JP2022139723A - Ejector and cooling system - Google Patents

Abstract

To suppress degradation of a cooling capacity in a high temperature environment.SOLUTION: An ejector includes: a cylindrical first diffuser portion having a first inflow port for allowing a first mixture fluid obtained by mixing a first drive fluid injected from a first nozzle and a suction fluid sucked from a suction port in accompany with the injection of the first drive fluid, to flow therein, and a first discharge port for discharging the first mixture fluid, and monotonously increased in an inner diameter from the first inflow port toward the first discharge port; a cylindrical second diffuser portion having a second discharge port for discharging a second mixture fluid obtained by mixing the first mixture fluid discharged from the first discharge port and a second drive fluid, a first part gradually increased in the inner diameter from the first discharge port toward the second discharge port, and a second part having a uniform inner diameter toward the second discharge port; and a second nozzle having an opening portion formed between a boundary between the first part and the second part, and the first inflow port, and discharging the second drive fluid.SELECTED DRAWING: Figure 3

Description

The present invention relates to ejectors and cooling systems.

2. Description of the Related Art Conventionally, an ejector that mixes a suction fluid generated by a driving fluid with the driving fluid and ejects the fluid has been proposed. For example, in Patent Document 1, a driving fluid is generated in the diffuser by injecting refrigerant from a nozzle portion downstream of the minimum diameter portion of the diffuser, and along with this, it is located upstream of the minimum diameter portion of the diffuser. An ejector is disclosed for sucking suction fluid from a suction port.

JP 2012-97733 A

An ejector such as that described in Patent Document 1 is applied to a cooling system that cools a medium for cooling manufacturing machines in a factory. Such refrigeration systems utilize a cooling fluid, such as cooling water or air, in a condenser that condenses the refrigerant. Here, for example, when the temperature of the cooling fluid rises in a high-temperature environment such as in summer, the temperature difference between the refrigerant discharged from the ejector and the cooling fluid becomes smaller, and the amount of heat transferred from the refrigerant to the cooling fluid becomes smaller. . Therefore, the refrigerant discharged from the ejector is less likely to be condensed by the condenser, and the pressure in the flow path connecting the ejector and the condenser increases. When the pressure rises, it becomes difficult for the refrigerant to be discharged from the ejector, which causes a problem that the flow rate of the suction fluid sucked by the ejector decreases and the cooling capacity decreases. In consideration of the above circumstances, one aspect of the present invention aims at suppressing a decrease in cooling capacity in a high-temperature environment.

An ejector according to one aspect of the present invention is a first mixed fluid obtained by mixing a first driving fluid ejected from a first nozzle and a suction fluid sucked from a suction port as the first driving fluid is ejected. and a first outlet for discharging the first mixed fluid, and the inner diameter monotonously increases from the first inlet to the first outlet. a first diffuser portion; a second outlet for discharging a second mixed fluid in which a first mixed fluid discharged from the first discharge port and a second driving fluid are mixed; a cylindrical second diffuser portion having a first portion whose inner diameter gradually increases toward the second outlet and a second portion whose inner diameter is constant toward the second outlet; and the first portion. and a second nozzle having an opening provided between the boundary with the second portion and the first inlet, and discharging the second driving fluid.

A cooling system according to one aspect of the present invention includes a steam generator that evaporates a refrigerant by heat exchange with a heat source; a first driving fluid that is the refrigerant evaporated in the steam generator; a first inlet into which a first mixed fluid mixed with the suction fluid sucked from the suction port as the driving fluid is ejected flows; and a first outlet for discharging the first mixed fluid. a cylindrical first diffuser portion having a monotonically increasing inner diameter from the first inlet toward the first outlet; and a first mixed fluid discharged from the first outlet; a second discharge port that discharges a second mixed fluid mixed with a second driving fluid that is a refrigerant evaporated in the steam generator; and an inner diameter that gradually increases from the first discharge port toward the second discharge port. A tubular second diffuser portion having a first portion and a second portion having a constant inner diameter toward the second outlet, a boundary between the first portion and the second portion, and the first diffuser portion. an ejector having an opening provided between the inflow port and a second nozzle for discharging the second driving fluid; a pump for sending the refrigerant condensed by the condenser to the steam generator; an expander for decompressing the refrigerant condensed by the condenser; and the refrigerant decompressed by the expander as a medium to be cooled. an evaporator that evaporates by heat exchange between and supplies the evaporated refrigerant to the suction port as the suction fluid; a supply state in which the second driving fluid is supplied from the steam generator to the second nozzle; and a switching mechanism for switching between a shutoff state in which supply of the second driving fluid from the steam generator to the second nozzle is shut off.

It is a figure which shows the structural example of the cooling system which concerns on embodiment. 4 is a block diagram illustrating a configuration for controlling a switching mechanism; FIG. It is a sectional view showing an example of composition of an ejector. FIG. 3 is a cross-sectional perspective view of an ejector; It is a schematic diagram of the ejector seen from the ejection port side. FIG. 4 is a block diagram illustrating the relationship between the temperature of the cooling fluid and the back pressure of the ejector; FIG. 2 is a configuration diagram of a cooling system according to contrast; It is a figure which shows the structural example of the ejector which concerns on a modification. It is a figure which shows the structural example of the ejector which concerns on a modification. It is a schematic diagram of the ejector which concerns on a modification.

Preferred embodiments of the present invention will be described below with reference to the drawings. Note that the dimensions and scale of each part in the drawings are appropriately different from the actual ones. Also, the drawings may be schematically shown for easy understanding. Furthermore, the scope of the present invention is not limited to the embodiments exemplified below unless there is a description to the effect that the present invention is specifically limited.

1. Embodiment FIG. 1 is a diagram showing a configuration example of a cooling system 100 according to an embodiment of the present invention. The cooling system 100 is a system that cools the medium to be cooled Q3. The medium Q3 to be cooled is a medium to be cooled by the cooling system 100, and is a fluid such as water, oil, or air.

As shown in FIG. 1, the cooling system 100 of the first embodiment includes a circulation channel 11, a branch channel 12, a branch channel 13, a steam generator 21, an ejector 22, a condenser 24, It has a pump 25 , an expander 31 , an evaporator 32 and a switching mechanism 40 .

A steam generator 21, an ejector 22, a condenser 24, and a pump 25 are installed in the circulation flow path 11 in the above order. The refrigerant in the circulation flow path 11 moves in the order of steam generator 21→ejector 22→condenser 24→pump 25→steam generator 21. FIG. That is, the circulation flow path 11 connects the steam generator 21, the ejector 22, the condenser 24, and the pump 25 in a ring shape. The refrigerant moving in the circulation flow path 11 is, for example, CFC substitute, hydrocarbon, carbon dioxide, ammonia, or the like.

The steam generator 21 is a heat exchanger (collector) that evaporates the refrigerant through heat exchange between the hot water Q1 supplied to the hot water flow path 91 as a heat source and the refrigerant in the circulation flow path 11 . The hot water Q1 supplied to the hot water flow path 91 is, for example, waste hot water such as factory waste water or used cooling water.

The ejector 22 includes an inflow port 22a, a suction port 22b, a discharge port 22c, and an inflow port 22d. A part of the vapor-phase refrigerant sent out from the steam generator 21 is supplied to the inlet 22a as the first driving fluid X1, and the other part is supplied to the inlet 22d as the second driving fluid X2. The ejector 22 sucks the refrigerant in the branch flow path 12 from the suction port 22b as the suction fluid Y1 due to the static pressure drop caused by the first driving fluid X1. The first driving fluid X1 supplied to the inflow port 22a, the second driving fluid X2 supplied to the inflow port 22d, and the suction fluid Y1 supplied to the suction port 22b are mixed to form a vapor-phase refrigerant after mixing. is pressurized by a diffuser, which will be described later, and then discharged from the discharge port 22c. As can be understood from the above description, the ejector 22 of this embodiment introduces a part of the refrigerant evaporated in the steam generator 21 from the inlet 22a as the first driving fluid X1, and the other part as the second driving fluid X1. It is introduced from the inflow port 22d as the fluid X2. The ejector 22 mixes the first driving fluid X1 and the second driving fluid X2 with the suction fluid Y1 introduced from the suction port 22b and discharges the mixture from the discharge port 22c. Details of the ejector 22 will be described later.

The condenser 24 condenses the vapor phase refrigerant discharged from the ejector 22 . Specifically, the condenser 24 condenses the refrigerant through heat exchange between the cooling fluid Q2 supplied to the heat radiation passage 92 and the refrigerant in the circulation passage 11 . The cooling fluid Q2 is, for example, cold industrial water or cooling water supplied from a circulating cooling tower. The refrigerant in the circulation flow path 11 is condensed by radiating heat to the cooling fluid Q2. For example, in a high-temperature environment such as summer, the temperature T of the cooling fluid Q2 may rise.

The pump 25 is a liquid-phase pump that delivers the liquid-phase refrigerant condensed by the condenser 24 to the steam generator 21 . The pressure of the refrigerant in the circulation flow path 11 is raised by the pump 25 to a pressure that allows the ejector 22 to suck the suction fluid Y1.

The branch channel 12 is a channel branched from the circulation channel 11 . That is, part of the refrigerant flowing through the circulation flow path 11 is supplied to the branch flow path 12 . Specifically, the branch flow path 12 connects a portion N1 between the condenser 24 and the pump 25 in the circulation flow path 11 and the suction port 22b of the ejector 22 . That is, the branch flow path 12 is a flow path that supplies the ejector 22 with the refrigerant that becomes the suction fluid Y1. The portion N1 corresponds to a branch point between the circulation flow path 11 and the branch flow path 12. FIG. The branch channel 12 is a channel having an expander 31 and an evaporator 32 . The evaporator 32 is positioned between the expander 31 and the suction port 22 b of the ejector 22 .

The branch channel 13 is a channel branched from the circulation channel 11 . That is, part of the refrigerant flowing through the circulation flow path 11 is supplied to the branch flow path 13 . Specifically, the branch channel 13 connects the part N2 between the steam generator 21 and the ejector 22 in the circulation channel 11 and the ejector 22 . That is, the branch flow path 13 is a flow path that supplies the ejector 22 with the coolant that will be the second driving fluid X2. A portion N2 corresponds to a branch point between the circulation flow path 11 and the branch flow path 13 . The branch channel 13 is a channel having a switching mechanism 40 which will be described later.

A portion of the refrigerant condensed by the condenser 24 is supplied to the expander 31 . The expander 31 expands the refrigerant in the branch flow path 12 by reducing the pressure. The expander 31 is any type of pressure reducing mechanism such as, for example, an electronic expansion valve, manual expansion valve, constant pressure expansion valve, orifice or capillary.

The evaporator 32 is a heat exchanger that evaporates the refrigerant through heat exchange between the cooling target medium Q3 supplied to the cooling target flow path 93 and the liquid-phase medium depressurized by the expander 31 . The evaporator 32 is positioned between the expander 31 and the suction port 22 b of the ejector 22 . The evaporator 32 supplies the vaporized refrigerant to the suction port 22b of the ejector 22 as a suction fluid Y1. The medium to be cooled Q3 is cooled using the latent heat of the refrigerant whose pressure has been lowered by the suction from the ejector 22 .

The switching mechanism 40 is installed in the branch channel 13 . Specifically, the switching mechanism 40 is positioned between the portion N2 of the circulation channel 11 and the ejector 22 . The switching mechanism 40 is an on-off valve that switches passage/blocking of the refrigerant in the branch flow path 13 . That is, the switching mechanism 40 is in either an open state in which the second driving fluid X2 supplied from the steam generator 21 to the branch flow path 13 passes through, or a blocking state in which the flow of the refrigerant in the branch flow path 13 is blocked. is set to

When the switching mechanism 40 is in the open state, part of the refrigerant sent from the steam generator 21 is supplied to the inlet 22a of the ejector 22 as the first driving fluid X1, and the other part of the refrigerant flows through the switching mechanism 40. It passes through and is supplied to the inlet 22d of the ejector 22 as the second drive fluid X2. On the other hand, when the switching mechanism 40 is in the shut-off state, the refrigerant sent out from the steam generator 21 is supplied only to the inlet 22a of the ejector 22 . That is, the supply of the second driving fluid X2 to the inlet 22d of the ejector 22 is stopped.

FIG. 2 is a block diagram illustrating a configuration for controlling the switching mechanism 40. As shown in FIG. As illustrated in FIG. 2 , the cooling system 100 has a temperature detector 51 and a controller 52 . The temperature detector 51 detects the temperature of the cooling fluid Q2 supplied to the heat radiation flow path 92. As shown in FIG. Any type of temperature sensor may be used as the temperature detector 51 .

The controller 52 controls the state of the switching mechanism 40 according to the temperature detected by the temperature detector 51 . Specifically, the control unit 52 controls the switching mechanism 40 to either the open state or the cutoff state according to the temperature. The control unit 52 includes, for example, a CPU (Central Processing Unit),
DSP (Digital Signal Processor) or ASIC (Application Specific Integra
ted Circuit).

The controller 52 maintains the switching mechanism 40 in the cut-off state when the temperature T of the cooling fluid Q2 is below the predetermined threshold RH. Then, when the temperature T changes from a value lower than the threshold RH to a value higher than the threshold RH, the controller 52 changes the switching mechanism 40 from the cut-off state to the open state. On the other hand, when the temperature T of the cooling fluid Q2 changes from a value exceeding the predetermined threshold RL to a value below the threshold RL, the control unit 52 changes the switching mechanism 40 from the open state to the cutoff state. The threshold RL is a numerical value equivalent to the threshold RH (RL=RH) or a numerical value lower than the threshold RH (RL<RH).

Next, the ejector 22 applied to the cooling system 100 will be described in detail. 3 is a cross-sectional view showing a configuration example of the ejector 22, and FIG. 4 is a cross-sectional perspective view of the ejector 22. As shown in FIG. In the following description, X-axis, Y-axis and Z-axis are assumed to be orthogonal to each other. The X-axis, Y-axis and Z-axis are common in all the drawings illustrated in the following description. As exemplified in FIGS. 3 and 4, one direction along the X axis when viewed from an arbitrary point is denoted as X1 direction, and the opposite direction to X1 direction is denoted as X2 direction. The X-axis direction is a direction that includes both the X1 direction and the X2 direction. Similarly, mutually opposite directions along the Y-axis from an arbitrary point are denoted as Y1 direction and Y2 direction. The Y-axis direction is a direction that includes both the Y1 direction and the Y2 direction. Also, directions opposite to each other along the Z-axis from an arbitrary point are denoted as Z1 direction and Z2 direction. The Z-axis direction is a direction including both the Z1 direction and the Z2 direction. Furthermore, the XY plane, which includes the X and Y axes, corresponds to the horizontal plane. The Z-axis is the axis along the vertical direction.

As shown in FIG. 3, the ejector 22 includes a first nozzle 220, a first case portion 221, a confluence portion 222, a mixing portion 223, a first diffuser portion 224, a second diffuser portion 225, a second It has a case portion 226 and a second nozzle 227 . These elements except for the second nozzle 227 are constructed integrally.

The first nozzle 220 is a tubular structure extending in the X-axis direction and having a passage 220a through which the first driving fluid X1 flows. The first nozzle 220 has a tapered surface 220s. The tapered surface 220s gradually decreases the inner diameter of the first nozzle 220 in the X1 direction. The first nozzle 220 has an injection port 220b that injects the first driving fluid X1. An inlet 220c located in the X2 direction of the first nozzle 220 is connected to the circulation flow path 11. As shown in FIG.

The first case portion 221 is a housing having an annular space 221a. The annular space 221 a is a space defined by the inner peripheral surface of the first case portion 221 and the outer peripheral surface of the first nozzle 220 . The annular space 221a surrounds the first nozzle 220 around the axis C1 of the ejector 22 around the X axis. The first case part 221 has an opening 221b connected to the branch flow path 12 .

The confluence portion 222 is a portion of the ejector 22 whose inner diameter gradually decreases from the annular space 221a in the X1 direction. The confluence portion 222 surrounds the end of the first nozzle 220 located in the X1 direction around the X axis with the axis C1 as the center. The mixing portion 223 is a portion of the ejector 22 that has a constant inner diameter in the X1 direction from the confluence portion 222 and extends in the X-axis direction. The inner diameter is larger than the inner diameter of the injection port 220 b of the first nozzle 220 .

The first diffuser portion 224 is a portion of the ejector 22 whose inner diameter monotonously increases in the X1 direction from the mixing portion 223 (inflow port 224a), and is configured in a cylindrical shape. The aforementioned "the inner diameter monotonically increases" means that it does not include a portion where the inner diameter decreases. Therefore, the portion where the inner diameter monotonically increases may include, for example, a portion where the inner diameter is constant. Specifically, the first diffuser section 224 does not need to include a portion where the inner diameter decreases from the inlet 224a to the outlet 224b. For example, the inner diameter is constant from the inlet 224a to the outlet 224b. It may contain a part that is

The first diffuser portion 224 has an inlet 224a and an outlet 224b. The inlet 224a is located on the boundary B1 between the mixing section 223 and the first diffuser section 224. As shown in FIG. The inlet 224a is an example of a "first inlet". The discharge port 224b is positioned on a boundary B2 between the first diffuser portion 224 and a second diffuser portion 225, which will be described later. The ejection port 224b is an example of a "first ejection port". The first diffuser portion 224 according to the present embodiment is a portion of the ejector 22 extending from the boundary B1 to the boundary B2.

The second diffuser portion 225 has an inlet 225c and an outlet 225d, and is configured in a tubular shape. The inlet 225c is located on the boundary B2, like the outlet 224b. The inlet 225c is an example of a "second inlet". The outlet 225 d is connected to the circulation flow path 11 . The outlet 225d is an example of a "second outlet". The inner diameter of the second diffuser portion 225 is larger than the inner diameter of the first diffuser portion 224 . The second diffuser section 225 according to this embodiment is composed of a first portion 225a and a second portion 225b. The first portion 225a is a portion of the ejector 22 whose inner diameter gradually increases from the boundary B2 (discharge port 224b) in the X1 direction. The second portion 225b is a portion of the ejector 22 that has a constant inner diameter in the X1 direction from the boundary B3. A boundary B3 is a boundary between the first portion 225a and the second portion 225b.

The second case portion 226 is a housing having an annular space 226a, and is configured integrally with the first diffuser portion 224 and the second diffuser portion 225. As shown in FIG. The annular space 226 a is a space defined by the outer peripheral surface of the first diffuser portion 224 and the inner peripheral surface of the second case portion 226 . The annular space 226a surrounds the outer peripheral surface of the first diffuser portion 224 around the X-axis with the axis C1 as the center. The annular space 226a is an example of an "annular channel." The second case part 226 has an opening 226b connected to the branch flow path 13 .

FIG. 5 is a schematic diagram of the ejector 22 viewed in the X2 direction. The second nozzle 227 is a gap penetrating the housing that defines the internal space of the first diffuser portion 224 and communicates with the annular space 226 a and the internal space of the second diffuser portion 225 . As shown in FIG. 5, the second nozzle 227 surrounds the discharge port 224b of the first diffuser portion 224 and has an annular shape around the X-axis centered on the axis C1. The second nozzle 227 has an opening 227a that is an ejection port for ejecting the second driving fluid X2. The opening 227a is provided at the boundary between the outlet 224b and the inlet 225c. That is, the opening 227a is positioned on the boundary B2. The opening 227a is an example of an "opening". The second nozzle 227 is configured such that its width in the Z-axis direction gradually decreases toward the X1 direction. 5, illustration of the first case portion 221 and the second case portion 226 is omitted.

When the first driving fluid X1 is injected from the injection port 220b of the first nozzle 220 into the confluence portion 222, the suction fluid Y1 is sucked into the confluence portion 222 through the opening 221b as the pressure in the confluence portion 222 decreases. . The first driving fluid X1 and the suction fluid Y1 that have merged in the merging portion 222 are mixed in the mixing portion 223 to become the first mixed fluid, and then flow into the first diffuser portion 224 through the inlet 224a. The first mixed fluid that has flowed into the first diffuser portion 224 is pressurized by the first diffuser portion 224 and discharged from the discharge port 224b.

The first mixed fluid discharged from the discharge port 224b flows into the second diffuser portion 225 from the inlet 225c. Here, when the switching mechanism 40 is controlled to be in the open state by the control unit 52, a part of the gaseous refrigerant sent out from the steam generator 21 is used as the second driving fluid X2 to move into the annular space 226a of the second case portion 226. , and the second driving fluid X 2 is discharged from the opening 227 a of the second nozzle 227 . As described above, the second nozzle 227 is configured such that the width in the Z-axis direction gradually decreases toward the X1 direction. That is, the cross-sectional area of the second nozzle 227 on the ZY plane gradually decreases toward the opening 227a and becomes the smallest at the opening 227a. Therefore, the flow velocity of the second driving fluid X2 flowing through the second nozzle 227 is maximized at the opening 227a, and the venturi effect reduces the pressure in the vicinity of the opening 227a. Therefore, the first mixed fluid discharged from the discharge port 224b is attracted toward the opening 227a, spreads radially outward, and moves in the X1 direction along the inner wall surface of the first portion 225a. In particular, since the opening 227a of the present embodiment surrounds the discharge port 224b of the first diffuser portion 224 as shown in FIG. 5, the first mixed fluid is more likely to spread radially outward. As a result, the pressure at which the first driving fluid X1 is ejected from the ejection port 224b (hereinafter referred to as back pressure B) is lower than when the second driving fluid X2 is not ejected from the opening 227a.

After that, the second driving fluid X2 ejected from the second nozzle 227 mixes with the first fluid mixture ejected from the ejection port 224b in the second diffuser portion 225 to become a second fluid mixture. The second mixed fluid is pressurized by the second diffuser portion 225 and discharged from the discharge port 225d. In addition, the above-mentioned "outer diameter" means a direction from the axis C1 toward the first portion 225a.

As described above, when the temperature T of the cooling fluid Q2 rises in a high-temperature environment, the temperature difference between the refrigerant discharged from the ejector 22 and the cooling fluid Q2 decreases, and the amount of heat transferred from the refrigerant to the cooling fluid Q2 increases. become smaller. Therefore, the refrigerant discharged from the ejector 22 is less likely to be condensed by the condenser 24, and the pressure in the circulation flow path 11 connecting the ejector 22 and the condenser 24 increases. When the pressure rises, it becomes difficult for the refrigerant to be discharged from the ejector 22, so that the flow rate of the suction fluid Y1 sucked by the ejector 22 (that is, the flow rate of the refrigerant flowing through the branch flow path 12) decreases, and the cooling system 100 There is a problem that the ability to cool the medium Q3 to be cooled (hereinafter referred to as "cooling ability") is reduced.

Incidentally, if the pressure of the first drive fluid X1 is increased, the flow rate of the suction fluid Y1 is increased. However, since the pressure of the first driving fluid X1 depends on the temperature difference between the hot water Q1 in the steam generator 21 and the refrigerant in the circulation passage 11, it is practically impossible to sufficiently increase the pressure of the first driving fluid X1. difficult in terms of Further, a method of suppressing the decrease in the temperature of the hot water Q1 by increasing the flow rate of the hot water Q1 and increasing the pressure of the first driving fluid X1 by increasing the evaporation temperature of the refrigerant is also conceivable. However, since the power required for the pump 25 that supplies the hot water Q1 to the hot water flow path 91 increases, there is also the problem that the scale of the entire apparatus or the cost required for cooling increases.

In consideration of the above circumstances, the ejector 22 provided in the cooling system 100 of the present embodiment ejects the second driving fluid X2 from the opening 227a by controlling the switching mechanism 40 to the open state by the control unit 52. do. Therefore, as described above, the back pressure B decreases. Therefore, even in an environment where the cooling fluid Q2 is at a high temperature, a sufficient flow rate of the fluid Y1 sucked by the ejector 22 is ensured, and a sufficient cooling capacity of the cooling system 100 is maintained.

FIG. 6 is a graph showing the relationship between the temperature T of the cooling fluid Q2 and the back pressure B of the ejector 22. As shown in FIG. In FIG. 6, the characteristic of this embodiment is illustrated with a solid line, and the characteristic of the contrast is illustrated with a dashed line. As illustrated in FIG. 7, the contrast is a configuration in which the branch flow path 13 and the switching mechanism 40 are omitted from the present embodiment. A comparative ejector 200 has a configuration in which the second diffuser portion 225, the second case portion 226 and the second nozzle 227 are omitted from the ejector 22 of the present embodiment. Furthermore, the operating limit Bmax in FIG. 6 is the maximum value of the back pressure B for achieving the target cooling capacity. That is, when the back pressure B exceeds the operating limit Bmax, the flow rate of the suction fluid Y1 in the ejector 22 is not sufficiently secured, and the target cooling capacity is not achieved.

As illustrated in FIG. 6, the back pressure B of the ejector 22 varies according to the temperature T of the cooling fluid Q2. Specifically, the higher the temperature T, the higher the back pressure B increases. In contrast, the back pressure B reaches the operating limit Bmax when the temperature T of the cooling fluid Q2 rises to a predetermined temperature T1 on the high temperature side. Therefore, the target cooling capacity cannot be achieved in an environment exceeding the temperature T1.

On the other hand, in the present embodiment, the switching mechanism 40 is opened when the temperature T of the cooling fluid Q2 reaches the threshold value RH from the low temperature side. That is, in an environment where the temperature T exceeds the threshold RH, as illustrated in FIG. 6, the back pressure B of the ejector 22 is reduced compared to the comparison. For example, in contrast, the backpressure B reaches the operating limit Bmax at temperature T1, whereas in this embodiment the backpressure B at temperature T1 falls below the operating limit Bmax. Therefore, in this embodiment, the target cooling capacity can be achieved even in an environment where the temperature of the cooling fluid Q2 exceeds the temperature T1. That is, according to this embodiment, the temperature range in which the cooling system 100 can operate can be expanded.

In some cases, a conventional cooling system employs a configuration having a plurality of ejectors. In contrast to such a cooling system, the cooling system 100 of this embodiment maintains a sufficient cooling capacity with a single ejector 22 . Therefore, in this embodiment, there is also an advantage that the cost for configuring the cooling system 100 can be reduced as compared with a cooling system having a plurality of ejectors.

2. MODIFIED EXAMPLES Specific modified aspects added to the above-exemplified forms are exemplified below. Two or more aspects arbitrarily selected from the following examples may be combined as appropriate within a mutually consistent range.

[Modification 1]
FIG. 8 is a diagram showing a configuration example of an ejector 22A according to a modification. The ejector 22A has the same configuration as the ejector 22 described above, except that the arrangement of the second case portion 226 and the second nozzle 227 is different from that of the ejector 22 . The second case portion 226 of the ejector 22A is positioned in the X2 direction from the second case portion 226 of the ejector 22, as shown in FIG. The second nozzle 227 of the ejector 22A is positioned in the X2 direction from the second nozzle 227 of the ejector 22 and communicates with the annular space 226a and the internal space of the first diffuser portion 224. As shown in FIG. Also in the ejector 22A, the first driving fluid X1 is ejected from the ejection port 227b and the second driving fluid X2 is ejected from the second nozzle 227, similarly to the ejector 22 of the above-described embodiment. Therefore, the same effect as the ejector 22 is realized in the ejector 22A as well.

[Modification 2]
FIG. 9 is a diagram showing a configuration example of an ejector 22B according to a modification. The ejector 22B has the same configuration as the ejector 22 described above, except that the arrangement of the second nozzle 227 is different from that of the ejector 22 . The second nozzle 227 of the ejector 22B passes through the first diffuser portion 224 and the first portion 225a in the X-axis direction and communicates with the annular space 226a and the internal space of the second diffuser portion 225. As shown in FIG. Also in the ejector 22B, the first driving fluid X1 is ejected from the ejection port 224b and the second driving fluid X2 is ejected from the second nozzle 227, similarly to the ejector 22 of the above-described embodiment. Therefore, the ejector 22B achieves the same effect as the ejector 22. As shown in FIG.

[Modification 3]
FIG. 10 is a schematic diagram of an ejector 22C according to a modification as viewed in the X2 direction. The ejector 22</b>C has the same configuration as the ejector 22 described above, except that the configuration of the second nozzle 227 is different from that of the ejector 22 . In the ejector 22, the second nozzle 227 is configured in an annular shape around the X-axis with the axis C1 as the center, but this is not restrictive. For example, as shown in FIG. 10, the second nozzles 227 may be formed intermittently around the X-axis centered on the axis C1. 10, illustration of the first case portion 221 and the second case portion 226 is omitted.

As described above, in the above-described embodiment, the opening 227a of the second nozzle 227 is located at the boundary (boundary B2) between the outlet 224b of the first diffuser section 224 and the inlet 225c of the second diffuser section 225. be provided. In Modification 1, as shown in FIG. 8, an opening 227a is provided between the inlet 224a and the boundary B2. Further, in Modification 2, as shown in FIG. 9, an opening 227a is provided between the boundary B2 and the boundary B3. Therefore, the opening 227a of the second nozzle 227 can be provided between the boundary B3 between the first portion 225a and the second portion 225b and the inlet 224a of the first diffuser portion 224. As shown in FIG.

[Modification 4]
Although the control unit 52 controls the switching mechanism 40 in the above embodiment, the method of controlling the switching mechanism 40 is not limited to the above example. For example, the state of the switching mechanism 40 may be changed according to manual operation by an administrator of the cooling system 100 . For example, in the above-described mode, an administrator may manually operate the switching mechanism 40 to set either the open state or the cutoff state. In addition, according to the configuration in which the control unit 52 controls the state of the switching mechanism 40 as in the above embodiment, the load on the administrator of the cooling system 100 can be reduced. Note that even if the control unit 52 executes one of the process of changing the switching mechanism 40 from the blocked state to the open state and the process of changing the switching mechanism 40 from the open state to the blocked state, and the other is executed by the administrator. good.

3. Supplement The effects described in this specification are merely descriptive or exemplary, and are not limiting. In other words, the present disclosure can provide other effects that are apparent to those skilled in the art from the description of this specification in addition to or instead of the above effects.

Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is obvious that those who have ordinary knowledge in the technical field of the present disclosure can conceive of various modifications or modifications within the scope of the technical idea described in the claims. is naturally within the technical scope of the present disclosure.

4. Supplementary Note For example, the following configuration can be grasped from the above-exemplified forms.

The ejector 22 according to one aspect (aspect 1) of the present disclosure includes the first driving fluid X1 ejected from the first nozzle 220 and the suction fluid Y1 sucked from the suction port 22b as the first driving fluid X1 is ejected. and a discharge port 224b for discharging the first mixed fluid. a first diffuser portion 224 having a shape, a discharge port 225d for discharging a second mixed fluid in which the first mixed fluid discharged from the discharge port 224b and the second driving fluid X2 are mixed, and a discharge port from the discharge port 224b A cylindrical second diffuser portion 225 having a first portion 225a whose inner diameter gradually increases toward 225d and a second portion 225b whose inner diameter is constant toward the discharge port 225d. A second nozzle 227 having an opening 227a provided between the boundary B3 with the portion 225b and the inlet 224a and ejecting the second driving fluid X2 is provided.

In the above aspect, the pressure in the vicinity of the second nozzle 227 is reduced by discharging the second driving fluid X2 from the second nozzle 227 . Therefore, the first mixed fluid discharged from the discharge port 224b of the first diffuser portion 224 is drawn toward the opening 227a and spreads radially outward. As a result, the pressure at which the first mixed fluid is ejected from the ejection port 224b is reduced compared to when the second driving fluid X2 is not ejected from the second nozzle 227. FIG. Therefore, even in an environment where the cooling fluid Q2 used in the condenser 24 is at a high temperature, the flow rate of the fluid Y1 sucked by the ejector 22 is sufficiently ensured, and the cooling capacity of the cooling system 100 is maintained.

According to the specific example of mode 1 (mode 2), the second diffuser section 225 further has an inlet 225c into which the first mixed fluid discharged from the outlet 224b flows, and surrounds the first diffuser section 224. , the annular space 226a through which the second driving fluid X2 flows; the second nozzle 227 is an annular nozzle that communicates with the annular space 226a and the second diffuser portion 225; It is an annular opening provided at the boundary with the inlet 225c and surrounding the outlet 224b. In the above aspect, the pressure in the vicinity of the annular opening 227a is reduced by discharging the second driving fluid X2 from the annular opening 227a. Therefore, the first mixed fluid discharged from the discharge port 224b of the first diffuser portion 224 is attracted toward the annular opening 227a and spreads radially outward. In particular, in the above aspect, since the opening 227a is formed in an annular shape so as to surround the discharge port 224b, the first mixed fluid is more likely to spread radially outward. As a result, the pressure at which the first mixed fluid is discharged from the discharge port 224b is reduced compared to the case where the second driving fluid X2 is not discharged from the annular opening 227a. Therefore, even in an environment where the cooling fluid Q2 used in the condenser 24 is at a high temperature, the flow rate of the fluid Y1 sucked by the ejector 22 is sufficiently ensured, and the cooling capacity of the cooling system 100 is maintained.

According to the specific example of Mode 1 (Mode 3), the annular space 226a surrounding the first diffuser portion 224 and through which the second driving fluid X2 flows is further provided, and the second nozzle 227 is formed by the annular space 226a and the first diffuser. Communicating with the portion 224, the opening 227a is provided between the boundary B2 between the first diffuser portion 224 and the second diffuser portion 225 and the inlet 224a.

According to the specific example of mode 1 (mode 4), the annular space 226a surrounding the first diffuser portion 224 and through which the second driving fluid X2 flows is further provided, and the second nozzle 227 includes the annular space 226a and the first portion. 225a, the opening 227a is provided between a boundary B3 between the first portion 225a and the second portion 225b and a boundary B2 between the first diffuser portion 224 and the second diffuser portion 225.

A cooling system 100 according to one aspect (aspect 5) of the present disclosure includes a steam generator 21 that evaporates a refrigerant by heat exchange with a heat source, a first driving fluid X that is the refrigerant evaporated in the steam generator 21, an inflow port 224a into which a first mixed fluid mixed with the suction fluid Y1 sucked from the suction port 22b as the first driving fluid X1 is ejected from the first nozzle 220; and a first mixed fluid discharged from the cylindrical first diffuser portion 224 and the discharge port 224b. and a second driving fluid X2, which is a refrigerant evaporated in the steam generator 21, and a second driving fluid X2 which is mixed with a second driving fluid X2. A cylindrical second diffuser portion 225 having a portion 225a and a second portion 225b having a constant inner diameter toward a discharge port 225d, a boundary B3 between the first portion 225a and the second portion 225b, and an inlet 224a and the second nozzle 227 for discharging the second driving fluid X2, and the refrigerant discharged from the ejector 22 is exchanging heat with the cooling fluid Q2. A condenser 24 for condensing, a pump 25 for sending the refrigerant condensed by the condenser 24 to the steam generator 21, an expander 31 for decompressing the refrigerant condensed by the condenser 24, and An evaporator 32 that evaporates the refrigerant by heat exchange with the medium to be cooled Q3 and supplies the evaporated refrigerant as the suction fluid Y1 to the suction port 22b. and a cutoff state in which the supply of the second driving fluid X2 from the steam generator 21 to the second nozzle 227 is cut off.

According to the specific example of aspect 5 (aspect 6), the control unit 52 is further provided for switching between the supply state and the cutoff state. In this aspect, switching between the supply state and the cutoff state allows switching between a state in which the second driving fluid X2 is supplied to the second nozzle 227 and a state in which the supply is stopped.

According to the specific example of mode 6 (mode 7), the temperature detection unit 51 that detects the temperature of the cooling fluid Q2 is further provided, and the control unit 52 switches the switching mechanism 40 according to the temperature detected by the temperature detection unit 51. control the state of In this aspect, the controller 52 controls the state of the switching mechanism 40 in accordance with the temperature of the cooling fluid Q2, so that the burden of manually changing the state of the switching mechanism 40 by the administrator is reduced.

DESCRIPTION OF SYMBOLS 100... Cooling system, 11... Circulation flow path, 12... Branch flow path, 21... Steam generator, 22... Ejector, 22a... Inflow port, 22b... Suction port, 22c... Discharge port, 22d... Inflow port, 24... Condensation 25 Pump 31 Expander 32 Evaporator 40 Switching mechanism 51 Temperature detector 52 Control unit 91 Hot water flow path 92 Heat dissipation flow path 93 Cooled flow path , 220... First nozzle, 221... First case portion, 221a... Annular space, 222... Merging part, 223... Mixing part, 224... First diffuser part, 224a... Inlet, 224b... Discharge port, 225... Second Diffuser part, 225a...first part, 225b...second part, 225c...inlet, 225d...outlet.

Claims (7)

a first inlet into which a first mixed fluid obtained by mixing a first driving fluid ejected from a first nozzle and a suction fluid sucked from a suction port along with ejection of the first driving fluid flows; a cylindrical first diffuser portion having a first discharge port for discharging one mixed fluid, the inner diameter of which monotonically increases from the first inlet toward the first discharge port;
a second outlet for ejecting a second mixed fluid in which a first mixed fluid ejected from the first outlet and a second driving fluid are mixed; a cylindrical second diffuser portion having a first portion with an inner diameter that gradually increases toward the second outlet and a second portion with a constant inner diameter toward the second outlet;
a second nozzle having an opening provided between the boundary between the first portion and the second portion and the first inlet, and ejecting the second driving fluid. The second diffuser section further has a second inlet into which the first mixed fluid discharged from the first outlet flows,
further comprising an annular flow path surrounding the first diffuser portion and through which the second driving fluid flows;
The second nozzle is an annular nozzle that communicates with the annular flow path and the second diffuser section,
The ejector according to claim 1, wherein the opening is an annular opening that is provided at a boundary between the first discharge port and the second inlet and surrounds the first discharge port. further comprising an annular flow path surrounding the first diffuser portion and through which the second driving fluid flows;
The second nozzle communicates with the annular flow path and the first diffuser section,
The ejector according to claim 1, wherein the opening is provided between a boundary between the first diffuser section and the second diffuser section and the first inlet. further comprising an annular flow path surrounding the first diffuser portion and through which the second driving fluid flows;
the second nozzle communicates with the annular channel and the first portion;
The ejector according to claim 1, wherein the opening is provided between a boundary between the first portion and the second portion and a boundary between the first diffuser portion and the second diffuser portion. a steam generator that evaporates the refrigerant by heat exchange with a heat source;
A first mixture in which the first driving fluid, which is the refrigerant evaporated in the steam generator, and the suction fluid sucked from the suction port as the first driving fluid is ejected from the first nozzle are mixed. A cylinder having a first inlet through which a fluid flows and a first outlet through which the first mixed fluid is discharged, the inner diameter of which monotonically increases from the first inlet toward the first outlet. a shaped first diffuser portion;
a second discharge port for discharging a second mixed fluid in which a first mixed fluid discharged from the first discharge port and a second driving fluid that is a refrigerant evaporated in the steam generator are mixed; a tubular second diffuser portion having a first portion whose inner diameter gradually increases from the outlet toward the second outlet and a second portion whose inner diameter is constant toward the second outlet;
a second nozzle having an opening provided between the boundary between the first portion and the second portion and the first inlet, and ejecting the second driving fluid;
a condenser that condenses the refrigerant discharged from the ejector by heat exchange with a cooling fluid;
a pump that delivers the refrigerant condensed by the condenser to the steam generator;
an expander that decompresses the refrigerant condensed by the condenser;
an evaporator that evaporates the refrigerant decompressed by the expander by heat exchange with a medium to be cooled, and supplies the evaporated refrigerant to the suction port as the suction fluid;
Switching between a supply state in which the second driving fluid is supplied from the steam generator to the second nozzle and a shutoff state in which the supply of the second driving fluid from the steam generator to the second nozzle is shut off. A cooling system comprising a switching mechanism and . The cooling system according to claim 5, further comprising a control unit that switches between the supply state and the cutoff state. further comprising a temperature detection unit that detects the temperature of the cooling fluid;
The cooling system according to claim 6, wherein the controller controls the state of the switching mechanism according to the temperature detected by the temperature detector.

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