JP2005155571A - Ejector and refrigerating system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ejector capable of ejecting an unsteady flow of the primary fluid from a nozzle and preventing the flow rate of the primary fluid per unit time from being considerably reduced, and a refrigerating system using the ejector. <P>SOLUTION: The ejector to perform suction and/or boosting of the secondary fluid by the jet of the primary fluid has a nozzle header 3 having a plurality of nozzles 2 to eject the unsteady flow of the primary fluid so that the interface between the primary fluid and the secondary fluid is substantially normal to the axial direction of the ejector. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an ejector that is used for vacuum generation, compression, pressure increase, and the like, and more particularly, to an ejector that makes a primary fluid flow unsteady and a refrigeration system using the ejector.

A conventional ejector sucks a low-pressure secondary fluid by injecting a primary fluid from a nozzle provided inside the diffuser at a high speed, and involves pressure conversion (energy exchange) between the primary fluid and the secondary fluid. We will let it flow out of the diffuser. When a refrigeration cycle is configured using an ejector, the vaporization heat generated when the secondary fluid is evaporated and sucked by connecting the evaporator containing the secondary fluid in a liquid phase state to the ejector. The cold generated by (evaporation latent heat) is used.
In a conventional ejector, the secondary fluid is sheared and mixed by the jet of the primary fluid at the interface where the primary fluid and the secondary fluid are in contact with each other, that is, the suction process is the difference in velocity between the primary fluid and the secondary fluid. Therefore, entropy increase, that is, loss of effective energy is inevitable because it is based on turbulence and vortex entrainment in the boundary region between both fluids. Moreover, since the primary fluid in a high energy state and the secondary fluid in a low energy state are directly mixed, a loss of effective energy is inevitable here. Due to these factors, the conventional ejector has a very low efficiency.

As means for solving these problems, the present applicant has already proposed an ejector in which the primary fluid ejected from the nozzle is an unsteady flow (see Patent Document 1).
In the invention disclosed in Patent Document 1, when the primary fluid in the high energy state and the secondary fluid in the low energy state are in direct contact, the interface between the two fluids is substantially perpendicular to their flow direction. By alternately flowing the fluids, energy exchange between the two fluids is performed reversibly, so that the effect of reducing energy loss during mixing is aimed at. As means for that, it has been invented that the primary fluid is an intermittent or pulsating unsteady flow.
JP 2002-333000 A

  In the invention disclosed in Patent Document 1, since the flow rate of the primary fluid is periodically changed, the flow rate of the primary fluid flowing per time is reduced as compared with the case where a steady flow is formed. It was inevitable. That is, when an ideal intermittent flow is formed, the flow rate per time is reduced to about 50% of that when a steady flow is formed. Therefore, although the energy conversion efficiency increases, the primary fluid flow rate that can be used decreases, so that it is necessary to increase the size of the ejector device in order to obtain energy equivalent to the conventional one.

  The present invention has been made in order to solve such a problem, and an unsteady flow of the primary fluid is ejected from the nozzle, and the flow rate of the primary fluid per hour is not significantly reduced. An object is to provide an ejector and a refrigeration system using the ejector.

In the ejector according to the present invention, the primary fluid is sucked and / or pressurized by the jet of the primary fluid, and the primary fluid and the secondary fluid have an interface substantially perpendicular to the ejector axial direction. A nozzle header having a plurality of nozzles for ejecting the unsteady flow is provided.
Here, the unsteady flow means that the flow of the primary fluid is an intermittent flow or a pulsating flow. “Intermittent flow” refers to a flow in which a fluid intermittently flows in one direction, and there is a moment when the flow rate of the fluid becomes zero. “Pulsating flow” refers to a fluid flow rate that fluctuates with time in the main flow direction and does not become zero even at the moment when the flow rate is minimized.

  In the ejector of the present invention, the nozzle header is provided with a plurality of nozzles for ejecting the unsteady flow of the primary fluid so that the interface between the primary fluid and the secondary fluid is substantially perpendicular to the ejector axial direction. The primary fluid flow rate per hour is not significantly reduced, but rather the available primary fluid flow rate can be increased. Therefore, the ejector device can be downsized. In addition, by making the primary fluid ejected from each nozzle unsteady and the interface with the secondary fluid perpendicular to the flow direction, the effective energy loss during suction and mixing of the secondary fluid is reduced, and the efficiency of the ejector is reduced. improves.

In the ejector of the present invention, a primary fluid control device is further provided so that the plurality of nozzles repeats periodic on / off of the primary fluid.
With the primary fluid control device, each nozzle generates a periodic intermittent flow, and the sum of the primary fluid flow rates ejected from the nozzles can be made almost constant at any time.
For this purpose, in the nozzle header, it is preferable that the plurality of nozzles be arranged uniformly or evenly on the same circumference.

The refrigeration system of the present invention is characterized in that a refrigeration cycle is configured by using the ejector according to any one of claims 1 to 3.
When the ejector of the present invention is used, pressure exchange is possible without reducing the flow rate of the fluid passing through the diffuser, thereby improving the efficiency of the ejector. Therefore, the flow rate ratio of the secondary fluid to the primary fluid (= [two Secondary fluid flow rate] / [primary fluid flow rate]) is increased, and the efficiency (COP) of the refrigerator is improved.

As described above, the ejector according to the present invention can exchange pressure without significantly reducing the primary fluid flow rate per hour, so that the loss of effective energy is suppressed and the ejector efficiency is greatly improved.
In addition, since the refrigeration system using the ejector of the present invention can increase the amount of cold heat, there is an effect of improving the efficiency (COP) as a refrigerator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic configuration diagram for explaining the basic principle of an ejector according to the present invention.
The ejector 1 mainly includes a nozzle header 3 having a plurality of nozzles 2 and a diffuser 4 in which the nozzle header 3 is installed on the central axis. The plurality of nozzles 2 are evenly arranged on the same circumference in the nozzle header 3, but the arrangement, the number, and the like of the nozzles 2 are not particularly limited. Reference numeral 5 denotes a primary fluid control device for controlling the primary fluid ejected from each nozzle 2 as an unsteady flow (intermittent flow or pulsating flow). The nozzle header 3 and the primary fluid heating device 6 are connected by a primary fluid supply pipe 7 via the primary fluid control device 5. A primary fluid supply device 8 composed of a pump or the like is connected to the primary fluid heating device 6. One end of a secondary fluid supply pipe 10 is connected to the secondary fluid introduction part 9 of the diffuser 4, and the other end of the pipe 10 is connected to a secondary fluid supply device 11 that is a secondary fluid supply source. The discharge flow of the primary fluid and the secondary fluid mixed in the ejector 1 is supplied to or discharged from another process, a condenser, the atmosphere, or the like through the outflow pipe 12 according to the purpose of use.

FIG. 2 schematically shows the flow pattern of the primary fluid in the present invention. For the sake of simplicity, the nozzle 2 will be described assuming that two nozzles are alternately switched. In practice, there may be any number of nozzles as long as there are two or more.
The primary fluid control device 5 alternately turns on and off the flow paths to the nozzles 2a and 2b. Therefore, an intermittent primary fluid flow (high pressure primary fluid mass) 14 is generated while shifting the phase from the respective nozzles 2a, 2b.
When the phenomenon is detected in a certain time by the switching action of the plurality of nozzles 2a and 2b, a local dense pressure distribution of the primary fluid is generated in the diffuser 4. In the vicinity of these nozzles 2a and 2b, a periodic sparse intermittent flow (high pressure primary fluid mass) 14 is generated, so the secondary fluid is a sparse intermittent flow (high pressure primary fluid mass) 14 of this primary fluid. Reversible energy is transferred locally between the interfaces. Moreover, since the interface is substantially perpendicular to the fluid flow direction (ejector axial direction), the loss of effective energy is suppressed, and thus the efficiency of the ejector is improved.
Furthermore, since the primary fluid is ejected from the other nozzle 2b during the time when the primary fluid is not ejected from one nozzle 2a, the primary fluid is always ejected from the whole nozzle header 3. Thus, the primary fluid flow rate per unit time due to intermittent flow can be increased rather than decreased. However, it is necessary to appropriately set the diameter, injection pressure, and injection time of each nozzle. Further, the ejector 1 can be downsized by increasing the primary fluid flow rate.

FIG. 3 is a diagram showing an example of the configuration of the primary fluid control device according to the present invention, FIG. 4 is a front view of the nozzle header, and FIG. 5 is a front view of the shutter of the shutter mechanism.
In this example, the primary fluid control device 5 is configured as a shutter mechanism 15 that rotates within the nozzle header 3. The shutter mechanism 15 attaches a shutter 17 to a rotary shaft 16 and rotates the rotary shaft 16 with a drive motor (not shown) to turn on / off the flow path to the nozzle 2. The nozzles 2 are equally arranged on the same circumference in the nozzle header 3, and the number of the nozzles 2 is 8 in this example, and the flow paths to the four nozzles 2 are turned ON / OFF simultaneously. The shutter 17 is provided with a notch-shaped opening 18 (see FIG. 5) or a through hole 19 (see FIG. 3).
Therefore, when the shutter 17 is rotated once, each nozzle 2 is turned ON / OFF four times, so that an intermittent flow for four cycles can be generated, and the sum of the primary fluid flow rates can be determined at any time. Can be made almost constant.

  FIG. 6 is a diagram showing another configuration example of the primary fluid control device in the present invention. In this example, the primary fluid control device 5 is configured as an electromagnetic valve switching device 20 that opens and closes the flow path of each nozzle 2. The nozzles 2 are arranged uniformly in the nozzle header 3 as a whole. An electromagnetic valve 21 is attached to the flow path of each nozzle 2, and the upstream side thereof is gathered in the primary fluid supply pipe 7. And each nozzle 2 generates an intermittent flow by switching the solenoid valves 21 one by one or a plurality at the same time by an external solenoid valve controller 22.

  As the primary fluid control device, in addition to the above configuration example, the periodic heating control method (bubble method) of the inner pipe provided in the primary fluid supply pipe disclosed in Patent Document 1, the cycle of the primary fluid supply device Supply control method (pump method such as diaphragm pump), periodic application control method of high electric field to the primary fluid heating device, etc., and the primary fluid supply is controlled by a fluid element that performs switching Can also be used.

  FIG. 7 is a diagram showing another configuration example of the ejector of the present invention. As shown in this figure, the nozzle header 3 and the primary fluid control device 5 can be installed inside and outside with the rear end wall 9a of the secondary fluid introduction part 9 interposed therebetween. By configuring in this way, the primary fluid control device 5 can be installed outside, so the configuration inside the ejector is simplified, and design and maintenance are easy.

FIG. 8 is a schematic diagram showing an example of an embodiment in which a refrigeration cycle is configured using the ejector of the present invention.
The ejector 1 is mainly configured by a nozzle header 3 provided with a plurality of nozzles 2, a diffuser 4, and a primary fluid control device 5. The nozzle header 3 is connected to a primary fluid heating device 6 and a primary fluid supply device 8 by a primary fluid supply pipe 7 via a primary fluid control device 5. The ejector 1 is connected to the evaporator 31 via the secondary fluid supply pipe 10. A condenser 32 is connected to the outflow side of the ejector 1 through an outflow pipe 12. The mixture of the primary fluid and the secondary fluid flowing into the condenser 32 is cooled by the cooling water pipe 33 connected to the condenser 32 and condensed. The condensed liquid flows through the pipe 34 and is returned to the primary fluid heating apparatus 6 by the primary fluid supply apparatus 8, and at the same time returns to the evaporator 31 through the secondary fluid return pipe 35 and the pressure reducing valve 36.
A temperature drop, that is, refrigeration occurs due to vaporization heat (evaporation latent heat) of the secondary fluid generated when the secondary fluid in the evaporator 31 is sucked by the ejector 1, and a cooling load 37 connected to the evaporator 31. Cool down.

  By using this ejector 1, the efficiency of the ejector is improved without reducing the discharge amount of the fluid passing through the diffuser 4 as described above. Therefore, the flow rate ratio of the secondary fluid to the primary fluid (= [secondary fluid flow rate] ] / [Primary fluid flow rate]) increases, that is, the amount of cold heat increases, so that the efficiency (COP) as a refrigerator is improved.

  In addition, as a heat source of the heat exchanger 38 connected to the primary fluid heating device 6, factory exhaust heat, exhaust gas heat, and the like are used in addition to power and fuel combustion. As the primary and secondary fluid refrigerants, water, chlorofluorocarbon, alcohol, ammonia, hydrocarbon refrigerant, or a mixture thereof can be used.

The schematic diagram for demonstrating the basic principle of the ejector of this invention. Explanatory drawing which shows the pattern of the flow of the primary fluid in this invention. The figure which shows the example of 1 structure of the primary fluid control apparatus in this invention. The front view of the nozzle header of FIG. The front view of the shutter of the shutter mechanism of FIG. The figure which shows another structural example of the primary fluid control apparatus in this invention. The figure which shows another structural example of the ejector of this invention. The schematic diagram of the refrigerating system of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ejector, 2 nozzle, 3 nozzle header, 4 Diffuser, 5 Primary fluid control apparatus, 6 Primary fluid heating apparatus, 7 Primary fluid supply piping, 8 Primary fluid supply apparatus, 9 Secondary fluid introduction part, 10 Secondary fluid supply piping , 11 Secondary fluid supply device, 12 Outflow pipe, 14 Intermittent flow (high pressure primary fluid mass), 15 Shutter mechanism, 16 Rotating shaft, 17 Shutter, 20 Solenoid valve switching device, 21 Solenoid valve, 22 Solenoid valve controller, 31 evaporator, 32 condenser

Claims (4)

  In an ejector that sucks and / or pressurizes a secondary fluid by a jet of the primary fluid, an unsteady flow of the primary fluid is ejected so that the interface between the primary fluid and the secondary fluid is substantially perpendicular to the ejector axial direction An ejector comprising a nozzle header having a plurality of nozzles.   2. The ejector according to claim 1, further comprising a primary fluid control device so that the plurality of nozzles repeats periodic on / off of the primary fluid. 3.   3. The ejector according to claim 1, wherein in the nozzle header, the plurality of nozzles are arranged uniformly on the whole or on the same circumference. 4. A refrigeration system comprising a refrigeration cycle using the ejector according to any one of claims 1 to 3.

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