Compressor water spray cooling control device and method

Abstract

The invention provides a compressor water spraying cooling control device and method. The compressor water spraying cooling control device comprises a machine side water spraying disc station, a machine side piping, a machine shell nozzle set and a compressor control system. The machine side water spraying disc station and the machine shell nozzle set are electrically connected with the compressor control system. The machine side water spraying disc station comprises a filter, a regulating valve, a stop valve and an instrument panel, the filter is used for filtering impurities, the regulating valve is used for controlling water spraying pressure, the stop valve is used for controlling opening and closing of the machine shell nozzle set, and the instrument panel is used for measuring temperature and pressure; the machine-side piping comprises a plurality of sets of piping bodies used for being connected with the machine-side water spraying disc station and the machine shell nozzle set. The machine shell nozzle set comprises a plurality of nozzle assemblies which are in one-to-one correspondence with the stop valves and used for stretching into the gas flow channel to spray water for cooling. The number of the nozzles can be precisely controlled, precise control over the outlet temperature of the compressor impeller is achieved, the device can be suitable for various working conditions, the equipment cost is reduced, the structure is simple, and installation is convenient.

Description

Technical Field

[0001] The present invention relates to the technical field of compressors, and in particular to a compressor water spray cooling control device and method. Background Art

[0002] During the operation of large mixed gas centrifugal compressors, the interstage temperature will continue to rise as the impeller does its work. Since some sulfides and carbon-based materials in the mixed gas will coke at high temperatures, the aerodynamic performance of the compressor will decrease. In severe cases, solid impact will cause damage to the rotor group. Therefore, it is necessary to cool the mixed gas at the impeller outlet where the temperature is high. In addition, the mixed gas also contains components that are easy to condense and crystallize. The amount of water sprayed needs to be controlled, and the temperature after cooling cannot be too low, otherwise it will also result in unqualified aerodynamic performance.

[0003] In the prior art, the gas is usually discharged from the compressor into a cooler for cooling and then returned to the compressor for compression. However, this method requires consideration of designing a volute chamber at the exhaust end of the impeller in the compressor cylinder to lead the gas out of the compressor, and designing an intake chamber at the return end of the next-stage impeller. The structural dimensions of the two are relatively large, which will greatly increase the axial length of the rotor group and the outer dimensions of the casing, and have an adverse effect on the overall size and rotor dynamics of the compressor. At the same time, after the gas is led out of the compressor, a separate cooler needs to be set up for cooling, and the corresponding front and rear pipes and instruments need to be configured, which increases both the floor space and the cost of the device. In addition, there is a certain positioning height difference between the equipment, which will also increase the civil engineering and installation costs.

[0004] Therefore, there is an urgent need for a compressor water spray cooling control device that can accurately control the compressor impeller outlet temperature and reduce equipment costs. Summary of the invention

[0005] Based on this, it is necessary to provide a compressor water spray cooling control device and method to address the above technical problems.

[0006] A compressor water spray cooling control device comprises: a machine-side water spray disc station, machine-side piping, a casing nozzle group and a compressor control system; the machine-side water spray disc station and the casing nozzle group are electrically connected to the compressor control system; the machine-side water spray disc station comprises a filter, a regulating valve, a shut-off valve and an instrument panel, the filter is used to filter impurities, the regulating valve is used to control the water spray pressure, the shut-off valve is used to control the opening and closing of the casing nozzle group, and the instrument panel is used to measure temperature and pressure; the machine-side piping comprises a plurality of piping groups for connecting the machine-side water spray disc station and the casing nozzle group; the casing nozzle group comprises a plurality of nozzle assemblies, the plurality of nozzle assemblies correspond to the shut-off valves one by one, and are used to extend into a gas flow channel for water spray cooling.

[0007] In one of the embodiments, the nozzle assembly includes a support pipe, a conduit and a nozzle group; the support pipe is welded to the compressor casing; the conduit is arranged inside the support pipe and is connected to the machine-side piping; the nozzle group includes two nozzles, and the two nozzles are diagonally distributed on the upper and lower casings of the compressor. The nozzle is arranged at the end of the conduit and can extend into the compressor casing and enter the gas flow channel to spray water for cooling.

[0008] In one of the embodiments, it also includes a buzzer and a voltage transformer, which are arranged at the regulating valve and emit an alarm when the regulating valve reaches a set pressure; the voltage transformer is electrically connected to the compressor control system and is used to convert high voltage into low voltage.

[0009] In one of the embodiments, a temperature sensor is further included. The temperature sensor is disposed between the filter and the regulating valve and is electrically connected to the compressor control system.

[0010] A compressor water spray cooling control method adopts a compressor water spray cooling control device as described above, comprising: obtaining corresponding operation data through an instrument panel, the operation data including measured compressor flow, impeller inlet temperature, impeller inlet pressure, impeller outlet temperature, impeller outlet pressure, water spray temperature and water spray pressure; calculating the water spray amount according to the operation data, and calculating the number of nozzle groups according to the water spray amount; controlling the opening of a regulating valve through a compressor control system to set the water spray pressure higher than the air flow pressure; controlling the cut-off valve through the compressor control system to open a number of nozzle assemblies corresponding to the number of nozzle groups to perform water spray cooling.

[0011] In one embodiment, the water spraying amount is calculated based on the operating data, and the formula is:

[0012]

[0013] Wherein, q is the water spraying amount, H1 is the impeller inlet enthalpy, Q is the measured compressor flow, H2 is the impeller outlet enthalpy, H3 is the saturated gas enthalpy, and H4 is the liquid enthalpy; wherein, the impeller inlet enthalpy is obtained according to the pressure-enthalpy diagram of the impeller inlet temperature and the impeller inlet pressure; the impeller outlet enthalpy is obtained according to the pressure-enthalpy diagram of the impeller outlet temperature and the impeller outlet pressure; the saturated gas enthalpy is obtained according to the pressure-enthalpy diagram of the water spraying temperature and the water spraying pressure; the liquid enthalpy is obtained according to the pressure-enthalpy diagram of the water spraying temperature and the water pressure after the regulating valve.

[0014] In one embodiment, the number of nozzle groups is calculated according to the water spraying amount, and the formula is:

[0015] n=q / q1

[0016] In the formula, q1 is the water spray volume of a single nozzle group, and n is the number of nozzle groups.

[0017] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: by electrically connecting the machine-side water spraying disk station, the casing nozzle group and the compressor control system, the machine-side water spraying disk station includes a filter, a regulating valve, a shut-off valve and an instrument panel, wherein the filter is used to filter impurities, the regulating valve is used to control the water spraying pressure, the shut-off valve is used to control the opening and closing of the casing nozzle group, and the instrument panel is used to measure temperature and pressure; the machine-side piping includes multiple groups of piping, connecting the machine-side water spraying disk station and the casing nozzle group, the casing nozzle group includes a number of nozzle assemblies corresponding to the shut-off valves, which are used to extend into the gas flow channel for water spraying and cooling, and the shut-off valve is used to accurately control the opening and closing of the corresponding nozzle assembly to achieve accurate control of the compressor impeller outlet temperature, avoid high-temperature coking during operation, or condensation or crystallization caused by low temperature, and can accurately control the number of opened nozzles according to the operating conditions of the compressor to meet the needs of various working conditions, greatly reducing the equipment cost, and the nozzle assembly will not increase the axial length and shell size of the rotor group, ensuring the streamlined and compact design of the compressor, simple structure, and easy installation. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of a compressor water spray cooling control device in one embodiment;

[0019] Figure 2 It is a structural schematic diagram of a water spray station beside a machine in one embodiment;

[0020] Figure 3 A schematic diagram of the structure of a housing nozzle assembly in one embodiment;

[0021] Figure 4 A schematic diagram of an application of a nozzle assembly in a compressor casing in one embodiment;

[0022] Figure 5 A schematic flow chart of a compressor water spray cooling control method in one embodiment;

[0023] Figure 6 FIG. 4 is a pressure-enthalpy diagram of the impeller inlet temperature and the impeller inlet pressure in one embodiment. DETAILED DESCRIPTION

[0024] Before describing the specific embodiments of the present invention, the overall concept of the present invention is described as follows:

[0025] The present invention is mainly developed for the compressor cooling process. At present, the structural dimensions of the compressor cooling device are relatively large, which has an adverse effect on the overall size and rotor dynamics of the compressor, making it difficult to achieve precise temperature control. After the gas is led out of the compressor, a separate cooler is required for cooling, which is costly.

[0026] Therefore, the present invention proposes a compressor water spray cooling control device, which electrically connects a machine-side water spray disk station, a casing nozzle group and a compressor control system. The machine-side water spray disk station includes a filter, a regulating valve, a shut-off valve and an instrument panel, wherein the filter is used to filter impurities, the regulating valve is used to control the water spray pressure, the shut-off valve is used to control the opening and closing of the casing nozzle group, and the instrument panel is used to measure temperature and pressure; the machine-side piping includes multiple groups of piping, connecting the machine-side water spray disk station and the casing nozzle group, the casing nozzle group includes a number of nozzle assemblies corresponding to the shut-off valves, which are used to extend into the gas flow channel for water spray cooling, and the opening and closing of the corresponding nozzle assemblies are controlled by the precise shut-off valve to achieve precise control of the compressor impeller outlet temperature, avoid high-temperature coking during operation, or condensation or crystallization caused by low temperature, and can accurately control the number of opened nozzles according to the operating conditions of the compressor to meet the needs of various working conditions, greatly reducing the equipment cost, and the nozzle assembly will not increase the axial length and shell size of the rotor group, ensuring the streamlined and compact design of the compressor, simple structure, and easy installation.

[0027] After introducing the overall concept of the present invention, in order to make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail by specific implementation methods in combination with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0028] In one embodiment, Figure 1-4 As shown, a compressor water spray cooling control device is provided, including: a machine-side water spray disc station 10, a machine-side piping 20, a casing nozzle group 30 and a compressor control system 40; the machine-side water spray disc station 10 and the casing nozzle group 30 are electrically connected to the compressor control system 40; the machine-side water spray disc station 10 includes a filter 11, a regulating valve 12, a shut-off valve 13 and an instrument panel 14, the filter 11 is used to filter impurities, the regulating valve 12 is used to control the water spray pressure, the shut-off valve 13 is used to control the opening and closing of the casing nozzle group 30, and the instrument panel 14 is used to measure temperature and pressure; the machine-side piping 20 includes multiple groups of piping, which are used to connect the machine-side water spray disc station 10 and the casing nozzle group 30; the casing nozzle group 30 includes a plurality of nozzle assemblies, and the plurality of nozzle assemblies correspond to the shut-off valve 13 one by one, and are used to extend into the gas flow channel for water spray cooling.

[0029] In this embodiment, the machine-side water spray station 10, the casing nozzle group 30 and the compressor control system 40 are electrically connected, and the machine-side water spray station 10 includes a filter 11, a regulating valve 12, a shut-off valve 13 and an instrument panel 14, wherein the filter 11 is used to filter impurities, the regulating valve 12 is used to control the water spray pressure, the shut-off valve 13 is used to control the opening and closing of the casing nozzle group 30, and the instrument panel 14 is used to measure the temperature and pressure; the machine-side piping 20 includes a plurality of piping groups, connecting the machine-side water spray station 10 and the casing nozzle group 30, and the casing nozzle group 30 includes a shut-off valve 13 and an instrument panel 14. A plurality of nozzle assemblies 13 corresponding to each other are used to extend into the gas flow channel for spraying water for cooling. The opening and closing of the corresponding nozzle assembly is controlled by the cut-off valve 13 to achieve precise control of the compressor impeller outlet temperature, avoid high-temperature coking during operation, or condensation or crystallization caused by low temperature, and can accurately control the number of opened nozzles according to the operating conditions of the compressor to meet the needs of various working conditions, greatly reducing the equipment cost, and the nozzle assembly will not increase the axial length of the rotor group and the shell size, ensuring the streamlined and compact design of the compressor, simple structure, and easy installation.

[0030] Specifically, the main functions of the machine-side water spray station 10 for cooling the compressor include cooling, sealing and lubricating, and preventing coking and carbon deposition. Fine droplets are formed by high-pressure micro-spraying technology. The droplets absorb a large amount of heat during evaporation, quickly reducing the temperature of the compressor and its surrounding environment, effectively preventing the compressor from shutting down due to high temperature, and improving its heat dissipation efficiency, reducing energy consumption and wear.

[0031] Specifically, the filter 11 is connected to the external desalted water to filter the impurities in the desalted water to prevent the impurities from entering the system and causing damage, thereby ensuring the cooling effect on the compressor. At the same time, a sewage outlet is provided behind the filter 11 for sewage treatment of impurities.

[0032] Among them, the nozzle assembly includes a support pipe 31, a conduit 32 and a nozzle group 33. The support pipe 31 is welded to the compressor casing; the conduit 32 is arranged inside the support pipe 31 and is connected to the machine-side piping 20; the nozzle group 33 includes two nozzles 331, and the two nozzles 331 are diagonally distributed on the upper and lower casings of the compressor. The nozzle 331 is arranged at the end of the conduit 32, and can extend into the compressor casing and enter the gas flow channel to spray water for cooling.

[0033] Specifically, the nozzle assembly is as follows Figure 3As shown, the nozzle assembly is provided with multiple groups, which correspond to the shut-off valve 13 one by one. The shut-off valve 13 is used to control the opening and closing of the nozzle assembly so as to realize accurate control of the required number of nozzles, and the nozzle assembly will not increase the axial length of the rotor group and the shell size, thereby ensuring the streamlined and compact design of the compressor. In the nozzle assembly, the support pipe 31 is welded to the compressor casing, the conduit 32 is arranged inside the support pipe 31, and is connected to the machine-side piping 20. The nozzle group 33 includes two nozzles 331, which are diagonally distributed in the upper and lower casings of the compressor. The nozzle 331 is arranged at the end of the conduit 32 and can be extended into the compressor casing to enter the gas flow channel for spraying water for cooling. The application scenario of the nozzle of the nozzle assembly extending into the gas flow channel of the compressor casing is as follows: Figure 4 shown.

[0034] In addition, the machine-side water spray station, machine-side piping and casing nozzle group can all be prefabricated in the factory, which is convenient for users to install on site. At the same time, all parts can be directly removed through the flange during maintenance, without the need to dismantle the entire machine, which is convenient and quick to operate. The above device has a compact structure and is placed next to the machine, occupying a small space and without installation height difference restrictions. The on-site installation is simple and convenient.

[0035] The device also includes a buzzer and a voltage transformer, which are arranged at the regulating valve 12. When the regulating valve 12 reaches the set pressure, an alarm sound is issued; the voltage transformer is electrically connected to the compressor control system 40 and is used to convert high voltage into low voltage.

[0036] Specifically, a buzzer is provided at the regulating valve 12, and an alarm sounds when the regulating valve 12 reaches the set pressure, so as to facilitate timely processing; the voltage transformer is electrically connected to the compressor control system 40, and can convert high voltage into low voltage, so as to facilitate voltage measurement using a voltmeter and upload it to the compressor control system 40, so that the compressor control system 40 can perform compressor water spray cooling control.

[0037] A temperature sensor is also included. The temperature sensor is disposed between the filter 11 and the regulating valve 12 and is electrically connected to the compressor control system 40 .

[0038] Specifically, the device is also provided with a temperature sensor, which is arranged between the filter 11 and the regulating valve 12, for measuring the temperature of the filtered water, and can be uploaded to the compressor control system 40 to determine the operating conditions of the compressor, thereby performing compressor water spray cooling control.

[0039] In one embodiment, Figure 5 As shown, a compressor water spray cooling control method is provided, which is implemented by using a compressor water spray cooling control device as described above, and includes the following steps:

[0040] Step S110, obtaining corresponding operating data through the instrument panel, the operating data including the measured compressor flow, impeller inlet temperature, impeller inlet pressure, impeller outlet temperature, impeller outlet pressure, spray water temperature and spray water pressure.

[0041] Specifically, when the compressor is running, the instrument panel can display its operating conditions and obtain relevant data of the compressor operating conditions, such as the measured compressor flow, impeller inlet temperature, impeller inlet pressure, impeller outlet temperature, impeller outlet pressure, spray water temperature and spray water pressure, etc.

[0042] Step S120, calculating the water spraying amount according to the operation data, and calculating the number of nozzle groups according to the water spraying amount.

[0043] Specifically, the cooling water spray volume is calculated based on all the acquired operating data, and the number of nozzle groups is calculated based on the water spray volume, thereby obtaining the number of nozzle groups that need to be opened to adapt to all working conditions.

[0044] The calculation formula for the water spray volume is:

[0045]

[0046] Wherein, q is the water spray volume, H1 is the impeller inlet enthalpy, Q is the measured compressor flow, H2 is the impeller outlet enthalpy, H3 is the saturated gas enthalpy, and H4 is the liquid enthalpy; wherein, the impeller inlet enthalpy is obtained according to the pressure-enthalpy diagram of the impeller inlet temperature and the impeller inlet pressure; the impeller outlet enthalpy is obtained according to the pressure-enthalpy diagram of the impeller outlet temperature and the impeller outlet pressure; the saturated gas enthalpy is obtained according to the pressure-enthalpy diagram of the water spray temperature and the water spray pressure; the liquid enthalpy is obtained according to the pressure-enthalpy diagram of the water spray temperature and the water pressure after the regulating valve.

[0047] Specifically, since the compressor working conditions are constantly changing, multiple nozzles need to be set up to correspond to different water spraying volumes. The working conditions of conventional centrifugal compressors vary from 70% to 120%. Taking a furnace gas compressor as an example, the design parameters of the maximum 120% working condition are taken to calculate the water spraying volume, and then the corresponding number of nozzles is selected according to the flow rate of a single nozzle to meet all working conditions. Taking a furnace gas mixture as the process medium as an example, the pressure-enthalpy diagram of the impeller inlet temperature and the impeller inlet pressure is as follows: Figure 6 shown.

[0048] The calculation formula for the number of nozzle groups is:

[0049] n=q / q1

[0050] Wherein, q1 is the water spraying volume of a single nozzle group (including two nozzles), n is the number of nozzle groups, and the number of nozzle groups corresponds to the operating condition of the compressor.

[0051] Specifically, when the compressor is running, the number of nozzle groups n that need to be opened is calculated based on the water spray volume and the water spray volume of a single group of nozzles, n=0, 1, 2...6, corresponding to the number of nozzle groups that need to be opened for 70%, 80%, 90%,...120% operating conditions of the compressor respectively.

[0052] Step S130, controlling the opening of the regulating valve through the compressor control system, and setting the water spraying pressure to be higher than the air flow pressure.

[0053] Specifically, the opening of the regulating valve is controlled by the compressor control system so that the water spraying pressure of the nozzle assembly when spraying water is slightly higher than the air flow pressure, thereby realizing atomized water spraying.

[0054] Step S140, controlling the shut-off valve through the compressor control system, opening the nozzle assemblies corresponding to the number of nozzle groups, and spraying water for cooling.

[0055] Specifically, the shut-off valve in the water spray station beside the machine is controlled by the compressor control system, thereby opening the nozzle assemblies corresponding to the number of nozzle groups, and spraying water to cool the airflow under the existing working conditions.

[0056] In this embodiment, corresponding operating data is obtained through the instrument panel, including the measured compressor flow, impeller inlet temperature, impeller inlet pressure, impeller outlet temperature, impeller outlet pressure, water spray temperature and water spray pressure. The water spray amount is calculated according to the operating data, and the number of nozzle groups is calculated according to the water spray amount, so as to achieve precise control of the water spray amount and meet various working conditions. The opening of the regulating valve is controlled by the compressor control system, and the water spray pressure is set higher than the air flow pressure to achieve atomized water spray, and the shut-off valve is controlled to open the nozzle assemblies corresponding to the calculated number of nozzle groups for water spray cooling, so as to achieve precise control of the compressor impeller outlet temperature, avoid high-temperature coking or low-temperature condensation, and meet various working conditions, reduce equipment costs, and facilitate installation.

[0057] In addition, the above control method collects the operating parameters of the compression impeller, obtains the water spraying volume after calculation, and the compressor control system controls the corresponding number of nozzles to spray water, thereby cooling the impeller outlet. The nozzles are selected and grouped according to the user's working conditions, thereby realizing automatic control of water spray cooling of all operating tools of the compressor.

[0058] Obviously, those skilled in the art should understand that the modules or steps of the present invention described above can be implemented by a general-purpose computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, and optionally, they can be implemented by a program code executable by a computing device, so that they can be stored in a computer storage medium (ROM / RAM, magnetic disk, optical disk) and executed by the computing device, and in some cases, the steps shown or described can be executed in a different order than that here, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. Therefore, the present invention is not limited to any specific combination of hardware and software.

[0059] The above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A compressor water spray cooling control device, characterized in that: include: Machine-side water spray station, machine-side piping, casing nozzle assembly and compressor control system; The machine-side water spraying disk station and the casing nozzle group are electrically connected to the compressor control system; The machine-side water spray station includes a filter, a regulating valve, a shut-off valve and an instrument panel, wherein the filter is used to filter impurities, the regulating valve is used to control the water spray pressure, the shut-off valve is used to control the opening and closing of the housing nozzle group, and the instrument panel is used to measure temperature and pressure; The machine-side piping includes a plurality of piping groups for connecting the machine-side water spraying station and the casing nozzle group; The housing nozzle group includes a plurality of nozzle assemblies, and the plurality of nozzle assemblies correspond to the cut-off valves one by one and are used to extend into the gas flow channel to spray water for cooling.

2. A compressor water spray cooling control device according to claim 1, characterized in that: The nozzle assembly includes a support pipe, a conduit and a nozzle group; the support pipe is welded to the compressor casing; the conduit is arranged inside the support pipe and is connected to the machine-side piping; the nozzle group includes two nozzles, the two nozzles are diagonally distributed on the upper and lower casings of the compressor, and the nozzle is arranged at the end of the conduit and can extend into the compressor casing and enter the gas flow channel to spray water for cooling.

3. A compressor water spray cooling control device according to claim 1, characterized in that: It also includes a buzzer and a voltage transformer, which are arranged at the regulating valve and emit an alarm when the regulating valve reaches a set pressure; the voltage transformer is electrically connected to the compressor control system and is used to convert a high voltage into a low voltage.

4. A compressor water spray cooling control device according to claim 1, characterized in that: A temperature sensor is also included. The temperature sensor is disposed between the filter and the regulating valve and is electrically connected to the compressor control system.

5. A compressor water spray cooling control method, characterized in that: The method is implemented by using a compressor water spray cooling control device as claimed in any one of claims 1 to 4, comprising the following steps: Obtain corresponding operating data through the instrument panel, wherein the operating data includes measured compressor flow, impeller inlet temperature, impeller inlet pressure, impeller outlet temperature, impeller outlet pressure, spray water temperature and spray water pressure; The water spraying amount is calculated according to the operation data, and the number of nozzle groups is calculated according to the water spraying amount; The opening of the regulating valve is controlled by the compressor control system, and the water spray pressure is set higher than the air flow pressure; The shut-off valve is controlled by the compressor control system to open the nozzle assemblies corresponding to the number of nozzle groups to spray water for cooling.

6. A compressor water spray cooling control method according to claim 5, characterized in that: The water spraying amount is calculated based on the operating data, and the formula is: Where q is the water injection volume, H1 is the impeller inlet enthalpy, Q is the measured compressor flow, H2 is the impeller outlet enthalpy, H3 is the saturated gas enthalpy, and H4 is the liquid enthalpy; Wherein, the impeller inlet enthalpy is obtained according to the pressure-enthalpy diagram of the impeller inlet temperature and the impeller inlet pressure; The impeller outlet enthalpy is obtained according to the pressure-enthalpy diagram of the impeller outlet temperature and the impeller outlet pressure; The saturated gas enthalpy is obtained according to the pressure-enthalpy diagram of the water spraying temperature and the water spraying pressure; The liquid enthalpy is obtained according to the pressure-enthalpy diagram of the water spraying temperature and the water pressure after the regulating valve.

7. A compressor water spray cooling control method according to claim 6, characterized in that: The formula for calculating the number of nozzle groups according to the water spraying amount is: n=q / q1 In the formula, q1 is the water spray volume of a single nozzle group, and n is the number of nozzle groups.

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