A pure air regenerative heater for a hypersonic wind tunnel

Abstract

The present application relates to the field of hypersonic ground test, disclose a kind of pure air regenerative heater for hypersonic wind tunnel, inner shell is equipped with heat accumulator, several heating channels and air channels are equipped on heat accumulator, several heating rods are correspondingly assembled in several heating channels, and the free space of stop sheet is all capped on several heating channels, so that temperature distribution of heat accumulator is uniform in heating process, while reducing the internal thermal stress of heat accumulator, the temperature uniformity of heated gas is increased, one end of several air channels is communicated with the air inlet of inlet end cover, the other end is communicated with the air outlet of outlet end cover, several heating channels and air channels are independent channels, high-temperature metal is closed using heat accumulator, the contact between airflow and high-temperature metal is reduced in heating process, prolongs the service life of heater. By extending into the shell and contacting with the wire through terminal post, inductive heating mode is adopted, and the working efficiency of the heater is improved.

Description

Technical Field

[0001] This invention relates to the field of hypersonic ground testing, specifically to a pure air regenerative heater for hypersonic wind tunnels. Background Technology

[0002] Ground testing of scramjet engines requires simulating real high-altitude, high-speed flight conditions, necessitating test facilities capable of providing matching high-temperature, high-pressure test airflow. Simulating total temperature is particularly crucial and important, and also one of the most challenging aspects of the entire test. Existing ground test equipment commonly employs heating methods including combustion heating, shock wave heating, electric arc heating, and regenerative heating technologies.

[0003] Regenerative heating ground test facilities can raise the temperature of the heat storage medium to a high temperature through combustion preheating or electric heating, storing the heat in the heat storage medium. In contrast, regenerative heating ground test facilities rely on heat exchange between the heat storage medium and the incoming airflow to obtain the high-enthalpy gas flow required for the test during the entire heating process, thus obtaining a relatively pure high-enthalpy test gas flow.

[0004] Most existing regenerative heaters heat the accumulator body through combustion preheating or resistance heating to achieve heat storage. Considering that combustion heating still produces reactants inside the heater (combustion chamber), the purity of the high-enthalpy air obtained by this type of heat storage method needs further improvement. Resistance heating, on the other hand, suffers from low heating efficiency, long heating time, and high power consumption, and it easily generates temperature gradients within the accumulator body, resulting in a less uniform temperature field. Summary of the Invention

[0005] In order to overcome the defects of the prior art, the present invention aims to provide a pure air regenerative heater for hypersonic wind tunnels, so as to solve the technical problems of low purity of high enthalpy air obtained by combustion preheating, low heating efficiency of resistance heating, long heating time, high power consumption, and low uniformity of temperature field obtained by regenerative heaters in the prior art.

[0006] This invention is achieved through the following technical solution:

[0007] A pure air regenerative heater for hypersonic wind tunnels includes several terminals, an inlet end cap, an outer shell, an insulation layer unit, wires, an inner shell, a heat storage body, several heating rods, a stop plate, and an outlet end cap. Both the inner and outer shells are cylindrical, with the inner shell fitted inside the outer shell. The insulation layer unit is assembled between the outer wall of the inner shell and the inner wall of the outer shell. The wires are disposed within the insulation layer unit. The inlet and outlet end caps are respectively installed at both ends of the outer shell, and the inlet end cap has several terminal mounting holes, thermocouple connection holes, and an air inlet. The several terminals are used for mounting... The hole extends into the outer shell and connects to the wire. The outlet end cap is provided with an air outlet. The heat storage body is cylindrical and horizontally assembled in the inner shell. The heat storage body is provided with several heating channels and air channels. Several heating rods are correspondingly assembled in several heating channels. One end of several air channels is connected to the air inlet of the inlet end cap, and the other end is connected to the air outlet of the outlet end cap. The stop plate is assembled between the heat storage body and the outlet end cap. The stop plate is provided with several axial air through holes. The several axial air through holes are connected to several air channels of the heat storage body, and the remaining space of the stop plate is sealed on several heating channels.

[0008] Preferably, the heating channels and air channels provided on the heat storage body are all centered on the center of the heat storage body, and the heating channels and air channels are arranged in a ring structure and staggered along the radial direction of the heat storage body.

[0009] Preferably, the heating rod is a slender cylindrical magnetic metal, and the heating rod is positioned inside the heating channel, abutting against the empty space of the stop plate.

[0010] Preferably, the stop plate has a cylindrical thin sheet structure, with a number of axial air passages centered on the center of the stop plate, and the number of axial air passages are arranged in a number of ring structures distributed along the radial direction of the stop plate, wherein the diameter of the axial air passages corresponds to the diameter of the air channel of the heat storage body.

[0011] Preferably, the inner shell has longitudinal protrusions at both ends on the side near the inlet end cover, forming a semi-closed structure. One end of the heat storage body is axially positioned inside the inner shell at the position of the longitudinal protrusion. The side of the inner shell near the outlet end cover is covered with a heat storage body end cover. The other end of the heat storage body is positioned on the heat storage body end cover by a stop piece. The structure of the heat storage body end cover is a stepped cylindrical structure, wherein the small-diameter outer surface of the heat storage body end cover is in contact with the inner surface of the inner shell.

[0012] Furthermore, isolation blocks are provided at both ends of the inner shell. The isolation blocks have a stepped cylindrical structure. The small-diameter surface of the isolation block near the inlet end cover contacts the longitudinal protrusion of the inner shell, and the large-diameter surface of the isolation block contacts the inner surface of the outer shell. The isolation block near the inlet end cover is provided with a through hole for the insertion of the terminal block. The small-diameter surface of the isolation block near the outlet end cover contacts the outer surface of the heat storage body end cover, and the large-diameter surface of the isolation block contacts the inner surface of the outer shell.

[0013] Preferably, the insulation layer unit includes an outer insulation layer and an inner insulation layer. The inner insulation layer is laid on the outer surface of the inner shell, and the wire is wound around the inner insulation layer. The outer insulation layer is laid on the inner insulation layer and wraps the wire around the inner insulation layer.

[0014] Preferably, the terminal mounting hole on the inlet end cover is tapered from the outside to the inside. One end of the terminal is connected to an external power source, and the other end is connected to a wire through the terminal mounting hole. A terminal sealing ring is provided between the terminal and the terminal mounting hole.

[0015] Furthermore, the terminal block includes an outlet connection section, a threaded section, a conical section, a cylindrical section, and a wiring section, wherein the outlet connection section is connected to an external power source, and the wiring section is connected to a wire; the threaded section, the conical section, and the cylindrical section are correspondingly arranged with the conical surfaces of the terminal block mounting holes.

[0016] Furthermore, the air inlet of the inlet end cover, several air channels of the heat storage body, several axial air through holes of the stop plate, and the air outlet of the outlet end cover are all horizontally arranged.

[0017] Compared with the prior art, the present invention has the following beneficial technical effects:

[0018] This invention provides a pure air regenerative heater for hypersonic wind tunnels. The inner shell houses a heat storage body with several heating channels and air channels. Several heating rods are correspondingly installed within these heating channels, and the remaining space of the stop plates covers all the heating channels, ensuring uniform temperature distribution within the heat storage body during heating. This reduces internal thermal stress and increases the temperature uniformity of the heated gas. One end of each air channel connects to the air inlet of the inlet end cap, and the other end connects to the air outlet of the outlet end cap. Both the heating channels and air channels are independent. The heat storage body effectively encloses the high-temperature metal, reducing contact between the airflow and the high-temperature metal during heating and extending the heater's lifespan. Induction heating is employed through terminals extending into the shell to contact the wires, improving the heater's efficiency, effectively reducing test preparation time, and increasing test efficiency.

[0019] Furthermore, the heating channels and air channels provided on the heat storage body are all centered on the center of the heat storage body, and the heating channels and air channels are arranged in a ring structure and staggered along the radial direction of the heat storage body, so that the heating channels and air channels can form independent channels, reducing the contact between the airflow and the high-temperature metal during the heating process and extending the service life of the heater.

[0020] Furthermore, the heating rod is a slender cylindrical magnetic metal. The heating rod is positioned inside the heating channel and abuts against the space of the stop plate, which reduces the contact between air and the heating rod, reduces the oxidation of the heating rod, and thus improves the service life of the heater.

[0021] Furthermore, the stop plate has a cylindrical thin sheet structure, with several axial air passages centered on the center of the stop plate. These axial air passages are arranged in several annular structures distributed along the radial direction of the stop plate. The diameter of the axial air passages corresponds to the size of the air channels in the heat storage body, which facilitates airflow within the heater and enables heat exchange through airflow.

[0022] Furthermore, the inner shell has longitudinal protrusions at both ends on the side near the inlet end cover, forming a semi-closed structure. One end of the heat storage body is axially positioned inside the inner shell at the longitudinal protrusion position. The side of the inner shell near the outlet end cover is covered with a heat storage body end cover, which facilitates the axial positioning of the heat storage body, heating rod, and stop plate, and improves the stability of the internal equipment of the heater.

[0023] Furthermore, isolation blocks are provided at both ends of the inner shell to prevent the inlet end cover and outlet end cover from getting too close to the heat storage body during the heating process, which would cause the end cover temperature to be too high, thus improving the protection of the inlet end cover and outlet end cover.

[0024] Furthermore, the insulation unit includes an outer insulation layer and an inner insulation layer. The inner insulation layer is laid on the outer surface of the inner shell, and the wire is wound around the inner insulation layer. The outer insulation layer is laid on the inner insulation layer and wraps the wire around the inner insulation layer to prevent heat loss during the heating process and improve the protection of the wire.

[0025] Furthermore, the terminal mounting holes on the inlet end cover are tapered from the outside to the inside. One end of the terminal is connected to an external power source, and the other end is connected to a wire through the terminal mounting hole. The terminal includes an outlet wiring section, a threaded section, a tapered section, a cylindrical section, and a wiring segment. The outlet wiring section is connected to the external power source, and the wiring segment is connected to the wire. The threaded section, tapered section, and cylindrical section are arranged to correspond to the tapered surface of the terminal mounting hole, which improves the sealing performance of the inlet end cover to the housing. Attached Figure Description

[0026] Figure 1This is a schematic diagram of the overall structure of the pure air heat storage heater of the present invention;

[0027] Figure 2 This is a partially enlarged schematic diagram of the present invention;

[0028] Figure 3 This is a partially enlarged view of the terminal assembly of the present invention;

[0029] Figure 4 This is a schematic diagram of the inlet end cap structure of the present invention;

[0030] Figure 5 This is a side view of the inlet end cap structure of the present invention;

[0031] Figure 6 This is a schematic diagram of the inner shell structure of the present invention;

[0032] Figure 7 This is a schematic diagram of the end face of the heat storage body of the present invention;

[0033] Figure 8 This is a schematic diagram of the inlet isolation block structure of the present invention;

[0034] Figure 9 This is a schematic diagram of the side structure of the inlet isolation block of the present invention;

[0035] Figure 10 This is a schematic diagram of the stop plate structure of the present invention;

[0036] In the diagram: 1-Terminal; 2-Inlet end cap; 3-Isolation block; 4-Outer shell; 5-Outer insulation layer; 6-Wire; 7-Inner insulation layer; 8-Inner shell; 9-Heat storage body; 10-Heating rod; 11-Stop plate; 12-Heat storage body end cap; 13-Outlet end cap; 14-Terminal sealing ring; 15-Air outlet; 21-Thermocouple connection hole; 22-Terminal connection hole; 23-Air inlet; 31-Terminal through hole. Detailed Implementation

[0037] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0038] The present invention will now be described in further detail with reference to the accompanying drawings:

[0039] The purpose of this invention is to provide a pure air regenerative heater for hypersonic wind tunnels, in order to solve the technical problems of low purity of high enthalpy air obtained by combustion preheating, low heating efficiency of resistance heating, long heating time, high power consumption, and low uniformity of temperature field obtained by existing regenerative heaters.

[0040] Specifically, according to Figure 1 As shown, the pure air heat storage heater includes several terminals 1, an inlet end cap 2, an outer shell 4, an insulation layer unit, wires 6, an inner shell 8, a heat storage body 9, several heating rods 10, a stop plate 11, and an outlet end cap 13. Both the inner shell 8 and the outer shell 4 are cylindrical, with the inner shell 8 fitted inside the outer shell 4. The insulation layer unit is assembled between the outer wall of the inner shell 8 and the inner wall of the outer shell 4. The wires 6 are disposed within the insulation layer unit. The inlet end cap 2 and the outlet end cap 13 are respectively installed at both ends of the outer shell 4. The inlet end cap 2 has several terminal mounting holes 22, thermocouple connection holes 21, and an air inlet 23. Several terminals 1 extend through the several terminal mounting holes 22. The heat storage body 9 is cylindrical and horizontally assembled inside the inner shell 8. The heat storage body 9 is provided with several heating channels and air channels. Several heating rods 10 are correspondingly assembled in several heating channels. One end of several air channels is connected to the air inlet 23 of the inlet end cover 2, and the other end is connected to the air outlet 15 of the outlet end cover 13. The stop plate 11 is assembled between the heat storage body 9 and the outlet end cover 13. The stop plate 11 is provided with several axial air through holes. The several axial air through holes are connected to several air channels of the heat storage body 9, and the empty space of the stop plate 11 is sealed on several heating channels.

[0041] Specifically, according to Figure 7 As shown, the heating channels and air channels provided on the heat storage body 9 are all centered on the center of the heat storage body 9, and the heating channels and air channels are arranged in a ring structure and staggered along the radial direction of the heat storage body 9.

[0042] The heat storage body 9 has N levels of circular heating channels and air channels distributed from the center to the edge, with each level of heating channels and air channels being staggered. The pitch circle of each level of the circular structure in the heat storage body 9 is centered on the center of the heat storage body, and the distance between adjacent pitch circles is the radius of the pitch circle of the second-level through-hole. The difference in the number of through-holes between two adjacent levels of the heat storage body 9 is the number of through-holes in the second level. The heat storage body 9 is made of high-purity alumina.

[0043] Specifically, the heating rod 10 is a slender cylindrical magnetic metal that can be used for induction heating; the heating rod 10 is positioned inside the heating channel and abuts against the empty space of the stop plate 11.

[0044] Specifically, according to Figure 10 As shown, the stop plate 11 has a cylindrical thin sheet structure. Several axial air passages are arranged with the center of the stop plate 11 as the center of the circle, and the several axial air passages are arranged in several ring structures distributed along the radial direction of the stop plate 11. The number of ring structures of the stop plate 11 is N / 2 levels. The pitch circle of each level of axial air passage is equal to that of the air channel of the heat storage body 9, and the diameter is the same. The material of the stop plate 11 is high-purity alumina.

[0045] Specifically, according to Figure 2 and Figure 6 As shown, the inner shell 8 has longitudinal protrusions at both ends near the inlet end cap 2, forming a semi-enclosed structure. One end of the heat storage body 9 is axially positioned within the inner shell 8, abutting against the longitudinal protrusion. A heat storage body end cap 12 is provided on the side of the inner shell 8 near the outlet end cap 13. The other end of the heat storage body 9 is positioned against the heat storage body end cap 12 via a stop piece 11. The heat storage body end cap 12 has a stepped cylindrical structure, with its small-diameter outer surface in contact with the inner surface of the inner shell 8. The inner shell 8 is made of high-temperature resistant metal to enhance the pressure resistance of the heater.

[0046] The inner shell 8 has isolation blocks 3 at both ends. The isolation blocks 3 are stepped cylindrical structures. The small-diameter surface of the isolation block 3 near the inlet end cover 2 contacts the longitudinal protrusion of the inner shell 8, and the large-diameter surface of the isolation block 3 contacts the inner surface of the outer shell 4. The isolation block 3 near the inlet end cover 2 has a through hole for the insertion of the terminal 1. The small-diameter surface of the isolation block 3 near the outlet end cover 13 contacts the outer surface of the heat storage body end cover 12, and the large-diameter surface of the isolation block 3 contacts the inner surface of the outer shell 4. The isolation blocks 3 effectively prevent the inlet end cover 2 and the outlet end cover 13 from getting too close to the heat storage body 9 during the heating process, which would cause the end cover temperature to be too high and damage the inlet end cover 2 and the outlet end cover 13.

[0047] Specifically, according to Figure 2 As shown, the insulation layer unit includes an outer insulation layer 5 and an inner insulation layer 7. The inner insulation layer 7 is laid on the outer surface of the inner shell 8. The wire 6 is wound around the inner insulation layer 7. The outer insulation layer 5 is laid on the inner insulation layer 7 and wraps the wire 6 around the inner insulation layer 7.

[0048] Specifically, according to Figure 4 and Figure 5As shown, the inlet end cap 2 has a stepped shape, with its smallest diameter equal to the inner diameter of the outer casing. It is installed on the end face of the outer casing and connected using a flange. Its end face includes two terminal block connection holes 22 and one thermocouple connection hole 21, used for connecting the terminal block and the thermocouple, respectively. The terminal block connection hole 22 extends from a conical surface to a flat surface from the inside out, and its conical angle and length match the terminal block. The outlet end cap has a similar configuration to the inlet end cap, and includes a terminal block through hole 31 to remove the two terminal block mounting holes, as shown. Figure 8 and Figure 9 As shown.

[0049] Among them, according to Figure 3 As shown, one end of terminal 1 is connected to an external power source, and the other end is connected to wire 6 through terminal mounting hole 22; wherein, a terminal sealing ring 14 is provided between terminal 1 and terminal mounting hole 22.

[0050] The terminal block 1 includes an outlet connection section, a threaded section, a conical section, a cylindrical section, and a connecting section. The outlet connection section is connected to an external power source, and the connecting section is connected to the wire 6. The threaded section, the conical section, and the cylindrical section are set to correspond to the conical surfaces of the terminal block mounting holes 22.

[0051] The present invention provides the working principle of a pure air regenerative heater for hypersonic wind tunnels:

[0052] Terminal 1 connects to an external high-frequency AC power source, thereby generating high-frequency AC current in conductor 6. Since the heat storage body 9 contains a heating rod 10, circulating eddy currents are generated inside the heating rod 10. These currents counteract the resistivity of the heating rod 10, generating localized heat in the middle of the heating rod. The heat is then conducted to the heat storage body 9 through the contact between the heating rod 10 and the heat storage body 9, raising the temperature of the heat storage body 9. Once the heating temperature meets the experimental requirements, pure cold air is allowed to circulate through the airflow channels of the heat storage body 9, exchanging heat with the heat storage body, thus achieving the purpose of heating the pure air.

[0053] In summary, this invention provides a pure air regenerative heater for hypersonic wind tunnels. The inner shell houses a heat storage body with several heating channels and air channels. Several heating rods are correspondingly installed within these heating channels, and the remaining space of the stop plates covers all the heating channels, ensuring uniform temperature distribution within the heat storage body during heating. This reduces internal thermal stress and increases the temperature uniformity of the heated gas. One end of each air channel connects to the air inlet of the inlet end cap, and the other end connects to the air outlet of the outlet end cap. Both the heating channels and air channels are independent. The heat storage body effectively encloses the high-temperature metal, reducing contact between the airflow and the high-temperature metal during heating and extending the heater's lifespan. Induction heating is employed by extending terminals into the shell to contact the wires, improving the heater's efficiency, effectively reducing test preparation time, and increasing test efficiency.

[0054] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A pure air regenerative heater for hypersonic wind tunnels, characterized in that, It includes several terminals (1), an inlet end cap (2), an outer shell (4), an insulation layer unit, wires (6), an inner shell (8), a heat storage body (9), several heating rods (10), a stop plate (11), and an outlet end cap (13); the inner shell (8) and the outer shell (4) are both cylindrical structures, with the inner shell (8) fitted inside the outer shell (4). The insulation layer unit is assembled between the outer wall of the inner shell (8) and the inner wall of the outer shell (4). The wires (6) are arranged inside the insulation layer unit. The inlet end cap (2) and the outlet end cap (13) are respectively covered at both ends of the outer shell (4), and the inlet end cap (2) is provided with several terminal mounting holes (22), thermocouple connection holes (21), and an air inlet (23); the several terminals (1) extend through the several terminal mounting holes (22). The heat storage body (9) is cylindrical and horizontally assembled in the inner shell (8). The heat storage body (9) is provided with several heating channels and air channels. Several heating rods (10) are correspondingly assembled in several heating channels. One end of several air channels is connected to the air inlet (23) of the inlet end cover (2), and the other end is connected to the air outlet (15) of the outlet end cover (13). The stop plate (11) is assembled between the heat storage body (9) and the outlet end cover (13). The stop plate (11) is provided with several axial air through holes. The several axial air through holes are connected to several air channels of the heat storage body (9), and the empty space of the stop plate (11) is sealed on several heating channels. The inner shell (8) has longitudinal protrusions at both ends on the side near the inlet end cap (2) to form a semi-closed structure. One end of the heat storage body (9) is axially positioned inside the inner shell (8) at the longitudinal protrusion position of the inner shell (8). The side of the inner shell (8) near the outlet end cap (13) is covered with a heat storage body end cap (12). The other end of the heat storage body (9) is positioned on the heat storage body end cap (12) by a stop piece (11). The structure of the heat storage body end cap (12) is a stepped cylindrical structure, wherein the small-diameter outer surface of the heat storage body end cap (12) is in contact with the inner surface of the inner shell (8). The terminal mounting hole (22) is set in a conical shape from the outside to the inside on the inlet end cover (2). One end of the terminal (1) is connected to an external power source, and the other end is connected to a wire (6) through the terminal mounting hole (22). A terminal sealing ring (14) is provided between the terminal (1) and the terminal mounting hole (22).

2. The pure air regenerative heater for hypersonic wind tunnels according to claim 1, characterized in that, The heating channels and air channels provided on the heat storage body (9) are all centered on the center of the heat storage body (9), and the heating channels and air channels are arranged in a ring structure and staggered along the radial direction of the heat storage body (9).

3. A pure air regenerative heater for hypersonic wind tunnels according to claim 1, characterized in that, The heating rod (10) is a slender cylindrical magnetic metal, and the heating rod (10) is positioned in the heating channel and abuts against the empty space of the stop plate (11).

4. A pure air regenerative heater for hypersonic wind tunnels according to claim 1, characterized in that, The stop plate (11) has a cylindrical thin sheet structure. Several axial air passages are arranged with the center of the stop plate (11) as the center, and the several axial air passages are arranged in several ring structures distributed along the radial direction of the stop plate (11). The axial air passages correspond to the aperture size of the air channel of the heat storage body (9).

5. A pure air regenerative heater for hypersonic wind tunnels according to claim 1, characterized in that, The inner shell (8) is provided with isolation blocks (3) at both ends. The isolation blocks (3) are stepped cylindrical structures. The small diameter surface of the isolation block (3) on the side near the inlet end cover (2) contacts the longitudinal protrusion of the inner shell (8), and the large diameter surface of the isolation block (3) contacts the inner surface of the outer shell (4). The isolation block (3) on the side near the inlet end cover (2) is provided with a through hole for the insertion of the terminal (1). The small diameter surface of the isolation block (3) on the side near the outlet end cover (13) contacts the outer surface of the heat storage body end cover (12), and the large diameter surface of the isolation block (3) contacts the inner surface of the outer shell (4).

6. A pure air regenerative heater for a hypersonic wind tunnel according to claim 1, characterized in that, The insulation layer unit includes an outer insulation layer (5) and an inner insulation layer (7). The inner insulation layer (7) is laid on the outer surface of the inner shell (8). The wire (6) is wound on the inner insulation layer (7). The outer insulation layer (5) is laid on the inner insulation layer (7) and wraps the wire (6) on the inner insulation layer (7).

7. A pure air regenerative heater for hypersonic wind tunnels according to claim 1, characterized in that, The terminal block (1) includes an outlet connection section, a threaded section, a conical section, a cylindrical section and a connection section, wherein the outlet connection section is connected to an external power source and the connection section is connected to a wire (6); the threaded section, the conical section, and the cylindrical section are set to correspond to the conical surface of the terminal block mounting hole (22).

8. A pure air regenerative heater for a hypersonic wind tunnel according to claim 1, characterized in that, The air inlet (23) of the inlet end cap (2), several air channels of the heat storage body (9), several axial air through holes of the stop plate (11) and the air outlet (15) of the outlet end cap (13) are all horizontally arranged.

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