CN112212541A - Single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input power and refrigerating capacity - Google Patents
Single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input power and refrigerating capacity Download PDFInfo
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B25/00—Machines, plants or systems, using a combination of modes of operation covered by two or more of the groups F25B1/00 - F25B23/00
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B49/00—Arrangement or mounting of control or safety devices
- F25B49/02—Arrangement or mounting of control or safety devices for compression type machines, plants or systems
- F25B49/022—Compressor control arrangements
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/14—Compression machines, plants or systems characterised by the cycle used
- F25B2309/1409—Pulse-tube cycles with pulse tube having special type of geometrical arrangements not being a coaxial, in-line or U-turn type
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B2309/00—Gas cycle refrigeration machines
- F25B2309/14—Compression machines, plants or systems characterised by the cycle used
- F25B2309/1411—Pulse-tube cycles characterised by control details, e.g. tuning, phase shifting or general control
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Abstract
The invention discloses a single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input power and refrigerating capacity. The invention provides a design application scheme of variable power operation and adjustment of refrigerating capacity for a large refrigerating capacity low-temperature system with three pulse tube cold heads driven by a single compressor, effectively solves the problem that the refrigerating capacity of a conventional low-temperature system is difficult to adjust correspondingly according to the requirements of user-side equipment, enables the same system to meet the requirements of users on different refrigerating capacities, enables the large-refrigerating capacity low-temperature system to have more convenient operation and control, stronger application scene adaptability and higher energy efficiency ratio, and has very positive significance for the application of a low-temperature refrigerator in the fields of intelligent power grids, advanced electric power, rail transit, efficient energy storage, high-end communication and the like.
Description
Technical Field
The invention relates to the field of refrigeration and low-temperature engineering, in particular to a single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input power and refrigerating capacity.
Background
In recent years, a high-temperature superconducting technology working at 77K plays an increasingly important role in the civil fields of smart power grids, advanced electric power, rail transit, high-efficiency energy storage, high-end communication and the like, so that urgent needs are provided for a super-high refrigerating capacity low-temperature refrigerating system which is applied in a related matched mode, and a pulse tube refrigerator becomes an ideal choice in the field due to the fact that a cold end of the pulse tube refrigerator is free of moving parts, low in vibration, low in abrasion, low in electromagnetic interference, simple in structure and long in service life.
The application in the field of high-temperature superconducting power needs to continuously provide ultra-large refrigerating capacity of hundreds of watts, thousands of watts and even tens of thousands of watts for a long time, and research and application of pulse tube refrigerators with ultra-large refrigerating capacity are developing vigorously. However, at present, the conventional refrigeration technologies at home and abroad generally only can provide a refrigerator with a fixed refrigeration capacity, and in practical application, a high-efficiency high-refrigeration-capacity low-temperature system which can be applied to various occasions is often needed, so that urgent needs are provided for research and application of pulse tube refrigerators with super-large refrigeration capacities, wherein input power and refrigeration capacity can be freely adjusted, but related technologies just start at home and abroad.
Disclosure of Invention
In view of the defects of the prior art, the invention provides a single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input work and refrigerating capacity.
The invention aims to provide a design and application scheme for driving a large-refrigerating-capacity low-temperature system with three pulse tube cold heads by using a single linear compressor to realize variable power consumption operation and adjustable refrigerating capacity, which explains the relation between energy flow distribution and related parameters of an electric control valve pipeline from the compressor to the cold head part, and aims to solve the problem that the refrigerating capacity of the low-temperature system at the current stage is difficult to adjust correspondingly along with the requirements of user-side equipment under the same temperature condition.
The single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input power and refrigerating output comprises a numerical control alternating current power supply 1, a linear compressor 2, a pressure wave transmission pipeline group 3, an electric control valve group 4, a pulse tube refrigerator cold head group 5, a cooling water system 6, a user side low-temperature circulating system 7 and a data acquisition and control system 8, and is characterized in that:
the numerical control alternating current power supply 1 is used for providing power for the linear compressor 2 and can output different voltages and currents according to specific application requirements; the linear compressor 2 is used for providing alternating sinusoidal pressure waves for the rear-end pulse tube refrigerator cold head set 5, and the output PV work and pressure waveforms of the compressor can be changed through parameter adjustment of the numerical control alternating current power supply 1; the pressure wave transmission pipeline group 3 with the electric control valve group 4 leads out a total transmission pipeline 3-0 from the outlet of the compressor and is divided into a branch pipeline I3-1 provided with an electric control valve I4-1, a branch pipeline II 3-2 provided with an electric control valve II 4-2 and a branch pipeline III 3-3 provided with an electric control valve III 4-3, and the pressure wave transmission pipeline group is used for transmitting the pressure wave of the linear compressor 2 to a cold head part of the pulse tube refrigerator, and the electric control valve group 4 can be matched with the power change of the linear compressor 2 to adjust the opening or the opening and closing state of the valve; the cold head group 5 of the pulse tube refrigerator consists of three groups of linear cold head I5-1, cold head II 5-2 and cold head III 5-3, the cold head I5-1 consists of a first aftercooler 9-1, a first regenerator 10-1, a first cold end heat exchanger 11-1, a first pulse tube 12-1, a first hot end heat exchanger 13-1, an inertia tube I14-1 and a first air reservoir 15-1, the cold head II 5-2 consists of a second aftercooler 9-2, a second regenerator 10-2, a second cold end heat exchanger 11-2, a second pulse tube 12-2, a second hot end heat exchanger 13-2, a second inertia tube 14-2 and a second air reservoir 15-2, and the cold head III 5-3 consists of a third aftercooler 9-3, a third regenerator 10-3, a third cold end heat exchanger 11-3, a third pulse tube 12-3, A hot end heat exchanger III 13-3, an inertia pipe III 14-3 and an air reservoir III 15-3; three groups of components in the pulse tube refrigerator cold head group 5 can work independently, randomly in a matching way or simultaneously, and kilowatt-level refrigerating capacity can be provided in a temperature region from liquid nitrogen to liquefied natural gas; the cooling water system 6 provides constant-temperature water circulation for the first aftercooler 9-1, the second aftercooler 9-2, the third aftercooler 9-3, the first hot-end heat exchanger 13-1, the second hot-end heat exchanger 13-2 and the third hot-end heat exchanger 13-3 to exchange heat, and a spare cooling water pipeline 6-0 interface is reserved according to requirements; the user side low-temperature circulating system 7 indirectly realizes heat exchange between user side equipment and a refrigerator cold end heat exchanger I11-1, a refrigerator cold end heat exchanger II 11-2 and a refrigerator cold end heat exchanger III 11-3 by using a low-temperature circulating pipeline 7-0 and taking low-temperature liquid as a medium, and provides a low-temperature environment for the equipment; the data acquisition and control system 8 has the functions of acquiring the temperature and refrigerating capacity isoparametric of the cold-end heat exchanger I11-1, the cold-end heat exchanger II 11-2 and the cold-end heat exchanger III 11-3 and controlling the opening of the electric control valve I4-1, the electric control valve II 4-2 and the electric control valve III 4-3, and is used for monitoring and adjusting the output electric parameters of the alternating current power supply and the cold head temperature and the output refrigerating capacity of the refrigerating machine in the variable power operation process, so that a single-compressor three-cold-head pulse tube refrigerating machine capable of freely adjusting the input power and the refrigerating capacity is formed.
The input work and the refrigerating output of the single-compressor three-cold-head pulse tube refrigerator for adjusting the cold head comprise the following specific implementation modes:
1) keeping the opening of the electric control valve group 4 unchanged, adjusting the voltage and the current of the numerical control alternating current power supply 1, thereby changing the output PV work of the linear compressor 2, namely changing the amplitude and the frequency of the mass flow and the pressure wave in the three cold head pipelines, and realizing the cold quantity adjustment of the pulse tube refrigerator cold head group 5; the mode not only changes the power of the compressor, but also changes the refrigerating capacity of the refrigerating machine;
2) keeping the voltage and the current of the numerical control alternating current power supply 1 unchanged, and adjusting the opening of the electric control valve group (4), namely changing the flow resistance of a branch pipeline I3-1, a branch pipeline II 3-2 and a branch pipeline III 3-3, thereby realizing the cold quantity distribution of each cold head; in the method, under the condition that the electric power of the linear compressor 2 is not changed, the refrigerating capacities and the distribution of the first cold head 5-1, the second cold head 5-2 and the third cold head 5-3 are changed;
3) within the range of rated working parameters of the linear compressor 2, the voltage and the current of the numerical control alternating current power supply 1 are adjusted, and the opening degree of the electric control valve group 4 is correspondingly changed, so that the working quantity of the cold heads can be selected according to the requirements of user equipment or the refrigerating capacities of the first cold head 5-1, the second cold head 5-2 and the third cold head 5-3 are adjusted, and the optimal coupling characteristic of the linear compressor 2 and the cold head group 5 of the pulse tube refrigerator in practical application is realized; the mode can simultaneously change the input power and the refrigerating capacity of the refrigerating machine and realize better coupling matching characteristic.
The method for determining the energy flow distribution and the relevant parameters in the pressure wave transmission pipeline group with the electrically controlled valve is as follows: in the pressure wave transmission pipeline group 3 with the electric control valve group 4, the parameter of the total transmission pipeline 3-0 is the dynamic pressure P0Pressure drop Δ P0Mass flow rate
Pushing Power (PV)]0(ii) a The dynamic pressure in the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3 is respectively P1、P2、P3Pressure drop of Δ P1、ΔP2、ΔP3Mass flow of
The push work is [ PV]1、[PV]2、[PV]3。
The pressure drop in a circular transfer tube can be expressed as:
in the expression (1), f is a friction factor, L is the axial length of the measured pressure drop pipeline, and dhThe pipeline wet cycle is shown, K is loss efficiency, rho is the average density of fluid working media in the pipeline, and u is the average flow velocity of the fluid.
The mass flow in a circular pipe can be expressed as:
in expression (2)
ArRadial cross-sectional area in the direction of flow of working gas, DrIs the inner diameter of a circular pipe.
At the electrically controlled valve group 4, both the pressure drop and the mass flow rate change with the opening of the valve, which can be respectively expressed as:
in the expression (3, 4), CdIs the flow coefficient of the pipeline, AfThe radial cross-sectional area of the working gas flowing through the valve, AhUpstream and downstream flow areas of the valve.
The relationship between the mass flow and the pushing work in the total transmission pipeline 3-0 in the pressure wave transmission pipeline group 3, the branch pipeline one 3-1, the branch pipeline two 3-2 and the branch pipeline three 3-3 can be expressed as follows:
[PV]0＝[PV]1+[PV]2+[PV]3 (6)
the specific working process of the single-compressor three-cold-head pulse tube refrigerator low-temperature system capable of freely adjusting input work and refrigerating capacity is as follows:
the numerical control alternating current power supply 1 provides variable voltage and current for the linear compressor 2, and a piston in the linear compressor 2 reciprocates to generate sinusoidal pressure waves; the piston moves forward, positive pressure waves sequentially pass through a main transmission pipeline 3-0, a branch pipeline I3-1, a branch pipeline II 3-2 and a branch pipeline III 3-3, an electric control valve I4-1, an electric control valve II 4-2 and an electric control valve III 4-3 are respectively arranged on the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3, and the mass flow and the PV work of the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3 to a cold head I5-1, a cold head II 5-2 and a cold head III 5-3 of a corresponding pulse tube refrigerator are controlled by adjusting the opening and closing of the valves; after the high-pressure and high-temperature gas input into the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3 and the cooling water system 6 fully exchange heat in the aftercooler I9-1, the aftercooler II 9-2 and the aftercooler III 9-3 in the pulse tube refrigerator cold head group 5, the high-pressure low-temperature gas is converted into high-pressure low-temperature gas, the high-pressure low-temperature gas enters the cold accumulator to exchange heat and is further cooled to the temperature close to that of the cold-end heat exchanger, the gas enters the pulse tube I12-1, the pulse tube II 12-2 and the pulse tube III 12-3 in the cold-end heat exchanger I11-1, the cold-end heat exchanger II 11-2 and the cold-end heat exchanger III 11-3 in a laminar flow mode, the heat insulation compression is realized, and heat is transferred to the first pulse tube hot end heat exchanger 13-1, the second pulse tube hot end heat exchanger 13-2, the third pulse tube hot end heat exchanger 13-3 and the cooling water system 6 along with the transmission direction of pressure waves to exchange heat; when a piston in the linear compressor 2 moves reversely, working gas in a compressor cavity expands, the pressure is reduced, gas expansion and oscillation refrigeration are realized in the pulse tube I12-1, the pulse tube II 12-2 and the pulse tube III 12-3, low-temperature gas passes through the cold-end heat exchanger I11-1, the cold-end heat exchanger II 11-2 and the cold-end heat exchanger III 11-3 to provide required refrigeration capacity for a user end system, then low-temperature gas enters the cold accumulator I10-1, the cold accumulator II 10-2 and the cold accumulator III 10-3 to realize a cold accumulation process, the low-temperature gas which is changed into high-temperature low-pressure gas enters a compression cavity of the linear compressor 2 after being cooled again by the aftercooler I9-1, the aftercooler II 9-2 and the aftercooler III 9-3, and the system enters the next cycle.
The invention has the advantages that:
1) the invention provides a design scheme of variable power operation and realization of adjustable application of refrigerating capacity for a large refrigerating capacity low-temperature system with three cold heads driven by a single compressor, and explains the relation between energy flow distribution and related parameters of pipelines with electric control valves from the compressors to the cold heads;
2) the invention provides adjustable voltage and current through the alternating current power supply to realize variable power operation of the linear compressor, and realizes the adjustment of the refrigerating capacity of each cold end through the opening and closing of the electric control valve or the change of the opening size state, thereby providing a new way for cold quantity distribution on three cold end heat exchangers and having great significance in the process of system design and actual application;
3) the invention solves the problem that the refrigerating capacity of the low-temperature system at the present stage is difficult to adjust correspondingly according to the requirements of the user terminal equipment under the same temperature condition, and the same set of system can meet different refrigerating capacity requirements of the user terminal equipment, so that the low-temperature system with large refrigerating capacity has more convenient operation and control, stronger application scene adaptability and higher energy efficiency ratio.
The invention provides a design application scheme of variable power operation and adjustable refrigerating capacity for a large refrigerating capacity low-temperature system with three pulse tube cold heads driven by a single compressor, can effectively solve the problem that the refrigerating capacity of a conventional low-temperature system is difficult to correspondingly adjust along with the requirement of user side equipment, enables the same system to meet the requirements of users on different refrigerating capacities, enables the large refrigerating capacity low-temperature system to have more convenient operation and control, stronger application scene adaptability and higher energy efficiency ratio, and has very positive significance for the application of a low-temperature refrigerator in the superconducting fields of intelligent power grids, advanced electric power, rail transit, high-efficiency energy storage, high-end communication and the like.
Drawings
FIG. 1 is a schematic diagram of a single-compressor three-cold-head pulse tube refrigerator with freely adjustable input work and refrigeration capacity;
FIG. 2 is a schematic diagram of a pressure wave transmission line between a compressor and a pulse tube refrigerator;
fig. 3 is a schematic diagram of the structure of the pulse tube refrigerator cold head, the cooling water system and the user equipment system;
fig. 4 is a schematic diagram of a data acquisition and control system.
Wherein: 1 is a numerical control alternating current power supply, 2 is a linear compressor, 3 is a pressure wave transmission pipeline group, 3-0 is a total transmission pipeline, 3-1 is a branch pipeline I, 3-2 is a branch pipeline II, 3-3 is a branch pipeline III, 4 is an electric control valve group, 4-1 is an electric control valve I, 4-2 is an electric control valve II, 4-3 is an electric control valve III, 5 is a pulse tube refrigerator cold head group, 5-0 is a refrigerator cold head vacuum Dewar, 5-1 is a cold head I, 5-2 is a cold head II, 5-3 is a cold head II, 6 is a cooling water system, 6-0 is a cooling water pipeline, 7 is a user side low temperature circulating system, 7-0 is a user side low temperature circulating pipeline, 8 is a data acquisition and control system, 9-1 is a rear cooler I, 9-2 is a rear cooler II, 9-3 is a rear cooler III, 10-1 is a first cold accumulator, 10-2 is a second cold accumulator, 10-3 is a third cold accumulator, 11-1 is a first cold-end heat exchanger, 11-2 is a second cold-end heat exchanger, 11-3 is a third cold-end heat exchanger, 12-1 is a first pulse tube, 12-2 is a second pulse tube, 12-3 is a third pulse tube, 13-1 is a first hot-end heat exchanger, 13-2 is a second hot-end heat exchanger, 13-3 is a third hot-end heat exchanger, 14-1 is a first inertia tube, 14-2 is a second inertia tube, 14-3 is a third inertia tube, 15-1 is a first gas reservoir, 15-2 is a second gas reservoir, and 15-3 is a third gas reservoir.
Detailed Description
The following describes embodiments of the present invention in further detail with reference to the accompanying drawings and examples.
Fig. 1 shows a single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input work and refrigerating capacity. The single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input power and refrigerating output comprises a numerical control alternating current power supply 1, a linear compressor 2, a pressure wave transmission pipeline group 3, an electric control valve group 4, a pulse tube refrigerator cold head group 5, a cooling water system 6, a user side low-temperature circulating system 7 and a data acquisition and control system 8, and is characterized in that:
the numerical control alternating current power supply 1 is used for providing power for the linear compressor 2 and can output different voltages and currents according to specific application requirements; the linear compressor 2 is used for providing alternating sinusoidal pressure waves for the rear-end pulse tube refrigerator cold head set 5, and the output PV work and pressure waveforms of the compressor can be changed through parameter adjustment of the numerical control alternating current power supply 1; the pressure wave transmission pipeline group 3 with the electric control valve group 4 leads out a total transmission pipeline 3-0 from the outlet of the compressor and is divided into a branch pipeline I3-1 provided with an electric control valve I4-1, a branch pipeline II 3-2 provided with an electric control valve II 4-2 and a branch pipeline III 3-3 provided with an electric control valve III 4-3, and the pressure wave transmission pipeline group is used for transmitting the pressure wave of the linear compressor 2 to a cold head part of the pulse tube refrigerator, and the electric control valve group 4 can be matched with the power change of the linear compressor 2 to adjust the opening or the opening and closing state of the valve; the cold head group 5 of the pulse tube refrigerator consists of three groups of linear cold head I5-1, cold head II 5-2 and cold head III 5-3, the cold head I5-1 consists of a first aftercooler 9-1, a first regenerator 10-1, a first cold end heat exchanger 11-1, a first pulse tube 12-1, a first hot end heat exchanger 13-1, an inertia tube I14-1 and a first air reservoir 15-1, the cold head II 5-2 consists of a second aftercooler 9-2, a second regenerator 10-2, a second cold end heat exchanger 11-2, a second pulse tube 12-2, a second hot end heat exchanger 13-2, a second inertia tube 14-2 and a second air reservoir 15-2, and the cold head III 5-3 consists of a third aftercooler 9-3, a third regenerator 10-3, a third cold end heat exchanger 11-3, a third pulse tube 12-3, A hot end heat exchanger III 13-3, an inertia pipe III 14-3 and an air reservoir III 15-3; three groups of components in the pulse tube refrigerator cold head group 5 can work independently, randomly in a matching way or simultaneously, and kilowatt-level refrigerating capacity can be provided in a temperature region from liquid nitrogen to liquefied natural gas; the cooling water system 6 provides constant-temperature water circulation for the first aftercooler 9-1, the second aftercooler 9-2, the third aftercooler 9-3, the first hot-end heat exchanger 13-1, the second hot-end heat exchanger 13-2 and the third hot-end heat exchanger 13-3 to exchange heat, and a spare cooling water pipeline 6-0 interface is reserved according to requirements; the user side low-temperature circulating system 7 indirectly realizes heat exchange between user side equipment and a refrigerator cold end heat exchanger I11-1, a refrigerator cold end heat exchanger II 11-2 and a refrigerator cold end heat exchanger III 11-3 by using a low-temperature circulating pipeline 7-0 and taking low-temperature liquid as a medium, and provides a low-temperature environment for the equipment; the data acquisition and control system 8 has the functions of acquiring the temperature and refrigerating capacity isoparametric of the cold-end heat exchanger I11-1, the cold-end heat exchanger II 11-2 and the cold-end heat exchanger III 11-3 and controlling the opening of the electric control valve I4-1, the electric control valve II 4-2 and the electric control valve III 4-3, and is used for monitoring and adjusting the output electric parameters of the alternating current power supply and the cold head temperature and the output refrigerating capacity of the refrigerating machine in the variable power operation process, so that a single-compressor three-cold-head pulse tube refrigerating machine capable of freely adjusting the input power and the refrigerating capacity is formed.
The input work and the refrigerating output of the single-compressor three-cold-head pulse tube refrigerator for adjusting the cold head comprise the following specific implementation modes:
1) keeping the opening of the electric control valve group 4 unchanged, adjusting the voltage and the current of the numerical control alternating current power supply 1, thereby changing the output PV work of the linear compressor 2, namely changing the amplitude and the frequency of the mass flow and the pressure wave in the three cold head pipelines, and realizing the cold quantity adjustment of the pulse tube refrigerator cold head group 5; the mode not only changes the power of the compressor, but also changes the refrigerating capacity of the refrigerating machine;
2) keeping the voltage and the current of the numerical control alternating current power supply 1 unchanged, and adjusting the opening of the electric control valve group (4), namely changing the flow resistance of a branch pipeline I3-1, a branch pipeline II 3-2 and a branch pipeline III 3-3, thereby realizing the cold quantity distribution of each cold head; in the method, under the condition that the electric power of the linear compressor 2 is not changed, the refrigerating capacities and the distribution of the first cold head 5-1, the second cold head 5-2 and the third cold head 5-3 are changed;
3) within the range of rated working parameters of the linear compressor 2, the voltage and the current of the numerical control alternating current power supply 1 are adjusted, and the opening degree of the electric control valve group 4 is correspondingly changed, so that the working quantity of the cold heads can be selected according to the requirements of user equipment or the refrigerating capacities of the first cold head 5-1, the second cold head 5-2 and the third cold head 5-3 are adjusted, and the optimal coupling characteristic of the linear compressor 2 and the cold head group 5 of the pulse tube refrigerator in practical application is realized; the mode can simultaneously change the input power and the refrigerating capacity of the refrigerating machine and realize better coupling matching characteristic.
Fig. 2 shows a pressure wave transmission line between the compressor and the pulse tube refrigerator. The method for determining the energy flow distribution and the relevant parameters in the group of pressure wave transmission pipelines with electrically controlled valves in the figure is as follows:
in the pressure wave transmission pipeline group 3 with the electric control valve group 4, the parameter of the total transmission pipeline 3-0 is the dynamic pressure P0Pressure drop Δ P0Mass flow rate
Pushing Power (PV)]0(ii) a The dynamic pressure in the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3 is respectively P1、P2、P3Pressure drop of Δ P1、ΔP2、ΔP3Mass flow of
The push work is [ PV]1、[PV]2、[PV]3。
The pressure drop in a circular transfer tube can be expressed as:
in the expression (1), f is a friction factor, L is the axial length of the measured pressure drop pipeline, and dhThe pipeline wet cycle is shown, K is loss efficiency, rho is the average density of fluid working media in the pipeline, and u is the average flow velocity of the fluid.
The mass flow in a circular pipe can be expressed as:
in expression (2)
ArRadial cross-sectional area in the direction of flow of working gas, DrIs the inner diameter of a circular pipe.
At the electrically controlled valve group 4, both the pressure drop and the mass flow rate change with the opening of the valve, which can be respectively expressed as:
in the expression (3, 4), CdIs the flow coefficient of the pipeline, AfThe radial cross-sectional area of the working gas flowing through the valve, AhUpstream and downstream flow areas of the valve.
The relationship between the mass flow and the pushing work in the total transmission pipeline 3-0 in the pressure wave transmission pipeline group 3, the branch pipeline one 3-1, the branch pipeline two 3-2 and the branch pipeline three 3-3 can be expressed as follows:
[PV]0＝[PV]1+[PV]2+[PV]3 (6)
fig. 3 is a schematic diagram of the structure of the pulse tube type refrigerator cold head, the cooling water system and the user equipment system, and fig. 4 is a schematic diagram of the data acquisition and control system. The specific working process of the single-compressor three-cold-head pulse tube refrigerator low-temperature system capable of freely adjusting input work and refrigerating capacity is as follows:
the numerical control alternating current power supply 1 provides variable voltage and current for the linear compressor 2, and a piston in the linear compressor 2 reciprocates to generate sinusoidal pressure waves; the piston moves forward, positive pressure waves sequentially pass through a main transmission pipeline 3-0, a branch pipeline I3-1, a branch pipeline II 3-2 and a branch pipeline III 3-3, an electric control valve I4-1, an electric control valve II 4-2 and an electric control valve III 4-3 are respectively arranged on the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3, and the mass flow and the PV work of the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3 to a cold head I5-1, a cold head II 5-2 and a cold head III 5-3 of a corresponding pulse tube refrigerator are controlled by adjusting the opening degree of each valve; after the high-pressure and high-temperature gas input into the branch pipeline I3-1, the branch pipeline II 3-2 and the branch pipeline III 3-3 and the cooling water system 6 fully exchange heat in the aftercooler I9-1, the aftercooler II 9-2 and the aftercooler III 9-3 in the pulse tube refrigerator cold head group 5, the high-pressure low-temperature gas is converted into high-pressure low-temperature gas, the high-pressure low-temperature gas enters the cold accumulator to exchange heat and is further cooled to the temperature close to that of the cold-end heat exchanger, the gas enters the pulse tube I12-1, the pulse tube II 12-2 and the pulse tube III 12-3 in the cold-end heat exchanger I11-1, the cold-end heat exchanger II 11-2 and the cold-end heat exchanger III 11-3 in a laminar flow mode, the heat insulation compression is realized, and heat is transferred to the first pulse tube hot end heat exchanger 13-1, the second pulse tube hot end heat exchanger 13-2, the third pulse tube hot end heat exchanger 13-3 and the cooling water system 6 along with the transmission direction of pressure waves to exchange heat; when a piston in the linear compressor 2 moves reversely, working gas in a compressor cavity expands, the pressure is reduced, gas expansion and oscillation refrigeration are realized in the pulse tube I12-1, the pulse tube II 12-2 and the pulse tube III 12-3, low-temperature gas passes through the cold-end heat exchanger I11-1, the cold-end heat exchanger II 11-2 and the cold-end heat exchanger III 11-3 to provide required refrigeration capacity for a user end system, then low-temperature gas enters the cold accumulator I10-1, the cold accumulator II 10-2 and the cold accumulator III 10-3 to realize a cold accumulation process, the low-temperature gas which is changed into high-temperature low-pressure gas enters a compression cavity of the linear compressor 2 after being cooled again by the aftercooler I9-1, the aftercooler II 9-2 and the aftercooler III 9-3, and the system enters the next cycle.
Finally, it should be noted that: it will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (3)
1. The utility model provides a three cold head pulse tube refrigerators of single compressor of free regulation input power and refrigerating output, includes numerical control alternating current power supply (1), linear compressor (2), pressure wave transmission pipeline group (3), automatically controlled valve group (4), pulse tube refrigerator cold head group (5), cooling water system (6), user side low temperature circulating system (7) and data acquisition and control system (8), its characterized in that:
the numerical control alternating current power supply (1) is used for providing power for the linear compressor (2) and outputting different voltages and currents according to specific application requirements; the linear compressor (2) is used for providing alternating sinusoidal pressure waves for a rear-end pulse tube refrigerator cold head set (5), and the output PV work and pressure waveform of the compressor are changed through parameter adjustment of the numerical control alternating current power supply (1); the pressure wave transmission pipeline group (3) with the electric control valve group (4) leads out a total transmission pipeline (3-0) from the outlet of the compressor and is divided into a branch pipeline I (3-1) provided with the electric control valve I (4-1), a branch pipeline II (3-2) provided with the electric control valve II (4-2) and a branch pipeline III (3-3) provided with the electric control valve III (4-3) and is used for transmitting pressure waves of the linear compressor (2) to a cold head part of the pulse tube refrigerator, and the electric control valve group (4) is matched with the power change of the linear compressor (2) to adjust the opening or the opening and closing state of the valve; the pulse tube refrigerator cold head group (5) comprises three groups of linear cold head I (5-1), cold head II (5-2) and cold head III (5-3), the cold head I (5-1) comprises a aftercooler I (9-1), a cold storage I (10-1), a cold end heat exchanger I (11-1), a pulse tube I (12-1), a hot end heat exchanger I (13-1), an inertia tube I (14-1) and an air reservoir I (15-1), the cold head II (5-2) comprises an aftercooler II (9-2), a cold storage II (10-2), a cold end heat exchanger II (11-2), a pulse tube II (12-2), a hot end heat exchanger II (13-2), an inertia tube II (14-2) and an air reservoir II (15-2), and the cold head III (5-3) comprises the aftercooler III (9-3), The cold accumulator III (10-3), the cold end heat exchanger III (11-3), the pulse tube III (12-3), the hot end heat exchanger III (13-3), the inertia tube III (14-3) and the air reservoir III (15-3); three groups of components in the pulse tube refrigerator cold head group (5) work independently, randomly in a matching way or simultaneously, and provide kilowatt-level refrigerating capacity in a temperature region from liquid nitrogen to liquefied natural gas; the cooling water system (6) provides constant-temperature water circulation for the aftercooler I (9-1), the aftercooler II (9-2), the aftercooler III (9-3), the hot end heat exchanger I (13-1), the hot end heat exchanger II (13-2) and the hot end heat exchanger III (13-3) to exchange heat, and a spare cooling water pipeline (6-0) interface is reserved according to requirements; the user side low-temperature circulating system (7) indirectly realizes heat exchange between user side equipment and a first refrigerator cold end heat exchanger (11-1), a second refrigerator cold end heat exchanger (11-2) and a third refrigerator cold end heat exchanger (11-3) by using a low-temperature circulating pipeline (7-0) and taking low-temperature liquid as a medium, and provides a low-temperature environment for the equipment; the data acquisition and control system (8) has the functions of acquiring the temperature and refrigerating capacity isoparametric of the first cold-end heat exchanger (11-1), the second cold-end heat exchanger (11-2) and the third cold-end heat exchanger (11-3) and controlling the opening degrees of the first electric control valve (4-1), the second electric control valve (4-2) and the third electric control valve (4-3), and is used for monitoring and adjusting the output electric parameters of the alternating current power supply and the cold head temperature and the output refrigerating capacity of the refrigerating machine in the variable power operation process, so that a single-compressor three-cold-head pulse tube refrigerating machine capable of freely adjusting the input power and the refrigerating capacity is formed together;
the specific working process of the low-temperature system of the refrigerator is as follows:
the numerical control alternating current power supply (1) provides variable voltage and current for the linear compressor (2), and a piston in the linear compressor (2) reciprocates to generate sinusoidal pressure waves; the piston moves forwards, positive pressure waves sequentially pass through a main transmission pipeline (3-0), a branch pipeline I (3-1), a branch pipeline II (3-2) and a branch pipeline III (3-3), an electric control valve I (4-1), an electric control valve II (4-2) and an electric control valve III (4-3) are respectively arranged on the branch pipeline I (3-1), the branch pipeline II (3-2) and the branch pipeline III (3-3), and the mass flow and the PV work of the corresponding pulse tube refrigerator cold head I (5-1), cold head II (5-2) and cold head III (5-3) are controlled by adjusting the opening and closing of each valve; after the high-pressure high-temperature gas input into the branch pipeline I (3-1), the branch pipeline II (3-2) and the branch pipeline III (3-3) fully exchanges heat with the cooling water system (6) by the aftercooler I (9-1), the aftercooler II (9-2) and the aftercooler III (9-3) in the pulse tube refrigerator cold head group (5), the high-pressure high-temperature gas is changed into high-pressure low-temperature gas which enters the regenerator to exchange heat and is further cooled to the temperature close to the cold end heat exchanger, the gas enters the pulse tube I (12-1), the pulse tube II (12-2) and the pulse tube III (12-3) in a laminar flow mode in the cold end heat exchanger I (11-1), the cold end heat exchanger II (11-2) and the cold end heat exchanger III (11-3), and adiabatic compression is realized and heat is transferred to the pulse tube hot end heat exchanger I (13-1) along with the transmission direction, The hot end heat exchanger II (13-2) and the hot end heat exchanger III (13-3) exchange heat with the cooling water system (6); when a piston in the linear compressor (2) moves reversely, working gas in a compressor cavity expands, the pressure is reduced, gas expansion and oscillation refrigeration are realized in the pulse tube I (12-1), the pulse tube II (12-2) and the pulse tube III (12-3), low-temperature gas provides required refrigeration capacity for a user end system through the cold end heat exchanger I (11-1), the cold end heat exchanger II (11-2) and the cold end heat exchanger III (11-3), then low-temperature gas enters the cold accumulator I (10-1), the cold accumulator II (10-2) and the cold accumulator III (10-3) to realize a cold accumulation process, the low-temperature gas which is changed into high-temperature low-pressure gas enters the linear compressor (2) compression cavity after being cooled again through the aftercooler I (9-1), the aftercooler II (9-2) and the aftercooler III (9-3), the system enters the next cycle again.
2. The single-compressor three-cold-head pulse tube refrigerator capable of freely adjusting input work and refrigerating capacity according to claim 1, wherein the refrigerating capacity of the pulse tube refrigerator cold head group (5) is adjusted by the following method:
the method comprises the steps that 1) the opening degree of an electric control valve group (4) is kept unchanged, and the voltage and the current of a numerical control alternating current power supply (1) are adjusted, so that the output PV work of a linear compressor (2) is changed, namely the amplitude and the frequency of mass flow and pressure waves in three cold head pipelines are changed, and the cold quantity adjustment of a pulse tube refrigerator cold head group (5) is realized; the mode not only changes the power of the compressor, but also changes the refrigerating capacity of the refrigerating machine;
the method 2) keeps the voltage and the current of the numerical control alternating current power supply (1) unchanged, and adjusts the opening of the electric control valve group (4), namely the flow resistance of a branch pipeline I (3-1), a branch pipeline II (3-2) and a branch pipeline III (3-3) is changed, thereby realizing the cold quantity distribution of each cold head; in the method, under the condition that the electric power of the linear compressor (2) is not changed, the refrigerating capacity and distribution of the first cold head (5-1), the second cold head (5-2) and the third cold head (5-3) are changed;
method 3) in the rated working parameter range of the linear compressor (2), adjust the voltage and current of the numerical control AC power supply (1), and change the opening of the electric control valve group (4) correspondingly, choose the quantity of cold head work or adjust the refrigeration capacity of cold head one (5-1), cold head two (5-2) and cold head three (5-3) according to the demand of the user equipment like this, realize the linear compressor (2) and pulse tube refrigerator cold head group (5) in the best coupling characteristic in the actual application; the mode simultaneously changes the input power and the refrigerating capacity of the refrigerating machine and realizes better coupling matching characteristic.
3. A single compressor three cold head pulse tube refrigerator with freely adjustable work input and refrigeration capacity as claimed in claim 1, characterized in that the method of determining the energy flow distribution and related parameters in the set of pressure wave transmission lines (3) with electrically controlled valves is as follows:
in the pressure wave transmission pipeline group (3) with the electric control valve group (4), the parameter of the total transmission pipeline (3-0) has dynamic pressure P0Pressure drop Δ P0Mass flow rate
Pushing Power (PV)]0(ii) a The dynamic pressure in the branch pipeline I (3-1), the branch pipeline II (3-2) and the branch pipeline III (3-3) is respectively P1、P2、P3Pressure drop of Δ P1、ΔP2、ΔP3Mass flow of
The push work is [ PV]1、[PV]2、[PV]3。
The pressure drop in the round transfer tube is expressed as:
in the expression (1), f is a friction factor, L is the axial length of the measured pressure drop pipeline, and dhThe pipeline wet cycle is shown, K is loss efficiency, rho is the average density of fluid working media in the pipeline, and u is the average flow velocity of the fluid.
The mass flow in a circular pipe is expressed as:
in expression (2)
ArRadial cross-sectional area in the direction of flow of working gas, DrIs the inner diameter of a circular pipe.
At the position of the electric control valve group (4), the pressure drop and the mass flow can be changed along with the opening of the valve, and are respectively expressed as:
in the expression (3, 4), CdIs the flow coefficient of the pipeline, AfThe radial cross-sectional area of the working gas flowing through the valve, AhUpstream and downstream flow areas of the valve.
The relation between the mass flow and the pushing work in the total transmission pipeline (3-0) in the pressure wave transmission pipeline group (3), the branch pipeline I (3-1), the branch pipeline II (3-2) and the branch pipeline III (3-3) is expressed as follows:
[PV]0＝[PV]1+[PV]2+[PV]3。 (6)
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| CN114576878A (en) * | 2022-02-28 | 2022-06-03 | 武汉高芯科技有限公司 | Double-cold-head high-power-weight-ratio linear low-temperature mechanical refrigerator |
| CN116052976A (en) * | 2023-03-29 | 2023-05-02 | 江西联创光电超导应用有限公司 | Coil device of superconducting magnet and control method thereof |
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