JP2009507162A - Heat exchanger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an improved heat exchanger.
A heat exchanger having at least one inlet (2) and an outlet for a medium to be cooled or heated and / or a medium to be cooled or medium to be heated, in particular a heat exchanger for an automobile. In
When the inlet (2) flows into the heat exchanger (1), a moving component in a tangential direction is superimposed on the flowing medium in the normal direction of motion before it and / or the main direction of motion directly following the inflow. It is formed so that it may be formed.
[Selection] Figure 3

Description

  The present invention relates to a heat exchanger according to the preamble of claim 1, in particular an automobile exhaust gas cooler (ie for the medium to be cooled or heated and / or for the medium to be cooled or heated) The present invention relates to a heat exchanger having an inlet and an outlet, in particular a heat exchanger for an automobile.

  In order to reduce the emission of particles and nitrogen oxides in diesel engines, exhaust gas recirculation is known, in which case either high pressure exhaust gas recirculation or low pressure exhaust gas recirculation is possible. In that case, the exhaust gas stream is cooled to a temperature of about 150 ° C. to 200 ° C. and mixed with the intake air. As a cooling medium in the exhaust gas cooler, a partial flow of engine coolant is usually used when the cooled intake air is at this temperature. In that case, the exhaust gas recirculation becomes more efficient as the gas outflow temperature in the exhaust gas cooler becomes lower. The same applies to other coolers that are also common for heat exchangers.

  Based on this prior art, the object of the present invention is to provide an improved heat exchanger.

  This object is achieved by a heat exchanger having the features of claim 1 (ie when the inlet flows into the heat exchanger as follows, ie the normal direction of motion and / or inflow before the flowing medium. It is solved by a heat exchanger characterized in that the motion component in the tangential direction is superimposed on the main motion direction that is directly continuous with the main motion direction. Preferred forms are the subject of the subclaims.

BEST MODE FOR CARRYING OUT THE INVENTION

  According to the invention, a heat exchanger, in particular for a motor vehicle, particularly preferably an exhaust gas cooler or a supercharged air cooler, has at least one inlet and outlet for the medium to be cooled or heated and / or the medium to be cooled or heated. In which case the inlet preferably flows into the heat exchanger, i.e. before the medium to be cooled or heated flows into the heat exchanger, in particular the inflow diffuser or the inflow case. The flowing medium is formed so that a tangential motion component is superimposed on the previous normal motion direction and / or the main motion direction directly following the inflow. Due to the tangential component of the flow velocity, the flow transition as it enters the heat exchanger, especially when the flow cross section changes, the flow does not detach much from the wall and is therefore more evenly distributed throughout the cross section. Is improved. In particular, it can reduce the peak flow velocity at the center, which usually occurs. Furthermore, the flow velocity increases somewhat in the outer region.

  The effect of this type of measure on the overall flow rate that depends on pressure loss is in some cases positive. This is because, due to the improved equidistribution in the flow passage of the heat exchanger, the pressure loss due to the formation of the inlet according to the invention may be more than compensated in some cases. A better equidistribution of the flow further results in possibly more uniform component parameters, which contributes to the reduction of mechanical stresses that are caused thermally.

  Preferably, a diffuser is provided or formed in the inlet region which further improves the flow profile in the inlet region.

  Within the inlet there is preferably a diffuser with a flow channel swivel arrangement, in particular a swivel. The flow in the flow channel swivel arrangement preferably has a tangential component, in which case the tangential component at the outer periphery is preferably greater than at the center.

  Preferably, the swivel body has a repeated portion used as a guide member that is uniformly distributed in the circumferential direction, and the repeated portion extends in the flow direction in the inflow region. The outflow region is formed so as to extend obliquely with respect to the flow direction in the inflow region. In that case, there are preferably 2 to 8 repeated portions, in particular 3 to 5, particularly preferably 4 portions.

  The flow channel swirl arrangement, or swirl, is preferably made of metal or metal alloy, in particular aluminum or aluminum alloy or special steel. It is preferably the same material used for the heat exchanger. In that case, the arrangement is preferably brazed or welded to the inlet or to the swivel body in the inlet. Since this can be done in one working process with brazing of the heat exchanger, the production costs are reduced, especially with regard to time consumption and required energy. By using the same material, different thermal expansion is avoided, so that the load of brazing joint (for example, solder joint) can be reduced, and safety and life are improved.

  According to an embodiment, one or more components of the heat exchanger are formed from a casting and the swivel is cast directly. Alternatively, the swivel body is formed by stamping from a sheet or cast part.

  Instead of providing a swivel body, the inflow in the region of the inlet into the flow passage of the inlet region can take place tangentially. In that case, the flow passage is both a simple pipe and a diffuser. Preferably, in addition to the tangential component, a component in the direction of the longitudinal axis of the flow passage is provided in order to further optimize the velocity distribution.

  Hereinafter, the heat exchanger will be described in detail using two embodiments with reference to the drawings.

  According to the first embodiment, there is provided a heat exchanger 1 formed by an exhaust gas cooler, such as used for cooling the exhaust gas that is recirculated by the turbocharger. In order to allow as even a distribution of the engine coolant used for exhaust gas cooling as possible, an exhaust gas cooler schematically shown in FIG. 1 in a circular area of polka dots in front of the coolant passage shown in cross section. As shown in detail in FIGS. 3 to 5, the inlet 2 is provided with a flow passage swirl arrangement 3.

  The flow passage swirl arrangement 3 is made of special steel, like the exhaust gas cooler, and is brazed to the exhaust gas cooler in the region of the inflow opening for the coolant, which is the individual component that forms the exhaust gas cooler. It is performed in the same working steps as brazing or welding.

  The flow passage swirl body arrangement 3 is formed as a diffuser 4 having a swirl body 5, in which case the cross section of the diffuser 4 is slightly widened in the flow direction. Inside the diffuser 4, there is provided a swivel body 5 comprising four guide members 6, which are connected to the diffuser 4 on the outside and connected to each other along the longitudinal axis of the diffuser 4 in the center. ing. The four guide members 6 are equally formed and distributed uniformly over the peripheral surface of the diffuser 4. Each guide member 6 has an inflow region 7 that extends parallel to the normal flow direction and extends parallel to the longitudinal axis of the diffuser 4. On the inflow side, the guide members 6 are bent and formed behind the relatively short inflow region 7 in which each guide member 6 extends radially from the center of the diffuser 4 to the diffuser 4. Has been. Here, in the region where the bending of the guide member 6 begins, the diameter of the diffuser 4 is also widened, so that in addition to or following the tangential velocity component of the flow, the radial velocity component is also superimposed. Coolant is better distributed to subsequent cross sections. From the inflow region 7 to the outflow region 8, each guide member 6 extends from the center of the diffuser 4 to the diffuser 4 in the radial direction (see FIG. 4).

  By providing the flow passage swirl arrangement 3, a flow is produced which extends substantially outwardly, adjoining the wall surface, and is therefore distributed relatively evenly over a larger cross section. In particular, the more uniform velocity distribution across the cross-section significantly reduces the peak flow velocity that normally occurs in the middle, where the coolant flow rate is generally the same.

  A significantly improved distribution of the coolant is evident when comparing the graphs shown in FIGS. 2a and 2b. In that case, the flow passage swirl arrangement 3 is used to significantly reduce the flow velocity in the middle region and correspondingly increase the flow velocity in the outer region, resulting in a much more uniform velocity distribution as a whole, This significantly improves the efficiency of the exhaust gas cooler.

  6 and 7 diagrammatically show a variant for providing a flow channel swivel arrangement 3 which can be made to have a uniform velocity distribution by forming the inlet region accordingly. It is shown. In that case, the inlet 2 to the heat exchanger 1 has a flow passage 9 such that the incoming medium is automatically supplied with a tangential component and the subsequent flow transition is formed into a thread or thread. Since it is located on the side of the end of the pipe (shown here as a pipe having a larger cross section than the supply conduit, but may also be a diffuser), the flow that exists as it exits the flow passage Are spread substantially outwardly, substantially adjoining the wall, and are therefore distributed relatively evenly over a larger cross section.

  Alternatively, in addition to the tangential component, a component in the direction of the subsequent flow path can also be provided at the same time by arranging the inlet accordingly.

1 schematically shows an exhaust gas cooler. It is a graph explaining the velocity distribution of the coolant flow in each passage in the conventional exhaust gas cooler. The deviation of the mass flow distribution from the equal distribution is shown in%. It is a graph explaining the velocity distribution of the coolant flow in each channel | path in the exhaust gas cooler which has a turning body in an inlet_port | entrance. The deviation of the mass flow distribution from the equal distribution is shown in%. It is a perspective view which shows flow path turning body arrangement | positioning. The revolving body of FIG. 3 is shown with the perspective view. It is a top view which shows the flow channel | form rotation body arrangement | positioning of FIG. Fig. 5 schematically shows a tangential inflow into the diffuser of the variant. It is a side view of the modification shown by FIG.

Claims (12)

In a heat exchanger having at least one inlet (2) and an outlet for the medium to be cooled or heated and / or the medium to be cooled or heated, in particular a heat exchanger for an automobile,
When the inlet (2) flows into the heat exchanger (1), a moving component in a tangential direction is superimposed on the flowing medium in the normal direction of motion before it and / or the main direction of motion directly following the inflow. It is formed so that it may be formed.   2. A heat exchanger according to claim 1, wherein a diffuser (4) is provided or formed in the region of the inlet (2).   3. Heat exchanger according to claim 1 or 2, characterized in that a diffuser (4) having a flow passage swirl arrangement (3), in particular a swirl (5), is provided in the inlet (2).   The flow in the flow passage swivel arrangement (3) has a tangential component, the tangential component being larger at the outer periphery than at the center. The heat exchanger according to item.   The swivel body (5) has a repeated portion used as a guide member (6) arranged uniformly distributed in the circumferential direction, and the repeated portion flows in the inflow region (7). 5. The flow-out region (8) is formed so as to extend in a direction and obliquely extend with respect to the flow direction in the flow-in region (7). Heat exchanger.   6. A heat exchanger according to claim 5, characterized in that there are 2 to 8 repeated parts of this type, in particular 3 to 5 parts.   7. The flow path swivel arrangement (3) or swivel body (5) is made of metal or metal alloy, in particular aluminum or aluminum alloy or special steel. The described heat exchanger.   8. The flow path swivel arrangement (3) or swivel body (5) is brazed and / or welded to the heat exchanger (1). Heat exchanger.   9. Inflow in the region of the inlet (2) into the flow passage (9) in the inlet region of the heat exchanger (1) takes place tangentially with respect to the flow passage (9). The heat exchanger of any one of Claims.   Inflow in the region of the inlet (2) into the flow passage (9) in the inlet region is effected tangentially with a component in the direction of the longitudinal axis of the flow passage (9). Item 11. The heat exchanger according to Item 9.   The heat exchanger according to any one of claims 1 to 10, characterized in that the heat exchanger (1) is an exhaust gas cooler.   The heat exchanger according to any one of the preceding claims, characterized in that the heat exchanger (1) is a supercharged air cooler.

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