CN115917161A

CN115917161A - Nozzle device for a jet pump and jet pump

Info

Publication number: CN115917161A
Application number: CN202180040898.3A
Authority: CN
Inventors: 丹尼尔·金提亚; 大卫·施耐德; 卢卡斯·加布里斯; 米哈尔·萨达克
Original assignee: Norma Germany GmbH
Current assignee: Norma Germany GmbH
Priority date: 2020-07-10
Filing date: 2021-06-10
Publication date: 2023-04-04
Also published as: WO2022008162A1; DE102020118330A1; JP2023533328A; KR20230014844A; US20230287903A1; EP4179213A1

Abstract

The invention discloses a nozzle arrangement for a jet pump, comprising a drive nozzle and a first suction nozzle, wherein the first suction nozzle is arranged radially outside the drive nozzle, and wherein the nozzle arrangement is arranged such that fluid flowing through the drive nozzle drives fluid flowing through the first suction nozzle. The invention also discloses a jet pump comprising the corresponding nozzle device.

Description

Nozzle device for a jet pump and jet pump

Technical Field

The invention relates to a nozzle arrangement for a jet pump, comprising a drive nozzle and a first suction nozzle, wherein the first suction nozzle is arranged radially outside the drive nozzle, and wherein the nozzle arrangement is arranged such that fluid flowing through the drive nozzle drives fluid flowing through the first suction nozzle. The invention also relates to a jet pump comprising a corresponding nozzle device.

Background

The jet pump is used to generate a secondary fluid flow from the primary drive fluid flow. The primary drive fluid is accelerated and directed to contact the secondary fluid by, for example, a pump. The velocity and pressure gradient between the two fluids ensures that the second fluid is accelerated by the first fluid flow. Thus, in an ejector pump, the second fluid flow is driven by the first fluid flow.

The ejector pump can be designed as a single-stage or multistage ejector pump comprising a plurality of pump stages and nozzles. One of the main disadvantages of jet pumps is the inefficiency caused by the high speed jet of the primary drive fluid mixing with the nearly stagnant secondary fluid.

It is therefore an object of the present invention to provide an improved jet pump and an improved jet pump nozzle geometry which exhibit superior efficiency compared to known jet pumps and jet pump nozzle geometries.

Disclosure of Invention

The main object of the present invention is to provide a spray pump which comprises at least one such nozzle device, by means of a nozzle device according to claim 1 and by means of a spray pump according to claim 10. Advantageous embodiments of the invention are the object of the dependent claims.

According to the invention, a nozzle arrangement for a jet pump is provided, the nozzle arrangement comprising a drive nozzle and a first suction nozzle, wherein the first suction nozzle is arranged radially outside the drive nozzle, and wherein the nozzle arrangement is designed such that a fluid flow through the drive nozzle drives a fluid flow through the first suction nozzle. In a simple embodiment, the drive nozzle outlet may be sufficiently close to the first suction nozzle outlet that the low pressure and high velocity fluid streams of the drive nozzle may interact with the fluid of the first suction nozzle.

The first suction nozzle can be positioned such that the shear stress at the interface between the jet and the suction mass flow is reduced or the fluid flow through the drive nozzle and the fluid flow through the first or further suction nozzles is reduced. This is related to the fact that the shear stress defined above is the product of the viscosity of the fluid and the velocity gradient. The latter can be very large in the jet pumps known in the art. High shear stresses lead to the generation of turbulence which in turn leads to the dissipation of the main energy, which is why the known jet pumps are inefficient. The jet pump and nozzle arrangement of the present invention provides enhanced jet pump efficiency because shear stress is reduced when mixing of two or more mass or fluid volume flows is induced.

In a preferred embodiment of the invention, the nozzle arrangement can be designed such that the first suction nozzle is arranged concentrically around the drive nozzle and/or the first suction nozzle comprises an axisymmetric volume, for example an annular volume. The drive nozzle and/or the first suction nozzle may comprise a nozzle wall portion having rotational symmetry, in particular around a central axis of one or both nozzles.

In a preferred embodiment of the invention, the nozzle device can be designed such that a first mixing tube is arranged downstream of the drive nozzle and the first suction nozzle. The first mixing pipe may be connected to an outer sidewall of the first suction nozzle. Specifically, the first mixing pipe and the outer side wall of the first suction nozzle may be integrally formed. The first mixing pipe, the driving nozzle, and the first suction nozzle may be disposed coaxially with each other.

In a preferred embodiment of the invention, the nozzle arrangement may be designed such that the first mixing pipe comprises a first diffuser section at the downstream end of the first mixing pipe. The first diffuser section may have a larger cross-sectional area than a portion of the first mixing tube that is further upstream from the first diffuser section. The first diffuser section of the first mixing tube may be disposed concentrically with the first mixing tube and/or the drive nozzle and/or other portion of the first suction nozzle.

In a preferred embodiment of the invention, the nozzle device may be designed such that a second suction nozzle is arranged downstream of the first mixing tube, wherein the nozzle device is designed such that a fluid flow flowing through the first mixing tube drives a fluid flowing through the second suction nozzle and/or wherein the second suction nozzle is arranged concentrically around the first mixing tube and/or wherein the second suction nozzle comprises an axisymmetric volume. The design and function of the second suction nozzle may comprise suitable features such as described in relation to the first suction nozzle.

In particular, the second suction nozzle may be positioned sufficiently close to the outlet of the first mixing tube such that the low pressure and high velocity fluid stream in the first mixing tube may interact with the fluid of the second suction nozzle. The second suction nozzle can be positioned such that the shear stress at the interface between the jet and the suction mass flow or the fluid flow through the first mixing tube and the fluid flow through the second suction nozzle is reduced.

In a preferred embodiment of the invention, the nozzle device may be designed such that the second mixing pipe is arranged downstream of the first mixing pipe and the second suction nozzle. The second mixing pipe may be connected to an outer sidewall of the second suction nozzle. In particular, the second mixing pipe and the outer side wall of the second suction nozzle may be integrally formed. The second mixing tube, the first mixing tube, the drive nozzle and/or the first suction nozzle and the second suction nozzle may be arranged coaxially to each other.

In a preferred embodiment of the invention, the nozzle device may be designed such that the second mixing pipe comprises a second diffuser section at the downstream end of the second mixing pipe. The second diffuser section may have a larger cross-sectional area than a cross-section of the second mixing tube, the cross-section of the second mixing tube being located in a portion further upstream of the second diffuser section. The second diffuser section may be arranged concentrically with the second mixing pipe and/or the drive nozzle and/or the first suction nozzle and/or the other part of the second suction nozzle.

In a preferred embodiment of the invention, the nozzle arrangement may be designed such that a first fluid flows through the drive nozzle and a second fluid flows through the first suction nozzle and/or the second suction nozzle, wherein the first fluid and the second fluid are of the same kind of fluid or wherein the first fluid and the second fluid are of different kinds of fluid. The first fluid flowing through the drive nozzle may be considered a drive fluid. The first and second fluids may be provided by the same fluid source or by different and separate fluid sources.

In a preferred embodiment of the invention, the nozzle arrangement may be designed such that the first fluid is a gas and the second fluid is a gas and/or the second fluid is a liquid. In general, the nozzle designs of the present invention may be used with any suitable combination of liquids and/or gases. In the case where gas is used as one or both of the fluids, one of air, fuel vapor, combustion gas, and a mixture thereof may be selected as the fluid.

The invention also relates to a jet pump comprising at least one nozzle device according to any one of claims 1 to 9. The term jet pump as used herein may be understood to include other components than a nozzle arrangement. Such additional components may include a power source, a pressure source, a control device, an electronic connection, a fluid connection, one or more fluid sources, and/or a fluid conduit.

Further details and advantages of the invention are described with reference to the embodiments shown in the drawings.

Drawings

Fig. 1 is a schematic view of a nozzle arrangement comprising one drive nozzle and two suction nozzles.

Fig. 2a to 2b are schematic views of a nozzle device according to the prior art.

Fig. 3a to 3b are schematic views of a nozzle arrangement according to the present invention.

Detailed Description

Fig. 1 shows a nozzle arrangement for a jet pump. The term jet pump as used herein is to be understood in a broad sense and may include any additional components other than the actual nozzle geometry shown in fig. 1. The nozzle arrangement comprises a drive nozzle 10 and a first suction nozzle 1, wherein the first suction nozzle 1 is arranged radially outside the drive nozzle 10, and wherein the nozzle arrangement is designed such that a fluid flow through the drive nozzle 10 drives a fluid through the first suction nozzle 1. The nozzle arrangement may be arranged around a centre line C. In particular, the nozzle arrangement may be at least partially symmetrical with respect to the centre line C.

The first suction nozzle 1 may be concentrically disposed around the driving nozzle 10. The drive nozzle 10 may have a circular cross-section and comprise a cylindrical conduit portion. Alternatively or additionally, the drive nozzle 10 may comprise a non-cylindrical conduit portion. The first suction nozzle 1 may comprise an axisymmetric volume or an axisymmetric duct portion. The duct portion of the drive nozzle 10 may be positioned at least partially within the duct portion of the first suction nozzle 1. In these cases, the nozzle arrangement may exhibit rotational symmetry around the centre line C at least at some locations along the centre line C.

Alternatively, the nozzle arrangement may exhibit reflection symmetry with respect to a plane including the centre line C and perpendicular to the projection plane of fig. 1. In this case, the suction nozzle 1 and the drive nozzle 10 may include, for example, a rectangular parallelepiped pipe portion or an approximately rectangular parallelepiped pipe portion. Furthermore, the nozzle arrangement may not exhibit reflective symmetry about the above defined plane, but may nevertheless comprise a conduit portion of full or at least partial cuboid geometry. The term conduit portion may at present be understood as a guide tube portion, which is delimited in radial direction by a solid wall. The solid wall may completely surround the conduit portion in a circumferential direction of the conduit portion.

The duct portions of the drive nozzle 10 and the first suction nozzle 1 may be at least partially separated by a first wall 11. The first wall 11 may comprise a conical portion and at least one cylindrical portion directly connected to the conical portion.

The right or downstream end of the first wall 11 can be regarded as an outlet portion of the drive nozzle 10, wherein the first fluid in the drive nozzle 10 meets the second fluid of the first suction nozzle 1 and the two fluids interact such that the second fluid is driven by the first fluid. The inner side of the first wall 11 may completely surround the drive nozzle 10 and thus itself define the cross-sectional area and shape of the drive nozzle 10. The outer side of the first wall 11 may define the inner boundary of the first suction nozzle 1. The inner and outer sides of the first wall 11 may comprise surfaces that are parallel or nearly parallel to each other. In particular, the first wall 11 may comprise at least one cylindrical portion or portion having a constant cross-sectional area in the direction of flow. This applies in particular to the most downstream part of the first wall 11 or to the part closer to the most downstream part of the first wall 11. This close alignment of the two sides of the first wall 11 ensures that the streamlines of the fluid passing through the drive nozzle 10 and the streamlines of the fluid passing through the first suction nozzle 1 are parallel or nearly parallel to each other when the fluids flow together or meet each other.

A first mixing pipe 3 is provided downstream of the outlet portion of the drive nozzle 10. The fluid flow direction is indicated by three arrows to the left and above the nozzle arrangement. The general flow direction in fig. 1 is from left to right, around and near the centerline C. The downstream position of the assembly is therefore located to the right of the nozzle arrangement assembly in fig. 1.

The first mixing pipe 3 is therefore arranged downstream of the drive nozzle 10 and the first suction nozzle 1. The diameter or cross-sectional area of the mixing tube 3 can be selected such that it can accommodate the combined volume flow of the drive nozzle 10 and the first suction nozzle 2.

The first mixing tube 3 may be defined by the second wall 32 and/or the first mixing tube 3 may comprise a partially or fully cylindrical conduit portion. The length of the first mixing tube 3 may be chosen to be 2 to 5 times the width or diameter of the mixing tube 3. In particular, the length of the mixing tube 3 may be selected to be 2.5 to 4 times the width or diameter of the mixing tube 3.

The first mixing pipe 3 may be designed to comprise a first diffuser section 31 at the downstream end of the first mixing pipe. The cross-sectional area, diameter or width of the first diffuser section 31 may be larger than other parts of the first mixing pipe 3, in particular the upstream part. The first diffuser section 31 may be located at the most downstream portion of the first mixing pipe 3, or may be close to the most downstream portion of the first mixing pipe 3. The first mixing pipe 3 and the first diffuser section 31 may be integrally formed by the second wall 32.

The first diffuser section 31 may be close to or may be part of a second suction nozzle 2, the second suction nozzle 2 being arranged downstream of the first mixing tube 3, wherein the nozzle arrangement is designed such that fluid flowing through the first mixing tube 3 drives fluid flowing through the second suction nozzle 2 and/or wherein the second suction nozzle 2 is arranged concentrically around the first mixing tube 3 and/or wherein the second suction nozzle 2 comprises an axisymmetric volume bounded by an inner wall and an outer wall.

As shown in the embodiment of fig. 1, the nozzle device may be a one-stage or multi-stage nozzle device comprising a plurality of

suction nozzles

1, 2 and/or drive nozzles 10. Thus, the most downstream part of the first mixing tube 3, in particular the outlet part of the first mixing tube 3, can be regarded as a further drive nozzle or a part of a further drive nozzle for driving the fluid through the second suction nozzle 2.

The geometry of the second suction nozzle 2 may correspond to the geometry of the first suction nozzle 1, since it may exhibit a rotational symmetry around the centre line C or a reflection symmetry similar to the above-mentioned reflection symmetry of the first suction nozzle 1.

Alternatively, asymmetric embodiments are also possible, as described above. Furthermore, the walls defining the second suction nozzle 2, i.e. the second wall 32 inside the second suction nozzle 2 and the further wall outside the second suction nozzle 2, may be oriented such that they bring the fluid passing through the second suction nozzle 2 into close alignment with the fluid passing through the first mixing pipe 3. In particular, the second suction nozzle 2 may be arranged such that the velocity vector of the fluid flowing through the second suction nozzle 2 approaches in direction and magnitude the velocity vector of the fluid flowing through the first mixing pipe 3. Thus, the boundary wall of the second suction nozzle 2 may be parallel and/or angled to the flow direction through the mixing tube 3, so that the fluid passing through the first mixing tube 3 and the fluid passing through the second suction nozzle 2 are mixed together with only minimal losses.

A second mixing pipe 4 may be disposed downstream of the first mixing pipe 3 and the second suction nozzle 2. The second mixing tube 4 may comprise a cylindrical conduit portion and/or a second diffuser stage 41 at the downstream end of the second mixing tube 4. The downstream end of the second mixing tube 4 may be connected or connectable to a fluid conduit.

During operation of the nozzle arrangement, the drive nozzle 10 is flowed through by a first fluid and the first suction nozzle 1 and/or the second suction nozzle 2 is flowed through by a second fluid, wherein the first fluid and the second fluid are of the same kind or wherein the first fluid and the second fluid are of different kinds. The first fluid driving the nozzle 10 drives the fluid, which may be a gas and/or a liquid, through the

suction nozzles

1, 2.

The first suction nozzle 1 or the two or

more suction nozzles

1, 2 may be annular or nearly annular nozzles, surrounding a circular drive nozzle 10 or at least partially surrounding other drive nozzles. The drive nozzle 10 may be concentrically or enclosed in a different manner. The drive nozzle 10 may be a drive air nozzle. The nozzle arrangement may be used with a turbocharger of an internal combustion engine. In this case the nozzle device may be considered as part of an injection pump for pumping gas from e.g. a fuel tank into an internal combustion engine.

The nozzles of the present invention may be designed such that the flow velocity and/or flow direction of adjacent nozzles are as similar as possible. In particular, the nozzle may be designed such that the flow direction and/or velocity of the first fluid flow leaving the drive nozzle 10 is as similar as possible to the second fluid flow leaving the first and/or

second suction nozzle

1, 2.

The nozzle arrangement and the corresponding ejector pump of the present invention in fact provide at least one

additional suction nozzle

1, 2, increasing the flow rate of the suction flow before it is mixed with the driving flow. The

additional suction nozzle

1, 2 effectively reduces the generation of turbulence during the mixing of at least two fluid streams, i.e. the first fluid stream and the second fluid stream. As a result, the power and efficiency of the pump is increased.

The power is supplied in the form of a drive mass flow to the respective jet pump, which is accelerated in the drive nozzle and accordingly generates a high-speed and low-pressure fluid jet. The low pressure that occurs serves to suck the suction mass flow into the pump or nozzle arrangement, which is mixed with the drive flow, i.e. the first fluid flow. The driving mass flow or first fluid flow and the suction mass flow or second fluid flow leave the pump or nozzle arrangement after passing through the one or

more diffuser sections

31, 41, which increases the pressure of the fluids.

One of the main advantages of the ejector pump is its simple design, without moving parts. The main drawbacks include the low efficiency of such pumps due to the high speed jet mixing with the almost stagnant fluid.

Fig. 2a shows a schematic diagram of a typical jet pump flow configuration known in the art. Figure 2b shows a simplified representation of the corresponding fluid flow. As shown in fig. 2a, the nozzle 10 is driven to produce a high velocity jet which draws in a suction mass flow which typically has a very low velocity.

Fig. 2b is an idealized representation of a typical jet pump flow. The low-velocity suction mass flow is indicated by short horizontal arrows. It is mixed with a high-speed jet indicated by a long horizontal arrow. The high speed gradients shown result in high shear stress. The flow shown in fig. 2b only takes into account the flow component in the jet direction, i.e. the horizontal direction.

The shear stress τ at the interface between the jet and the suction mass flow or between the first fluid flow and the second fluid flow, respectively, increases with the velocity gradient of the respective fluid flow. The latter is usually very large due to the large difference in velocity of the two fluid flows. High shear stress leads to the generation of turbulence which in turn leads to the dissipation of the main energy, which is responsible for the low efficiency of the ejector pump. A more efficient jet pump needs to reduce the shear stress caused by the mixing of the two mass flows. Since the jet velocity is determined by the necessary pumping pressure, the only way to reduce the shear stress at the interface is to increase the flow rate of the suction flow in the direction of the jet.

Figures 3a and 3b show a flow configuration of an ejector pump in which the suction flow is accelerated before mixing with the jet, thereby reducing the velocity gradient. This reduces shear stress and therefore reduces the turbulence generated and the energy dissipated. As a result, energy losses are less and the ejector pump efficiency is higher. In fig. 3a, the jet pump or nozzle arrangement comprises a drive nozzle 10 for sucking the fluid and a first suction nozzle 1. Figure 3b shows an idealized representation of the corresponding flow. The suction flow velocity is indicated by the shorter horizontal arrows and the jet velocity is indicated by the longer horizontal arrows. It can be seen that the length difference and the speed difference are smaller than in the case shown in fig. 2 b. Thus, the shear stress is reduced. As before, the flow shown in fig. 3b only takes into account the flow component in the direction of the jet (i.e. the horizontal direction). The

suction nozzle

1, 2 may be designed to direct the second fluid flow such that it approaches the first fluid flow in a direction parallel thereto or at a very small angle. To achieve this effect, the

suction nozzles

1, 2 may comprise a respective angled boundary.

The invention is particularly useful for ventilation of the crankcase and the oil tank of a vehicle. Due to blow-by and fuel evaporation, these components require ventilation using the respective jet pump to meet current emission regulations. Here, the air supplied to the internal combustion engine may be used as the driving fluid or the first fluid. The air provided may be compressed air, for example from a turbocharger or compressor. The present invention provides a high performance means for venting these components when idling engines and full throttle operation result in low and high drive pressures. At the same time, the present invention provides an injection pump with low air or drive fluid consumption when the engine is running at full speed.

The present invention is not limited to any of the above-described embodiments or features. The invention may include various additions or modifications to the described embodiments.

All the features and advantages, including structural details, spatial arrangements and procedural steps, which can be derived from the claims, the description and the drawings, are essential to the invention both individually and in the most diverse combinations.

Reference numerals

1. A first suction nozzle

2. Second suction nozzle

3. First mixing tube

4. Second mixing tube

10. Drive nozzle

11. First wall

31. A first diffuser section

32. Second wall

41. Second diffuser section

C center line

Claims

1. A nozzle arrangement for a spray pump, comprising: comprising a drive nozzle (10) and a first suction nozzle (1), wherein the first suction nozzle (1) is arranged radially outside the drive nozzle (10), and wherein the nozzle arrangement is arranged such that fluid flowing through the drive nozzle (10) drives fluid flowing through the first suction nozzle (1).

2. A nozzle arrangement according to claim 1, wherein: the first suction nozzle (1) is arranged concentrically around the drive nozzle (10) and/or the first suction nozzle (1) comprises an axisymmetric volume.

3. A nozzle arrangement according to claim 1 or 2, wherein: a first mixing pipe (3) is arranged at the downstream of the driving nozzle (10) and the first suction nozzle (1).

4. A nozzle arrangement according to claim 3, wherein: the first mixing pipe (3) comprises a first diffuser section (31) at the downstream end of the first mixer (3).

5. A nozzle arrangement according to claim 3 or 4, wherein: downstream of the first mixing tube (3) a second suction nozzle (2) is arranged, wherein the nozzle arrangement is arranged such that fluid flowing through the first mixing tube (3) drives fluid flowing through the second suction nozzle (2), and/or wherein the second suction nozzle (2) is arranged concentrically (3) around the first mixing tube, and/or wherein the second suction nozzle (2) comprises an axisymmetric volume.

6. The nozzle arrangement of claim 5, wherein: a second mixing pipe (4) is arranged downstream of the first mixing pipe (3) and the second suction nozzle (2).

7. The package configuration of claim 6, wherein: the second mixing duct (4) comprises a second diffuser section (41) at the downstream end of the second mixing duct (4).

8. A nozzle arrangement according to any one of the preceding claims, wherein: the first fluid flows through the drive nozzle and the second fluid flows through the first suction nozzle (1) and/or the second suction nozzle (2), wherein the first fluid and the second fluid are of the same kind of fluid or wherein the first fluid and the second fluid are of different kinds of fluid.

9. A nozzle arrangement according to claim 8, wherein: the first fluid is a gas and the second fluid is a gas and/or the second fluid is a liquid.

10. An injection pump, characterized by: comprising at least one nozzle device according to any one of claims 1 to 9.