Methodology for calculating gas fire extinguishing. Online calculation of the cost of gas fire extinguishing Tasks of regulatory authorities

Firefighting

SELECTION AND CALCULATION OF GAS FIRE FIGHTING SYSTEM

A. V. Merkulov, V. A. Merkulov

CJSC "Artsok"

The main factors influencing optimal choice installations gas fire extinguishing(UGP): type of flammable load in the protected premises (archives, storage facilities, radio-electronic equipment, technological equipment etc.); the size of the protected volume and its leakage; type of gas fire extinguishing agent (GOTV); the type of equipment in which GFFS should be stored, and the type of UGP: centralized or modular.

The correct choice of gas fire extinguishing installation (GFP) depends on many factors. Therefore, the purpose of this work is to identify the main criteria that influence the optimal choice of gas fire extinguishing installation and the principle of its hydraulic calculation.

The main factors influencing the optimal choice of gas fire extinguishing installation. Firstly, the type of flammable load in the protected premises (archives, storage facilities, radio-electronic equipment, technological equipment, etc.). Secondly, the size of the protected volume and its leakage. Thirdly, the type of gas fire extinguishing agent. Fourth, the type of equipment in which the gas extinguishing agent should be stored. Fifthly, the type of gas fire extinguishing installation: centralized or modular. The last factor can only occur if there is a need for fire protection of two or more premises at one facility. Therefore, we will consider the mutual influence of only the four factors listed above, i.e. on the assumption that the facility requires fire protection for only one room.

Certainly, right choice gas fire extinguishing installations should be based on optimal technical and economic indicators.

It should be especially noted that any of the gas fire extinguishing agents approved for use will extinguish a fire, regardless of the type of combustible material, but only when the standard fire extinguishing concentration is created in the protected volume.

The mutual influence of the above factors on the technical and economic parameters of a gas fire extinguishing installation will be assessed.

Based on the condition that in Russia the following gas fire extinguishing agents are allowed for use: freon 125, freon 318C, freon 227ea, freon 23, CO2, K2, Ar and a mixture (No. 2, Ar and CO2) having trademark Inergen.

According to the method of storage and methods of control of gaseous fire extinguishing agents in gas fire extinguishing modules (GFM), all gaseous fire extinguishing agents can be divided into three groups.

The first group includes freon 125, 318C and 227ea. These refrigerants are stored in a gas fire extinguishing module in liquefied form under the pressure of a propellant gas, most often nitrogen. Modules with the listed refrigerants, as a rule, have operating pressure, not exceeding 6.4 MPa. The amount of refrigerant during operation of the installation is monitored using a pressure gauge installed on the gas fire extinguishing module.

Freon 23 and CO2 make up the second group. They are also stored in liquefied form, but are forced out of the gas fire extinguishing module under the pressure of their own saturated vapors. The working pressure of modules with the listed gas fire extinguishing agents must have a working pressure of at least 14.7 MPa. During operation, the modules must be installed on weighing devices that provide continuous monitoring of the mass of freon 23 or CO2.

The third group includes K2, Ag and Inergen. These gaseous fire extinguishing agents are stored in gaseous fire extinguishing modules in a gaseous state. Further, when we consider the advantages and disadvantages of gas fire extinguishing agents from this group, we will focus only on nitrogen.

This is due to the fact that N2 is the most effective (lowest extinguishing concentration) and has the lowest cost. The mass of the listed gas fire extinguishing agents is controlled using a pressure gauge. Lg or Inergen are stored in modules at a pressure of 14.7 MPa or more.

Gas fire extinguishing modules, as a rule, have a cylinder capacity not exceeding 100 liters. At the same time, modules with a capacity of more than 100 liters, according to PB 10-115, are subject to registration with the Gosgortekhnadzor of Russia, which entails quite a large number of restrictions on their use in accordance with the specified rules.

The exception is isothermal modules for liquid dioxide carbon (MIZHU) with a capacity from 3.0 to 25.0 m3. These modules are designed and manufactured to store carbon dioxide in quantities exceeding 2500 kg in gas fire extinguishing installations. Isothermal modules for liquid carbon dioxide are equipped with refrigeration units and heating elements, which allows you to maintain the pressure in the isothermal tank in the range of 2.0 - 2.1 MPa at an ambient temperature from minus 40 to plus 50 ° C.

Let's look at examples of how each of the four factors influences the technical and economic indicators of a gas fire extinguishing installation. The mass of the gas fire extinguishing agent was calculated according to the method set out in NPB 88-2001.

Example 1. It is required to protect radio-electronic equipment in a room with a volume of 60 m3. The room is conditionally sealed, i.e. K2 « 0. We summarize the calculation results in table. 1.

Economic justification table. 1 in specific numbers has a certain difficulty. This is due to the fact that the cost of equipment and gas extinguishing agent from manufacturers and suppliers varies. However, there is a general tendency that as the cylinder capacity increases, the cost of the gas fire extinguishing module increases. 1 kg CO2 and 1 m3 N are close in price and two orders of magnitude less than the cost of refrigerants. Analysis of the table 1 shows that the cost of installing a gas fire extinguishing system with refrigerant 125 and CO2 is comparable in value. Despite the significantly higher cost of freon 125 compared to carbon dioxide, the total price of freon 125 - gas fire extinguishing module with a 40 liter cylinder will be comparable or even slightly lower than the carbon dioxide - gas fire extinguishing module with 80 liter cylinder - weighing device set. We can definitely state that the cost of installing a gas fire extinguishing system with nitrogen is significantly higher compared to the two previously considered options, because Two modules with maximum capacity are required. More space will be required to accommodate

TABLE 1

Freon 125 36 kg 40 1

CO2 51 kg 80 1

of two modules in a room and, naturally, the cost of two modules with a volume of 100 liters will always be higher than the cost of a module with a volume of 80 liters with a weighing device, which, as a rule, is 4 - 5 times cheaper than the module itself.

Example 2. The room parameters are similar to example 1, but it is not radio-electronic equipment that needs to be protected, but an archive. The calculation results are similar to the first example and are summarized in table. 2.

Based on the analysis of table. 2, we can clearly say that in this case, the cost of installing a gas fire extinguishing system with nitrogen is significantly higher than the cost of installing gas fire extinguishing systems with freon 125 and carbon dioxide. But unlike the first example, in this case it can be more clearly noted that the installation of gas fire extinguishing with carbon dioxide has the lowest cost, because with a relatively small difference in cost between a gas fire extinguishing module with a cylinder with a capacity of 80 and 100 liters, the price of 56 kg of freon 125 significantly exceeds the cost of a weighing device.

Similar dependencies will be traced if the volume of the protected premises increases and/or its leakage increases, because all this causes a general increase in the amount of any type of gas extinguishing agent.

Thus, just based on two examples it is clear what to choose optimal installation gas fire extinguishing for fire protection of the premises is possible only after considering at least two options with various types gas fire extinguishing agents.

However, there are exceptions when a gas fire extinguishing installation with optimal technical and economic parameters cannot be used due to certain restrictions imposed on gas extinguishing agents.

TABLE 2

Name of GFSF Quantity of GFCF Cylinder capacity MGP, l Quantity of MGP, pcs.

Freon 125 56 kg 80 1

CO2 66 kg 100 1

Such restrictions primarily include the protection of critical facilities in seismic zones (for example, nuclear power facilities, etc.), where the installation of modules in earthquake-resistant frames is required. In this case, the use of freon 23 and carbon dioxide is excluded, because modules with these gaseous fire extinguishing agents must be installed on weighing devices that prevent their rigid fastening.

TO fire protection premises with constantly present personnel (air traffic control rooms, rooms with control panels of nuclear power plants, etc.) are subject to restrictions on the toxicity of gaseous fire extinguishing agents. In this case, the use of carbon dioxide is excluded, because The volumetric fire extinguishing concentration of carbon dioxide in the air is lethal to humans.

When protecting volumes of more than 2000 m3, from an economic point of view, the most acceptable is the use of carbon dioxide filled in an isothermal module for liquid carbon dioxide, compared to all other gaseous fire extinguishing agents.

After a feasibility study, the amount of gas fire extinguishing agents required to extinguish the fire and the preliminary number of gas fire extinguishing modules become known.

Nozzles must be installed in accordance with the spray patterns specified in technical documentation nozzle manufacturer. Distance from nozzles to ceiling (ceiling, suspended ceiling) should not exceed 0.5 m when using all gas fire extinguishing agents, with the exception of K2.

Pipe distribution, as a rule, should be symmetrical, i.e. nozzles must be equally distant from the main pipeline. In this case, the flow of gaseous fire extinguishing agents through all nozzles will be the same, which will ensure the creation of a uniform fire extinguishing concentration in the protected volume. Typical examples of symmetrical piping are shown in Fig. 1 and 2.

When designing piping, you should also consider correct connection outlet pipelines (rows, branches) from the main.

A cross-shaped connection is possible only if the flow rates of gas extinguishing agents 01 and 02 are equal in value (Fig. 3).

If 01 Ф 02, then opposite connections of rows and branches with the main pipeline must be spaced in the direction of movement of gaseous fire extinguishing agents at a distance b exceeding 10 D, as shown in Fig. 4, where D - inner diameter main pipeline.

When designing the piping of a gas fire extinguishing installation, no restrictions are imposed on the spatial connection of pipes when using gas fire extinguishing agents belonging to the second and third groups. And for the piping of a gas fire extinguishing installation with gaseous fire extinguishing agents of the first group, there are a number of restrictions. This is caused by the following.

When pressurizing freon 125, 318C or 227ea in the gas fire extinguishing module with nitrogen to the required pressure, nitrogen is partially dissolved in the listed freons, and the amount of dissolved nitrogen in the freons is proportional to the boost pressure.

b>10D ^ N Y

After opening the shut-off and starting device of the gas fire extinguishing module, under the pressure of the propellant gas, the refrigerant with partially dissolved nitrogen flows through the piping to the nozzles and through them exits into the protected volume. In this case, the pressure in the “modules - piping” system decreases as a result of the expansion of the volume occupied by nitrogen in the process of displacing the freon and the hydraulic resistance of the piping. Partial release of nitrogen from the liquid phase of the refrigerant occurs and a two-phase environment “mixture of the liquid phase of the refrigerant - gaseous nitrogen” is formed. Therefore, a number of restrictions are imposed on the piping of a gas fire extinguishing installation using the first group of gas fire extinguishing agents. The main purpose of these restrictions is aimed at preventing the separation of the two-phase medium inside the pipework.

When designing and installing, all piping connections of a gas fire extinguishing installation must be made as shown in Fig. 5, and it is prohibited to perform them in the form shown in Fig. 6. In the figures, arrows show the direction of flow of gas fire extinguishing agents through the pipes.

In the process of designing a gas fire extinguishing installation, the piping layout, pipe length, number of nozzles and their elevations are determined in axonometric form. To determine the internal diameter of the pipes and the total area of ​​the outlet openings of each nozzle, it is necessary to perform a hydraulic calculation of the gas fire extinguishing installation.

The methodology for performing hydraulic calculations of a gas fire extinguishing installation with carbon dioxide is given in the work. Calculating a gas fire extinguishing installation with inert gases is not a problem, because in this case, the flow of inertia

gases occur in the form of a single-phase gaseous medium.

Hydraulic calculation of a gas fire extinguishing installation using freons 125, 318C and 227ea as a gas fire extinguishing agent is difficult process. The use of the hydraulic calculation technique created for freon 114B2 is unacceptable due to the fact that in this technique the flow of freon through pipes is considered as a homogeneous liquid.

As noted above, the flow of refrigerants 125, 318C and 227ea through pipes occurs in the form of a two-phase medium (gas - liquid), and with decreasing pressure in the system, the density of the gas-liquid medium decreases. Therefore, in order to maintain a constant mass flow of gaseous fire extinguishing agents, it is necessary to increase the speed of the gas-liquid medium or the internal diameter of the pipelines.

A comparison of the results of full-scale tests with the release of refrigerants 318Ts and 227ea from a gas fire extinguishing installation showed that the test data differed by more than 30% from the calculated values ​​​​obtained using a method that does not take into account the solubility of nitrogen in the refrigerant.

The influence of the solubility of the propellant gas is taken into account in the methods of hydraulic calculation of a gas fire extinguishing installation, in which refrigerant 13B1 is used as a gas extinguishing agent. These methods are not general in nature. Designed for hydraulic calculation of a gas fire extinguishing installation with only 13B1 freon at two values ​​of MHP nitrogen boost pressure - 4.2 and 2.5 MPa and; at four values ​​in operation and six values ​​in operation, the coefficient of filling of the modules with refrigerant.

Taking into account the above, a problem was set and a methodology was developed for the hydraulic calculation of a gas fire extinguishing installation with refrigerants 125, 318Ts and 227ea, namely: with a given total hydraulic resistance of the gas fire extinguishing module (entrance to the siphon tube, siphon tube and shut-off device) and the known pipe For the wiring of a gas fire extinguishing installation, find the distribution of the mass of refrigerant passing through the individual nozzles, and the time of expiration of the estimated mass of refrigerant from the nozzles into the protected volume after the simultaneous opening of the shut-off and starting device of all modules. When creating the methodology, we took into account the unsteady flow of a two-phase gas-liquid mixture "freon - nitrogen" in a system consisting of gas fire extinguishing modules, pipelines and nozzles, which required knowledge of the parameters of the gas-liquid mixture (pressure, density and velocity fields) at any point in the pipeline system at any time .

In this regard, the pipelines were divided into elementary cells in the direction of the axes by planes perpendicular to the axes. For each elementary volume, the equations of continuity, momentum and state were written.

In this case, the functional relationship between pressure and density in the equation of state of the gas-liquid mixture was related by a relationship using Henry's law under the assumption of homogeneity of the gas-liquid mixture. The nitrogen solubility coefficient for each of the freons under consideration was determined experimentally.

To perform hydraulic calculations of a gas fire extinguishing installation, a calculation program in Fortran language was developed, which was named "ZALP".

The hydraulic calculation program allows, for a given gas fire extinguishing installation scheme, which generally includes:

Gas fire extinguishing modules filled with gas extinguishing agents pressurized with nitrogen to pressure Рн;

Collector and main pipeline;

Switchgears;

Distribution pipelines;

Nozzles on bends, determine:

Installation inertia;

Time of release of the estimated mass of gaseous fire extinguishing agents;

Time of release of the actual mass of gaseous fire extinguishing agents; - mass flow of gaseous fire extinguishing agents through each nozzle. The testing of the "2АЛР" hydraulic calculation method was carried out by triggering three existing gas fire extinguishing installations and on an experimental stand.

It was found that the calculation results using the developed method satisfactorily (with an accuracy of 15%) coincide with the experimental data.

Hydraulic calculations are performed in the following sequence.

According to NPB 88-2001, the calculated and actual mass of freon is determined. The type and number of gas fire extinguishing modules is determined from the condition of the maximum permissible module filling factor (freon 125 - 0.9 kg/l, freon 318C and 227ea - 1.1 kg/l).

The boost pressure pH of gaseous fire extinguishing agents is set. As a rule, pH is taken in the range from 3.0 to 4.5 MPa for modular and from 4.5 to 6.0 MPa for centralized installations.

A diagram of the piping of the gas fire extinguishing installation is drawn up, indicating the length of the pipes, elevations of the connection points of the piping and nozzles. The internal diameters of these pipes and the total area of ​​the outlet openings of the nozzles are pre-set under the condition that this area should not exceed 80% of the area of ​​the internal diameter of the main pipeline.

The listed parameters of the gas fire extinguishing installation are entered into the "2АЛР" program and a hydraulic calculation is performed. The calculation results may have several options. Below we will look at the most typical ones.

The release time of the estimated mass of gas extinguishing agent is Tr = 8-10 s for a modular installation and Tr = 13 -15 s for a centralized one, and the difference in costs between nozzles does not exceed 20%. In this case, all parameters of the gas fire extinguishing installation are selected correctly.

If the release time of the estimated mass of gas extinguishing agent is less than the values ​​​​indicated above, then the internal diameter of the pipelines and the total area of ​​the nozzle openings should be reduced.

If the standard release time for the calculated mass of the gas fire extinguishing agent is exceeded, the boost pressure of the gas fire extinguishing agent in the module should be increased. If this measure does not allow meeting regulatory requirements, then it is necessary to increase the volume of propellant gas in each module, i.e. reduce the filling factor of the gas extinguishing agent module, which entails an increase total number modules in a gas fire extinguishing installation.

Performance regulatory requirements according to the difference in flow rates between the nozzles, it is achieved by reducing the total area of ​​the outlet openings of the nozzles.

LITERATURE

1. NPB 88-2001. Fire extinguishing and alarm systems. Design norms and rules.

2. SNiP 2.04.09-84. Fire automatics of buildings and structures.

3. Fire Protection Equipment - Automatic Fire Extinguishing Systems using Halogenated Hydrocarbns. Part I. Halon 1301 Total Flooding Systems. ISO/TS 21/SC 5 N 55E, 1984.

Calculation of gas fire extinguishing is carried out during the development of projects and is carried out by a specialist - design engineer. It involves determining the amount of substance required for extinguishing, the required number of modules, and hydraulic calculations. It also includes work on installation suitable diameter pipeline, determining the time required to supply gas to the room, taking into account the width of the openings and the area of ​​each individual protected room.

Calculating the mass of the gas extinguishing agent allows you to calculate the required volume of freon used for. The following fire extinguishing agents are used to extinguish fire:

• carbon dioxide;
• nitrogen;
• argon inergen;
• sulfur hexafluoride;
• freons (227, 23, 125 and 218).

Fire extinguishing system gas type for 6 cylinders

Depending on the principle of action, fire extinguishing compounds are divided into groups:

1. Deoxidants are substances that act as a fire extinguishing concentration, creating a dense cloud around the flame. This concentration prevents the access of oxygen necessary to maintain the combustion process. As a result, the fire goes out.
2. Inhibitors are special fire extinguishing compounds that can interact with burning substances. As a result, combustion slows down.

Calculation of the mass of gas extinguishing agent

Calculation of the standard volume concentration allows you to determine what mass of gaseous substances will be required to extinguish the fire. Calculation of gas fire extinguishing is carried out taking into account the main parameters of the protected premises: length, width, height. You can find out the required mass of the composition using special formulas, which take into account the mass of the refrigerant required to create the gas concentration required for fire extinguishing in the volume of the room, the density of the compositions, as well as the coefficient of leakage of the concentration for fire extinguishing from containers and other data.

Design of a gas fire extinguishing system

The design of a gas fire extinguishing system is carried out taking into account the following factors:

• the number of rooms in the room, their volume, installed structures in the form of suspended ceilings;
• the location of the openings, as well as the number and width of constantly open openings;
• temperature and humidity indicators in the room;
• features, number of people on site.

Scheme of operation of the gas fire extinguishing system

Other factors are also taken into account, depending on individual characteristics design, target affiliation, staff work schedule, if we are talking about an enterprise.

Selection and location of gas fire extinguishing modules

The calculation of gas fire extinguishing also includes such a moment as the choice of module. This is done taking into account the physical and chemical properties concentrate. The filling coefficient is determined. More often this value is in the range: 0.7-1.2 kg/l. Sometimes it is necessary to install several modules to one collector. In this case, the volume of the pipeline is important, the cylinders must be the same size, one type of filler is selected, and the pressure of the propellant gas is the same. Location is allowed in the protected premises itself, or outside it - in close proximity. The distance from the gas container to the heating system object is at least one meter.

Connected module gas system industrial fire extinguishing

After choosing the location for gas fire extinguishing installations, a hydraulic calculation should be made. During the hydraulic calculation, the following parameters are determined:

• pipeline diameter;
• time of departure of the train from the module;
• area of ​​nozzle outlet openings.

You can make hydraulic calculations either independently or using special programs.

When the calculation results are received and the installation is completed, it is necessary to instruct personnel in accordance with. Special attention is paid to the regulatory framework, drawing up and posting an evacuation plan, and familiarization with the instructions.

Personnel briefing and training on the use of funds personal protection in case of fire

Authorized supervisory authorities

Institutions exercising control:

• Mrs. Supervision;
• safety department;
• fire technical commission.

Compact gas fire extinguishing module for small spaces

Tasks of regulatory authorities

Responsibilities include monitoring compliance regulatory framework, ensuring the proper level of safety and security of objects. Such authorities require:

• bringing the working conditions of employees to established standards;
• installation of warning systems and automatic fire extinguishing systems;
• eliminating the use of flammable materials for repairs and finishing;
• requirement to eliminate any fire safety violations.

Conclusion

Upon completion of the process, the company issues project documentation in accordance with existing standards and requirements. The results of the work are provided to the customer for review.

Currently, gas fire extinguishing is effective, environmentally safe and universal method fire fighting on early stage occurrence of a fire.

Calculation of the installation of gas fire extinguishing systems is widely used at facilities where the use of other fire fighting systems – powder, water, etc. – is undesirable.

Such objects include premises with electrical equipment, archives, museums, exhibition halls, warehouses with explosive substances located there, etc.

Gas fire extinguishing and its undeniable advantages

In the world, including Russia, gas fire extinguishing has become one of the widely used methods of eliminating the source of fire due to a number of undeniable advantages:

• minimization negative influence on environment due to the release of gases;
• ease of removing gases from the room;
• precise distribution of gas over the entire area of ​​the room;
• non-damage to property, valuables and equipment;
• functioning over a wide temperature range.

Why is a gas fire extinguishing calculation necessary?

To select a particular installation for a room or facility, a clear calculation of gas fire extinguishing is required. Thus, a distinction is made between centralized and modular complexes. The choice of one type or another depends on the number of premises that need to be protected from fire, the area of ​​the facility and its type.

Taking these parameters into account, gas fire extinguishing is calculated, with mandatory consideration of the mass of gas required to eliminate the source of fire in a certain area. For such calculations, special methods are used, taking into account the type of fire extinguishing agent, the area of ​​the entire room and the type of fire-fighting installation.

For calculations, the following parameters must be taken into account:

• room area (length, ceiling height, width);
• object type (archive, server rooms, etc.);
• the presence of open openings;
• type of flammable substances;
• fire hazard class;
• degree of distance of the security console from the premises.

The need to calculate gas fire extinguishing

Fire extinguishing calculations – preliminary stage before installing a gas fire extinguishing system on site. To ensure the safety of people and the safety of property, it is necessary to carry out a clear calculation of the equipment.

The validity of the calculation of gas fire extinguishing and subsequent installation at the facility is determined by regulatory documentation. The use of this system in server rooms, archives, museums and data centers is mandatory. In addition, such installations are installed in car parks closed type, in repair shops, warehouse-type premises. The calculation of fire extinguishing directly depends on the size of the room and the type of goods stored in it.

The undeniable advantage of gas fire extinguishing over powder or water installations is its lightning-fast response and operation in the event of a fire, while objects or materials in the room are reliably protected from the negative effects of fire extinguishing agents.

At the design stage, the amount of fire extinguishing agent required to extinguish the fire is calculated. The further functioning of the complex depends on this stage.

When designing gas fire extinguishing systems, the task arises of determining time to enter the room required quantity fire extinguishing agent at given parameters of the hydraulic system. The ability to carry out such a calculation allows you to select the optimal characteristics of a gas fire extinguishing system that provides the required release time of the required amount of fire extinguishing agent.

In accordance with clause 8.7.3 of SP 5.13130.2009, it must be ensured that at least 95% of the mass of gaseous fire extinguishing agent required to create the standard fire extinguishing concentration in the protected room is supplied within a time interval not exceeding 10 s for modular installations and 15 s for centralized gas fire extinguishing installations, in which fire extinguishing agents are used as a fire extinguishing agent liquefied gases(except carbon dioxide).

Due to lack of approved domestic methods In order to determine the time of release of the fire extinguishing agent into the room, this method for calculating gas fire extinguishing was developed. This technique allows using computer technology to carry out calculating the release time of the fire extinguishing agent for gas fire extinguishing systems based on freons, in which the fire extinguishing agent is in cylinders (modules) in a liquid state under the pressure of a propellant gas, which ensures the required rate of gas exit from the system. Wherein the fact of dissolution of the propellant gas in the liquid fire extinguishing agent is taken into account. This method of calculating gas fire extinguishing is the basis computer program TACT-Gas, in its part concerning the calculation of gas fire extinguishing systems based on freons and new fire extinguishing agent Novec 1230(freon FK-5-1-12).

No need to rush to conclusions!
These formulas only show consumption in numbers.
Let's take a break from the “candy wrappers” and pay attention to the “candy” and its “filling”. And “candy” is formula A.16. What is she describing? Losses on the pipeline section taking into account the consumption of nozzles. Let’s look at it, or rather, what’s in brackets. The left part describes the wiring of the main part of the pipeline and the processes in the cylinder or gas fire extinguishing station; it is of little interest to us now, as a kind of constant for wiring, but the right is of particular interest! This is all the zest with a sum sign! To simplify the notation, let's transform the rightmost part inside the bracket space: (n^2*L)/D^5.25 into this form: n^2*X. Let's say that you have six nozzles on a section of pipeline. Along the first section to the first nozzle (counting from the side of the cylinder), you have GFFE flowing to all six nozzles, then the losses in the section will be the losses before the nozzle plus what leaks further along the pipeline, the pressure will be less than if there was a plug after the nozzle. Then the right side will look like: 6^2*X1 and we will get the parameter “A” for the first nozzle. Next, we come to the second nozzle and what do we see? And the fact that part of the gas is consumed by the first nozzle, plus what was lost in the pipe on the way to the nozzle, and what will leak further (taking into account the flow rate at this nozzle). Now the right side will already take the form: 6^2*X1+5^2*X2 and we will get the parameter “A” on the second nozzle. And so on. So you have expenses for each nozzle. By summing up these costs, you will receive the consumption of your installation and the release time of the GFFE. Why is everything so complicated? Very simple. Let’s assume that the wiring has the same six nozzles and branching (let’s assume that the right arm has two nozzles, and the left one has 4), then we will describe the sections:
1) GFFE flows through it to all nozzles: 6^2*X1;
2) it flows along it to two nozzles on the right shoulder 6^2*X1+2^2*X2 – Parameter “A” for the first nozzle;
3) Parameter “A” for the second nozzle on the right shoulder 6^2*X1+2^2*X2+1^2*X3;
4) Parameter “A” for the third pipe nozzle or the first nozzle on the left shoulder: 6^2*X1+4^2*X4;
5) and so on “according to the text”.
I deliberately “teared off a piece” of the main pipeline to the first section for greater readability. In the first section, the flow rate is for all nozzles, and in the second and fourth section only for two on the right shoulder and four on the left, respectively.
Now you see in the numbers that the consumption on 20 nozzles is always greater than on one with the same parameters as 20.
In addition, with the naked eye you can see what the difference is between the costs between the “dictating” nozzles, that is, the nozzles located in the most advantageous place of the pipe distribution (where least losses and the highest flow rate) and vice versa.
That's all!