Spraying system hydraulic iterative calculation method based on nozzle working pressure fitting

Abstract

The invention discloses a spraying system hydraulic iterative calculation method based on nozzle working pressure fitting. The method comprises the steps that S1, spraying system pipe network information is obtained; s2, selecting a to-be-most unfavorable point nozzle in the pipe network; s3, by taking the quasi most disadvantageous point nozzle as a starting point, calculating to obtain the transfer flow of each nozzle and each pipe section in the pipe network and the head loss of each pipe section, and obtaining the working pressure of the real most disadvantageous point nozzle; s4, verifying whether calculation results of S1 to S3 meet specification requirements or not; according to the method, calculation can be conducted according to regular arrangement and irregular arrangement of the nozzles and the pipelines, calculation is conducted in a calculation mode completely different from a characteristic coefficient method, and the calculation mode and design parameter values in the calculation process both meet various requirements specified by the national standard; compared with the prior art, the calculation result is more suitable for the actual operation condition of the spraying system, and a more reliable design basis is provided for the design scheme of the spraying system.

Description

Technical Field

[0001] The invention relates to the field of fire fighting technology, and in particular to a hydraulic iteration calculation method for a sprinkler system based on nozzle working pressure fitting. Background Art

[0002] An automatic sprinkler system is a building fire protection system that automatically sprays water to control and extinguish fires when a fire occurs through a network of sprinklers and pipes installed inside the building. This system can respond quickly to fires and reduce the damage caused by fires.

[0003] In the related art, the hydraulic calculation methods of existing automatic sprinkler fire extinguishing systems are roughly divided into three types: the effective area method, the characteristic coefficient method, and the hydraulic calculation method based on the proportional relationship between the flow rates of each sprinkler on the water distribution branch pipe and the water pressure balance equation.

[0004] Among them, the calculation results of the effective area method are conservative, ignoring the impact of pipeline head loss on the working pressure of the nozzle. It assumes that the water spray volume of each nozzle in the effective area is the same as the water spray volume of the nozzle at the most unfavorable point. The design flow rate of the system is equal to the product of the flow rate of the nozzle at the most unfavorable point and the number of nozzles in the effective area. The calculation result is quite different from the actual flow rate.

[0005] The characteristic coefficient law is only applicable to the case where the sprinklers and water distribution branches are arranged regularly. In actual projects, since the protected area is not a regular rectangle, or the position of individual sprinklers is adjusted to meet the minimum clearance requirement between sprinklers and obstacles, the pipelines and sprinklers are "irregularly arranged" in most cases, resulting in difficulties in the application of the characteristic coefficient method.

[0006] The hydraulic calculation method based on the proportional relationship between the flow rates of each nozzle on the water distribution branch and the water pressure balance equation combines some calculation methods of the effective area method and the characteristic coefficient method, making up for the shortcomings of the effective area method and the characteristic coefficient method. It is a commonly used calculation method in two-dimensional design software on the market; but the disadvantages are also very obvious. This method ignores the influence of the head loss of the pipes and fittings between the nozzle and the water distribution branch on the working pressure of the nozzle. It still uses an ideal calculation model, which is not completely consistent with the actual situation. In actual situations, there is no proportional relationship between the flow rates of each nozzle on the same water distribution branch.

[0007] With the rise of BIM technology and the improvement of design model accuracy, the above three methods can no longer meet the industry's accuracy and safety requirements for fire protection system design. Summary of the invention

[0008] In order to solve the above problem, the present invention provides a hydraulic iterative calculation method for a sprinkler system based on nozzle working pressure fitting to solve the problem.

[0009] In order to achieve the above objectives, this application provides the following technical solutions:

[0010] A method for iterative hydraulic calculation of a sprinkler system based on nozzle working pressure fitting includes S1: obtaining sprinkler system pipe network information; S2: selecting a nozzle at a simulated most unfavorable point in the pipe network; S3: taking the nozzle at the simulated most unfavorable point as a starting point, calculating and obtaining the transfer flow of each nozzle and each pipe section in the pipe network and the head loss of each pipe section, and obtaining the working pressure of the nozzle at the real most unfavorable point; S4: verifying whether the calculation results of S1-S3 meet the requirements of the specification; S5: calculating the water pump head of the pipe network.

[0011] The S3 includes: step 1, step 2 and step 3; wherein: step 1: calculate the transfer flow and head loss of each pipe section from the nozzle PT1 to the intersection of the two adjacent spray branches through S101-S106; step 2: calculate the transfer flow and head loss of each pipe section from the intersection of the two spray branches to the nozzle at the end of the next pipe network through S201-S203; step 3: according to the hydraulic calculation method of step 1 and step 2, obtain the transfer flow and water pressure of each pipe section from the intersection of the other two spray branches to the nozzle at the end of the next pipe network in the pipe network, thereby obtaining the pressure value at the entrance of the entire pipe network.

[0012] The step 1 specifically includes: S101: Calculate the transfer flow rate q of the nozzle at the most unfavorable point by the following formula PT1 : Where K is the nozzle flow coefficient; P PT1 is the working pressure of the nozzle at the most unfavorable point; S102: Calculate the hydraulic gradient per meter of the pipe section by the following formula In the formula, q a-b is the transfer flow rate of pipe section ab, d a-b is the calculated inner diameter of pipe section ab, C is the Haicheng-William coefficient; S103: Calculate the head loss h of the pipe section by the following formula 水损a-b :h 水损a-b =i a-b *l a-b ; In the formula, l a-b is the sum of the actual length and equivalent length of pipe section ab; S104: Calculate the height difference loss h of the pipe section by the following formula 高差a-b :h 高差a-b =0.1*l a-b ; S105: Calculate the working pressure P of the next nozzle (the second nozzle) after the nozzle at the most unfavorable point by the following formula PT2 : In the formula, q PT2 is the transfer flow of the second nozzle; S106: By analogy with S101-S105, the transfer flow and head loss of each pipe section between the nozzle PT1 and the intersection of the two adjacent spray branches can be obtained.

[0013] The step 2 specifically includes: Step 201: Assume that the design working pressure of each nozzle in the transfer flow of each pipe section from the intersection of two sections of the spray branch pipe to the nozzle at the end of the next pipe network is P 设x-n , where x is the nozzle number and n is the number of iterations; Step 202: Set the initial design pressure value P of each nozzle 设x-0 Equal to the minimum working pressure P of the sprinkler at the most unfavorable point min Step 203: According to step A to step F, the transfer flow rate q of each nozzle in each pipe section from the intersection of the two spray branches to the nozzle at the end of the next pipe network is obtained. x-n At the same time, the transfer flow rate q of each pipe section within the range can be obtained r-t And the head loss of each pipe section h 水损r-t , and finally obtain the calculated working pressure P of each nozzle 计x-n .

[0014] Steps A to F in step 203 specifically include: Step A: Calculate the nozzle transfer flow rate q by the following formula: x-n : Step B: Calculate the hydraulic gradient i of the pipe section using the formula in S102 r-t :Step C: Calculate the head loss h of each pipe section using the formula in S103 水损r-t Step D: Through the inlet pressure, the head loss and the height difference loss of each pipe section, and according to the inheritance relationship between the transfer flow of adjacent pipe sections and the equal relationship between the starting and ending pressures of adjacent pipe sections, the calculated working pressure P of each nozzle is obtained by back-calculating back to each nozzle. 计x-n :Step E: Calculate the absolute value of the difference between the calculated pressure and the design pressure of each nozzle. If |P 计x-n -P 设x-n |<0.01, the iteration stops, otherwise proceed to step F.

[0015] The step F comprises: Step a: Calculate the pressure difference ΔP from each nozzle to the inlet by the following formula x-n ; Step b: set the adjustment coefficient α of the nozzle design working pressure; Step c: calculate the design working pressure P of each nozzle at the n+1th iteration 设x-(n+1) ; Step d, all the newly obtained P 设x-(n+1) The value is substituted into step A until the requirement in step E is met, and the iteration stops. At this time, the design working pressure of each nozzle is equal to the calculated working pressure value, which is the actual working pressure of the nozzle. The transfer flow and head loss of each pipe section are the final results.

[0016] The inlet pressure difference ΔP x-n The calculation formula is: ΔP x-n =P5-P 计x-n; Where P5 is the water pressure at the intersection of the two spray branches, P 计x-n Calculated working pressure for the nozzle.

[0017] The adjustment coefficient of the nozzle design working pressure Where m is the number of nozzles.

[0018] Design working pressure of the nozzle at the n+1th iteration Among them, if there is P 设x-(n+1) <0, then the α value is halved and all P 设x-(n+1) value until all P 设x-(n+1) >0, get P 设x-(n+1) The value of and the value of α.

[0019] The calculation formula for the pipe network water pump head is:

[0020] H=(1.20~1.40)∑P p +P0+Zh c ;

[0021] Where: H is the pump head or the water supply pressure of the system population; ∑P p is the cumulative value of the water head loss along the pipeline and locally; P0 is the working pressure of the nozzle at the truly most unfavorable point; Z is the elevation difference between the nozzle at the truly most unfavorable point and the lowest water level of the fire water tank or the horizontal center line of the system inlet pipe, h c It is the minimum water pressure of the urban pipeline network when water is directly pumped from the urban municipal pipeline network.

[0022] Compared with the prior art, the beneficial technical effects of the present invention are:

[0023] 1. The design scheme is not limited: the present invention can calculate both "regular arrangement" and "irregular arrangement" of nozzles and pipelines, and adopts a calculation method completely different from the characteristic coefficient method for calculation.

[0024] 2. The calculation results are more accurate: The present invention adopts a calculation model that is more in line with reality. The calculation method and the design parameter values ​​in the calculation process all meet the requirements specified in national standards. The calculation results are more in line with the actual operating conditions of the sprinkler system than the prior art, providing a more reliable design basis for the sprinkler system design scheme.

[0025] 3. The design scheme is safer: the head loss of the sprinkler system calculated by the present invention is more comprehensive and complete, and the calculated system design flow is larger than the calculated value obtained by the prior art. The design scheme formulated based on this is safer and more reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0027] Figure 1 It is a schematic diagram of the process in this embodiment;

[0028] Figure 2 Schematic diagram of the pipe network in this embodiment;

[0029] Figure 3 is a trend diagram of the variable function f(x) in this embodiment;

[0030] Figure 4 It is a specific sub-process calculation diagram for each specific pipe section in this embodiment. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0032] Example

[0033] Reference Figure 1-Figure 4 , which is a hydraulic iterative calculation method for a sprinkler system based on nozzle working pressure fitting disclosed by the present invention, comprising:

[0034] S1, obtain the sprinkler system pipe network information;

[0035] S2, select the nozzle at the proposed most unfavorable point in the pipe network, and number the nozzles and pipe sections within the action area of ​​the nozzle at the proposed most unfavorable point;

[0036] For example, Figure 2 For example, the nozzle numbers are: PT1, PT2, PT3, ..., PT20, and the pipe section numbers are: PT1-1, 1-2, PT2-2, 2-3, ..., PT20-27, 27-9, 9-10;

[0037] S3, taking the nozzle at the proposed most unfavorable point as the starting point, calculate and obtain the transfer flow of each nozzle and each pipe section in the pipe network and the head loss of each pipe section, and obtain the working pressure of the nozzle at the real most unfavorable point;

[0038] Reference Figure 2In this embodiment, node 5, node 8, and node 9 are the confluence nodes of the main pipeline. Specifically, the confluence node is the connection point in the pipeline that is connected to the nozzle.

[0039] The hydraulic calculation of the trunk pipeline can be divided into four sections: PT1-5, PT5-8, PT8-9, and PT9-10, and the hydraulic calculation of the branch pipeline can be divided into three sections: PT6-5, PT9-8, and PT16-9.

[0040] Therefore, the specific calculation steps of S3 include: step 1, step 2 and step 3:

[0041] Step 1, calculating the transfer flow and head loss of each pipe section from the sprinkler PT1 to the intersection of the two adjacent sprinkler branches (including both ends) through S101-S106;

[0042] In this embodiment, the intersection of the two spray branch pipes adjacent to the spray head PT1 is node 5. Therefore, in this embodiment, step 1 includes the following steps:

[0043] S101, calculate the transfer flow rate q of the nozzle at the most unfavorable point (nozzle PT1) by the following formula: PT1 :

[0044]

[0045] Where K is the nozzle flow coefficient; P PT1 The working pressure of the nozzle at the most unfavorable point;

[0046] Among them, the working pressure of the nozzle at the intended most unfavorable point is determined according to the relevant requirements in Chapter 5 of GB50084-2017 "Design Specifications for Automatic Sprinkler Fire Extinguishing Systems";

[0047] S102, calculate the hydraulic gradient i per meter of the pipe section by the following formula a-b :

[0048]

[0049] In the formula, q a-b is the transfer flow rate of pipe section ab, d a-b is the calculated inner diameter of pipe section ab, C is the Haicheng-William coefficient;

[0050] Therefore, in this embodiment, the hydraulic gradient per meter of the pipe section PT1-1 is

[0051] In the formula, q PT1 is the transfer flow of the nozzle at the most unfavorable point; C is the Haicheng-William coefficient; d PT1-1is the calculated inner diameter of pipe section PT1-1;

[0052] S103, calculate the head loss h of the pipe section by the following formula 水损a-b :

[0053] h 水损a-b =i a-b *l a-b ;

[0054] In the formula, i a-b is the hydraulic gradient per meter of pipe section ab; l a-b It is the sum of the actual length and equivalent length of pipe section ab;

[0055] Therefore, in this embodiment, the head loss h of the pipe section PT1-1 is 水损PT1-1 =i PT1-1 *l PT1-1 ;

[0056] In the formula, i PT1-1 is the hydraulic gradient per meter of pipe section PT1-1; l PT1-1 It is the sum of the actual length and equivalent length of pipe section PT1-1;

[0057] S104, calculate the height difference loss h of the pipe section by the following formula 高差a-b :

[0058] h 高差a-b =0.1*l a-b ;

[0059] Therefore, in this embodiment, the height difference loss h of the pipe section PT1-1 is 高差PT1-1 =0.1*l PT1-1 ;

[0060] In the formula, l PT1-1 The sum of the actual length and equivalent length of pipe section PT1-1;

[0061] S105, calculate the working pressure P of the next nozzle (the second nozzle) after the nozzle at the most unfavorable point by the following formula PT2 :

[0062]

[0063] In the formula, q PT2 is the transfer flow of the second nozzle;

[0064] And: A=P PT1 +h 水损PT1-1 -h 高差PT1-1 +h 水损PT1-2 +h 高差PT2-2 ;

[0065]

[0066] In the formula, h 水损1-2 is the head loss of pipe section 1-2, which is calculated according to the formula in S102-S103, where the transfer flow rate q of pipe section 1-2 1-2 =q PT1 ;h 高差PT2-2 is the height difference loss of the pipe section PT2-2, which is calculated according to the formula in S104.

[0067] In this embodiment, by creating PT2 is a function of the independent variable, and Newton's iteration method is used to To solve, specifically:

[0068] Let independent variable function f(x) = i*x 2 +j*x 1.85 -k, where i, j, and k are all greater than 0;

[0069] From f'(x)=2ix+1.85jx 0.85 , we can see that the function f(x) is continuous and monotonically increasing in the domain (0, +∞);

[0070] From f”(x)=1.5725jx -0.15 +2i, we can see that the function f(x) is a concave function in the domain (0, +∞), and the trend of the function is as follows Figure 3 As shown:

[0071] Using Newton's iteration method, we can find the approximate unique solution of f(x)=0:

[0072]

[0073] In the formula, x n+1 represents the n+1th value of x; x n represents the nth value of x; when x n+1 -x n If it is less than 0.001, it can be considered that:

[0074] q PT2 =x n+1 ; Then q PT2 Substitution P can be obtained from PT2 The value of .

[0075] S106, by analogy with S101-S105, the transfer flow and head loss of each pipe section between the sprinkler PT1 and the intersection of the two adjacent sprinkler branches (including both ends) can be obtained;

[0076] Among them, there can be: pipe section ac, pipe section bc, pipe section cd;

[0077] Since the transfer flow of adjacent pipe sections has an inheritance relationship, we have

[0078] q c-d =q a-c +q b-c ;

[0079] In the formula, q c-d is the transfer flow of pipe section cd; q a-c is the transfer flow of pipe section ac; q b-c is the transfer flow of pipe section bc.

[0080] Since the pressures at the start and end points of adjacent pipe sections are equal, we have

[0081]

[0082] Where P a , P b , P c , P d They represent the pressures at nodes a, b, c and d respectively; h 水损a-c 、h 水损b-c 、h 水损c-d are the head losses of pipe sections ac, bc and cd respectively; h 高差a-c 、h 高差b-c 、h 高差c-d They are the height difference losses of pipe section ac, pipe section bc and pipe section cd respectively;

[0083] Therefore, in this embodiment, the hydraulic calculation results of the pipe section PT1-5 are shown in the following table:

[0084]

[0085]

[0086] Step 2: Calculate the intersection of the two spray branches to the next nozzle at the end of the pipe network through S201-S203 (see Figure 2 In this embodiment, the range is the transfer flow and head loss of each pipe section from PT6 to PT5.

[0087] Step 201, assume that the design working pressure of each nozzle in the transfer flow of each pipe section from the intersection of two sections of the spray branch pipe to the nozzle at the end of the next pipe network is P 设x-n , where x is the nozzle number and n is the number of iterations;

[0088] Step 202, according to the requirements of the "Automatic Sprinkler Fire Extinguishing System Design Specification", it can be known that the minimum working pressure P of the sprinkler head at the most unfavorable point of the system min , the initial design pressure value P of each nozzle can be set设x-0 =P min ;

[0089] Step 203, according to step A to step F, obtain the transfer flow rate q of each nozzle in the transfer flow rate of each pipe section from the intersection of two sections of the spray branch pipe to the nozzle at the end of the next pipe network x-n At the same time, the transfer flow rate q of each pipe section within the range can be obtained r-t And the head loss of each pipe section h 水损r-t , and finally obtain the calculated working pressure P of each nozzle 计x-n .

[0090] Step A, calculate the nozzle transfer flow rate q by the following formula x-n :

[0091]

[0092] Step B, calculate the hydraulic gradient i of the pipe section by the formula in S102 r-t :

[0093] Step C, calculate the head loss h of each pipe section using the formula in S103 水损r-t ;

[0094] Step D, based on the basic principles of hydraulics, through the inlet pressure, the head loss of each pipe section and the height difference loss, and based on the inheritance relationship between the transfer flow of adjacent pipe sections and the equal relationship between the starting and ending pressures of adjacent pipe sections, reverse the calculation back to each nozzle to obtain the calculated working pressure P of each nozzle. 计x-n ;

[0095] Therefore, in this embodiment, the 0th hydraulic calculation results of the pipe section PT6-5 are shown in the following table:

[0096]

[0097]

[0098] Step E: Calculate the absolute value of the difference between the calculated pressure and the design pressure of each nozzle. If the |P 计x-n -P 设x-n |<0.01, the iteration stops, otherwise proceed to step F;

[0099] Wherein, step F specifically comprises:

[0100] Step a: Calculate the pressure difference ΔP from each nozzle to the inlet by the following formula x-n ;

[0101] ΔP x-n =P5-P 计x-n ; ΔP x-nis the inlet pressure difference. In this embodiment, the inlet pressure difference represents the difference between the working pressure of each nozzle and the pressure P5 of node No. 5; P5 is the water pressure of node No. 5 (i.e., the intersection of two sections of the spray branch pipe); P 计x-n is the calculated working pressure of the nozzle;

[0102] Step b: Assume the adjustment coefficient α of the nozzle design working pressure, let

[0103]

[0104] In the formula, m is the number of nozzles;

[0105] Step c: Calculate the design working pressure of each nozzle at the n+1th iteration using the following formula:

[0106]

[0107] Where P 设x-(n+1) The design working pressure of each nozzle in the n+1th iteration calculation;

[0108] Among them, if there is P 设x-(n+1) <0, then the α value is halved and all P 设x-(n+1) value until all P 设x-(n+1) >0, get P 设x-(n+1) The value of and the value of α;

[0109] Step d: All newly obtained P 设x-(n+1) The value is substituted into step A until the requirement in step E is met, and the iteration stops. At this time, the design working pressure of each nozzle is equal to the calculated working pressure value, which is the actual working pressure of the nozzle. The transfer flow and head loss of each pipe section are the final results.

[0110] Step 3, according to the hydraulic calculation method of step 1 and step 2, the transfer flow rate of each pipe section from the intersection of the other two sections of the sprinkler branch pipe to the nozzle at the end of the next pipe network and the water pressure of each node are obtained, so as to obtain the pressure value at the entrance of the entire pipe network, among which the nozzle with the smallest working pressure in the calculation result is the nozzle at the real most unfavorable point;

[0111] S4, verify whether the calculation results of S1-S3 meet the requirements of the specification: the average water spray intensity within the enclosed range of any four sprinklers within the effective area at the truly most unfavorable point, the light hazard and medium hazard levels should not be lower than 85% of the values ​​specified in Table 5.0.1 of Section 9.1.5 of GB50084-2017 "Design Specifications for Automatic Sprinkler Fire Extinguishing Systems": the serious hazard level and warehouse hazard level should not be lower than the values ​​specified in Table 5.0.1 and Table 5.0.4-1 and Table 5.0.4-5 of the specification;

[0112] S5. According to the requirements of Section 9.2.4 of GB50084-2017 "Design Specifications for Automatic Sprinkler Fire Extinguishing Systems", calculate the water pump head of the pipe network (water supply pressure at the system inlet) H:

[0113] H=(1.20~1.40)∑P p +P0+Zh c ;

[0114] Where: H is the pump head (water supply pressure at the system inlet); ∑P p It is the cumulative value of the head loss along the pipeline and the local head loss. The local head loss of the alarm valve should be determined according to the product sample or test data. When the above data is not available, the wet alarm valve takes a value of 0.04MPa, the thousand-type alarm valve takes a value of 0.02MPa, the pre-action device takes a value of 0.08MPa, the rain alarm valve takes a value of 0.07MPa, and the water flow indicator takes a value of 0.02MPa; P0 is the working pressure of the sprinkler at the real most unfavorable point; Z is the elevation difference between the sprinkler at the real most unfavorable point and the lowest water level of the fire water tank or the horizontal center line of the system inlet pipe. When the lowest water level of the system inlet pipe or the fire water tank is higher than the sprinkler at the real most unfavorable point, Z should take a negative value (MPa); h c is the minimum water pressure of the urban pipe network when pumping water directly from the urban municipal pipe network (MPa); when pumping water from the fire water tank, h c Take 0.

[0115] In summary, the present invention proposes a method for calculating the head loss of the pipe section between the nozzle and the water distribution branch pipe, uses the Newton iteration method to obtain the transfer flow of the nozzle, and thus calculates the head loss of the pipe section between the nozzle and the water distribution branch pipe, and assigns multiple values ​​to the nozzle working pressure, and corrects it through calculation steps, so as to accurately calculate the actual working pressure of each nozzle and the head loss of each pipe section of the complex pipe network;

[0116] The patent of the present invention can calculate both the "regular arrangement" and "irregular arrangement" of sprinklers and pipes, and adopts a calculation method that is completely different from the characteristic coefficient method. Furthermore, the patent of the present invention adopts a calculation model that is more in line with reality, and the calculation method and the design parameter values ​​in the calculation process meet the requirements specified in national standards. The calculation results are more in line with the actual operating conditions of the sprinkler system than the prior art, providing a more reliable design basis for the sprinkler system design scheme. Finally, the sprinkler system head loss calculated by the patent of the present invention is more comprehensive and complete, and the calculated system design flow is larger than the calculated value obtained by the prior art, and the design scheme formulated based on this is safer and more reliable.

[0117] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for iterative calculation of hydraulic power of a sprinkler system based on nozzle working pressure fitting, characterized in that: include: S1: Get the sprinkler system network information; S2: Select the nozzle at the most unfavorable point in the pipe network; S3: Taking the nozzle at the proposed most unfavorable point as the starting point, calculate and obtain the transfer flow of each nozzle and each pipe section in the pipe network and the head loss of each pipe section, and obtain the working pressure of the nozzle at the real most unfavorable point; S4: Verify whether the calculation results of S1-S3 meet the specification requirements; S5: Calculate the water pump head of the pipe network.

2. The method for hydraulic iteration calculation of a sprinkler system based on nozzle working pressure fitting according to claim 1 is characterized in that: S3 includes: step 1, step 2 and step 3; wherein: Step 1: Calculate the transfer flow and head loss of each pipe section between the sprinkler PT1 and the intersection of the two adjacent sprinkler branches through S101-S106; Step 2: Calculate the transfer flow and head loss of each pipe section from the intersection of two sections of sprinkler branches to the sprinkler head at the end of the next pipe network through S201-S203; Step 3: Based on the hydraulic calculation method of steps 1 and 2, obtain the transfer flow rate and water pressure of each node in the pipe network from the intersection of the other two spray branches to the nozzle at the end of the next pipe network, so as to obtain the pressure value at the entrance of the entire pipe network.

3. The method for hydraulic iteration calculation of a sprinkler system based on nozzle working pressure fitting according to claim 2 is characterized in that: The step 1 specifically includes: S101: Calculate the transfer flow rate q of the nozzle at the most unfavorable point by the following formula PT1 : Where K is the nozzle flow coefficient; P PT1 The working pressure of the nozzle at the most unfavorable point; s102: Calculate the hydraulic gradient i per meter of the pipe section by the following formula: a-b : In the formula, q a-b is the transfer flow rate of pipe section ab, d a-b is the calculated inner diameter of pipe section ab, C is the Hessian-Williams coefficient; S103: Calculate the head loss h of the pipe section by the following formula 水损a-b : h 水损a-b =i a-b *l a-b ; In the formula, l a-b It is the sum of the actual length and equivalent length of pipe section ab; S104: Calculate the height difference loss h of the pipe section by the following formula 高差a-b : h 高差a-b ＝0.1*l a-b ； s105: After calculating the most unfavorable point nozzle, the working pressure P of the second nozzle is calculated by the following formula PT2 : Where, qPT2 is the transfer flow rate of the second nozzle; And: A=P PT1 +h 水损PT1-1 -h 高差PT1-1 +h 水损PT1-2 +h 高差PT2-2 ; In the formula, h 水损1-2 is the head loss of pipe section 1-2; h 高差PT2-2 is the height difference loss of pipe section PT2-2; S106: By analogy with S101-S105, the transfer flow and head loss of each pipe section between the sprinkler PT1 and the intersection of the two adjacent sprinkler branches can be obtained.

4. The method for hydraulic iteration calculation of a sprinkler system based on nozzle working pressure fitting according to claim 3 is characterized in that: The step 2 specifically includes: Step 201: Assume that the design working pressure of each nozzle in the transfer flow of each pipe section from the intersection of two sections of the spray branch pipe to the nozzle at the end of the next pipe network is P 设x-n , where x is the nozzle number and n is the number of iterations; Step 202: Set the initial design pressure value P of each nozzle 设x-0 Equal to the minimum working pressure P of the sprinkler at the most unfavorable point min ; Step 203: According to Step A to Step F, the transfer flow rate q of each nozzle in the transfer flow rate of each pipe section from the intersection of two sections of the spray branch pipe to the nozzle at the end of the next pipe network is obtained. x-n At the same time, the transfer flow rate q of each pipe section within the range can be obtained r-t And the head loss of each pipe section h 水损r-t , and finally obtain the calculated working pressure P of each nozzle 计x-n .

5. The method for iterative calculation of hydraulic power of a sprinkler system based on nozzle working pressure fitting according to claim 4, characterized in that: Steps A to F in step 203 specifically include: Step A: Calculate the nozzle transfer flow rate q by the following formula x-n : Step B: Calculate the hydraulic gradient i of the pipe section using the formula in S102 r-t : Step C: Calculate the head loss h of each pipe section using the formula in S103 水损r-t ; Step D: Through the inlet pressure, the head loss of each pipe section and the height difference loss, and based on the inheritance relationship between the transfer flow of adjacent pipe sections and the equal relationship between the starting and ending pressures of adjacent pipe sections, reverse the calculation back to each nozzle to obtain the calculated working pressure P of each nozzle. 计x-n : Step E: Calculate the absolute value of the difference between the calculated pressure and the design pressure of each nozzle. If the |P 计x-n -P 设x-n |<0.01, the iteration stops, otherwise proceed to step F.

6. The method for hydraulic iteration calculation of a sprinkler system based on nozzle working pressure fitting according to claim 5, characterized in that: The step F comprises: Step a: Calculate the pressure difference ΔP from each nozzle to the inlet by the following formula x-n ; Step b: setting the adjustment coefficient α of the nozzle design working pressure; Step c: Calculate the design working pressure P of each nozzle at the n+1th iteration 设x-(n+1) ; Step d, all the newly obtained P 设x-(n+1) The value is substituted into step A until the requirement in step E is met, and the iteration stops. At this time, the design working pressure of each nozzle is equal to the calculated working pressure value, which is the actual working pressure of the nozzle. The transfer flow and head loss of each pipe section are the final results.

7. The method for iterative calculation of hydraulic power of a sprinkler system based on nozzle working pressure fitting according to claim 6, characterized in that: The inlet pressure difference ΔP x-n The calculation formula is: △P x-n =P5-P 计x-n ; Where P5 is the water pressure at the intersection of the two spray branches, P 计x-n Calculated working pressure for the nozzle.

8. The method for iterative calculation of hydraulic power of a sprinkler system based on nozzle working pressure fitting according to claim 7, characterized in that: The adjustment coefficient of the nozzle design working pressure Where m is the number of nozzles.

9. The method for iterative calculation of hydraulic power of a sprinkler system based on nozzle working pressure fitting according to claim 8, characterized in that: Design working pressure of the nozzle at the n+1th iteration Among them, if there is P 设x-(n+1) <0, then the α value is halved and all P 设x-(n+1) value until all P 设x-(n+1) >0, get P 设x-(n+1) The value of and the value of α.

10. The method for iterative calculation of hydraulic power of a sprinkler system based on nozzle working pressure fitting according to claim 9, characterized in that: The calculation formula for the pipe network water pump head is: H=(1.20~1.40)∑P p +P0+Z-h c ; Where: H is the pump head or the water supply pressure of the system population; ∑P p is the cumulative value of the water head loss along the pipeline and locally; P0 is the working pressure of the nozzle at the truly most unfavorable point; Z is the elevation difference between the nozzle at the truly most unfavorable point and the lowest water level of the fire water tank or the horizontal center line of the system inlet pipe, h c It is the minimum water pressure of the urban pipeline network when water is directly pumped from the urban municipal pipeline network.

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