WO2006063825A1

WO2006063825A1 - Ventilating system comprising means for limiting backflow

Info

Publication number: WO2006063825A1
Application number: PCT/EP2005/013475
Authority: WO
Inventors: Stéphane MOREAU; Manuel Henner; Aurélien LEVASSEUR; Bruno Demory
Original assignee: Valeo Systemes D'essuyage
Priority date: 2004-12-15
Filing date: 2005-12-15
Publication date: 2006-06-22
Also published as: FR2879266A1; FR2879266B1

Abstract

The invention concerns a ventilating system (10) comprising a fan (12) mounted rotatable about a main axis (A) of rotation relative to a shroud (14), wherein the fan (12) includes an annular peripheral skirt (20) and an outer radial rib (20) extending from the outer cylindrical surface (20e) of the annular skirt (20), and wherein the shroud (14) comprises: an inner cylindrical surface (14i) extending spaced away from and opposite the outer cylindrical surface (20e) of the annular skirt (20); a series of axial walls (26) which are angularly distributed about the main axis (A) of rotation and an inner flange (28) extending inwards of the shroud (14) from the inner cylindrical surface (14i) of the shroud (14), characterized in that the radial flange (28) is arranged axially upstream of the axial walls (36).

Description

"Fan system having means for limiting the flow of stray air."

The invention proposes a fan system which comprises means for limiting the flow rate of the flow of air flowing against the current in an annular duct extending between the fan and the peripheral shroud.

The invention more particularly proposes a fan system, in particular for cooling the motor of a motor vehicle, comprising a fan mounted for rotation around a principal axis A of rotation with respect to a peripheral fairing of the fan which is fixed to the the engine of the vehicle, so as to produce a flow of air generally coaxial with the main axis A of rotation of the fan, wherein the fan comprises:

a central mounting core on a drive shaft in rotation of the fan;

- Blades angularly distributed around the main axis A of rotation, and each of which extends generally radially outwardly of the fan from the central core;

- A peripheral annular skirt coaxial with the main axis A of rotation, a concave inner cylindrical face is fixed to the outer radial end of each blade; and an outer annular radial rib which extends radially outwardly of the fan, from the convex outer cylindrical face of the annular skirt, and wherein the fairing comprises:

- A concave inner cylindrical face which extends radially at a distance and vis-à-vis the convex outer cylindrical face of the annular skirt;

a series of generally axial walls which are distributed angularly around the main axis A of rotation, each axial wall extending in a generally axial plane, and extending radially from the concave inner cylindrical face of the shroud, such that its axial free radial end edge is located at a distance from the convex outer cylindrical face of the annular skirt; and an inner annular radial cheek which extends radially inwardly of the fairing from the concave inner cylindrical face of the fairing.

A conventional system for cooling the engine of a motor vehicle comprises in particular a heat exchanger, or radiator, which is traversed by a coolant liquid, called coolant, and a fan system for producing a flow of air through the radiator.

A certain quantity of the heat of the coolant is then dissipated in this air flow passing through the radiator, which makes it possible to reduce the temperature of the coolant.

The fan system includes a helical fan which is rotatably mounted relative to a shroud around an axis generally coaxial with the airflow to be produced. The fairing attached to the radiator, it carries a fan drive motor in rotation, and it extends radially around the fan, so that it has a concave inner cylindrical face which extends radially vis-à-vis an outer annular face of the peripheral skirt of the fan.

The concave inner cylindrical face of the shroud and the outer annular face of the peripheral skirt of the ventilator define an annular duct in which part of the air flow produced by the fan is able to flow against the current relative to the flow of the fan. main air flow.

This part of the main airflow forms a spurious airflow that reduces the overall efficiency of the fan system.

To limit the flow of this spurious air flow, the fan system comprises a set of axial walls and a cheek annular radial carried by the shroud and an annular radial rib carried by the fan, which are arranged in the annular conduit.

The radial fairing of the fairing and the radial rib of the fan are shaped so as to reduce the axial component value of the parasitic flux, and the walls are arranged so as to reduce the tangential component value of the parasitic air flow, compared with the main axis of the airflow produced by the fan. The document WO-A-02.38962 describes such a fan system for which the radial fairing of the fairing is arranged downstream of the axial walls and the radial rib of the fan is arranged upstream of the axial walls.

However, although it makes it possible to effectively reduce the formation of the parasitic air flow, such an arrangement of the radial cheek and the radial rib with respect to the axial walls causes an increase in the air pressure in the ducts. axial delimited by the axial walls.

The pressurized air that is present in all the axial ducts produces a resistant torque between the fairing and the fan, which reduces the overall efficiency of the fan system.

The object of the invention is to propose a fan system which comprises means for limiting the formation of the parasitic air flow without increasing the value of the resistive torque.

For this purpose, the invention proposes a fan system as described above, characterized in that the radial cheek is arranged axially upstream of the axial walls, with respect to the direction of flow of the air flow. According to other features of the invention:

the radial cheek comprises an annular radial face downstream with respect to the direction of flow of the air flow which is connected to the annular edge of the free radial end of the radial cheek radially with the axial edge of free radial end of each axial wall;

- The radial cheek is arranged downstream and at a distance from the radial rib, with respect to the direction of flow of the air flow; - The annular free radial end edge of the radial flange extends radially vis-à-vis and at a distance from the convex outer cylindrical face of the annular skirt;

- The downstream end edge of the annular skirt is located upstream of the downstream end edge of each axial wall, relative to the direction of flow of the air flow;

the downstream end edge of the annular skirt is situated axially in line with the downstream end edge of each axial wall;

- The downstream end edge of the annular skirt is located downstream of the upstream end edge of each axial wall, relative to the flow direction of the air flow.

Other characteristics and advantages of the invention will appear on reading the detailed description which follows for the understanding of which reference will be made to the appended figures among which:

- Figure 1 is a schematic perspective view of a fan system comprising a fairing and a fan according to the invention;

- Figure 2 is a detail on a larger scale and with tearing of the fan system shown in Figure 1;

- Figure 3 is a section of the fan system shown in Figure 2, in an axial plane located angularly between two consecutive axial walls.

In the following description, identical, similar or similar elements will be designated by the same reference numerals. The upstream-downstream orientation will also be adopted as being the axial direction relative to the main axis of rotation and from the top to the bottom with reference to the figures.

There is shown in the figures a fan system 10 which is a component of an engine cooling system of a motor vehicle (not shown).

The fan system 10 includes a peripheral fairing 14 which is attached to the vehicle radiator (not shown) and a fan 12 which is rotatably mounted relative to the fairing 14 about a main axis A of rotation.

The fan 12 comprises a central core 16 through which the fan 12 is mounted on a drive shaft (not shown) in rotation about the main axis A of main rotation rotation. The core 16 is an element of revolution coaxial with the main axis A of main rotation rotation, and it mainly comprises a central annular radial wall 16a which carries mounting means on the drive shaft (not shown), and an outer cylindrical wall 16b. The fan 12 comprises blades 18 which are distributed angularly about the main axis A of rotation, and each of which extends radially outwardly from the outer cylindrical wall 16b of the core.

The fan 12 is a fan of the helical type, that is to say that the blades 18 are shaped so as to produce a main air flow "G" (Figure 3) coaxial with the main axis A of rotation when the rotation of the fan 12.

The fan 12 also comprises a peripheral annular skirt 20 which extends coaxially with the main axis A of rotation, and whose concave inner cylindrical face 20i is connected to the outer radial end 18a of each blade 18.

The shroud 14 extends radially around the fan 12, and it has a concave inner cylindrical face 14i coaxial with the main axis A of rotation which is located radially in facing relation to and away from the convex outer cylindrical face 20e of the annular skirt 20.

The figures show a fairing 14 which is annular in shape coaxial with the main axis A of main rotation rotation. However, it will be understood that the shape of the fairing 14 is not limited to this single annular shape.

As can be seen in more detail in FIG. 3, the external cylindrical face 20e of the annular skirt 20 and the internal cylindrical face 14i of the fairing delimit an annular duct 22 coaxial with the main axis A of rotation.

When the fan system 10 is in operation, the fan 12 produces the main air flow "G", and the air pressure downstream of the fan 12 is greater than the air pressure upstream of the fan 12. difference in air pressure between the upstream and downstream of the fan 12 promotes the flow of a portion of the main air flow "G" in the annular duct 22.

This part of the main air flow "G" forms a parasitic air flow "F" which circulates in the annular duct 22 against the short circuit relative to the main air flow "G", that is to say from downstream to upstream, thereby reducing the total air flow produced by the fan system 10.

Furthermore, the rotation of the fan 12 relative to the shroud 14, which makes it possible to obtain the axial flow of the main air flow "G", with respect to the main axis A of rotation, also causes a rotational movement. the main air flow "G" around the main axis A of rotation.

The parasitic "F" air flow is consequently also driven in a rotational movement around the main axis A of rotation, before it enters the annular duct 22, that is to say it comprises an axial component, and a tangential component, with respect to the main axis A of rotation. To limit the flow rate of this "F" flow of parasitic air, the fan 12 comprises an external annular radial rib 24 which extends radially outwardly of the fan 12 from the outer cylindrical face 20e of the annular skirt 20, and the fairing 14 carries a series of generally axial walls 26 which are angularly distributed around the main axis A rotation at a constant interval, and an inner annular radial cheek 28 coaxial with the main axis A of rotation.

The radial rib 24 extends inside the annular duct 22 so that its free radial end annular edge 24a extends opposite and at a distance from the internal cylindrical face 14i of the fairing 14.

The radial flange 28 extends in a radial plane relative to the main axis A of rotation and extends radially inside the annular duct 22 from the inner cylindrical face 14i of the fairing 14 so that its annular edge free radial end 28a extends vis-à-vis and away from the outer cylindrical face 20e of the annular skirt 20.

Each axial wall 26 extends in a generally axial plane relative to the main axis A of rotation, and it extends radially inside the annular duct 22 from the inner cylindrical face 14i of the fairing 14 so that its axial edge of free radial end 26a extends opposite and at a distance from the outer cylindrical face 20e of the annular skirt 20.

The axial walls 26, the radial cheek 28 and the radial rib 24 cooperate with each other so as to reduce the formation of the flow "F" of stray air.

According to the invention, the axial walls 26, the radial flange 28 and the radial rib 24 are arranged axially in

The annular duct 22 so that the radial cheek 28 is arranged upstream of the axial walls, with respect to the direction of flow of the main air flow G. In addition, the radial rib 24 is arranged axially upstream with respect to the axial walls 26 and with respect to the radial cheek 28, that is to say that the radial cheek 28 is arranged axially between the axial walls 26 of a part and the radial rib 24 on the other hand.

According to a preferred embodiment of the invention, the radial flange 28 comprises a downstream annular radial face 28b (FIG. 3) which is connected to the upstream end radial edge 26b of each axial wall 26. Thus, the annular duct 22 is divided by the radial cheek

28 in a downstream portion 22a in which are arranged the axial walls 26 and at which the parasitic air flow "F" enters the annular duct 22, and an upstream portion 22b in which the radial rib 24 and the radial cheek 28 are arranged.

The downstream portion 22a of the annular duct 22 is divided by the axial walls 26 into a plurality of parallel axial channels 30 which are distributed angularly about the main axis A of rotation.

As can be seen in FIG. 3, the axial channels 30 are shaped so that when the parasitic "F" air flow enters the downstream portion 22a, the parasitic "F" air flow divides into several streams. secondary 32.

In addition, the tangential component of the parasitic "F" air flow causes a vortex movement of each secondary flow 32 around the main axis B of the associated axial channel 30.

At the output of the associated axial channel 30 at the level of the radial cheek 28, each secondary stream 32 mixes with the other secondary streams 32 to form the parasitic "F" air flow again. The swirling motion of each secondary flow

32 in the associated axial duct 30 causes a significant reduction, or even the cancellation of the tangential component of the parasitic "F" air flow when it is reformed at the level of the cheek radial 28, while the axial component of the parasitic "F" air flow remains largely unchanged.

The parasitized "F" air flow thus reformed opens out from the downstream portion 22a of the annular duct 22 and then enters the upstream portion 22b of the annular duct 22.

As can be seen in FIG. 3, the radial cheek 28 and the radial rib 24 are arranged in the upstream portion 22b of the annular duct 22 so that they form a baffle which creates a significant pressure drop in the air flow. "F" parasite running through it.

The pressure drop experienced by the parasitic "F" air flow makes it possible to significantly limit the flow rate of the parasitic "F" air flow.

Furthermore, the pressure drop is formed at the upstream portion 22b of the annular duct 22, it therefore does not cause an increase in the air pressure in the annular duct 22, and therefore the value of the resistant torque is not significantly increased despite the presence of this chicane. As mentioned above, the radial flange 28 is shaped so that its downstream annular radial face 28b is connected to the upstream end radial edge 26b of each axial wall 26. In addition, according to an embodiment variant of FIG. According to the invention, the radial flange 28 extends radially from the concave inner cylindrical face 14i of the fairing 14 so that its free radial end annular edge 28 is flush with the radially free end axial edge 26a of each wall 26.

According to another aspect of the invention, the downstream end edge 20a of the annular skirt 20 is situated axially upstream of the downstream end edge 26c of each axial wall 26 and downstream of the upstream end radial edge 26b of each axial wall 26.

Thus, a downstream part of each axial duct 30 opens out radially towards the inside of the control system. fan 10, which facilitates the penetration of each secondary flow 32 in the associated axial duct 30, in a direction tangential to the main axis A of rotation, thereby promoting the vortex movement of each secondary flow 32 in the duct axial 30 associated.

According to an alternative embodiment (not shown) of this aspect of the invention, each secondary stream 32 penetrates axially into the associated axial duct 30. For this purpose, the downstream end edge 20a of the annular skirt 20 is situated axially in line with the downstream end edge 26c of each axial wall 26, and according to yet another variant embodiment of this aspect of the invention, the downstream end edge 20a of the annular skirt 20 is located axially downstream of the downstream end edge 26c of each axial wall 26. Finally, the radial rib 24 is positioned axially on the annular skirt 20 so that it extends radially from the upstream end edge 20c of the annular skirt 20.

However, it will be understood that the invention is not limited to this embodiment of the annular skirt 20 and the radial rib 24, and that the radial rib 24 can be located axially downstream of the upstream end edge 20c of the annular skirt 20.

Claims

A fan system (10), in particular for cooling the motor of a motor vehicle, comprising a fan (12) rotatably mounted about a main axis (A) of rotation with respect to a peripheral fairing (14). to the fan (12) which is attached to the engine of the vehicle, so as to produce a flow of air (G) generally coaxial with the main axis (A) of rotation of the fan (12), wherein the fan (12) comprises: - a central core (16) for mounting on a rotary drive shaft of the fan (12);

- Blades (18) angularly distributed around the main axis (A) of rotation, and each of which extends generally radially outwardly of the fan (12) from the central core! (16);

- A peripheral annular skirt (20) coaxial with the main axis (A) of rotation, a concave inner cylindrical face (20i) is fixed to the outer radial end (18a) of each blade (18); - and an outer annular radial rib (24) extending radially outwardly of the fan (12), from the outer cylindrical (20e) convex face of the annular skirt (20), and wherein the shroud (14) has:

- A concave inner cylindrical face (14i) which extends radially at a distance and vis-à-vis the convex outer cylindrical face (20e) of the annular skirt (20);

- a series of generally axial walls (26) which are angularly distributed around the main axis (A) of rotation, each axial wall (26) extending in a generally axial plane, and extending radially from the cylindrical face concave internal member (14i) of the fairing (14), so that its free radial end axial edge (26a) is located at a distance from the convex outer cylindrical face (20e) of the annular skirt (20); - and an inner annular radial cheek (28) extending radially inwardly of the fairing (14) from the concave inner cylindrical face (14i) of the fairing (14), characterized in that the radial cheek (28) is arranged axially upstream of the axial walls (26), with respect to the direction of flow of the air flow (G).

2. Fan system (10) according to the preceding claim, characterized in that the radial flange (28) comprises a downstream annular radial face (28b) relative to the direction of flow of the air flow (G) which is connected at the upstream end radial edge (26b) of each axial wall (26).

3. Fan system (10) according to the preceding claim, characterized in that the free radial end annular edge (28a) of the radial flange (28) is flush with the radial end radially free end edge (26a) of each axial wall (26).

4. Fan system (10) according to any one of the preceding claims, characterized in that the radial cheek (28) is arranged downstream and at a distance from the radial rib (24), with respect to the direction of flow of the air flow (G).

5. Fan system (10) according to any one of the preceding claims, characterized in that the annular free radial end edge (28a) of the radial flange (28) extends radially vis-a-vis and away from the convex outer cylindrical face (20e) of the annular skirt (20).

6. Fan system (10) according to any one of the preceding claims, characterized in that the downstream end edge (20a) of the annular skirt (20) is located upstream the downstream end edge (26c) of each axial wall (26), relative to the direction of flow of the air flow (G).

7. Fan system (10) according to any one of claims 1 to 5, characterized in that the downstream end edge (20a) of the annular skirt (20) is located axially to the right of the downstream end edge (26c) of each axial wall (26).

8. Fan system (10) according to any one of the preceding claims, characterized in that the downstream end edge (20a) of the annular skirt is located downstream of the upstream end edge of (26b) each wall axial (26), with respect to the flow direction of the air flow (G).