阅读说明：本技术 采用混合工质的喷射器增效的j-t制冷循环系统及控制方法 (J-T refrigeration cycle system adopting mixed working medium ejector for efficiency enhancement and control method ) 是由 鱼剑琳 俞梦琪 刘晔 白涛 晏刚 钱苏昕 于 2021-01-08 设计创作，主要内容包括：本发明公开了一种采用混合工质的喷射器增效J-T制冷循环系统及控制方法,该系统包括压缩机,冷却器,第一回热器,可调喷射器,第二回热器,电子膨胀阀,蒸发器和控制器；该系统通过配置喷射器,利用第一回热器出口的高压混合工质作为一次流体,引射来自第二回热器出口的低压两相混合工质,从而提高压缩机的吸气压力,降低功耗；该系统取消了喷射器增效循环中常用的气液分离器,简化了制冷系统,避免了喷射器增效系统中常见的回油问题；与采用气液分离器的系统相比,该系统分别通过第一回热器和第二回热器以保证压缩机吸气为过热气体和电子膨胀阀进口为过冷液体,将降低进入蒸发器的混合工质焓值,有效提高系统制冷量和系统效率。(The invention discloses an ejector synergistic J-T refrigeration cycle system adopting mixed working media and a control method, wherein the system comprises a compressor, a cooler, a first heat regenerator, an adjustable ejector, a second heat regenerator, an electronic expansion valve, an evaporator and a controller; the system uses the high-pressure mixed working medium at the outlet of the first heat regenerator as a primary fluid by configuring an ejector to eject the low-pressure two-phase mixed working medium from the outlet of the second heat regenerator, thereby improving the suction pressure of the compressor and reducing the power consumption; the system cancels a gas-liquid separator which is commonly used in the synergistic circulation of the ejector, simplifies a refrigeration system and avoids the common oil return problem in the synergistic system of the ejector; compared with a system adopting a gas-liquid separator, the system ensures that the suction gas of the compressor is superheated gas and the inlet of the electronic expansion valve is supercooled liquid through the first heat regenerator and the second heat regenerator respectively, so that the enthalpy value of a mixed working medium entering the evaporator is reduced, and the refrigerating capacity and the system efficiency of the system are effectively improved.)

1. An ejector synergistic J-T refrigeration cycle system adopting mixed working media is characterized in that: the system comprises a compressor (101), a cooler (102), a first heat regenerator (103), an adjustable ejector (104), a second heat regenerator (105), an electronic expansion valve (106) and an evaporator (107); the exhaust outlet of the compressor (101) is connected with the inlet of the cooler (102); the outlet of the cooler (102) is connected with the hot flow side inlet of the first heat regenerator (103); the outlet of the hot flow side of the first heat regenerator (103) is connected with the primary flow inlet of the adjustable ejector (104); the outlet of the adjustable ejector (104) is divided into two paths, and one path is connected with the hot flow side inlet of the second heat regenerator (105); the hot flow side outlet of the second heat regenerator (105) is connected with the inlet of the evaporator (107) through an electronic expansion valve (106); the outlet of the evaporator (107) is connected with the cold flow side inlet of the second regenerator (105); the cold flow side outlet of the second regenerator (105) is connected with the secondary flow inlet of the adjustable ejector (104); the other path of the outlet of the adjustable ejector (104) is connected with the cold flow side inlet of the first heat regenerator (103); the cold flow side outlet of the first heat regenerator (103) is connected with the suction inlet of the compressor (101) to form a whole refrigeration cycle system; a first temperature measuring point (1) and a first pressure measuring point (2) are arranged at an outlet of a cold flow side of the first heat regenerator (103); a second temperature measuring point (3) and a second pressure measuring point (4) are arranged at the outlet of the heat flow side of the second regenerator (105); a controller (108) is arranged in the refrigeration cycle system, the input end of the controller (108) is connected with a first temperature measuring point (1), a first pressure measuring point (2), a second temperature measuring point (3) and a second pressure measuring point (4), and the output end of the controller (108) is connected with a driving mechanism of the adjustable ejector (104) and a driving mechanism of the electronic expansion valve (106); the controller (108) converts the received pressure signal into a temperature signal, then obtains the superheat degree of the outlet of the first heat regenerator (103) and the supercooling degree of the outlet of the second heat regenerator (105) respectively, and finally outputs adjusting signals to driving mechanisms of the adjustable ejector (104) and the electronic expansion valve (106) respectively.

2. The ejector enhanced J-T refrigeration cycle system using mixed working fluid as claimed in claim 1, wherein: the outlet of the hot flow side of the first heat regenerator (103) is connected with the primary flow inlet of the adjustable ejector (104), and the high-pressure liquid fluid in the path is used as the working fluid of the adjustable ejector (104) to inject the low-pressure mixed working medium from the outlet of the cold flow side of the second heat regenerator (105); the two mixed working mediums are fully mixed in a mixing chamber of the adjustable ejector (104) and are discharged from an outlet of a diffusion chamber of the adjustable ejector (104) in a two-phase medium-pressure state; by configuring the adjustable ejector, the suction pressure of the compressor (101) is improved by utilizing the boosting effect of the adjustable ejector, the pressure ratio of the compressor (101) is reduced, and therefore the power consumption of the compressor (101) is reduced.

3. The ejector enhanced J-T refrigeration cycle system using mixed working fluid as claimed in claim 1, wherein: the outlet of the adjustable ejector (104) is not provided with a gas-liquid separator, but is divided into two paths, one path is connected with the cold flow side inlet of the first heat regenerator (103), and the cold flow side outlet of the first heat regenerator (103) is connected with the air suction port of the compressor (101); the method comprises the steps of arranging a first heat regenerator (103), heating a gas-liquid two-phase mixed working medium in the path to an overheated gas-state mixed working medium in the first heat regenerator (103), enabling the mixed working medium entering a compressor (101) to be in an overheated state, preventing the compressor (101) from sucking liquid, connecting the other path of an outlet of an adjustable ejector (104) with a hot flow side inlet of a second heat regenerator (105), connecting a hot flow side outlet of the second heat regenerator (105) with an inlet of an electronic expansion valve (106), and cooling the path of the two-phase mixed working medium in the second heat regenerator (105) to be an overcooled liquid mixed working medium by arranging the second heat regenerator (105), so that the mixed working medium entering the electronic expansion valve (106) is cooled to an overcooled state, the enthalpy value of the mixed working medium is reduced, and the refrigerating capacity and the system efficiency are improved.

4. The ejector enhanced J-T refrigeration cycle system using mixed working fluid as claimed in claim 1, wherein: the diameter of the throat part of the nozzle of the adjustable ejector (104) is variable, and the area of the throat part of the nozzle is controlled through the axial position of an adjustable needle in the center of the nozzle, so that the flow rate of the mixed working medium at the outlet of the cooler (102) is adjusted.

5. The method for controlling an ejector-enhanced J-T refrigeration cycle system using a mixed working fluid according to any one of claims 1 to 4, wherein: when the refrigeration cycle system normally operates, the compressor (101) is started, a suction opening of the compressor (101) is connected with a cold flow side outlet of the first heat regenerator (103), the controller (108) acquires the temperature T1 of a first temperature measuring point (1) and the pressure P2 of a first pressure measuring point (2) at the cold flow side outlet of the first heat regenerator (103) on line, and the controller (108) outputs corresponding adjusting signals to a driving mechanism of the adjustable ejector (104) to adjust the throat area of the nozzle, so that the mixed working medium at the cold flow side outlet of the first heat regenerator (103) is heated to an overheated state; a heat flow side outlet of the second heat regenerator (105) is connected with an inlet of the electronic expansion valve (106), the controller (108) acquires the temperature T3 of a second temperature measuring point (3) and the pressure P4 of a second pressure measuring point (4) of the heat flow side outlet of the second heat regenerator (105), and the controller (108) outputs corresponding adjusting signals to a driving mechanism of the electronic expansion valve (106) to adjust the opening degree of the electronic expansion valve (106) so that the mixed working medium at the heat flow side outlet of the second heat regenerator (105) is cooled to a supercooled state;

the controller (108) outputs a corresponding adjusting signal to a driving mechanism of the adjustable ejector (104) to adjust the throat area of the nozzle, so that the specific method for heating the mixed working medium at the outlet of the cold flow side of the first heat regenerator (103) to an overheated state is as follows: the controller (108) collects the temperature T1 and the pressure P2 of the cold flow side outlet of the first heat regenerator (103) on line, converts the pressure P2 into the saturation temperature T2 of the mixed working medium under corresponding pressure, and enables delta 1 to be T1-T2; the controller 108 sets the degree of superheat to θ 1 and the control accuracy to Δ; when the delta 1 is theta 1 +/-delta, namely the mixed working medium is in an overheating state and the overheating is theta 1 +/-delta, the controller (108) does not output an adjusting signal; when delta 1 is less than theta 1-delta, the controller (108) outputs an adjusting signal to a driving mechanism of the adjustable ejector (104), the throat area of a nozzle is increased, the flow of an outlet of the cooler (102) is increased, namely, the heat exchange quantity of the first heat regenerator (103) is increased, the superheat degree of a mixed working medium at an outlet of a cold flow side of the first heat regenerator (103) is increased, and the driving mechanism of the adjustable ejector (104) does not act until the superheat degree is increased to theta 1; when delta 1 is larger than theta 1+ delta, the controller (108) outputs an adjusting signal to a driving mechanism of the adjustable ejector (104), the throat area of a nozzle is reduced, the flow of an outlet of the cooler (102) is reduced, namely the heat exchange quantity of the first heat regenerator (103) is reduced, so that the superheat degree of a mixed working medium at an outlet of a cold flow side of the first heat regenerator (103) is reduced, and the driving mechanism of the adjustable ejector (104) does not act until the superheat degree is reduced to theta 1;

the specific method that the controller (108) outputs a corresponding adjusting signal to a driving mechanism of the electronic expansion valve (106) to adjust the opening degree of the electronic expansion valve (106) so that the mixed working medium at the hot flow side outlet of the second heat regenerator (105) is cooled to the supercooled state is as follows: the controller (108) acquires the temperature T3 and the pressure P4 of the cold flow side outlet of the second heat regenerator (105) on line, converts the pressure P4 into the saturation temperature T4 of the mixed working medium under corresponding pressure, and enables delta 2 to be T3-T4; the controller 108 sets the supercooling degree as theta 2 (theta 2 is more than 0), and sets the control precision as delta; namely, when the mixed working medium is in a supercooled state and is supercooled by theta 2 +/-delta, the controller (108) does not output an adjusting signal; when delta 2 < -theta 2 < -delta, the controller (108) outputs an adjusting signal to a driving mechanism of the electronic expansion valve (106), reduces the opening degree of the electronic expansion valve (106), reduces the flow of an outlet of the evaporator (107), namely reduces the heat exchange quantity of the second heat regenerator (105), reduces the supercooling degree of the mixed working medium at an outlet of a heat flow side of the second heat regenerator (105), and the driving mechanism of the electronic expansion valve (106) does not act until the supercooling degree is reduced to theta 2; when delta 2 > -theta 2+ delta, the controller (108) outputs an adjusting signal to a driving mechanism of the electronic expansion valve (106), the opening degree of the electronic expansion valve (106) is increased, the flow of an outlet of the evaporator (107) is increased, namely, the cold quantity of the second heat regenerator (105) is increased, so that the supercooling degree of the mixed working medium at the outlet of the heat flow side of the second heat regenerator (105) is increased, and the driving mechanism of the electronic expansion valve (106) does not act until the supercooling degree is increased to theta 2 ℃.

Technical Field

The invention belongs to the technical field of refrigeration and low temperature, and particularly relates to a mixed working medium throttling refrigeration cycle system applied to the synergy of an ejector of a low-temperature refrigerator (a refrigerator) and a control method.

Background

With the development of medical technology and the improvement of industrialization level, people have more and more demands on low-temperature refrigeration technology. A low-temperature freezer (refrigerator) is an incubator in which the temperature in the incubator is reduced to-80 ℃ or lower, and is generally used for storing valuable medical supplies or industrial materials. Currently, there are refrigeration methods for obtaining low temperatures of-80 ℃ and below: cascade type compression refrigeration, self-cascade type compression refrigeration, mixed working medium throttling refrigeration applying Joule-Thomson effect (J-T effect), and the like. The J-T throttling refrigeration adopting the mixed working medium has the advantages of few system components, stable work and the like, and the 120-plus 240K temperature region can be realized only by adopting single-stage compression. However, the mixed working medium throttling refrigeration adopts the expansion valve as the only throttling device, so that large throttling loss exists, and the refrigeration performance is low.

The ejector has the advantages of simple structure, no moving part, reliable work and the like, and when the ejector is applied to a vapor compression refrigeration system, the expansion work lost in the throttling process can be effectively recovered, the suction pressure of the compressor is improved, and the power consumption of the compressor is reduced. However, most of the prior art uses a combination of an ejector and a gas-liquid separator to increase the suction pressure of the refrigeration cycle and to ensure that the compressor suction is free of liquid. The gas-liquid separator causes a complex system, and the refrigerating machine oil is easily accumulated at the bottom of the gas-liquid separator, which causes difficulty in oil return of the compressor.

Disclosure of Invention

In order to solve the above problems in the prior art, an object of the present invention is to provide a J-T refrigeration cycle system and a control method using ejector synergy of mixed working media. On the basis of the traditional mixed working medium throttling refrigeration system, an ejector and a second heat regenerator are introduced. The system does not adopt a gas-liquid separator commonly used in the synergistic cycle of the ejector, but performs flow division at the outlet of the ejector, and two heat regenerators are arranged to respectively ensure that the mixed working medium of the compressor is in a supercooled liquid state without carrying liquid during air extraction and the inlet of the electronic expansion valve. Therefore, the new circulation improves the suction pressure of the compressor and reduces the power consumption of the compressor by configuring the ejector; meanwhile, the common oil return problem in the ejector synergy system is avoided, and the enthalpy value of the mixed working medium entering the evaporator is reduced through secondary heat return, so that the working performance of the refrigeration cycle system is obviously improved, and a certain promotion effect is provided for the application of the mixed working medium throttling refrigeration cycle in the ultra-low temperature refrigerator.

In order to achieve the purpose, the technical scheme of the invention is as follows:

an ejector synergistic J-T refrigeration cycle system adopting mixed working media comprises a compressor 101, a cooler 102, a first heat regenerator 103, an adjustable ejector 104, a second heat regenerator 105, an electronic expansion valve 106 and an evaporator 107; the exhaust outlet of the compressor 101 is connected with the inlet of the cooler 102; the outlet of the cooler 102 is connected with the hot-side inlet of the first heat regenerator 103; the hot flow side outlet of the first recuperator 103 is connected to the primary flow inlet of the variable ejector 104; the outlet of the adjustable ejector 104 is divided into two paths, and one path is connected with the hot flow side inlet of the second heat regenerator 105; the hot-side outlet of the second regenerator 105 is connected to the inlet of the evaporator 107 via an electronic expansion valve 106; the outlet of evaporator 107 is connected to the cold-flow-side inlet of second regenerator 105; the cold flow side outlet of the second regenerator 105 is connected to the secondary flow inlet of the tunable ejector 104; the other path of the outlet of the adjustable ejector 104 is connected with the cold flow side inlet of the first heat regenerator 103; the cold flow side outlet of the first heat regenerator 103 is connected with the suction inlet of the compressor 101 to form a whole refrigeration cycle system; a first temperature measuring point 1 and a first pressure measuring point 2 are arranged at an outlet of the cold flow side of the first heat regenerator 103; a second temperature measuring point 3 and a second pressure measuring point 4 are arranged at the outlet of the heat flow side of the second regenerator 105; a controller 108 is arranged in the refrigeration cycle system, the input end of the controller 108 is connected with a first temperature measuring point 1, a first pressure measuring point 2, a second temperature measuring point 3 and a second pressure measuring point 4, and the output end of the controller 108 is connected with a driving mechanism of the adjustable ejector 104 and a driving mechanism of the electronic expansion valve 106; the controller 108 converts the received pressure signal into a temperature signal, then obtains the superheat degree of the outlet of the first regenerator 103 and the supercooling degree of the outlet of the second regenerator 105, and finally outputs the adjusting signal to the driving mechanisms of the adjustable ejector 104 and the electronic expansion valve 106.

The hot-flow side outlet of the first heat regenerator 103 is connected with the primary flow inlet of the adjustable ejector 104, and the high-pressure liquid fluid in the path is used as the working fluid of the adjustable ejector 104 to inject the low-pressure mixed working medium from the cold-flow side outlet of the second heat regenerator 105; the two mixed working mediums are fully mixed in the mixing chamber of the adjustable ejector 104 and are discharged from the outlet of the diffusion chamber of the adjustable ejector 104 in a two-phase medium-pressure state; by configuring the adjustable ejector, the suction pressure of the compressor 101 is increased by its boosting effect, the pressure ratio thereof is reduced, and thus the power consumption of the compressor 101 is reduced.

The outlet of the adjustable ejector 104 is not provided with a gas-liquid separator, but is divided into two paths, one path is connected with the cold flow side inlet of the first heat regenerator 103, and the cold flow side outlet of the first heat regenerator 103 is connected with the air suction port of the compressor 101; by configuring the first heat regenerator 103, the gas-liquid two-phase mixed working medium in the path is heated to be an overheated gas-state mixed working medium in the first heat regenerator 103, so that the mixed working medium entering the compressor 101 is in an overheated state, and the compressor 101 is prevented from sucking air and carrying liquid; the other path of the outlet of the adjustable ejector 104 is connected with the hot flow side inlet of the second heat regenerator 105, and the hot flow side outlet of the second heat regenerator 105 is connected with the inlet of the electronic expansion valve 106; by configuring the second heat regenerator 105, the two-phase mixed working medium of the path is cooled to be a supercooled liquid mixed working medium in the second heat regenerator 105, so that the mixed working medium entering the electronic expansion valve 106 is cooled to be in a supercooled state, the enthalpy value of the mixed working medium is reduced, and the refrigerating capacity and the system efficiency are improved.

The throat diameter of the nozzle of the adjustable ejector 104 is variable, and the area of the throat of the nozzle is controlled by the axial position of an adjustable needle in the center of the nozzle, so that the flow of the mixed working medium at the outlet of the cooler 102 is adjusted.

When the refrigerating cycle system normally operates, the compressor 101 is started, the air suction port of the compressor 101 is connected with the cold flow side outlet of the first heat regenerator 103, the controller 108 acquires the temperature T1 of the first temperature measuring point 1 and the pressure P2 of the first pressure measuring point 2 at the cold flow side outlet of the first heat regenerator 103 on line, and the controller 108 outputs corresponding adjusting signals to the driving mechanism of the adjustable ejector 104 to adjust the throat area of the nozzle, so that the mixed working medium at the cold flow side outlet of the first heat regenerator 103 is heated to an overheated state; the outlet on the hot flow side of the second thermal regenerator 105 is connected with the inlet of the electronic expansion valve 106, the controller 108 acquires the temperature T3 at the second temperature measuring point 3 and the pressure P4 at the second pressure measuring point 4 at the outlet on the hot flow side of the second thermal regenerator 105, and the controller 108 outputs a corresponding adjusting signal to the driving mechanism of the electronic expansion valve 106 to adjust the opening degree of the electronic expansion valve 106, so that the mixed working medium at the outlet on the hot flow side of the second thermal regenerator 105 is cooled to a supercooled state;

the controller 108 outputs a corresponding adjusting signal to the driving mechanism of the adjustable ejector 104 to adjust the throat area of the nozzle, so that the specific method for heating the mixed working medium at the cold flow side outlet of the first heat regenerator 103 to the superheated state is as follows: the controller 108 acquires the temperature T1 and the pressure P2 of the outlet of the cold flow side of the first heat regenerator 103 on line, calculates the saturation temperature T2 of the mixed working medium corresponding to the pressure P2 according to a refrigerant thermodynamic calculation equation by taking the pressure P2 as an input parameter, and enables delta 1 to be T1-T2; the controller 108 sets the degree of superheat to θ 1 and the control accuracy to Δ; when the δ 1 is θ 1 ± Δ, that is, the mixed working medium is in an overheated state, and the overheated θ 1 ± Δ, the controller 108 does not output the adjustment signal; when the delta 1 is less than theta 1-delta, the controller 108 outputs an adjusting signal to a driving mechanism of the adjustable ejector 104, the throat area of a nozzle is increased, the flow of the outlet of the cooler 102 is increased, namely, the heat exchange quantity of the first heat regenerator 103 is improved, the superheat degree of the mixed working medium at the outlet of the cold flow side of the first heat regenerator 103 is increased, and the driving mechanism of the adjustable ejector 104 does not act until the superheat degree is increased to theta 1; when the delta 1 is larger than theta 1+ delta, the controller 108 outputs an adjusting signal to a driving mechanism of the adjustable ejector 104, the throat area of a nozzle is reduced, the flow of the outlet of the cooler 102 is reduced, namely, the heat exchange quantity of the first heat regenerator 103 is reduced, so that the superheat degree of the mixed working medium at the outlet of the cold flow side of the first heat regenerator 103 is reduced, and the driving mechanism of the adjustable ejector 104 does not act until the superheat degree is reduced to the theta 1;

the specific method for the controller 108 to output the corresponding adjustment signal to the driving mechanism of the electronic expansion valve 106 for adjusting the opening degree of the electronic expansion valve 106 so that the mixed working medium at the hot flow side outlet of the second heat regenerator 105 is cooled to the supercooled state is as follows: the controller 108 acquires the temperature T3 and the pressure P4 of the outlet of the cold flow side of the second heat regenerator 105 on line, calculates the saturation temperature T4 of the mixed working medium corresponding to the pressure P4 according to a refrigerant thermodynamic property calculation equation by taking the pressure P4 as an input parameter, and makes delta 2 be T3-T4; the controller 108 sets the supercooling degree as theta 2 (theta 2 is more than 0), and sets the control precision as delta; that is, when the mixed working medium is in the overcooled state and the overcooled state is θ 2 ± Δ, the controller 108 does not output the adjustment signal; when delta 2 < -theta 2 < -delta, the controller 108 outputs the adjusting signal to the driving mechanism of the electronic expansion valve 106, reduces the opening degree of the electronic expansion valve 106, reduces the flow at the outlet of the evaporator 107, namely reduces the heat exchange quantity of the second heat regenerator 105, reduces the supercooling degree of the mixed working medium at the outlet of the heat flow side of the second heat regenerator 105, and the driving mechanism of the electronic expansion valve 106 does not act until the supercooling degree is reduced to theta 2; when delta 2 > -theta 2+ delta, the controller 108 outputs the adjusting signal to the driving mechanism of the electronic expansion valve 106, the opening degree of the electronic expansion valve 106 is increased, the flow rate of the outlet of the evaporator 107 is increased, namely, the cold quantity of the second heat regenerator 105 is increased, so that the supercooling degree of the mixed working medium at the outlet of the heat flow side of the second heat regenerator 105 is increased, and the driving mechanism of the electronic expansion valve 106 does not act until the supercooling degree is increased to theta 2 ℃.

Compared with the conventional J-T mixed working medium throttling refrigeration cycle system, the novel ejector synergistic mixed working medium throttling refrigeration cycle system has the following beneficial effects:

(1) the ejector used by the system has the advantages of simple structure, stable operation and the like; the pressure boosting capacity of the ejector can effectively improve the suction pressure of the compressor and reduce the pressure ratio of the inlet and the outlet of the compressor, thereby reducing the power consumption of the compressor.

(2) The system eliminates a gas-liquid separator at the outlet of the ejector, so the system is simpler, and the oil return problem which is common in an ejector synergy system is avoided.

(3) The system adopts a first heat regenerator 103 and a second heat regenerator 105, which respectively ensure that the inlet air of the compressor is superheated gaseous mixed working medium and the inlet of the electronic expansion valve is supercooled liquid mixed working medium; on the one hand, the enthalpy value of the mixed working medium entering the evaporator is reduced, and the refrigerating capacity is improved; on the other hand, the evaporation pressure of the mixed working medium in the evaporator is improved, and the pressure ratio of the compressor is reduced, so that the system efficiency is effectively improved.

Drawings

FIG. 1 is a schematic view of a refrigeration cycle system of the present invention;

fig. 2 is a flow chart of the control method 1 of the invention;

fig. 3 is a flowchart of the control method 2 of the present invention.

In the figure: 1. a compressor suction port temperature measuring point 2, a compressor suction port pressure measuring point 3, an electronic expansion valve inlet temperature measuring point 4, an electronic expansion valve inlet pressure measuring point 101, a compressor 102, a cooler 103, a first regenerator 104, an adjustable ejector 105, a second regenerator 106, an electronic expansion valve 107, an evaporator 108 and a controller.

Detailed Description

The invention is further described below with reference to the accompanying drawings.

As shown in fig. 1, the ejector synergistic J-T refrigeration cycle system using mixed working medium of the present invention includes a compressor 101, a cooler 102, a first heat regenerator 103, an adjustable ejector 104, a second heat regenerator 105, an electronic expansion valve 106, and an evaporator 107; the exhaust outlet of the compressor 101 is connected with the inlet of the cooler 102; the outlet of the cooler 102 is connected with the hot-side inlet of the first heat regenerator 103; the hot flow side outlet of the first recuperator 103 is connected to the primary flow inlet of the variable ejector 104; the outlet of the adjustable ejector 104 is divided into two paths, and one path is connected with the hot flow side inlet of the second heat regenerator 105; the hot-side outlet of the second regenerator 105 is connected to the inlet of the evaporator 107 via an electronic expansion valve 106; the outlet of evaporator 107 is connected to the cold-flow-side inlet of second regenerator 105; the cold flow side outlet of the second regenerator 105 is connected to the secondary flow inlet of the tunable ejector 104; the other path of the outlet of the adjustable ejector 104 is connected with the cold flow side inlet of the first heat regenerator 103; the cold flow side outlet of the first heat regenerator 103 is connected with the suction inlet of the compressor 101 to form a whole refrigeration cycle system; a first temperature measuring point 1 and a first pressure measuring point 2 are arranged at an outlet of the cold flow side of the first heat regenerator 103; a second temperature measuring point 3 and a second pressure measuring point 4 are arranged at the outlet of the heat flow side of the second regenerator 105; a controller 108 is arranged in the refrigeration cycle system, the input end of the controller 108 is connected with a first temperature measuring point 1, a first pressure measuring point 2, a second temperature measuring point 3 and a second pressure measuring point 4, and the output end of the controller 108 is connected with a driving mechanism of the adjustable ejector 104 and a driving mechanism of the electronic expansion valve 106; the controller 108 converts the received pressure signal into a temperature signal, then obtains the superheat degree of the outlet of the first regenerator 103 and the supercooling degree of the outlet of the second regenerator 105, and finally outputs the adjusting signal to the driving mechanisms of the adjustable ejector 104 and the electronic expansion valve 106.

With reference to fig. 1, the working method of the ejector-enhanced J-T refrigeration cycle system comprises the following steps: the high-pressure gaseous mixed working medium at the outlet of the compressor 101 enters the cooler 102 and is cooled into a gas-liquid two-phase mixed working medium in an isobaric state; the part of the two-phase mixed working medium enters a first heat regenerator 103 and is cooled into a saturated liquid mixed working medium; the high-pressure liquid mixed working medium enters a primary flow inlet of the ejector 104, and is used as a working fluid to expand and reduce pressure in a nozzle to eject saturated gaseous mixed working medium from a cold flow side outlet of the second heat regenerator 105; the two mixed working mediums are fully mixed in the ejector 104, and are discharged from the outlet of the ejector 104 after being boosted; the gas-liquid two-phase mixed working medium in the medium-pressure state at the outlet of the ejector 104 is divided into two paths, wherein the two-phase mixed working medium in one path enters the second heat regenerator 105 as a hot flow side and is condensed into a mixed working medium in a supercooled liquid state; the part of the supercooled liquid mixed working medium enters an expansion valve 106 to be throttled and decompressed to become a low-temperature and low-pressure two-phase mixed working medium, and then enters an evaporator 107 to be evaporated and absorb heat, so that the refrigeration effect is achieved; the gas-liquid two-phase mixed working medium at the outlet of the evaporator 107 continues to enter the second heat regenerator 105 as a cold flow side for precooling, and then is heated into a two-phase mixed working medium; the two-phase mixed working medium at the outlet of the second heat regenerator 105 is used as a secondary fluid and is injected by the injector 104; the other path of the gas-liquid two-phase mixed working medium in the medium pressure state at the outlet of the ejector 104 is used as the cold flow side of the first heat regenerator 103 to cool the gas-liquid two-phase mixed working medium coming out of the cooler 102, and the gas-liquid two-phase mixed working medium is heated to be overheated gaseous mixed working medium and then enters the compressor 101, so that the whole refrigeration cycle process is completed.

According to the control method of the ejector synergistic J-T refrigeration cycle system adopting the mixed working medium, when the refrigeration cycle system normally operates, the compressor 101 is started, the air suction port of the compressor 101 is connected with the cold flow side outlet of the first heat regenerator 103, the controller 108 acquires the temperature T1 of the first temperature measuring point 1 and the pressure P2 of the first pressure measuring point 2 at the cold flow side outlet of the first heat regenerator 103 on line, and the controller 108 outputs corresponding adjusting signals to the driving mechanism of the adjustable ejector 104 to adjust the throat area of the nozzle, so that the mixed working medium at the cold flow side outlet of the first heat regenerator 103 is heated to an overheated state; the outlet on the hot flow side of the second thermal regenerator 105 is connected with the inlet of the electronic expansion valve 106, the controller 108 acquires the temperature T3 at the second temperature measuring point 3 and the pressure P4 at the second pressure measuring point 4 at the outlet on the hot flow side of the second thermal regenerator 105, and the controller 108 outputs a corresponding adjusting signal to the driving mechanism of the electronic expansion valve 106 to adjust the opening degree of the electronic expansion valve 106, so that the mixed working medium at the outlet on the hot flow side of the second thermal regenerator 105 is cooled to a supercooled state;

as shown in fig. 2, the specific method for the controller 108 to output a corresponding adjustment signal to the driving mechanism of the adjustable ejector 104 for adjusting the throat area of the nozzle so that the mixed working fluid at the outlet of the cold flow side of the first heat regenerator 103 is heated to the superheated state is as follows: the controller 108 acquires the temperature T1 and the pressure P2 of the outlet of the cold flow side of the first heat regenerator 103 on line, calculates the saturation temperature T2 of the mixed working medium corresponding to the pressure P2 according to a refrigerant thermodynamic calculation equation by taking the pressure P2 as an input parameter, and enables delta 1 to be T1-T2; the controller 108 sets the degree of superheat to θ 1 and the control accuracy to Δ; when the δ 1 is θ 1 ± Δ, that is, the mixed working medium is in an overheated state, and the overheated θ 1 ± Δ, the controller 108 does not output the adjustment signal; when the delta 1 is less than theta 1-delta, the controller 108 outputs an adjusting signal to a driving mechanism of the adjustable ejector 104, the throat area of a nozzle is increased, the flow of the outlet of the cooler 102 is increased, namely, the heat exchange quantity of the first heat regenerator 103 is improved, the superheat degree of the mixed working medium at the outlet of the cold flow side of the first heat regenerator 103 is increased, and the driving mechanism of the adjustable ejector 104 does not act until the superheat degree is increased to theta 1; when the delta 1 is larger than theta 1+ delta, the controller 108 outputs an adjusting signal to a driving mechanism of the adjustable ejector 104, the throat area of a nozzle is reduced, the flow of the outlet of the cooler 102 is reduced, namely, the heat exchange quantity of the first heat regenerator 103 is reduced, so that the superheat degree of the mixed working medium at the outlet of the cold flow side of the first heat regenerator 103 is reduced, and the driving mechanism of the adjustable ejector 104 does not act until the superheat degree is reduced to the theta 1;

as shown in fig. 3, the specific method for the controller 108 to output the corresponding adjustment signal to the driving mechanism of the electronic expansion valve 106 to adjust the opening degree of the electronic expansion valve 106 so that the mixed working medium at the hot side outlet of the second regenerator 105 is cooled to the sub-cooled state is as follows: the controller 108 acquires the temperature T3 and the pressure P4 of the outlet of the cold flow side of the second heat regenerator 105 on line, calculates the saturation temperature T4 of the mixed working medium corresponding to the pressure P4 according to a refrigerant thermodynamic property calculation equation by taking the pressure P4 as an input parameter, and makes delta 2 be T3-T4; the controller 108 sets the supercooling degree as theta 2 (theta 2 is more than 0), and sets the control precision as delta; that is, when the mixed working medium is in the overcooled state and the overcooled state is θ 2 ± Δ, the controller 108 does not output the adjustment signal; when delta 2 < -theta 2 < -delta, the controller 108 outputs the adjusting signal to the driving mechanism of the electronic expansion valve 106, reduces the opening degree of the electronic expansion valve 106, reduces the flow at the outlet of the evaporator 107, namely reduces the heat exchange quantity of the second heat regenerator 105, reduces the supercooling degree of the mixed working medium at the outlet of the heat flow side of the second heat regenerator 105, and the driving mechanism of the electronic expansion valve 106 does not act until the supercooling degree is reduced to theta 2; when delta 2 > -theta 2+ delta, the controller 108 outputs the adjusting signal to the driving mechanism of the electronic expansion valve 106, the opening degree of the electronic expansion valve 106 is increased, the flow rate of the outlet of the evaporator 107 is increased, namely, the cold quantity of the second heat regenerator 105 is increased, so that the supercooling degree of the mixed working medium at the outlet of the heat flow side of the second heat regenerator 105 is increased, and the driving mechanism of the electronic expansion valve 106 does not act until the supercooling degree is increased to theta 2 ℃.

In summary, with this control method, the first heat regenerator 103 needs to heat the mixed working medium at the air inlet of the compressor 101 to an overheated state to prevent the air intake of the compressor from carrying liquid. The second heat regenerator 105 is required to cool the mixed working medium at the inlet of the electronic expansion valve 106 to a supercooled state, so as to increase the content of liquid entering the evaporator, reduce the enthalpy value, increase the refrigerating capacity of the evaporator and improve the system efficiency.