow regulating valve at the i-th moment;

[0097] z i — the water level of the water filling object at the i-th moment;

[0098] S i — the horizontal cross-sectional area of the water filling object at the i-th moment;

[0099] h i — the hydraulic loss of the water conveying pipe network at the i-th moment;

[0100] t i — the time at the i-th moment.

[0101] (2) Collect and arrange the basic parameters of the water pump and valve joint control water filling system, as follows:

[0102] ① the pump characteristic curve H = f(Q);

[0103] ② the flow resistance and opening curve of the flow regulating valve ξ = ξ(α);

[0104] ③ the pipe network characteristic curve h = λ·Q 2 + (z-Z0);

[0105] ④ the water level change law of the water filling object S = S(z);

[0106] ⑤ the flow control requirement of the water filling object Q ≤ Q * , and Q * = S × V * ;

[0107] ⑥ the water level control requirement of the water filling object z ≤ Z * .

[0108] (3) Initial boundary conditions

[0109] Assume that T y is much smaller than △τ, and the influence of the flow regulating valve action process on the water filling system within each period is not considered;

[0110] At the initial time (i=0), t=0s, z0=Z0, S0=S(z0).

[0111] (4) Simultaneous solution of basic equations

[0112] At any time period i, the following equations are established:

[0113] Q * i =S i ×V * ,

[0114] ξ i =ξ(α i ),

[0115] h i =λ·Q i 2 +(z i -Z0),

[0116] f(Q i )=h i +ξ i Q i 2 ,

[0117] Q i =Q * i ,

[0118] t i =i△τ,

[0119] Solve for ξ i , α i , Q i , H i , z i , S i , h i , t i .

[0120] (5) Equation iteration and its criteria

[0121] At the end of any i-th period, the water level of the water-filled object is z i+1 =z i +Q i △τ / S i ;

[0122] If z i+1 <Z * , then enter the calculation of the next period (i+1), t i+1 =t i +△τ;

[0123] If z i+1≥Z * Then the calculation is finished and the calculation result is outputted.

[0124] (6) Result output

[0125] The following results can be obtained through the above calculation:

[0126] ① The flow regulating valve opening action curve: α = α(t);

[0127] ② The water level process change curve of the water filling object: z = z(t);

[0128] ③ The water pump valve joint control water filling system flow change curve: Q = Q(t);

[0129] ④ The water pump working point motion locus: f(Q, H, i).

[0130] (7) Water filling process simulation and analysis

[0131] According to the parameters obtained through the above calculation, the water filling process of the water pump valve joint control system can be simulated, and the technical and economic indexes of the parameter change can be analyzed:

[0132] ① According to the flow regulating valve opening action curve, whether the flow regulating valve opening is in a reasonable range and whether the valve action process will produce adverse effects such as cavitation can be analyzed, and reasonable suggestions for the flow regulating valve selection and design of the water pump valve joint control system can be provided.

[0133] ② According to the water level process change curve of the water filling object, whether the water level change is reasonable can be analyzed, and guiding basis for the operation and management of the water filling object can be provided.

[0134] ③ According to the water pump valve joint control water filling system flow change curve, whether the pipe network flow change range is reasonable can be analyzed, and reasonable suggestions for the pipe network design of the water pump valve joint control system can be provided.

[0135] ④ According to the water pump working point motion locus, whether the water pump can safely operate in the water filling process and whether the water pump efficiency is efficient can be analyzed, and reasonable suggestions for the water pump selection and design of the water pump valve joint control system can be provided.

[0136] (8) Open loop control method of water pump valve joint control system

[0137] Through the calculation and analysis of the above steps (1) to (7), the open loop control method of the water pump valve joint control system is proposed, including the flow regulating valve opening control value of each period, the pipe network flow control value of each period, the water level of the water filling object of each period, and the relevant suggestions for the water pump valve joint control water filling system.

[0138] The contents not described in detail in the specification belong to the prior art known to those skilled in the art.

Claims

1. An open loop control method suitable for a water pump and valve co-control water filling system, characterized in that: The water pump valve joint control water filling system comprises a water inlet pool, a water pump and a water filling object connected in sequence and a flow regulating valve arranged on a pipeline system between the water pump and the water filling object; The open loop control method suitable for the water pump valve joint control water filling system comprises the following steps: S1: setting initial parameters of the water pump valve joint control water filling system; S2: acquiring basic parameters of the water pump valve joint control water filling system, wherein the basic parameters comprise a water pump characteristic curve, a flow regulating valve flow resistance opening degree curve, a pipeline network characteristic curve, a water level change rule of the water filling object, a flow control requirement of the water filling object and a water level control requirement of the water filling object; S3: setting initial boundary conditions of the water pump valve joint control water filling system; S4: calculating a flow regulating valve opening degree action curve, a water filling object water level process change curve, a water pump valve joint control water filling system flow change curve and a water pump working point motion trajectory of the water pump valve joint control water filling system in a water filling process according to the initial parameters, the basic parameters and the initial boundary conditions of the water pump valve joint control water filling system, so as to control the water pump valve joint control water filling system in an open loop mode; In the step S1, the initial parameters comprise: Q--water pump and pipeline network flow; H--water pump lift; ξ--flow resistance coefficient of the flow regulating valve; α--opening degree of the flow regulating valve; z--water level of the water filling object; Z0--initial value of the water level of the front pool; S--horizontal cross-sectional area of the water filling object; h--water loss of the water conveying pipeline network; λ--water loss coefficient of the water conveying pipeline network; Q * - control flow of the water-filled object, water-filled system V * — the water filling object water filling control flow rate; Z * — the target value of the water level of the water-filled object; i--time period sequence number, i=0, 1, 2, 3, 4……; △τ--calculation time step; t--time; T y - time of full opening or full closing of the flow regulating valve Q i - water pump and pipe network flow at time i; H i - the water pump head at the i-th instant; ξ i - flow resistance coefficient of the flow regulating valve at the i-th instant; a i - the opening of the flow regulating valve at the i-th instant; z i - water level of the water-filled object at the i-th moment; S i —Horizontal cross-sectional area of ​​the water-filled object at the i-th moment; h i - hydraulic losses of the water distribution network at the i-th time instant; t i — time at the i-th moment; In the step S4, the process of calculating the flow regulating valve opening degree action curve, the water filling object water level process change curve, the water pump valve joint control water filling system flow change curve and the water pump working point motion trajectory of the water pump valve joint control water filling system in the water filling process comprises: At any i time period, the following equations are solved simultaneously: Q * i = S i x V * , ξ i = ξ(α i ), h i = λ · Q i 2 + (z i - Z0), f(Q i ) = h i + ξ i Q i 2 , H i = f(Q i ), Q i = Q * i , t i = iΔτ, Solving for ξ i , α i , Q i , H i , z i , S i , h i , t i ; Equation loop iteration and its criterion condition: At the end of any i-th period, the water level of the water-filled object is z i+1 =z i +Q i △τ / S i ; If z i+1 < Z * then the calculation for the next period (i+1) is entered, t i+1 = t i + Δτ; If z i+1 ≥ z * , then the calculation is finished and the result is output.

2. The open loop control method for water pump and valve co-control water charging system according to claim 1, characterized in that: In the step S2, The calculation formula of the water pump characteristic curve is H=f(Q); The calculation formula of the flow regulating valve flow resistance opening degree curve is ξ=ξ(α); The calculation formula of the pipe network characteristic curve: h = λ · Q 2 + (z - Z0); The calculation formula of the water level change rule of the water filling object is S=S(z); The calculation formula of the flow control requirement of the water-filled object: Q≤Q * , and Q * = S x V * ; The calculation formula of water level control requirement of the water-filled object: z≤Z * .

3. The open loop control method for water pump and valve co-control water charging system according to claim 1, characterized in that: In the step S3, the initial boundary conditions comprise: Assume T y Much less than △τ, without considering the influence of the flow regulating valve action process on the water filling system in each period; At an initial time (i=0), t=0s, z0=Z0 and S0=S(z0).

4. The open loop control method for water pump and valve co-control water charging system according to claim 1, characterized in that: In the step S4, the calculation results comprise: The flow regulating valve opening degree action curve is α=α(t); The water filling object water level process change curve is z=z(t); The water pump valve joint control water filling system flow change curve is Q=Q(t); The water pump working point motion trajectory is f(Q, H, i).

5. The open loop control method for water pump and valve co-control water charging system according to claim 1, characterized in that: In the step S4, the flow regulating valve does not need to feed back pressure, flow, valve front and back pressure difference signals until the water filling object is filled with water.

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