A method for designing side-type water inlet / outlet for connecting flat turning tunnel

Abstract

The application discloses a side-type water inlet / outlet design method for connecting a plane turning tunnel, relates to the field of hydraulic power generation, and introduces a flow deviation coefficient β and an inlet flow distribution restriction coefficient C i on the basis of existing design manuals and specifications, and gives clear definitions and calculation methods of the parameters. The flow deviation coefficient β quantifies the influence degree of the flow deviation effect of a turning tunnel on the distribution of the water inlet / outlet, and the inlet flow distribution restriction coefficient C i limits the adjustment range of the distribution pier, and can greatly save workload and improve optimization efficiency. The application only needs to adjust the arrangement form of the distribution pier, and can realize the goal of uniform distribution of the water inlet / outlet under different operation conditions, has strong adaptability, breaks through the space limitation constraint that the arrangement position of the plane turning tunnel needs to be away from the water inlet / outlet by 30-40 times of the tunnel diameter, and saves the investment cost of the power station.

Description

Technical Field

[0001] This invention relates to the field of hydropower generation, and in particular to a design method for a side-type inlet / outlet for connecting a planar turning tunnel. Background Technology

[0002] Among various energy storage methods, pumped storage power stations have become an important form of large-scale renewable energy development due to their advantages such as peak shaving, frequency regulation, and black start. The inlet / outlet, as a fundamental structure in a pumped storage power station system, is a key component for achieving water flow control and hydropower utilization. Its hydraulic characteristics directly affect the safe and efficient operation of the power station. The arrangement often adopts a side-type inlet / outlet, typically divided into three or four flow channels by two diversion piers. The diversion ratio of each flow channel is one of the important indicators for evaluating the internal hydraulic characteristics of the inlet / outlet. According to design specifications, "the flow non-uniformity between adjacent side and central flow channels should not exceed 10%."

[0003] In pumped storage power station design, the inlet / outlet is connected to the generator unit via a pressurized water conveyance tunnel. Therefore, the flow pattern inside the pressurized water conveyance tunnel has a significant impact on the hydraulic characteristics of the inlet / outlet. To ensure good flow patterns inside the inlet / outlet, pressurized water conveyance tunnels are generally straight tunnels, avoiding bends or placing bends at a distance from the inlet / outlet (more than 30-40 times the tunnel diameter). However, due to geological conditions or overall cost constraints, the arrangement of pressurized tunnels in actual projects inevitably involves planar turning tunnels. When the planar turning section of the tunnel is close to the inlet / outlet, the flow deviation phenomenon at the bend will directly affect the flow distribution at the inlet / outlet, leading to uneven flow distribution in each channel. Currently, research on side-mounted inlets / outlets focuses on optimizing the shape of the inlet / outlet connected to straight tunnels, rarely considering the impact of planar turning tunnels on the hydraulic characteristics of the inlet / outlet, especially when the downstream straight section of the planar turning tunnel has a limited length (less than 10D). Summary of the Invention

[0004] To address the above technical problems, this invention provides a side-type inlet / outlet design method for connecting planar turning tunnels, which saves workload, improves optimization efficiency, has strong adaptability, and saves power plant investment costs.

[0005] To achieve the above objectives, the present invention provides the following solution:

[0006] This invention provides a design method for a side inlet / outlet of a connecting planar turning tunnel, comprising the following steps:

[0007] Step 1: Based on the actual engineering operating conditions, design the initial shape of the side inlet / outlet to obtain the basic design parameters of the initial shape of the side inlet / outlet: the number of diversion piers n, and the width w at the minimum flow section of each orifice. i The height h at the minimum flow cross section of each orifice i ;

[0008] Step 2: Calculate the flow control area coefficient A for each orifice of the initial body shape. i The calculation formula is:

[0009]

[0010] In the formula, w i h is the width at the minimum flow cross-section of each orifice. i is the height of the minimum flow cross section of each orifice, n is the number of diversion piers, and i is the orifice number;

[0011] Step 3: Calculate the flow distribution coefficient Q at each orifice under the initial outflow condition. ji Where j = 1, the calculation formula is as follows:

[0012]

[0013] Step 4: Calculate the flow distribution coefficient Q of each orifice under the initial flow condition. ji Where j = 2, the calculation formula is as follows:

[0014]

[0015] Step 5: Flow rate distribution coefficient Q at each orifice ji The target value determination index is: (Q) ji ) max -(Q ji ) min ≤10%, if Q 1i Q 2i If all parameters meet the target range, then the initial body shape meets the standard flow distribution requirements, and the design is complete; if Q 1i Or Q 2i If the target range is not met, then optimize the design.

[0016] Step 6: Calculate the velocity distribution coefficient V at each orifice under the initial outflow condition. i The calculation method is as follows:

[0017]

[0018] In the formula, A i Q is the flow channel control area coefficient for the i-th orifice under outflow conditions. 1iLet be the flow distribution coefficient of the i-th orifice under the outflow condition;

[0019] Step 7: Calculate the flow deflection coefficient β at the inlet / outlet under the initial flow conditions. The calculation method is as follows:

[0020] β=(V i ) max / (V i ) min (5);

[0021] Step 8: Calculate the adjustment value ΔA for the flow channel control area coefficient. i The calculation method is as follows:

[0022] If Q 1i >30%,

[0023] If Q 1i <20%,

[0024] Step 9: Calculate the inlet / outlet constraint coefficient C i The calculation formula is as follows:

[0025] If Q 1i >30%, C i ≤Q 2i -20% (8)

[0026] If Q 1i <20%, C i ≤30%-Q 2i (9);

[0027] Step 10: Based on the initial flow distribution coefficient Q at each orifice during outflow, 1i Flow channel control area coefficient adjustment value ΔA i and the inlet / outlet ratio constraint coefficient C i Adjust the area of ​​the minimum flow cross section of each flow channel;

[0028] Step 11: Repeat steps 2 through 10 until the judgment criteria are met.

[0029] Preferably, in step two, n takes the value of 2 or 3, and i takes the value of 1, 2, 3 or 1, 2, 3, 4.

[0030] Preferably, in step ten, the adjustment method for the area of ​​the minimum flow cross-section of each flow channel is as follows:

[0031] If Q 1i >30%, reduce the area of ​​the minimum flow cross-section of the i-hole, and make

[0032] If Q 1i<20%, and when no flow separation occurs on the two side walls of orifice i, increase the area of ​​the minimum flow cross-section of orifice i, and make

[0033] If Q 1i <20%, and when flow separation occurs on a certain side wall of the i-hole, the flow separation phenomenon on the wall should be weakened or eliminated first.

[0034] Preferably, in step ten, if Q 1i <20%, and flow separation occurs on the right wall of orifice i, shifting the flow divider on the right side of orifice i to the left; if Q 1i <20%, and flow separation occurs on the left wall of hole i, causing the diversion pier on the left side of hole i to shift to the right.

[0035] Preferably, in step ten, during the process of adjusting the area of ​​the minimum flow cross section of each flow channel, the area of ​​the minimum flow cross section of the side hole flow channel is adjusted first, and then the area of ​​the minimum flow cross section of the middle hole flow channel is adjusted.

[0036] The present invention achieves the following technical effects compared to the prior art:

[0037] The design method for side inlets / outlets of connecting planar turning tunnels of the present invention introduces a flow deviation coefficient β and an inlet / outlet flow separation constraint coefficient C based on existing design manuals and specifications. i These two new design parameters are presented, along with their clear definitions and calculation methods. The influence of the bend flow deviation effect on the inlet / outlet flow split is quantified using the flow deviation coefficient β, and the inlet flow split constraint coefficient C... i Limiting the adjustment range of the diversion piers can greatly save workload and improve optimization efficiency. This invention only requires adjusting the arrangement of the diversion piers to achieve the goal of uniform diversion of water at the inlet / outlet under different operating conditions. It is highly adaptable and breaks through the spatial constraint that the arrangement of planar turning tunnels must be 30 to 40 times the diameter of the inlet / outlet, thus saving power plant investment costs. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A flowchart illustrating the side inlet / outlet design method for connecting planar turning tunnels provided by the present invention;

[0040] Figure 2 This is a schematic diagram of the structure of a side-type inlet / outlet and a pressurized water conveyance tunnel.

[0041] Figure 3 A schematic diagram of a side-mounted inlet / outlet with three flow channels and four flow paths;

[0042] Figure 4 A cross-sectional schematic diagram of a side-type inlet / outlet with three flow channels and four flow paths;

[0043] Figure 5 This is a schematic diagram of the flow distribution at the starting section of the side pier in the original scheme;

[0044] Figure 6 This is a schematic diagram of the flow distribution at the starting section of the central pier in the original plan;

[0045] Figure 7 A schematic diagram of the flow distribution at the starting section of the side pier after adopting the side inlet / outlet design method for connecting planar turning tunnels of the present invention.

[0046] Figure 8 This is a schematic diagram of the flow distribution at the starting section of the central pier after adopting the improved design method of the side inlet / outlet of the connecting plane turning tunnel of the present invention.

[0047] Explanation of reference numerals in the attached drawings: 1. First hole; 2. Second hole; 3. Third hole; 4. Fourth hole; 5. Starting section of the side pier; 6. Starting section of the middle pier; 7. Diversion pier. Detailed Implementation

[0048] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0049] The purpose of this invention is to provide a design method for side inlets / outlets of connecting planar turning tunnels, which saves workload, improves optimization efficiency, has strong adaptability, and saves power plant investment costs.

[0050] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0051] In this embodiment, the side-type inlet / outlet of a pumped storage power station connects to a planar turning tunnel. Due to space constraints, the length of the straight tunnel section between the planar turning tunnel and the inlet / outlet is only 6 times the tunnel diameter. For example... Figure 5 and Figure 6As shown, analysis of the velocity distribution at the inlet / outlet of a water conveyance tunnel connected to a planar bend reveals that the flow deviation effect of the planar bend tunnel results in uneven flow distribution across the four inlet / outlet orifices: orifices 1 and 2 have low velocities and minimal flow distribution, while orifices 3 and 4 have high velocities and significant flow distribution. However, current design manuals and standards primarily focus on the design methods for side-mounted inlets / outlets connected to long, straight tunnels, and have not yet provided clear regulations or relevant reference values ​​for the design of inlets / outlets connected to planar bend tunnels.

[0052] like Figures 1-4 As shown, this embodiment introduces a flow deflection coefficient β and an inlet flow splitting constraint coefficient C. i These two new design parameters, along with their defined values, are used to provide a design method for side inlets / outlets of connecting planar turning tunnels, comprising the following steps:

[0053] Step 1: Based on the actual engineering operating conditions, design the initial shape of the side inlet / outlet to obtain the basic design parameters of the initial shape of the side inlet / outlet: the number of diversion piers n, and the width w at the minimum flow section of each orifice. i The height h at the minimum flow cross section of each orifice i ;

[0054] Step 2: Calculate the flow control area coefficient A for each orifice of the initial body shape. i Flow channel control area coefficient A i The ratio of the minimum flow cross-sectional area of ​​each orifice channel to the sum of the minimum flow cross-sectional areas of all orifice channels represents the design flow capacity of each orifice channel. The calculation formula is as follows:

[0055]

[0056] In the formula, w i h is the width at the minimum flow cross-section of each orifice. i , where n is the height of the minimum flow cross section of each orifice, n is the number of diversion piers 7, and i is the orifice number;

[0057] Step 3: Calculate the flow distribution coefficient Q at each orifice under the initial outflow condition. ji Where j = 1, the calculation formula is as follows:

[0058]

[0059] Step 4: Calculate the flow distribution coefficient Q of each orifice under the initial flow condition. ji Where j = 2, the calculation formula is as follows:

[0060]

[0061] Step 5: Flow rate distribution coefficient Q at each orifice ji The target value determination index is: (Q) ji ) max -(Q ji ) min ≤10%, if Q 1i Q 2i If all parameters meet the target range, then the initial body shape meets the standard flow distribution requirements, and the design is complete; if Q 1i Or Q 2i If the target range is not met, then optimize the design.

[0062] Flow distribution coefficient Q ji The ratio of the flow rate through each orifice to the total flow rate is given by , where j = 1, and Q is the flow rate distribution coefficient for each orifice under outflow conditions. 1i When j=2, Q is the flow distribution coefficient of each orifice under the inflow condition. 2i Flow distribution coefficient Q ji This reflects the actual flow capacity of each orifice under the influence of the bend flow deviation effect.

[0063] Step 6: Calculate the velocity distribution coefficient V at each orifice under the initial outflow condition. i Flow velocity distribution coefficient V i This represents the velocity distribution of water entering each orifice, calculated as follows:

[0064]

[0065] In the formula, A i Q is the flow channel control area coefficient for the i-th orifice under outflow conditions. 1i Let be the flow distribution coefficient of the i-th orifice under the outflow condition;

[0066] Step 7: Calculate the flow deviation coefficient β at the inlet / outlet under the initial flow conditions. The flow deviation coefficient β is the ratio of the maximum to the minimum value of the velocity distribution coefficient. The flow deviation coefficient β reflects the degree of flow deviation at the inlet / outlet caused by the bend flow deviation effect. The larger the value, the more severe the flow deviation. The calculation method is as follows:

[0067] β=(V i ) max / (V i ) min (5);

[0068] Step 8: Calculate the adjustment value ΔA for the flow channel control area coefficient. i The calculation method is as follows:

[0069] If Q 1i >30%,

[0070] If Q1i <20%,

[0071] Step 9: Calculate the inlet / outlet constraint coefficient C i Inlet / outlet constraint coefficient C i This refers to the adjustable range of the flow split ratio of each orifice when the water flows into the inlet / outlet, provided that the flow splitting at each orifice meets the specifications. The calculation formula is as follows:

[0072] If Q 1i >30%, C i ≤Q 2i -20% (8)

[0073] If Q 1i <20%, C i ≤30%-Q 2i (9);

[0074] Inlet / outlet constraint coefficient C i The purpose is to achieve the goal of meeting the specifications for both the outflow split ratio and the inflow split ratio. This is because the inflow split ratio is affected by the inflow conditions and exhibits the characteristic of large splits on both sides and small splits in the middle. If the control area of ​​a certain orifice is increased or decreased excessively in order to meet the specifications for the outflow split ratio, it may result in the inflow split ratio being too large or too small and failing to meet the specifications.

[0075] Step 10: Based on the initial flow distribution coefficient Q at each orifice during outflow, 1i Flow channel control area coefficient adjustment value ΔA i and the inlet / outlet ratio constraint coefficient C i Adjust the area of ​​the minimum flow cross section of each flow channel;

[0076] Step 11: Repeat steps 2 through 10 until the judgment criteria are met.

[0077] Specifically, in step two, n takes the value of 2 or 3, and i takes the value of 1, 2, 3 or 1, 2, 3, 4.

[0078] Specifically, in step ten, the adjustment method for the area of ​​the minimum flow cross-section of each flow channel is as follows:

[0079] If Q 1i >30%, reduce the area of ​​the minimum flow cross-section of the i-hole, and make

[0080] If Q 1i <20%, and when no flow separation occurs on the two side walls of orifice i, increase the area of ​​the minimum flow cross-section of orifice i, and make

[0081] If Q 1i<20%, and when flow separation occurs on a certain side wall of orifice i, the flow separation phenomenon on the wall should be weakened or eliminated first. Specifically, if Q 1i <20%, and flow separation occurs on the right wall of orifice i, shifting the diversion pier 7 on the right side of orifice i to the left; if Q 1i <20%, and flow separation occurs on the left wall of hole i, causing the diversion block 7 on the left side of hole i to shift to the right.

[0082] Specifically, in step ten, during the process of adjusting the area of ​​the minimum flow cross section of each flow channel, the area of ​​the minimum flow cross section of the side hole flow channel is adjusted first, and then the area of ​​the minimum flow cross section of the middle hole flow channel is adjusted.

[0083] In this specific embodiment, the lower reservoir of a pumped storage power station adopts a side-type inlet / outlet arrangement. The inlet / outlet is connected to the generator unit through a planar turning tunnel. Due to space constraints, the length of the straight tunnel section between the planar turning tunnel and the inlet / outlet is only 6 times the tunnel diameter. The flow deflection effect of the planar turning tunnel leads to uneven flow distribution at each orifice of the inlet / outlet. To address this problem, the method in this embodiment is used to optimize the shape of the inlet / outlet, as follows:

[0084] Step 1: Based on the engineering design conditions and with reference to the current design manual and design specifications, design the basic shape of the side inlet / outlet to obtain the initial shape parameters: the number of diversion piers 7 n=3, the widths of the minimum flow section of the one-hole 1, two-hole 2, three-hole 3, and four-hole 4 are w1=1.902m, w2=2.057m, w3=2.057m, and w4=1.902m respectively, and the heights of the minimum flow section of the one-hole 1, two-hole 2, three-hole 3, and four-hole 4 are h1=10.039m, h2=10.222m, h3=10.222m, and h4=10.039m respectively.

[0085] Step 2: Using formula (1), the flow control area coefficients for the initial body shape with one hole 1, two holes 2, three holes 3, and four holes 4 are calculated as A1 = 23.8%, A2 = 26.2%, A3 = 26.2%, and A4 = 23.8%, respectively.

[0086] Step 3: Using formula (2), calculate the flow distribution coefficients Q for the initial outflow conditions of orifice 1, orifice 2, orifice 3, and orifice 4. 11 =18.84%, Q 12 =16.37%, Q 13 =30.32%, Q 14 =34.47%.

[0087] Step 4: Using formula (3), calculate the flow distribution coefficients Q for the initial body shape inlet conditions of orifice 1, orifice 2, orifice 3, and orifice 4, respectively. 21=27.04%, Q 22 =22.79%, Q 23 =22.92%, Q 24 =27.07%. It can be seen that the inflow condition is affected by the forebay, and the split ratio shows the characteristics of large split on both sides and small split in the middle.

[0088] Step 5, Outflow Condition: (Q) 1i ) max -(Q 1i ) min =18.1%≤10%, does not meet the specification requirements; Inflow condition: (Q 2i ) max -(Q 2i ) min =4.28% ≤ 10%, which meets the specification requirements. Since the outflow split ratio does not meet the specification requirements, the inlet / outlet shape needs to be optimized.

[0089] Step 6: When calculating the initial outflow condition using formula (4), the velocity distribution coefficients of orifice 1, orifice 2, orifice 3, and orifice 4 are V1 = 0.79, V2 = 0.62, V3 = 1.16, and V4 = 1.45, respectively.

[0090] Step 7: When using formula (5) to calculate the initial body shape outflow condition, the deflection coefficient β of the inlet / outlet is 2.34.

[0091] Step 8: Calculate the adjustment values ​​of the control area coefficient for each flow channel using formulas (6) and (7), and obtain: ΔA1≥0.50%, ΔA2≥1.55%, ΔA3≥0.14%, ΔA4≥1.91%.

[0092] Step 9: Calculate the flow split ratio constraint coefficient of each flow channel using formulas (8) and (9), and obtain: C1≤2.94%, C2≤7.07%, C3≤2.96%, C4≤7.05%.

[0093] Step 10, as follows Figure 2 As shown, the starting position of the side abutment is different from that of the center abutment, as follows: Figure 5 and Figure 6 As shown, the velocity distribution at the starting section 5 of the side pier, the starting section 6 of the middle pier, and the intermediate sections of the two shows that the flow deviation phenomenon at the bend results in low velocity and less flow splitting at the first hole 1 and the second hole 2, while high velocity and large flow splitting at the third hole 3 and the fourth hole 4. In addition, the improper arrangement of the right side pier position leads to flow separation on the right wall of the second hole 2, reducing the effective flow area of ​​the second hole 2.

[0094] like Figure 7 and Figure 8As shown, the optimization design is carried out using the method in this embodiment. Specifically, the control area of ​​the flow channels on both sides is first adjusted, and priority should be given to reducing the flow separation phenomenon on the right wall of the second hole 2. Shifting the right side block to the left can increase the flow area of ​​the first hole 1 on the one hand, and weaken or eliminate the flow separation phenomenon on the right wall of the second hole 2 on the other hand; shifting the left side block to the left can reduce the flow area of ​​the fourth hole 4.

[0095] According to the calculation results in step ten, 0.50% ≤ ΔA1 ≤ 1.26%, 1.55% ≤ ΔA2 ≤ 3.02%, 0.14% ≤ ΔA3 ≤ 1.26%, and 1.91% ≤ ΔA4 ≤ 3.01%. Here, ΔA... i When calculating within the range of C, take C. i The maximum value is calculated.

[0096] In this embodiment, the flow control area coefficient of orifice 1 is increased by 0.63%, the flow control area coefficient of orifice 2 is increased by 2.27%, the flow control area coefficient of orifice 3 is decreased by 0.15%, and the flow control area coefficient of orifice 4 is decreased by 2.75%. After redesign, the optimized scheme achieves uniform flow distribution in both inlet and outlet conditions, meeting the specifications. The inlet / outlet flow distribution under different operating conditions compared to the original scheme in this embodiment is shown in Table 1.

[0097] Table 1 Comparison of inlet / outlet flow distribution under different operating conditions between this embodiment and the original scheme.

[0098]

[0099] It is evident that, under power generation conditions, the flow distribution coefficients for orifices 1, 2, 3, and 4 in the original outflow scheme are 18.84%, 16.37%, 30.32%, and 34.47%, respectively. The maximum difference in flow distribution coefficients among the orifices reaches 18.10%, failing to meet the specification requirement that the difference in flow distribution coefficients among the orifices should not exceed 10%. This indicates that, due to the influence of the planar turning tunnel, the two orifices on the inner side of the turning section (orifices 1 and 2) experience less flow diversion, while the two orifices on the outer side of the turning section (orifices 3 and 4) experience greater flow diversion.

[0100] In contrast, this embodiment significantly reduces the flow deviation phenomenon caused by the planar turning tunnel, resulting in flow distribution coefficients of 27.06%, 22.93%, 22.96%, and 27.05% for the outflow conditions of orifice 1, orifice 2, orifice 3, and orifice 4, respectively. The maximum difference in flow distribution coefficients among the orifices is 4.13%, which meets the specification requirement that the difference in flow distribution coefficients among the orifices should not exceed 10%, thus solving the problem of uneven flow distribution in the outflow conditions caused by the flow deviation phenomenon in the planar turning tunnel.

[0101] As can be seen, in order to solve the problem of uneven inlet / outlet flow distribution caused by flow deviation at bends, this embodiment creatively introduces a flow deviation coefficient β and an inlet flow splitting constraint coefficient C. i Two design parameters are given, along with their explicit definitions and calculation methods. Among them, the flow deflection coefficient β quantifies the influence of the bend flow deflection effect on the inlet / outlet flow separation, and the inlet flow separation constraint coefficient C... i The limited adjustment range significantly reduces workload and improves optimization efficiency. Furthermore, the design method in this embodiment only requires adjusting the arrangement of the diversion piers 7 to achieve uniform flow distribution at the inlet / outlet under different operating conditions. It is highly adaptable and overcomes the spatial constraint that the location of the turning tunnel must be 30-40 times the diameter of the inlet / outlet, thus greatly saving on power plant investment costs. Compared to existing technologies, the design method in this embodiment has the advantages of simplicity, economy, efficiency, and strong adaptability.

[0102] This specification uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A design method for a side-type inlet / outlet of a connecting planar turning tunnel, characterized in that, Includes the following steps: Step 1: Based on the actual engineering operating conditions, design the initial shape of the side inlet / outlet to obtain the basic design parameters of the initial shape of the side inlet / outlet: the number of diversion piers n, and the width w at the minimum flow section of each orifice. i The height h at the minimum flow cross section of each orifice i ; Step 2: Calculate the flow control area coefficient A for each orifice of the initial body shape. i The calculation formula is: In the formula, w i h is the width at the minimum flow cross-section of each orifice. i is the height of the minimum flow cross section of each orifice, n is the number of diversion piers, and i is the orifice number; Step 3: Calculate the flow distribution coefficient Q at each orifice under the initial outflow condition. ji Where j = 1, the calculation formula is as follows: Step 4: Calculate the flow distribution coefficient Q of each orifice under the initial flow condition. ji Where j = 2, the calculation formula is as follows: Step 5: Flow rate distribution coefficient Q at each orifice ji The target value determination index is: (Q) ji ) max -(Q ji ) min ≤10%, if Q 1i Q 2i If all parameters meet the target range, then the initial body shape meets the standard flow distribution requirements, and the design is complete; if Q 1i Or Q 2i If the target range is not met, then optimize the design. Step 6: Calculate the velocity distribution coefficient V at each orifice under the initial outflow condition. i The calculation method is as follows: In the formula, A i Q is the flow channel control area coefficient for the i-th orifice under outflow conditions. 1i Let be the flow distribution coefficient of the i-th orifice under the outflow condition; Step 7: Calculate the flow deflection coefficient β at the inlet / outlet under the initial flow conditions. The calculation method is as follows: β=(V i ) max / (V i ) min (5); Step 8: Calculate the adjustment value ΔA for the flow channel control area coefficient. i The calculation method is as follows: If Q 1i >30%, If Q 1i <20%, Step 9: Calculate the inlet / outlet constraint coefficient C i The calculation formula is as follows: If Q 1i >30%, C i ≤Q 2i -20% (8) If Q 1i <20%, C i ≤30%-Q 2i (9); Step 10: Based on the initial flow distribution coefficient Q at each orifice during outflow, 1i Flow channel control area coefficient adjustment value ΔA i and the inlet / outlet ratio constraint coefficient C i Adjust the area of ​​the minimum flow cross section of each flow channel; Step 11: Repeat steps 2 through 10 until the judgment criteria are met.

2. The side inlet / outlet design method for connecting planar turning tunnels according to claim 1, characterized in that, In step two, n takes the value of 2 or 3, and i takes the value of 1, 2, 3 or 1, 2, 3, 4.

3. The side inlet / outlet design method for connecting planar turning tunnels according to claim 1, characterized in that, In step ten, the adjustment method for the minimum cross-sectional area of ​​each flow channel is as follows: If Q 1i >30%, reduce the area of ​​the minimum flow cross-section of the i-hole, and make If Q 1i <20%, and when no flow separation occurs on the two side walls of orifice i, increase the area of ​​the minimum flow cross-section of orifice i, and make If Q 1i <20%, and when flow separation occurs on a certain side wall of the i-hole, the flow separation phenomenon on the wall should be weakened or eliminated first.

4. The side inlet / outlet design method for connecting planar turning tunnels according to claim 3, characterized in that, In step ten, if Q 1i <20%, and flow separation occurs on the right wall of hole i, causing the diversion pier on the right side of hole i to shift to the left; If Q 1i <20%, and flow separation occurs on the left wall of hole i, causing the diversion block on the left side of hole i to shift to the right.

5. The side inlet / outlet design method for connecting planar turning tunnels according to claim 3, characterized in that, In step ten, during the process of adjusting the minimum flow cross-sectional area of ​​each flow channel, the minimum flow cross-sectional area of ​​the side hole flow channel is adjusted first, and then the minimum flow cross-sectional area of ​​the central hole flow channel is adjusted.

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