Ejector having a curved guide to improve flow efficiency and cooling apparatus having the same

As an ejector of the present disclosure and a cooling apparatus having the same include a suction guide unit at least partially having a curved surface so that the ejector guides a flow of a refrigerant, a structure is improved and thus a flow loss can be reduced. Also, through the improved structure, a mixture rate between a refrigerant passing through a nozzle unit and a refrigerant passing through a suction unit is improved, so that pressure rising efficiency can be increased to reduce a compressor load, and thus energy efficiency can be increased due to an increase in efficiency of the ejector.

This application claims the benefit of Korean Patent Application No. 2014-0192808, filed on Dec. 30, 2014 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND

The present disclosure relates to an ejector and a cooling apparatus having the same, and more specifically, to an ejector having a structure improved to increase efficiency and a cooling apparatus having the same.

Generally, a cooling apparatus is configured of a compressor, a condenser, an evaporator, and an expansion device. The compressor compresses a refrigerant at a high temperature and high pressure, and the condenser condenses the refrigerant discharged from the compressor and converts the refrigerant into a liquid refrigerant. The expansion device reduces the temperature and pressure of the refrigerant, discharged from the condenser, to a state that the evaporator requires through a throttling process. While the refrigerant is evaporated by absorbing heat from the surrounding air when passing through the evaporator, the refrigerant becomes a saturated air state at an outlet of the evaporator, and then when the refrigerant is introduced into the compressor again, a cycle is formed.

In this process, energy efficiency of the cooling apparatus is obtained by dividing a cooling load of the evaporator by a compressor load of the compressor. That is, to increase energy efficiency, the cooling load of the evaporator should be increased, or the compression load of the compressor should be decreased.

An ejector is provided to reduce the compression load of the compressor and to increase a pressure of gaseous refrigerant introduced into the compressor. Specifically, the ejector is configured to increase pressures of the introduced two-phase refrigerants. However, in a process of mixing the two-phase refrigerants moving in the ejector, when a flow loss is generated, there is a problem in which pressure rising efficiency is reduced.

SUMMARY

It is an aspect of the present disclosure to provide an ejector capable of increasing flow efficiency of fluid passing through the ejector and a cooling apparatus having the same.

In accordance with one aspect of the present disclosure, an ejector includes a nozzle unit in which a first refrigerant moves, a suction unit which is formed to surround the nozzle unit and forms a suction path in which a second refrigerant moves between the nozzle unit and the suction unit, a mixing unit being in communication with the suction unit and configured to form a mixed fluid of the first refrigerant and the second refrigerant, and a diffuser unit which extends from the mixing unit in a direction of an ejector center axis passing through centers of the nozzle unit, the suction unit, and the mixing unit and is configured to convert kinetic energy of the mixed fluid discharged from the mixing unit into pressure energy, wherein the suction unit may include a suction port into which the second refrigerant is introduced into the suction unit, and a suction guide unit which has at least one guide curved surface having a curved inner surface and has a cross-sectional area of the suction path reduced in a flow direction of the first refrigerant.

The guide curved surface may be formed of a curved line in which cross-sections in the direction of the ejector center axis are symmetrical to each other.

The guide curved surface may include a concave guide curved surface configured to guide a flow of the second refrigerant so that the second refrigerant moves toward the ejector center axis, and a convex guide curved surface arranged at a more downstream side than the concave guide curved surface and provided to have a cross-sectional area of the suction path more gently reduced than that of the concave guide curved surface.

When a radius curvature of the concave guide curved surface, R_c, and a radius curvature of the convex guide curved surface, R_v, R_c<R_v may be satisfied.

The convex guide curved surface may extend from the concave guide curved surface.

Slopes of tangents at which the concave guide curved surface and the convex guide curved surface meet may be identical to each other.

The guide curved surface may include a convex guide curved surface configured to guide a movement direction of the second refrigerant passing through the suction guide unit to a movement direction of the first refrigerant, wherein a radius curvature of the convex guide curved surface, R_v, and a diameter of the mixing unit, d_m, may satisfy a relation of 0.4≤R_v/d_m≤2.7.

The nozzle unit may include a nozzle body configured to form an appearance, and a nozzle guide unit configured to form a nozzle path in the nozzle body, wherein the nozzle guide unit may include a nozzle introducing unit configured to guide so that the first refrigerant is introduced to an inside of the nozzle body, a nozzle converging unit which is formed so that a diameter of the nozzle path is reduced in a movement direction of the first refrigerant to a nozzle neck having a smaller diameter than that of the nozzle introducing unit, and a nozzle dispersing unit formed so that a diameter of the nozzle path is increased in the movement direction of the first refrigerant from the nozzle neck and configured to guide a discharging of the first refrigerant to the inside of the ejector, wherein the nozzle converging unit may have a variation in diameter greater than that of the nozzle dispersing unit with respect to the movement direction of the first refrigerant.

A dispersing angle of the nozzle dispersing unit, α, may satisfy a relation of 0.5°≤α≤2°.

The nozzle dispersing unit may have an outlet having a smaller diameter than that of an inlet of the nozzle converging unit.

A length of the nozzle dispersing unit, L_nd, and a diameter of the nozzle neck with respect to the movement direction of the first refrigerant, d_th, may satisfy a relation of 10≤L_nd/d_th≤50.

The nozzle body may include a nozzle tip configured to form an outlet of the nozzle dispersing unit, and an outer diameter of the nozzle tip, d_tip, and an inner diameter of the mixing unit, d_m, may form a relation of d_tip/d_m<1.

The outer diameter of the nozzle tip, d_tip, and an inner diameter of the nozzle tip, d_do, may form a relation of 1<d_tip/d_do<1.8.

A slope between the ejector center axis and an outer surface of the nozzle body forming the nozzle tip, β, may be less than or equal to a slope between the ejector center axis and an inner surface of the suction guide unit, ψ.

The slope (β) may satisfy 5°≤β≤30°.

The slope (ψ) may satisfy 20°≤ψ≤60°.

The diffuser unit may include a diffuser body extending from the mixing unit, and a diffuser guide unit provided on an inner surface of the diffuser body to form a diffuser path through which the mixed fluid formed by the mixing unit is discharged and formed that a cross-sectional area of the diffuser path is increased in a flow direction of the mixed fluid, wherein the diffuser guide unit may include a diffuser curved surface having a curved inner surface.

The diffuser curved surface may be formed of a curved line in which cross-sections with respect to the ejector center axis are symmetrical to each other.

The diffuser curved surface may include a convex diffuser curved surface formed that a cross-sectional area of the diffuser path is increased and formed to be convex from the diffuser body toward the ejector center axis, and a concave diffuser curved surface arranged at a more downstream side than the convex diffuser curved surface and formed to be concave from the diffuser body from the ejector center axis.

The diffuser guide unit may further include a curved surface connection unit which has a slope identical to slopes of tangents of an upstream side of the concave diffuser curved surface and a downstream side of the convex diffuser curved surface and connects the convex diffuser curved surface with the concave diffuser curved surface.

With respect to the direction of the ejector center axis, an angle between a slope of a diameter of an outlet of the concave diffuser curved surface and a nozzle center axis may be greater than 0.

The diameter of the mixing unit, d_m, and the outer diameter of the nozzle tip, d_tip, may satisfy a relation of 1.2≤d_m/d_tip≤3.

A diameter of the mixing unit, d_m, and a length of the mixing unit, L_m, may satisfy a relation of 4.5≤L_m/d_m≤28.

A diameter of the mixing unit, d_m, and a length of the diffuser unit, L_d, may satisfy a relation of 7≤L_d/d_m≤31.

A distance between an outlet of the nozzle unit and an inlet of the mixing unit, L_n, and a diameter of the mixing unit, d_m, may satisfy a relation of 0.2≤L_n/d_m≤2.5.

In accordance with another aspect of the present disclosure, an ejector includes a nozzle unit in which a first refrigerant moves, a suction unit suctioning a second refrigerant by a flow of the first refrigerant discharged from the nozzle unit and formed to surround the nozzle unit, a mixing unit which is in communication with the suction unit and forms a mixed fluid of the first refrigerant and the second refrigerant, and a diffuser unit configured to convert kinetic energy of the mixed fluid of the first refrigerant and the second refrigerant, discharged from the mixing unit, into pressure energy, wherein the nozzle unit may include a nozzle body forming a nozzle path therein, and a nozzle tip provided at an end part of the nozzle body and forming an outlet of the nozzle path, wherein an outer diameter d_tip of the nozzle tip and an inner diameter d_m of the mixing unit may form a relation of d_tip/d_m<1.

The outer diameter of the nozzle tip, d_tip, and an inner diameter of the nozzle tip, d_do, may form a relation of 1<d_tip/d_do<1.8.

The nozzle unit may further include a nozzle guide unit forming a nozzle path in the nozzle body, wherein the nozzle guide unit may include a nozzle introducing unit configured to guide so that the first refrigerant is introduced into an inside of the nozzle body, a nozzle converging unit having a diameter of the nozzle path reduced in a movement direction of the first refrigerant to a nozzle neck having a smaller diameter than that of the nozzle introducing unit, and a nozzle dispersing unit formed so that the diameter of the nozzle path is increased in the movement direction of the first refrigerant from the nozzle neck to guide a discharging of the first refrigerant to the inside of the ejector, wherein a dispersing angle of the nozzle dispersing unit, a, may satisfy a relation of 0.5°≤α≤2°.

A slope with an outer surface of the nozzle body forming the nozzle tip from an ejector center axis, β, may be less than or equal to a slope with an inner surface of a suction guide unit from the ejector center axis, ψ.

A length of the nozzle dispersing unit with respect to a movement direction of the first refrigerant, L_nd, and a diameter of a nozzle neck, d_th, may satisfy a relation of 10≤L_nd/d_th≤50.

In accordance with still another aspect of the present disclosure, a cooling apparatus includes a first refrigerant circuit configured so that a refrigerant discharged from a compressor moves to a suction side of the compressor through a condenser, an ejector, and a vapor-liquid separator, and a second refrigerant circuit configured so that the refrigerant is suctioned into a suction port of the ejector and is circulated through the ejector, the vapor-liquid separator, a first expansion device, a first evaporator, and a second evaporator, wherein the ejector may include a nozzle unit in which a first refrigerant moves, a suction unit configured to suction a second refrigerant by a flow of the first refrigerant discharged from the nozzle unit and surround the nozzle unit, a mixing unit being in communication with the suction unit and forming a mixed fluid of the first refrigerant and the second refrigerant, and a diffuser unit configured to convert kinetic energy of the mixed fluid of the first refrigerant and the second refrigerant, discharged from the mixing unit, into pressure energy, wherein the suction unit may include a suction port through which the second refrigerant is introduced into an inside of the suction unit, and a tubular suction guide unit which forms a path in which the second refrigerant moves so that the second refrigerant introduced into the suction port moves along a flow of the first refrigerant and is formed so that a cross-sectional area of the path is reduced in a flow direction of the first refrigerant, wherein the tubular suction guide unit includes at least one guide curved surface having a cross-section curved in a fluid movement direction.

In accordance with yet another aspect of the present disclosure, an ejector includes a nozzle unit in which a first refrigerant moves, a suction unit configured to suction a second refrigerant by a flow of the first refrigerant discharged from the nozzle unit and surround the nozzle unit, a mixing unit being in communication with the suction unit and configured to form a mixed fluid of the first refrigerant and the second refrigerant, and a diffuser unit extending from the mixing unit with respect to an ejector center axis passing through centers of the nozzle unit, the suction unit, and the mixing unit and configured to convert kinetic energy of the mixed fluid, discharged from the mixing unit, into pressure energy, wherein the suction unit may include a suction port into which the second refrigerant is introduced into the suction unit, and a suction guide unit forming a suction path in which the second refrigerant moves so that the second refrigerant introduced into the suction port moves to the mixing unit along a flow of the first refrigerant, wherein the suction guide unit includes a first suction guide unit having a first angle between an inner surface of the first suction guide unit and a diffuser center axis, and a second suction guide unit which is connected with the first suction guide unit at a downstream side of the first suction guide unit and forms a second angle with the diffuser center axis to be smaller than the first angle.

The ejector of the present disclosure and the cooling apparatus having the same can increase fluid flow efficiency by improving a structure of a path of fluid and improve performance of the ejector.

DETAILED DESCRIPTION

Hereinafter, embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings.

FIG. 1is a view of a cooling apparatus1according to a first embodiment of the present disclosure,FIG. 2is a P-h diagram of the cooling apparatus1ofFIG. 1according to the first embodiment of the present disclosure, andFIG. 3is a cross-sectional view of an ejector100according to the first embodiment of the present disclosure.

The cooling apparatus1includes a compressor10that is connected to a condenser20, an evaporator40, and the ejector100, through a refrigerant tube500, forming a closed loop refrigerant circuit.

Specifically, the cooling apparatus1includes a first refrigerant circuit P1, and a second refrigerant circuit P2.

The first refrigerant circuit P1is configured so that a refrigerant discharged from the compressor10is moved to a suction side of the compressor10through the condenser20, the ejector100, and a vapor-liquid separator50. The second refrigerant circuit P2is configured so that the refrigerant is suctioned to a suction unit130of the ejector100and circulated through the ejector100, the vapor-liquid separator50, an expansion device30, and the evaporator40.

A working refrigerant moving in the cooling apparatus1may include HC-based Isobutane R600a, propane R290, HFC-based R134a, and HFO-based R1234yf.

A coefficient of performance (COP) in the cooling apparatus1may be represented as a ratio of a cooling load of the evaporator40to a load of the compressor10. In the embodiment of the present disclosure, a solution of increasing the COP by reducing a compression load expressed by the compressor10, by using the ejector100having an improved structure will be described.

In the description of the present disclosure, a refrigerant (not shown) moving in the first refrigerant circuit P1and a refrigerant (not shown) moving in the second refrigerant circuit P2may be the same, but may have different phases. For the convenience of the description, the refrigerant moving in the first refrigerant circuit P1is defined as a first refrigerant, and the refrigerant moving in the second refrigerant circuit P2is defined as a second refrigerant.

The ejector100is provided to increase a pressure of a discharged refrigerant by mixing the phases of the first and second refrigerants and to reduce a compression load.

The ejector100may include a nozzle unit110, the suction unit130, a mixing unit140, and a diffuser unit150. The refrigerant discharged from the condenser20is referred as a first refrigerant, and the refrigerant discharged from the evaporator40is referred as a second refrigerant. The first refrigerant flows to the mixing unit140through the nozzle unit110, and the second refrigerant is suctioned to the suction unit130and is mixed with the first refrigerant in the mixing unit140, and then the mixed refrigerant is discharged from the ejector100through the diffuser unit150. A detailed configuration of the ejector100will be described below in detail.

When the first refrigerant passes through the nozzle unit110, ideally, the first refrigerant is isentropic-expanded, and an enthalpy difference before and after the nozzle unit110becomes a speed difference of the first refrigerant, and thus the first refrigerant may spurt from an outlet of the nozzle unit110at a high speed.

In the diffuser unit150, speed energy of the mixed refrigerant of the first refrigerant and the second refrigerant is converted into pressure energy to have an effect of pressure rising, and a compression load is reduced when the refrigerant is suctioned into the compressor10, and thus efficiency of a cycle is increased.

A refrigerant flow in the ejector100will be described.

The first refrigerant discharged from the condenser20is introduced into an inlet of the nozzle unit110of the ejector100(1″). While the first refrigerant passes through the nozzle unit110in the ejector100, a flow velocity of the first refrigerant is increased and a pressure of the first refrigerant is decreased (1b″).

The first refrigerant moves at the outlet of the nozzle unit110at a reduced pressure, and the second refrigerant (2″) moving in a saturated air state via the evaporator40through the second refrigerant circuit P2is suctioned into the suction unit130of the ejector100by a pressure difference between the second refrigerant (2″) and the first refrigerant having a pressure relatively lower than a saturated pressure (2b″).

The first refrigerant that has passed through the nozzle unit110and the second refrigerant that suctioned through the suction unit130are mixed in the mixing unit140of the ejector100(3″). When the mixed refrigerant passes through the diffuser unit150, which may have a fan shape, and which is formed in an outlet unit of the ejector100, a flow velocity of the mixed refrigerant is reduced and a pressure thereof is increased, and thus the mixed refrigerant is introduced into the vapor-liquid separator50.

A gaseous refrigerant in the vapor-liquid separator50is introduced into the suction unit130of the compressor10(4″), and a liquid refrigerant (6″) in a reduced temperature and pressure state is introduced into the evaporator40through the expansion device30(7″). While the refrigerant is evaporated by absorbing heat from the surrounding air while passing through the evaporator40, the refrigerant at an outlet of the evaporator40becomes a saturated air state (2″). The refrigerant in the saturated air state is continuously circulated by being suctioned into the suction unit130of the ejector100.

Thus, a pressure of the refrigerant suctioned into the compressor10in a cycle in which the ejector100is provided is more increased than in a cycle in which the ejector100is not provided. When the refrigerant introduced into the compressor10is compressed to a condensing temperature, a load amount of the compressor10is reduced. Since the mostly liquid refrigerant flows in the evaporator40provided on the second refrigerant circuit P2through the vapor-liquid separator50, cooling performance is increased, and thus the COP of the entire cycle is increased.

FIG. 4is an enlarged view of a suction unit of the ejector according to the first embodiment of the present disclosure,FIG. 5is an enlarged view of a nozzle unit of the ejector according to the first embodiment of the present disclosure,FIG. 6Ais a graph of a pressure rising rate according to a shape of the nozzle unit of the ejector according to the first embodiment of the present disclosure,FIG. 6Billustrates nozzle units ofFIG. 6Ahaving variously shaped nozzle tips according to the first embodiment of the present disclosure, andFIG. 7is a partially enlarged view of the ejector according to the first embodiment of the present disclosure.

The ejector100will be described.

The ejector100includes the nozzle unit110, the suction unit130, the mixing unit140, and the diffuser unit150. The nozzle unit110, the suction unit130, the mixing unit140, and the diffuser unit150may have a shape of a body of revolution with respect to an ejector center axis100a. The nozzle unit110, the suction unit130, the mixing unit140, and the diffuser unit150may be formed in parallel to a direction of the ejector center axis100a.

The suction unit130will be first described.

The suction unit130is provided so that a second refrigerant moving in the second refrigerant circuit P2is introduced and moved. The second refrigerant is suctioned from the suction unit130and is mixed with the first refrigerant in the mixing unit140. A suction path130ain which the second refrigerant moves is formed between the nozzle unit110and the suction unit130.

The second refrigerant is suctioned into the suction unit130by a flow of the first refrigerant discharged from the nozzle unit110, and surrounds at least part of the nozzle unit110. Specifically, the second refrigerant may move through the suction path130aformed by an outer diameter of the nozzle unit110and an inner diameter of the suction unit130. Specifically, the suction path130amay be formed by the outer diameter of the nozzle unit110and inner diameters of a suction tube134and a suction guide unit136to be described below. For the configuration, the suction unit130is spaced apart from the nozzle unit110and surrounds a circumference of the nozzle unit110.

The suction unit130has an approximately cylindrical shape and may be provided so that a diameter gets smaller in a movement direction of the second refrigerant.

The suction unit130may include a suction port132and the suction guide unit136.

The suction port132is provided so that the second refrigerant is introduced into the suction unit130. The suction port132is connected with an outlet unit of the evaporator40, so that the second refrigerant discharged from the evaporator40is introduced into the suction unit130of the ejector100through the suction port132. Specifically, as described above, since the first refrigerant moves at the outlet of the nozzle unit110at a reduced pressure and the second refrigerant is moved in a saturated air state, the second refrigerant is suctioned into the suction unit130of the ejector100by a pressure difference between the second refrigerant and the first refrigerant having a relatively lower pressure. The second refrigerant introduced into the suction unit130through the suction port132is moved to the suction guide unit136to be described below along an inner side of the suction tube134. The suction tube134is provided to be in communication with the suction port132, and is spaced apart from the circumference of the nozzle unit110and surrounds the nozzle unit110. The suction tube134may be formed in an approximately cylinder shape.

The suction guide unit136is provided to form at least part of the suction path130a. Specifically, the suction path130ais formed by the outer diameter of the nozzle unit110and the inner diameter of the suction guide unit136. The suction guide unit136is provided so that a cross-sectional area of the suction path130ais reduced in a flow direction of the first refrigerant. The suction guide unit136may be provided in a tubular shape.

Since a path cross-sectional area of the mixing unit140is formed to be smaller than a cross-sectional area of the suction path130a, the second refrigerant introduced into the suction unit130has a flow velocity increased while moving to the mixing unit140. As the flow velocity of the first refrigerant discharged from the nozzle unit110and the flow velocity of the second refrigerant moving in the suction unit130correspond to each other, mixture efficiency of the first refrigerant and the second refrigerant in the mixing unit140is increased, and thus a structure of the suction unit130increasing the flow velocity of the second refrigerant becomes important.

The second refrigerant passing through the suction guide unit136is provided to move along a flow of the first refrigerant by a pressure difference between the first and second refrigerants. The suction guide unit136is formed so that a cross-sectional area of the suction path130ais reduced in a flow direction of the first refrigerant. While the refrigerant is moved from the suction unit130to the mixing unit140, as an angle in which the suction guide unit136forming the suction path130ais folded is small and the suction guide unit136has a streamlined shape, a flow loss is reduced, thereby increasing pressure rise efficiency of the ejector100.

The suction guide unit136may include a guide curved surface138. The guide curved surface138is provided to form the suction path130aand is provided so that a cross-sectional area of the suction path130ais reduced in a movement direction of the first refrigerant. Also, the guide curved surface138is provided so that a flow loss of the second refrigerant moving in the suction guide unit136is reduced. A shape of the guide curved surface138is not limited, and at least a portion of the guide curved surface138may have a curved surface. Specifically, the suction guide unit136may include one of the guide curved surface138may be provided so that a cross-section in the direction of the ejector center axis100ahas a curved shape symmetrical with respect to the ejector center axis100a.

The guide curved surface138may include a concave guide curved surface138aand/or a convex guide curved surface138b.

The concave guide curved surface138ais provided to guide a flow of the second refrigerant so that the second refrigerant moves toward the ejector center axis100a. The suction guide unit136is formed so that a cross-sectional area of the suction path130ais reduced in a movement direction of the second refrigerant, and thus the concave guide curved surface138ais formed so that a cross-sectional area of the suction path130ais reduced from the suction tube134to the suction guide unit136. According to the configuration, the second refrigerant has a flow toward the ejector center axis100aalong with a flow in the direction of the ejector center axis100a.

As described above, the concave guide curved surface138ais provided to guide a flow of the second refrigerant moving in the suction tube134by bending the flow of the second refrigerant to the suction guide unit136. The concave guide curved surface138amay have a curvature of R_c.

The concave guide curved surface138aand the suction tube134may have the same slope at a contact point. Also, the concave guide curved surface138aand the convex guide curved surface138bto be described below may have the same slope at a contact point.

The convex guide curved surface138bis arranged downstream from the concave guide curved surface138a, and a cross-sectional area of the suction path130ain the convex guide curved surface138bis reduced more gently than in the concave guide curved surface138a. The convex guide curved surface138bguides a movement direction of the second refrigerant in a movement direction of the first refrigerant. The convex guide curved surface138bmay have a curvature of R_v. The convex guide curved surface138band the mixing unit140may have the same slope at a contact point. Preferably, the curvature R_v of the convex guide may be formed 0.4 to 2.7 times a diameter of the mixing unit140.

That is, the curvature R_v of the convex guide curved surface138band a diameter d_m of the mixing unit140satisfy a relation of 0.4≤R_v/d_m≤2.7.

According to the configuration, a flow loss may be minimized in a process in which both the first refrigerant introduced through the nozzle unit110and the second refrigerant introduced through the suction unit130move to the mixing unit140.

The convex guide curved surface138bmay extend from the concave guide curved surface138a. According to the configuration, the suction path130amay be formed in a streamline shape and may reduce the flow loss. The tangential slopes at a point at which the concave guide curved surface138aand the convex guide curved surface138bmeet may be same.

Unlike in the embodiment, a tubular surface is formed between the convex guide curved surface138band the concave guide curved surface138a, and both configurations may be connected. In this case, both ends of the tubular surface may be connected with the convex guide curved surface138band the concave guide curved surface138aat the same slope at a part at which the convex guide curved surface138band the concave guide curved surface138ameet the both ends, respectively.

A radius curvature of the concave guide curved surface138a, R_c, may be formed to be smaller than a radius curvature of the convex guide curved surface138b, R_v. Thus, R_c<R_v. When the radius curvature of the concave guide curved surface138a, R_c, is formed to be greater than the radius curvature of the convex guide curved surface138b, R_v, a cross-sectional area of the suction unit130is sharply reduced, and thus a flow loss of the second refrigerant may be generated. Therefore, the radius curvature of the concave guide curved surface138a, R_c, is formed to be smaller than the radius curvature of the convex guide curved surface138b, R_v, so that a cross-sectional area of the suction path130aconnected to the mixing unit140is gradually reduced, and thus a flow velocity of the second refrigerant may be gradually increased.

Since the suction path130aof the suction unit130is formed by an inner surface of the suction unit130and an outer surface of the nozzle unit110, it is preferable that a cross-sectional area of the suction path130abe gradually reduced in a movement direction of the second refrigerant.

The nozzle unit110may be provided so that the first refrigerant moves. Specifically, when the first refrigerant passes through the nozzle unit110, the first refrigerant may be ideally isentropic-expanded. The first refrigerant introduced through the nozzle unit110may be mixed with the second refrigerant in the mixing unit140. The nozzle unit110is provided so that a nozzle path110ais formed therein.

The nozzle unit110may include a nozzle body112forming an appearance, and a nozzle guide unit120forming the nozzle path110ain the nozzle body112.

The nozzle guide unit120may include a nozzle introducing unit122, a nozzle converging unit124, a nozzle neck126, and a nozzle dispersing unit128.

The nozzle introducing unit122is provided to guide the first refrigerant to the nozzle converging unit124and the nozzle dispersing unit128. A nozzle inlet123may be formed in the nozzle introducing unit122. The nozzle inlet123is in communication with an outlet unit of the condenser20, so the first refrigerant discharged from an outlet unit of the condenser20may be introduced.

The nozzle converging unit124is provided so that a diameter of a path is reduced in a movement direction of the first refrigerant to the nozzle neck126having a diameter smaller than that of the nozzle introducing unit122. The nozzle converging unit124is connected to the nozzle introducing unit122, and a diameter of the nozzle converging unit124is gradually reduced to be smaller than that of the nozzle introducing unit122, and thus a flow velocity of the first refrigerant is increased.

The nozzle dispersing unit128is formed so that a diameter of the nozzle path110ais increased in a movement direction of the first refrigerant from the nozzle neck126. A pressure of the first refrigerant having a flow velocity increased when the first refrigerant passes through the nozzle converging unit124is reduced when the first refrigerant passes through the nozzle dispersing unit128. The first refrigerant passing through the nozzle neck126may be discharged to the inside of the ejector100through the nozzle dispersing unit128.

A slope in which a diameter of the nozzle converging unit124is reduced in a movement direction of the first refrigerant, that is a ratio of a maximum diameter of the nozzle converging unit124to a length of the nozzle converging unit124with respect to a nozzle center axis, becomes smaller than a ratio of the maximum diameter of the nozzle dispersing unit128to a length of the nozzle dispersing unit128with respect to the nozzle center axis. In other words, a variation in a diameter of the nozzle converging unit124for the same movement distance of the first refrigerant is greater than a variation in a diameter of the nozzle dispersing unit128.

Specifically, an angle between opposite inner surfaces in the nozzle converging unit124, Φc, is smaller than an angle between opposite inner surfaces in the nozzle dispersing unit128, α.

When a dispersing angle of the nozzle dispersing unit128, α, is excessively greater, a point in which delamination is generated gets gradually closer to the nozzle dispersing unit128in a movement of the first refrigerant passing through the nozzle dispersing unit128, and thus there is a problem in which a flow velocity at an outlet of the nozzle dispersing unit128is reduced. Also, when a dispersing angle of the nozzle dispersing unit128, α, is excessively smaller, a point in which delamination is generated in a flow of the first refrigerant passing through the nozzle dispersing unit128gets farther from the nozzle dispersing unit128. However, since the first refrigerant is not easily moved, there is a problem in which a flow velocity is reduced. Therefore, it is preferable that the dispersing angle α of the nozzle dispersing unit128be formed at a slope of 0.5° to 2°. Also, it is preferable that a diameter of an outlet of the nozzle dispersing unit128be formed to be smaller than a diameter of an inlet of the nozzle converging unit124.

The nozzle neck126is provided between the nozzle converging unit124and the nozzle dispersing unit128to communicate both configurations thereof. The nozzle neck126has the smallest diameter of the diameters of sections of the nozzle converging unit124and the nozzle dispersing unit128, the first refrigerant passing through the nozzle converging unit124passes through the nozzle neck126to be introduced into the nozzle dispersing unit128. A length of the nozzle dispersing unit128, L_nd, and a diameter of the nozzle neck126, d_th, may be formed to satisfy a relation of 10≤L_nd/d_th≤50 with respect to a movement direction of the first refrigerant.

The nozzle body112has an approximately cylindrical shape and may have a triangular pyramid shape so that the outer diameter becomes smaller toward the outlet of the nozzle dispersing unit128.

The nozzle body112may include a nozzle tip114provided at an end part of the nozzle body112, that is, an outlet side of the nozzle dispersing unit128. That is, the outlet of the nozzle dispersing unit128is provided in the center of the nozzle tip114.

When an outer diameter of the nozzle tip114is excessively greater, movement of a fluid flowing to the mixing unit140is interrupted, thereby reducing flow efficiency. Therefore, the nozzle tip114having an inner diameter in which the outlet of the nozzle dispersing unit128is maintained and an outer diameter in which movement of the fluid is not interrupted is needed.

Therefore, an outer diameter of the nozzle tip114, d_tip, may be provided to form a relation of d_tip/d_m<1 with an inner diameter of the mixing unit140, d_m. Preferably, d_tip may be provided to form a relation of 1.2≤d_m/d_tip≤3. Also, the outer diameter of the nozzle tip114, d_tip, may be provided to form a relation of 1<d_tip/d_do<1.8 with a diameter of the outlet of the nozzle dispersing unit128, d_do. According to the configuration, the first refrigerant discharged from the nozzle dispersing unit128can flow to the mixing unit140without an interruption due to the nozzle tip114, and at the same time, a shape of a discharged part of the first refrigerant formed in the nozzle dispersing unit128can be prevented from being deformed.

Relation between a slope between an outer surface of the nozzle body112forming the nozzle tip114and the ejector center axis100aand a slope between an inner surface of the suction guide unit136and the ejector center axis100aalso has an effect on flow efficiency of the ejector100. When a slope between the ejector center axis100aand the outer surface of the nozzle body112forming the nozzle tip114is referred as β, and a slope between the ejector center axis100aand the inner surface of the suction guide unit136is referred as ψ, a relation of β≤ψ is formed. According to the relation, a suction path130ahaving a cross-sectional area reduced by the suction guide unit136and the nozzle unit110may be formed.

Satisfying the relation, β may be preferably formed at 5° to 30°, and ψ may be preferably formed at 20° to 60°.

FIG. 6Ais a graph illustrating a pressure rising in the nozzle unit110, andFIG. 6Billustrates the nozzle unit110having variously shaped nozzle tips114.

InFIG. 6A(a), the relation of β≤ψ is satisfied, but the nozzle tip114has a relation of d_tip/d_do>1.8. In (b), the nozzle tip114has a relation of d_tip/d_do>1.8, and an end part of the nozzle tip114is rounded. In (c), the nozzle tip114has a relation of d_tip/d_do>1.8, and an end part of the nozzle tip114is rounded to be larger than in (b). In (d), as described above, the nozzle tip114has a shape satisfying relations of 1<d_tip/d_do<1.8 and β≤ψ.

From (a) to (d), shapes of the nozzle dispersing units128are the same, but shapes of the nozzle body112and the nozzle tip114are different.FIG. 6aillustrates pressure rising efficiency of the first refrigerant according to a change in the shape. Therefore, like in the embodiment of the present disclosure, when the nozzle body112satisfies the relations of 1<d_tip/d_do<1.8 and β≤ψ, flow efficiency of the first refrigerant may be improved.

The diffuser unit150is provided to convert kinetic energy of a fluid to pressure energy. A flow velocity of the first refrigerant is increased when the first refrigerant passes through the nozzle unit110, and the first refrigerant and the second refrigerant are mixed when passing through the mixing unit140. Speed energy of a mixed fluid mixed in the mixing unit140is converted into pressure energy in the diffuser unit150, and pressure rising occurs. Therefore, when the fluid is suctioned into the compressor10, a compression load is reduced, and thus efficiency of cycle is increased.

The diffuser unit150may extend from the mixing unit140along the ejector center axis100a. The diffuser unit150may include a diffuser body152that has a funnel shape and a diffuser guide unit154.

The diffuser guide is provided inside the diffuser body152to form a diffuser path in which the mixed fluid formed by the mixing unit140moves. The diffuser path formed by the diffuser guide has a cross-sectional area increased in a movement direction of the fluid.

The mixing unit140is provided to mix the first refrigerant with the second refrigerant. The pressure rising rate in the ejector100is important to reduce a compression load of the compressor10through the ejector100, and the pressure rising rate varies depending on a difference of a mixture degree of the first refrigerant and the second refrigerant in the mixing unit140.

The outer diameter of the nozzle tip114, d_tip, and the diameter of the mixing unit140, d_m, may satisfy a relation of 1.2≤d_m/d_tip≤3, and the diameter of the mixing unit140, d_m, and the length of the mixing unit140, L_m, may satisfy a relation of 4.5≤L_m/d_m≤28. The diameter of the mixing unit140, d_m, and a length of the diffuser, L_d, may satisfy a relation of 7≤L_d/d_m≤31. Also, a distance between an outlet of the nozzle unit110and an inlet of the mixing unit140, L_n, and the diameter of the mixing unit140, d_m, satisfy a relation of 0.2≤L_n/d_m≤2.5.

According to the configuration, a flow loss can be minimized when the first refrigerant and the second refrigerant are mixed in the mixing unit140.

Hereinafter, an ejector according to a second embodiment of the present disclosure and a cooling apparatus having the same will be described.

Configurations of the embodiment overlapped with those of the above-described embodiment will be omitted.

FIG. 8is a cross-sectional view of an ejector according to a second embodiment of the present disclosure.

An ejector200includes the nozzle unit110, a suction unit230, the mixing unit140, and the diffuser unit150. The nozzle unit110, the suction unit230, the mixing unit140, and the diffuser unit150may have a shape of a body of revolution with respect to an ejector center axis200a. The nozzle unit110, the suction unit230, the mixing unit140, and the diffuser unit150are formed in parallel to each other in a direction of the ejector center axis200a.

The suction unit230is provided so that the second refrigerant flowing in the second refrigerant circuit P2is introduced to move therein. The second refrigerant is suctioned from the suction unit230and is mixed with the first refrigerant in the mixing unit140. The suction unit230includes a suction path230a, formed between the nozzle unit110and the suction unit230, in which the second refrigerant moves.

The second refrigerant is suctioned to the suction unit230by a flow of the first refrigerant discharged from the nozzle unit110, and surrounds at least part of the nozzle unit110. Specifically, the second refrigerant may flow through the suction path230aformed by an outer diameter of the nozzle unit110and an inner diameter of the suction unit230. Specifically, the suction path230amay be formed by the outer diameter of the nozzle unit110and inner diameters of a suction guide unit236and a suction tube234to be described below. According to the configuration, the suction unit230is spaced apart from the nozzle unit110and surrounds a circumference of the nozzle unit110.

The suction unit230has an approximately cylinder shape and has a diameter reduced in a movement direction of the second refrigerant.

The suction unit230may include a suction port232and the suction guide unit236.

The suction port232is provided so that the second refrigerant is introduced into the suction unit230. The suction port232is connected with an outlet of the evaporator40and is provided so that the second refrigerant discharged from the evaporator40is introduced into the suction unit230of the ejector200through the suction port232. Specifically, as described above, at the outlet of the nozzle unit110, the first refrigerant moves at a reduced pressure and the second refrigerant moves in a saturated air state, and thus the second refrigerant is suctioned into the suction unit230of the ejector200by a pressure difference between the second refrigerant and the first refrigerant having a relatively lower pressure. The second refrigerant introduced into the suction unit230through the suction port232moves to the suction guide unit236to be described below along an inner side of the suction tube234.

The suction tube234is in communication with the suction port232, and is spaced apart from the circumference of the nozzle unit110and surrounds the nozzle unit110. The suction tube234may have an approximately cylindrical shape.

The suction guide unit236is provided to form at least part of the suction path230a. Specifically, the suction path230ais formed by the outer diameter of the nozzle unit110and the inner diameter of the suction guide unit236. The suction guide unit236is provided that a cross-sectional area of the suction path230ais reduced in a flow direction of the first refrigerant. The suction guide unit236may have a tubular shape.

Since a cross-sectional area of a path in the mixing unit140is formed to be smaller than a cross-sectional area of the suction path230a, a flow velocity is increased while the second refrigerant introduced into the suction unit230moves to the mixing unit140. As a flow velocity of the first refrigerant discharged from the nozzle unit110and a flow velocity of the second refrigerant moving in the suction unit230correspond to each other, a mixture rate of the first refrigerant and the second refrigerant in the mixing unit140is increased, and thus a structure of the suction unit230capable of efficiently increasing the flow velocity of the second refrigerant becomes important.

The second refrigerant passing through the suction guide unit236is moved by a pressure difference between the first and second refrigerants along a flow of the first refrigerant. The suction guide unit236is formed so that a cross-sectional area of the suction path230ais reduced in a flow direction of the first refrigerant.

The suction guide unit236may include a first suction guide unit236aand a second suction guide unit236b. An inner surface of the first suction guide unit236aforms a first angle with the ejector center axis200a. An inner surface of the second suction guide unit236bforms a second angle with the ejector center axis200a. The second angle is formed to be smaller than the first angle. In the embodiment of the present disclosure, for the convenience of the description, it is described that the suction guide unit236includes the first suction guide unit236aand the second suction guide unit236b, but the suction guide unit236may include a plurality of the suction guide units236. That is, the suction guide unit236includes from the first suction guide unit236ato the nth suction guide unit, and n is not limited.

According to the configuration, since a cross-sectional area of the suction path230ais gradually reduced, a flow loss of the second refrigerant passing through the suction path230amay be reduced. Also, as n is greater, the suction guide unit236has a shape similar to streamline, and thus a flow loss of the second refrigerant may be reduced.

An ejector according to a third embodiment of the present disclosure and a cooling apparatus having the same will be described.

Configurations of the embodiment overlapped with those of the above-described embodiment will be omitted.

FIG. 9is a cross-sectional view of an ejector according to a third embodiment of the present disclosure.

An ejector300includes the nozzle unit110, the suction unit130, the mixing unit140, and a diffuser unit350.

The diffuser unit350is provided to convert kinetic energy of a fluid to pressure energy. A flow velocity of the first refrigerant is increased when the first refrigerant passes through the nozzle unit110, and the first refrigerant and the second refrigerant are mixed when the first refrigerant passes through the mixing unit140. Speed energy of a mixed fluid mixed in the mixing unit140is converted into pressure energy in the diffuser unit350, and pressure rising occurs. Thus, when a fluid is suctioned into the compressor10, a compression load is reduced, and thus efficiency of a cycle is reduced.

The diffuser unit350may extend from the mixing unit140along an ejector center axis300a. The diffuser unit350includes a diffuser body352that has a funnel shape and a diffuser guide unit354.

The diffuser guide is provided on an inner surface of the diffuser body352, and a diffuser path in which the mixed fluid formed by the mixing unit140moves is formed. The diffuser path formed by the diffuser guide is formed so that a cross-sectional area of a path is increased in a flow direction of the fluid.

The diffuser guide unit354may include a diffuser curved surface356having a curved inner surface.

The diffuser curved surface356is formed so that a cross-section is symmetric with respect to the ejector center axis300a.

The diffuser curved surface356may include a convex diffuser curved surface356aand a concave diffuser curved surface356b.

The convex diffuser curved surface356ais formed so that a cross-sectional area of the diffuser path is increased in a movement direction of the mixed fluid, and the convex diffuser curved surface356ais formed to be convex toward the ejector center axis300a. Since an upstream part of the convex diffuser curved surface356ais connected with the mixing unit140, a slope of a tangent at a part in which the convex diffuser curved surface356ais connected with the mixing unit140may be identical to a slope of the mixing unit140. Specifically, a slope formed with an inner surface of the mixing unit140with respect to the ejector center axis300amay be identical to a slope at a part in which the convex diffuser curved surface356ais connected with the mixing unit140.

The concave diffuser curved surface356bis arranged more downstream than the convex diffuser curved surface356aand is formed to be concave from the ejector center axis300a. Both the convex diffuser curved surface356aand the concave diffuser curved surface356bare provided to minimize a flow loss of fluid passing through the diffuser unit350. A downstream part of the concave diffuser curved surface356bforms an outlet unit of the diffuser unit350.

A downstream part of the concave diffuser curved surface356bis parallel to the ejector center axis300ato eject the first refrigerant discharged from the diffuser unit350, or a slope from the ejector center axis300ain a movement direction of the mixed fluid may be more than or equal to 0.

The diffuser guide unit354may further include a curved surface connection unit356cconnecting the concave diffuser curved surface356bwith the convex diffuser curved surface356a. A slope of the curved surface connection unit356cmay be identical to slopes of tangents at a downstream part of the convex diffuser curved surface356aand an upstream part of the concave diffuser curved surface356b.

A configuration of the convex diffuser curved surface356a, the concave diffuser curved surface356b, and the curved surface connection unit356cmay change lengths and radius curvatures thereof depending on a size or use of the ejector300.

In the embodiment of the present disclosure, the curved surface connection unit356cis arranged between the convex diffuser curved surface356aand the concave diffuser curved surface356b, but the curved surface connection unit356cmay be omitted. When the curved surface connection unit356cis omitted, slopes of tangents at a part in which the convex diffuser curved surface356aand the concave diffuser curved surface356bmeet are identical to each other.

While specific embodiments of the present disclosure have been illustrated and described above, the disclosure is not limited to the aforementioned specific embodiments. Those skilled in the art may variously modify the disclosure without departing from the gist of the disclosure claimed by the appended claims and the modifications are within the scope of the claims.