Heat exchanger for placement on a rotor having a rotating shaft, particularly a shell-and-tube heat exchanger
Patent Information
- Application Number
- JP2024537894
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-12-22
- Filing Date
- 2022-12-22
- Publication Date
- 2026-01-07
AI Technical Summary
Heat transfer between media in shell-and-tube heat exchangers is significantly lower than expected when used with rotors, particularly in rotary heat pumps, due to non-uniform distribution of the second heat exchange medium under centrifugal acceleration.
A heat exchanger design that includes a throttling device and flow grid to compensate for pressure differences caused by centrifugal forces, ensuring uniform flow of the second heat exchange medium through channels by asymmetrically throttling the flow based on distance from the axis of rotation.
The design achieves a substantially uniform flow rate and improved heat transfer efficiency by compensating for pressure differences, enhancing the effectiveness of heat exchange in rotary systems.
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Abstract
Description
[Technical field]
[0001] The present invention relates to a heat exchanger, particularly a shell-and-tube heat exchanger, for use with a rotor having a rotating shaft, [Background technology]
[0002] a first heat exchange channel for conducting a first heat exchange medium, in particular a liquid;
[0003] second heat exchange channels for conducting a second heat exchange medium, in particular a gas, preferably a noble gas, which in the assembled and used state of the heat exchanger comprise at least one inner heat exchange channel close to the axis of rotation and an outer heat exchange channel further away from the axis of rotation;
[0004] a distribution element expanding, preferably conically expanding, in a direction of flow of the second heat exchange medium for supplying the second heat exchange medium from an inlet opening in the distribution element to an inlet opening in the second heat exchange channel;
[0005] and a confluence element tapering, preferably substantially conically tapering, in the direction of flow of the second heat exchange medium for discharging the second heat exchange medium from an outlet opening in the second heat exchange channel to an outlet opening in the confluence element.
[0006] The invention further relates to a rotor, in particular a rotary heat pump, comprising a rotating shaft and a heat exchanger.
[0007] Finally, the invention relates to a method for exchanging heat between a first heat exchange medium, in particular a liquid, and a second heat exchange medium, in particular a gas, preferably a noble gas, inside a rotor, comprising:
[0008] Rotate the rotor around the axis of rotation,
[0009] Guiding a first heat exchange medium along a first heat exchange channel of a heat exchanger;
[0010] The second heat exchange medium is guided along a second heat exchange channel of the heat exchanger at different distances from the axis of rotation of the rotor.
[0011] A rotary heat pump is known from WO2015 / 103656, in which centrifugal acceleration of a rotor is used to generate different pressure or temperature levels, where high-temperature heat is extracted from a compressed working medium and low-temperature heat is supplied to an expanded working medium. For this purpose, the rotary heat pump comprises an inner heat exchanger and an outer heat exchanger arranged substantially parallel to the rotation axis of the rotor. The inner heat exchanger is configured to exchange heat at a lower temperature and the outer heat exchanger is configured to exchange heat at a higher temperature.
[0012] In addition, in stationary applications, shell-and-tube heat exchangers are often used, in which the working medium flows through a bundle of tubes arranged in a cylindrical housing shell. The heat exchange medium flows through the shell spaces in a loop formed by baffle plates. This type of heat exchanger promises particularly good heat transfer between the two media. In such stationary applications of shell-and-tube heat exchangers, the incoming flow of the working medium is divided symmetrically with respect to the main direction of flow in order to distribute the working medium accordingly among the individual tubes.
[0013] However, attempts to use known shell-and-tube heat exchangers with rotors, particularly rotary heat pumps, have shown that the heat transfer between the media is significantly less than expected.
[0014] The general state of the art is further illustrated by GB 1 383 690 A and CH 576 615 A5. Summary of the Invention [Problem to be solved by the invention]
[0015] It is therefore an object of the present invention to mitigate or eliminate the drawbacks of the state of the art. It is an object of the present invention to provide a heat exchanger which has a high efficiency, preferably when used in a rotor. [Means for solving the problem]
[0016] This object is achieved by a heat exchanger according to claim 1, a rotor according to claim 8 and a method according to claim 13. Preferred embodiments are set forth in the dependent claims.
[0017] According to the invention, there is provided an apparatus for homogenizing a flow through second heat exchange channels, the apparatus comprising a throttling member designed to throttle to different degrees an inner flow of a second heat exchange medium passing through an inner one of the second heat exchange channels and an outer flow of the second heat exchange medium passing through an outer one of the second heat exchange channels between an inlet opening of a distribution element and an outlet opening of a merging element.
[0018] For purposes of this disclosure, location and direction designations refer to the intended use of the heat exchanger as part of the rotor. "Upstream" and "Downstream" refer to the direction of flow of the second heat exchange medium. "Radial" and "Axial" refer to the axis of rotation of the rotor. "Inwardly" means closer to the axis of rotation of the rotor and "Outwardly" means further away from the axis of rotation. Distance refers to the radial distance from the axis of rotation.
[0019] The present invention is therefore based on the surprising discovery that a uniform distribution of the second heat exchange medium does not allow an effective operation of a heat exchanger under the effect of centrifugal acceleration. The present invention solves this problem in that different pressure differences of the side streams of the second heat exchange medium flowing at different distances from the axis of rotation between the inlet opening in the distribution element and the outlet opening in the merging element are at least partially, preferably substantially completely compensated.
[0020] Advantageously, in this way a substantially uniform flow through the second heat exchange channel can be achieved.
[0021] From the comprehensive flow analysis, the main cause of the different pressure difference of the side flows is that the first flow flows out, the outer flow along the outside of the second heat exchange channel is compressed by centrifugal force before heat exchange with the first heat exchange medium, and then flows inside the confluence element toward the outlet and is expanded thereby. For the inner flow, the sequence is reversed, as the inner flow of the distribution element flows inward with the first flow and is expanded by centrifugal force, and then flows outward with the first heat exchange medium along the inside of the second heat exchange channel before the inner flow of the confluence element is directed outward toward the outlet and is compressed thereby.
[0022] When the second heat exchange medium in the second heat exchange channel releases heat to the first heat exchange medium, a pressure difference is created by first compressing the second heat exchange medium at a low density before the heat exchange, i.e. from the inlet opening of the second heat exchange medium collected through the inlet opening in the external heat exchange channel to the inlet opening in the external heat exchange channel, then heat dissipation occurs in the external heat exchange channel, thereby decreasing the temperature of the second heat exchange medium and therefore increasing the density in the case of a substantially isobaric heat exchange, and then the second heat exchange medium expands again at a relatively high density, i.e. from the outlet opening in the external heat exchange channel to the collection of the second heat exchange medium at the outlet opening. Since the second heat exchange medium is compressed at a low density (low pressure difference) and expanded at a high density (high pressure difference), when this flow thread is taken into account, an additional pressure difference remains, which is required when flowing through the outer heat exchange channel. As a result of this, the second heat exchange medium is favored by the inner heat exchange channel of the second heat exchange channel. The opposite is true if heat is supplied to the second heat exchange medium by the first heat exchange medium, which then favors the outer ones of the second heat exchange channels.
[0023] In the present invention, the additional pressure difference is compensated for by means of throttling members which throttle the outer and inner flows to different degrees between the inlet opening in the distribution element and the outlet opening in the merging element, i.e. create different flow resistances.
[0024] When heat dissipation occurs from the second heat exchange medium to the first heat exchange medium in the second heat exchange channel, the throttling member is configured to throttle the inner flow more than the outer flow.
[0025] When heat is supplied from the first heat exchange medium to the second heat exchange medium in the second heat exchange channel, the throttling member is configured to throttle the outer flow to a greater extent than the inner flow.
[0026] The throttling element is therefore configured to asymmetrically throttle the flow of the second heat exchange medium relative to the central axis or axis of symmetry of the heat exchanger. With the throttling element, the second heat exchange medium is subjected to essentially the same pressure difference as it flows through the heat exchanger from the inlet to the outlet opening. Advantageously, in this way, the flow through the second heat exchange channel is substantially uniform, so that the second heat exchange medium along the second heat exchange channel comprises in each case substantially the same average flow velocity or substantially the same volumetric flow rate (provided that the second flow channels preferably have the same flow cross-section).
[0027] In a preferred embodiment, the heat exchanger is designed as a shell-and-tube heat exchanger. The shell-and-tube heat exchanger preferably comprises a tube bundle with a plurality of tubes, each having a substantially circular cross section and surrounding a second heat exchange channel. The tubes preferably extend parallel to one another. The tube bundle can be arranged in a preferably cylindrical housing. The first heat exchange medium is guided through a first heat exchange channel extending into the housing. A deflection element for the first heat exchange medium is preferably provided in the housing.
[0028] The deflection elements are preferably arranged substantially perpendicular to the tubes. Preferably the deflection elements in the housing leave recesses for the first heat exchange medium, the recesses being preferably arranged alternately on opposite sides. As a result, the first heat exchange medium is guided in a loop through the interior of the housing, the first heat exchange medium flowing partly transversely to the tubes with the second heat exchange channels.
[0029] In a first preferred embodiment, the throttle device comprises a throttle orifice plate with throttle openings, the throttle openings further away from the axis of rotation and the throttle openings closer to the axis of rotation being of different sizes. The throttle orifice plate can be arranged upstream of the inlet opening, in particular immediately upstream of the inlet opening, or downstream of the outlet opening, in particular immediately downstream of the outlet opening. In an embodiment for dissipating heat from the second heat exchange medium, the throttle openings further away from the axis of rotation are larger than the throttle openings closer to the axis of rotation. In an embodiment for supplying heat to the second heat exchange medium, the throttle openings further away from the axis of rotation are smaller than the throttle openings closer to the axis of rotation. An advantage of this embodiment of the throttle member is the simple constructive implementation. Moreover, the heat exchanger can be set to a specific operating point by simply replacing the throttle orifice plate.
[0030] The restrictor orifice plate is preferably arranged upstream of the second heat exchange channels, so that the second heat exchange medium is fed through a restrictor opening into each of the second heat exchange channels exactly one by one. Alternatively, the restrictor orifice plate may be arranged downstream of the second heat exchange channels, so that the second heat exchange medium is discharged from each of the second heat exchange channels through exactly one restrictor opening.
[0031] In the following, preferred embodiments of the throttling orifice plate are described with reference to an embodiment for dissipating heat from a second heat exchange medium along a second heat exchange channel. Thus, the principle can be applied when supplying heat to a second heat exchange medium, where a greater throttling is provided by means of smaller throttling openings with a greater distance outward from the axis of rotation.
[0032] The throttle orifice plate preferably comprises at least one first throttle opening at a first distance from the axis of rotation and at least one second throttle opening at a second distance from the axis of rotation of the rotor, the second distance being greater than the first distance, the second throttle opening being greater than the first throttle opening. The throttle orifice plate preferably comprises at least one third throttle opening at a third distance from the axis of rotation, preferably greater than the second distance, the at least one third throttle opening being greater than the at least one second throttle opening. The throttle orifice plate comprises at least one fourth throttle opening at a fourth distance from the axis of rotation, preferably greater than the third distance, the at least one fourth throttle opening being greater than the at least one third throttle opening. Of course, the throttle orifice plate can comprise further throttle openings further away from the axis of rotation of the rotor, the throttle openings further away from the axis of rotation being in each case larger than the throttle openings closer to the axis of rotation.
[0033] In a preferred embodiment, the heat exchanger comprises a plurality of rows of second heat exchange channels, each of the second heat exchange channels of each row being substantially the same distance from the rotation axis of the rotor. Correspondingly, the throttle orifice plate preferably comprises a plurality of rows, each having a plurality of throttle openings, the rows further away from the rotation axis and the rows closer to the rotation axis being provided with throttle openings of different sizes. When dissipating heat, the rows of throttle openings further away from the rotation axis include larger throttle openings than the rows of throttle openings closer to the rotation axis.
[0034] Thus, there may be provided a first row of first iris apertures, each at substantially a first distance from the axis of rotation, a second row of second iris apertures, each at substantially a second distance from the axis of rotation, a third row of third iris apertures, preferably each at substantially a third distance from the axis of rotation, a fourth row of fourth iris apertures, preferably each at substantially a fourth distance from the axis of rotation, and further iris apertures, preferably each at a further distance from the axis of rotation.
[0035] To allow the second heat exchange medium to be supplied to the individual second heat exchange channels, a distribution element is arranged upstream of the second heat exchange channels (in the direction of flow of the second heat exchange medium), the distribution element being enlarged, i.e. formed with an increasing cross section in the direction of flow of the second heat exchange medium. The distribution element allows the distribution of the flow of the second heat exchange medium at the inlet of the heat exchanger into the individual flows in the second heat exchange channels. Preferably, the distribution element is conically enlarged.
[0036] In a second preferred embodiment, a flow grid is disposed within the distribution element, the flow grid comprising individual distribution channels expanding in the direction of flow, each distribution channel comprising a head portion and an end portion.
[0037] In a second embodiment of the throttle element, the head and / or end portions of the distribution channels further away from the axis of rotation contain different flow cross sections than the head and / or end portions of the distribution channels closer to the axis of rotation. The advantage of this embodiment is that a flow grid is generally useful for good distribution and flow guidance in order to keep pressure losses as low as possible. Advantageously, this flow grid can also be designed as a throttle element in which an asymmetric cross-sectional expansion is achieved to compensate for the different pressure differences depending on the distance from the axis of rotation. The head portion is connected to the inlet of the heat exchanger. The end portion guides the second heat exchange medium to the inlet opening of the second heat exchange channel. In the case of dissipating heat from the second heat exchange medium to the first heat exchange medium, the head and / or end portions of the distribution channels further away from the axis of rotation contain a larger flow cross section than the head and / or end portions of the distribution channels closer to the axis of rotation.
[0038] The flow grid preferably comprises exactly one distribution channel per second heat exchange channel, such that the second heat exchange medium is fed exactly to one of the second heat exchange channels via each distribution channel. The distribution channels are separated from one another by individual walls, which are preferably provided with upright and lateral walls. The upright walls serve on the one hand to ensure a uniform distribution in the tangential direction (so that the above-mentioned problem of different pressures does not arise here), but also have the advantage that the lateral walls provided for the radial distribution of the flow are supported against deflections under the effect of centrifugal forces.
[0039] In the following, a preferred embodiment of the flow grid is described with reference to an embodiment for dissipating heat from the second heat exchange medium along the second heat exchange channel, which allows the principle of heat supply to be transferred if a large constriction is achieved over a distance outward from the axis of rotation.
[0040] The flow grid preferably comprises at least one first distribution channel at a first distance from the axis of rotation and at least one second distribution channel at a second distance from the axis of rotation of the rotor, the second distance being greater than the first distance and the head and / or end portion having a larger flow cross section than the head and / or end portion of the first distribution channel. Preferably the flow lid comprises at least one third distribution channel at a third distance from the axis of rotation, the third distance being greater than the second distance and the head and / or end portion of the third distribution channel having a larger flow cross section than the head and / or end portion of the second distribution channel. Preferably the flow grid comprises at least one fourth distribution channel at a fourth distance from the axis of rotation, the fourth distance being greater than the third distance and the head and / or end portion of the fourth distribution channel having a larger flow cross section than the head and / or end portion of the third distribution channel. Of course, the flow grid may comprise further distribution channels at further distances from the axis of rotation, the flow cross section in the head and / or end portions increasing with distance from the axis of rotation.
[0041] The flow grid preferably comprises at least one first row having a plurality of individual, i.e. separate, first distribution channels substantially at a first distance from the axis of rotation, a second row having a plurality of second distribution channels substantially at a second distance from the axis of rotation, a third row having a plurality of third distribution channels preferably substantially at a third distance from the axis of rotation, a fourth row having a plurality of fourth distribution channels preferably substantially at a fourth distance from the axis of rotation, and further rows preferably each having a plurality of further distribution channels.
[0042] In a first variant, the head parts of the distribution channels further away from the axis of rotation have a larger flow cross-section than the head parts of the distribution channels closer to the axis of rotation, and the end parts of the distribution channels further away from the axis of rotation have substantially the same flow cross-section as the end parts of the distribution channels closer to the axis of rotation. This embodiment is particularly advantageous for constructive reasons if the second heat exchange channels have the same flow cross-section. Thus, in this variant, the second heat exchange medium can flow asymmetrically into the flow grid, during the inflow the flow cross-section increases with the distance from the axis of rotation. On the other hand, the outflow from the flow grid can take place symmetrically, i.e. with essentially the same flow cross-section.
[0043] In a second variant, the end portions of the distribution channels further away from the axis of rotation have a larger flow cross-section than the end portions of the distribution channels closer to the axis of rotation, and the head portions of the distribution channels further away from the axis of rotation have substantially the same flow cross-section as the head portions of the distribution channels closer to the axis of rotation. This embodiment is particularly simple in terms of construction. Thus, in this variant, the inflow into the flow grid can be symmetrical, whereas the outflow from the flow grid can be asymmetrical.
[0044] In a third variant, the head and end portions of the distribution channels are further away from the axis of rotation and respectively have a larger flow cross section than the head and end portions of the distribution channels, which are closer to the axis of rotation. Thus, in this variant, both the inflow to the flow grid and the outflow from the flow grid can be performed asymmetrically, i.e. with a larger flow cross section with increasing distance from the axis of rotation.
[0045] The asymmetric distribution of the second heat exchange medium by means of the flow grid results in the axially closer flows of the second heat exchange medium flowing through a smaller flow cross section before exiting the heat exchanger than the axially more distant flows of the second heat exchange medium, such that the axially closer flows experience a higher pressure loss than the axially more distant flows, so that the pressure difference between the axially closer and axially more distant second heat exchange channels is at least partially, preferably substantially completely compensated.
[0046] Furthermore, a flow grid may be arranged in the joining element, the flow grid comprising individual joining channels in the joining element tapering in the direction of flow, each joining channel comprising a head portion (on the side of the outlet opening in the second heat exchange channel) and an end portion (on the side opposite the outlet opening). In order to form a throttle member, the head and / or end portions of the joining channels further away from the axis of rotation and the head and / or end portions of the joining channels closer to the axis of rotation comprise different flow cross-sections.
[0047] In a third preferred embodiment, the device for homogenizing a flow through a second heat exchange channel comprises an agitator, in particular a spiral agitator, in the second heat exchange channel, the agitator further away from the axis of rotation and the agitator closer to the axis of rotation causing different pressure losses, the agitator further away from the axis of rotation causing a lower pressure loss when dissipating heat from the second heat exchange medium along the second heat exchange channel than the agitator closer to the axis of rotation.
[0048] For this purpose, the agitators further away from the axis of rotation and the agitators closer to the axis of rotation can include different helix lengths. In case of dissipating heat from the second heat exchange medium along the second heat exchange channel, the agitators further away from the axis of rotation can have a larger inclination than the agitators closer to the axis of rotation.
[0049] The advantage of the agitator over the previously described embodiment of the throttling device is that not only can the pressure drop in the second heat exchange channel be adjusted to different degrees at different distances from the axis of rotation to achieve a uniform flow through the second flow path, but also that heat transfer is increased due to increased turbulence during heat transfer.
[0050] In a fourth embodiment, the outer and inner channels of the second heat exchange channel for forming the throttle member are provided with different flow cross sections of different diameters in the case of tubes with a circular cross section.
[0051] In a preferred application, in one of the aforementioned embodiments, the rotor, in particular a rotary heat pump, is provided with a heat exchanger.
[0052] In a first preferred embodiment, the central axis or axis of symmetry of the heat exchanger is located at a radial distance, i.e. with an axial offset, from the axis of rotation.
[0053] In a second preferred embodiment, the central axis of the heat exchanger is arranged substantially in line with the axis of rotation, again with the second heat exchange channels having different distances from the axis of rotation.
[0054] In the rotor, the second heat exchange channels preferably extend substantially parallel to the axis of rotation and at a different radial distance from the axis of rotation, and the first heat exchange channels may extend in a portion essentially perpendicular to the second heat exchange channels, as in a shell-and-tube heat exchanger.
[0055] In one preferred embodiment, the rotor comprises a compression unit in which the second heat exchange medium is guided by centrifugal force away from the rotation axis to increase the pressure, and an expansion unit in which the second heat exchange medium is guided by centrifugal force towards the rotation axis to decrease the pressure.
[0056] In this embodiment of the rotor, preferably at least one inner heat exchanger relative to the axis of rotation and at least one outer heat exchanger relative to the axis of rotation are provided. Depending on the embodiment, the outer heat exchanger and / or the inner heat exchanger may be configured according to any one of the above embodiments of the heat exchanger.
[0057] The method of the invention for exchanging heat between a first heat exchange medium, in particular a liquid, and a second heat exchange medium, in particular a gas, preferably a rare gas, inside a rotor comprises the steps of: Rotate the rotor around the axis of rotation, The first heat exchange medium is guided along a first heat exchange channel of the heat exchanger and the second heat exchange medium is guided along a second heat exchange channel of the heat exchanger at different distances from the axis of rotation of the rotor, and the flow through the second heat exchange channel is homogenized by throttling to different extents an inner flow of the second heat exchange medium closer to the axis of rotation and an outer flow of the second heat exchange medium further away from the axis of rotation. Includes steps.
[0058] In a preferred embodiment, heat dissipation from the second heat exchange medium to the first heat exchange medium occurs along a second heat exchange channel, the inner flow of the second heat exchange medium being throttled more than the outer flow of the second heat exchange medium. [Brief description of the drawings]
[0059] [Figure 1] FIG. [Figure 2A] FIG. 2 shows a heat exchanger 7, also called heat transfer system, in a possible embodiment. [Figure 2B] FIG. 2 shows a simplified form of a heat exchanger 7. [Diagram 3]FIG. 4 is a diagram showing the flow of a second heat exchange medium flowing into a heat exchanger 7. [Figure 4] FIG. 2 is a schematic diagram of a heat exchanger 7 when used as the outer (high pressure) heat exchanger 6. [Diagram 5] This is a rough calculation of the pressure difference between the flow paths in revolutions per minute (rpm). [Figure 6] FIG. 1 illustrates a first embodiment according to the present invention. [Figure 7] FIG. 1 illustrates a first embodiment according to the present invention. [Figure 8] FIG. 13 illustrates another embodiment according to the present invention. [Figure 9] FIG. 13 illustrates another embodiment according to the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0060] The invention will be explained below with reference to preferred exemplary embodiments shown in the drawings.
[0061] FIG. 1 shows a rotor 1, which in the illustrated embodiment is implemented as a device for converting mechanical energy into thermal energy (and vice versa). The device operates in particular as a rotary heat pump. The rotor 1 comprises a rotation axis 2, which is horizontal during operation and for example the rotor 1 is rotated by means of a motor (not shown). The rotor 1 comprises a compressor unit 3, inside which the working medium is guided away from the rotation axis 2 by centrifugal force in order to increase the pressure. Furthermore, the rotor 1 comprises an expansion unit 4, inside which the working medium is guided towards the rotation axis 2 in order to reduce the pressure. The working medium is preferably guided in a closed circuit in the rotor 1. The rotor 1 also comprises a number of internal heat exchangers 5 (low pressure heat exchangers) and a number of external heat exchangers 6 (high pressure heat exchangers). In the internal heat exchanger 5 and the external heat exchanger 6, heat exchange takes place between a first heat exchange medium and a second heat exchange medium, i.e. the working medium. Such an apparatus is shown, for example, in WO 2015 / 103656, which has different types of heat exchange.
[0062] 2A shows a heat exchanger 7, also called heat transfer system, in an embodiment that can be realized with the internal heat exchanger 5 and / or the external heat exchanger 6. The heat exchanger 7 is described below, for example, for use as the external heat exchanger 6, i.e. as a high-pressure heat exchanger. The heat exchanger 7 comprises an inlet element 8, through which the second heat exchange medium, i.e. the working medium, is fed to the heat exchanger 7, and an outlet element 9, through which the second heat exchange medium leaves the heat exchanger 7.
[0063] In the illustrated embodiment, the heat exchanger 7 is designed as a shell-and-tube heat exchanger. The shell-and-tube heat exchanger comprises a cylindrical housing 10 in which a tube bundle is arranged. The tube bundle comprises elongated tubes 11 arranged parallel to each other at a radial and circumferential distance. The tubes 11 comprise in their interior a second heat exchange channel 12 for a second heat exchange medium. The tubes 11 are respectively held at both ends of a tube sheet in the form of a bottom plate 11A (see FIG. 2B). The first heat exchange medium is led into the interior of the housing 10 via a feed line 13 and, after heat exchange with the second heat exchange medium, is discharged from the housing 10 via a discharge line 14. Inside the housing 10, the first heat exchange medium flows in a first heat exchange channel 15 in which a deflection element 16 is formed such that the first heat exchange medium flows alternately in opposite directions across the tubes 11, i.e., alternately downwards and upwards in the position shown. Meanwhile the first heat exchange medium is deflected by means of a deflection element 16 into the adjacent channel.
[0064] As can also be seen in Fig. 2A, between the inlet element 8 and the inlet side of the housing 10, the heat exchanger 7 comprises a distribution element 17 with an inlet opening 17A, which is enlarged in the direction of flow of the second heat exchange medium. Furthermore, between the outlet element 9 and the outlet side of the housing 10, the heat exchanger 7 comprises a merging element 18 with an outlet opening 18A for merging the individual flows of the second heat exchange medium after flowing through the second heat exchange channels 12. The merging element 18 tapers in the direction of flow of the second heat exchange medium.
[0065] FIG. 2B shows the heat exchanger 7 in simplified form, with arrows indicating the gas entry and distribution into the individual second heat exchange channels 12 within the housing 10.
[0066] In principle, the embodiment of the heat exchanger 7 as a shell-and-tube heat exchanger is very advantageous for use with the rotor 1. However, to effectively use the heat transfer surface, it is essential that the flow through the second heat exchange channels 12 is uniform.
[0067] As can be seen from Fig. 3, it is clear that the flow of the second heat exchange medium (see arrows 20) entering the heat exchanger 7 must be divided equally among the separate second flow paths 12, i.e. the tubes of the tube bundle. For this purpose, a flow grid 21 may be arranged in the distribution element 17 with individual distribution channels 22 which expand continuously along the flow grid 21. The distribution channels 22 are designed identically according to Fig. 3 in order to achieve an even distribution.
[0068] However, it has surprisingly been shown that in the rotational state of the rotor 1 under high centrifugal accelerations, a number of phenomena occur which prevent a uniform flow by simply splitting the incoming flow of the second heat exchange medium. It has been recognized that the reason for this is that different densities occur at different radial distances from the center of rotation of the separate second flow passages 12 during the entry and exit of the second heat exchange medium, in this case gas.
[0069] As can be seen in figure 4 with reference to the schematic diagram of the heat exchanger 7 when used as an external (high pressure) heat exchanger 6, heat is intended to be transferred during operation from the second heat exchange medium (hereinafter also called gas for short) to the first heat exchange medium (hereinafter also called liquid or water for short). On the right side the inflow occurs at a relatively high temperature and on the left side the outflow occurs at a relatively low temperature after the heat transfer. This makes the density of the outflow side higher than the density of the inflow side.
[0070] To illustrate the technical effects, the following assumptions and simplifications are made for the model calculations: Average radius of rotation axis: 900mm Radial extension of the heat exchanger 7 (from the innermost of the second heat exchange channel 12 to the outermost of the heat exchange channel 12): 100 mm Average pressure in the heat exchanger: 120bar Average temperature: 400K Gas: Krypton
[0071] If the gas flow is assumed to be ideal, i.e. without taking into account real gas properties, and occurs only under gravitational acceleration, and the heat exchanger is oriented so that the gravitational acceleration has the same direction as the centrifugal acceleration, the pressure difference between the outermost and innermost flow passages is 0.14 mbar and is not taken into account due to minimal effect.
[0072] Figure 5 shows a rough calculation of the pressure difference between the flow paths ("outside" in Figure 4 - arrow 23, "inside" in Figure 4 - arrow 24) in revolutions per minute (rpm), which reveals the effect of rotation on the heat exchanger 7. The radial distance of the outermost channel from the axis of rotation 2 is indicated by arrow 25, and the radial distance of the innermost channel from the axis of rotation 2 is indicated by arrow 26. The main direction of gas flow is indicated by arrow 27. At a speed of the rotor 1 of 1,800 rpm, this difference is 0.46 bar and is therefore about 3,300 times greater than under the acceleration of gravity (corresponding to the ratio of accelerations). As a result, if no other measures are taken, the gas will favor the inner channel, since the gas in the inner region experiences an increase in pressure, while the gas through the outermost channel experiences a decrease in pressure. In addition, reverse flows may occur, as a result of which the gas flows from right to left on the inside and from left to right on the outside. As a result, more flow energy is required and less effective heat exchanger surface is available, since in most cases only the inner area of the heat exchanger is used.
[0073] 6 and 7 show a first embodiment according to the invention of a heat exchanger 7 for an external heat exchanger 6, only the differences with respect to the previous embodiment being explained below.
[0074] In this embodiment, a device 30 for homogenizing the flow through the second heat exchange channel 12 is provided, in order to compensate for the different pressure differences of the second heat exchange medium, which are caused by the different radial distances of the second heat exchange channel 12 from the rotation axis 2 of the rotor 2.
[0075] In the illustrated embodiment, the device 30 for homogenizing the flow through the second heat exchange channels 12 is a throttling device for throttling the individual second heat exchange channels 12 to different degrees, whereby the flow of the second heat exchange medium which is closer to the axis of rotation 2, i.e. which involves a smaller radial distance, is throttled more than the flow of the second heat exchange medium which is further from the axis of rotation 2, i.e. which involves a larger radial distance.
[0076] 6 and 7, the throttle device comprises a disk-shaped throttle orifice plate 31 which is circular in the flow direction of the second heat exchange medium and has a plurality of circular throttle openings 32 arranged immediately upstream of the inlet openings 29 in the second heat exchange channel 12. The throttle openings 32 are arranged in rows, the diameter of the throttle openings 32 increasing from row to row outwards, i.e. away from the axis of rotation 2. Within a row, the throttle openings 32 have the same diameter.
[0077] In the embodiment according to Fig. 8, a flow grid 21 of asymmetric design (with respect to the central axis 36 of the heat exchanger 7) is provided as device 30 for homogenizing the flow through the second heat exchange channels. The distribution channels 22 of the flow grid 21 each have a head portion 22A and an end portion 22B. In the embodiment shown, the flow cross section of the head portion 22A increases with the distance from the axis of rotation 2, while the end portion 22B has the same flow cross section. Between the head portion 22A and the end portion 22B there is a middle portion 22C, which provides a continuous transition from the head portion 22A to the end portion 22B.
[0078] In the embodiment according to Fig. 9, a spiral agitator 33 is inserted in the second heat exchange channel 12. To form the device 30, various spiral agitators 33 are provided, which cause a lower pressure loss in the second heat exchange medium, the further away from the axis of rotation 2. For this purpose, the spiral agitators 33 which are further away from the axis of rotation 2 can include a larger spiral length (see arrow 34) than the agitators 33 which are closer to the axis of rotation 2 (see arrow 35). [Explanation of symbols]
[0079] 1 Rotor 2 Rotation Axis 3 Compression Unit 4. Expansion Unit 5 Internal heat exchanger 6 External heat exchanger 7 Heat exchanger 8 Entry Elements 9 Exit element 10. Housing 11 Tube 11A Tube Sheet 12 Second heat exchange channel 13 Supply Line 14 Discharge Line 15 First heat exchange channel 16 deflection elements 17 Distribution elements 17A Entrance opening 18A exit opening 18 Confluence elements 20 Arrow 21 Flow Grid 22 Distribution Channels 22A Head part 22B Central part 22C end part 23 Arrow 24 Arrow 25 Arrow 26 Arrow 27 Arrow 28 Outlet opening 29 Inflow opening 30 Device for equalizing flow 31 Restriction orifice plate 32 Aperture 33 Agitator 34 Arrow 35 Arrow 36 Central axis?
Claims
1. A heat exchanger (7) for being arranged on a rotor (1) having a rotation axis (2), comprising: a first heat exchange channel (15) for guiding a first heat exchange medium; second heat exchange channels (12) for guiding a second heat exchange medium, the second heat exchange channels (12) including, in an assembled state of use, at least one inner heat exchange channel closer to the axis of rotation (2) and an outer heat exchange channel further away from the axis of rotation (2); a distribution element (17) expanding in the direction of flow of the second heat exchange medium to feed the second heat exchange medium from inlet openings (17A) in the distribution element (17) to inlet openings (29) in the second heat exchange channels (12); a confluence element (18) tapering in a direction of flow of the second heat exchange medium for discharging the second heat exchange medium from an outlet opening (28) of the second heat exchange channel (12) to an outlet opening (18A) of the confluence element (18); Equipped with a device (30) for homogenizing the flow through the second heat exchange channels (12), the device (30) comprising a throttling member for throttling to different degrees an inner flow of the second heat exchange medium through the inner heat exchange channels and an outer flow of the second heat exchange medium through the outer heat exchange channels between the inlet opening (17A) of the distribution element (17) and the outlet opening (18A) of the confluence element (18). Heat exchanger (7).
2. The throttle member comprises a throttle orifice plate (31) having a throttle opening (32); the aperture openings (32) further away from the axis of rotation (2) and the aperture openings (32) closer to the axis of rotation (2) have different dimensions; A heat exchanger (7) according to claim 1, characterized in that it
3. The throttling orifice plate (31) comprises a plurality of rows each having a plurality of throttling openings (32); The rows further away from the axis of rotation (2) and the rows closer to the axis of rotation (2) have apertures (32) of different sizes. A heat exchanger (7) according to claim 2, characterized in that
4. the distribution element (17) comprises a flow grid (21) having individual distribution channels (22) expanding in the direction of flow of the second heat exchange medium, Each of the distribution channels (22) comprises a head portion (22A) and an end portion (22B); A heat exchanger (7) according to any one of claims 1 to 3, characterized in that
5. the head portion (22A) and / or the end portion (22B) of the distribution channel (22) further away from the rotation axis (2) and the head portion (22A) and / or the end portion (22B) of the distribution channel (22) closer to the rotation axis (2) comprise different flow cross sections to form the throttle element, A heat exchanger (7) according to claim 4, characterized in that
6. an agitator (33) is provided in the second heat exchange channel (12) to form the throttle member; The agitators (33) further away from the rotation axis (2) and the agitators (33) closer to the rotation axis (2) cause different pressure losses. A heat exchanger (7) according to claim 1, characterized in that it
7. The agitator (33) is a spiral agitator, The spiral agitators (33) further away from the rotation axis (2) and the spiral agitators (33) closer to the rotation axis (2) have different spiral lengths. A heat exchanger (7) according to claim 6, characterized in that
8. A rotation axis (2), A heat exchanger (7) according to claim 1; A rotor (1) that is a rotary heat pump.
9. 9. Rotor (1) according to claim 8, characterized in that the second heat exchange channels (12) extend parallel to the axis of rotation (2).
10. a compressor unit (3) in which the second heat exchange medium is guided away from the rotating shaft (2) to increase its pressure; an expansion unit (4) in which the second heat exchange medium is guided towards the rotation axis (2) to reduce its pressure; A rotor (1) according to claim 8 or claim 9, characterized by:
11. an internal heat exchanger (5) for the rotating shaft (2); an external heat exchanger (6) for the rotating shaft (2); The rotor (1) according to claim 8, characterized by:
12. The outer heat exchanger (6) is designed according to claim 1, The throttle member is configured to throttle the inner flow of the second heat exchange medium passing through the inner heat exchanger (5) more than the outer flow of the second heat exchange medium passing through the outer heat exchanger (6). A rotor (1) according to claim 11, characterized in that
13. A method for exchanging heat between a first heat exchange medium and a second heat exchange medium inside a rotor (1), comprising: Rotating the rotor (1) around a rotation axis (2), guiding said first heat exchange medium along a first heat exchange channel (15) of a heat exchanger (7); guiding the second heat exchange medium along second heat exchange channels (12) of a heat exchanger (7) at different distances from the rotation axis (2) of the rotor (1); Heat exchange occurs between the first heat exchange medium and the second heat exchange medium along the first heat exchange channel (15) and the second heat exchange channel (12).
1. A method comprising: homogenizing the flow through the second heat exchange channel (12) by throttling the internal flow of the second heat exchange medium closer to the axis of rotation (2) and the external flow of the second heat exchange medium further away from the axis of rotation (2) to different extents; A method characterized by:
14. A heat exchanger (7) as described in claim 1, characterized in that the heat exchanger (7) is a shell-and-tube heat exchanger.
15. A heat exchanger (7) as described in claim 1, characterized in that the first heat exchange medium is a liquid.
16. A heat exchanger (7) as described in claim 1, characterized in that the second heat exchange medium is a gas.
17. A heat exchanger (7) as described in claim 16, characterized in that the gas is an inert gas.
18. A heat exchanger (7) as described in claim 1, characterized in that the distribution element (17) expands conically in the flow direction of the second heat exchange medium to feed the second heat exchange medium from an inlet opening (17A) in the distribution element (17) to an inlet opening (29) in the second heat exchange channel (12).
19. A heat exchanger (7) as described in claim 1, characterized in that the confluence element (18) tapers conically in the flow direction of the second heat exchange medium to discharge the second heat exchange medium from the outlet opening (28) of the second heat exchange channel (12) to the outlet opening (18A) of the confluence element (18).
20. A heat exchanger (7) as described in claim 2, characterized in that the orifice plate (31) has the throttling opening (32) upstream of the inlet opening (29) or downstream of the outlet opening (28).