KR100530692B1 - Turbo machine - Google Patents

Abstract

The present invention relates to a cooling structure of the heating portion of a turbomachine (turbo compressor, turbo blower) that rotates at high speed. In particular, the turbomachine according to the present invention includes a drive shaft, a rotor integrally press-fitted with the drive shaft, and the rotor. A drive unit including a stator having an inner circumferential surface spaced apart from the outer circumferential surface by an air gap; A support comprising a casing, a drive support for supporting the drive, a bearing, and a bearing housing; A compression unit comprising an impeller connected to the drive shaft, an air circulation passage for circulating air to the front suction side of the impeller, a diffuser installed on a rear outer circumferential surface of the impeller, a shroud communicating with the diffuser, and a volute casing; And an air inlet formed at one side of the casing, an air discharge ring provided adjacent to the side end of the rotor, and air formed inside the stator such that air flows from the outer circumferential surface of the stator toward the outer circumferential surface of the rotor. A cooling unit including an inlet hole and a heat dissipation fin formed on an outer side of the stator; Characterized in that it comprises a.

Description

Turbo machine

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbo machine, such as a turbo compressor and a turbo blower, which rotates at high speed, and more particularly, to a cooling structure of a heating part of a turbo machine. In order to discharge heat generated from the rotor by forced convection through an air gap between the rotor and the stator, at the cylindrical end of the rotor, that is, on one side of the end ring A turbo machine is provided for installing a fan and allowing air to be supplied to and circulated in the air gap.

In general, turbomachines such as turbo compressors and turbo blowers, which are characterized by high efficiency and light weight, have been used to realize high-speed rotation by using a gearbox for a constant speed motor, but recently high speed bearing and high speed inverter (Invertor) technology, etc. Power generation has made it possible to commercialize the technology of directly rotating the motor at high speed.

Conventional turbomachines, as shown in FIG. 1, have an impeller 131 on one side of a shaft 111 integral with a rotor 112 and bearings 126a, 126b, and 127. Is installed, and the impeller, which obtains the rotational force by the rotation of the rotor connected to the shaft, rotates at a high speed (usually tens of thousands of RPM or more) and is compressed by passing through a diffuser (132) by the centrifugal force (Gas). ) Is collected in a volute casing 134 and discharged to the outside.

The shaft 111, the rotor 112, the bearings 126a, 126b, 127, and the impeller 131 are supported by bearing housings 124a and 124b fixed to the casing 121. Rotate without leaving the track.

However, since the power of the motor is the product of rotational speed and torque, and the size of the motor is proportional to the torque, the high speed motor is much smaller than the regular constant speed motor of the same capacity, resulting in insufficient motor heat dissipation area. Therefore, it is important to cool the heat generated by the motor.

In order to solve the problem of efficiency degradation and reliability caused by heat generation of the motor as described above, conventionally, a casing 121 is installed on the outer circumferential surface of the stator 113 as shown in FIG. 1, and a motor heat dissipation fin ( Fin; 123 is installed and cooled by forced convection using a fan (142), or a cooling jacket (150) between the casing 121 and the outer peripheral surface of the stator (Stator 113) as shown in FIG. Has been attempted to circulate water for cooling.

However, the cooling structure shown in FIG. 1 is simple but directly cools the stator 113, the rotor 112, the coil 114, and the bearing portions 126a, 126b, and 127 of the motor, which generate heat. Instead, all of the heat generated is cooled only through the pins 123 installed in the casing 121, so that sufficient cooling is difficult.

In addition, since the cooling structure shown in FIG. 2 is water-cooled, it is effective for cooling, but the inconvenience of additionally requiring a water circulation device due to the need to circulate the cooling water, and requires a separate power source for water circulation, increases operating costs. There is a problem.

In order to solve the problems as described above, the configuration as shown in Figure 3 has been proposed.

As shown in Fig. 3, the turbomachine according to the present invention shows the overall configuration in which the drive / support and the compression section are each configured separately and are coupled by thermal cutoff gaps 260a and 260b.

At this time, the drive unit is composed of a motor consisting of a drive shaft 211 and the rotor 212 and the stator 213, the support is formed for their support and protection.

An air inlet 241 is installed on one side of the casing 221 surrounding the outside, which is one element of the support, and an air circulation passage 236a is provided on the other side after the sucked air cools the inside. 236b).

The suction port is provided on the outer circumferential surface of the stator 213 and the bearing housings 224a and 224b in the turbomachine by installing the first heat dissipation fin 214 and the second heat dissipation fin 225a and 225b to facilitate heat exchange. Air sucked in through the cooling fins (214, 225a, 225b) and the coil of the stator 213 directly cools.

In addition, the compression unit consisting of the impellers (231a, 231b), diffusers (232a, 232b), shrouds (233a, 233b) and the volute casings (234a, 234b) are formed symmetrically on both sides of the drive shaft, respectively In addition, the air discharged through the air circulation passages 236a and 236b is sucked up, compressed or compressed by a predetermined pressure, and then discharged.

At this time, when the turbo machine is operated, power generated by the induced current of the rotor 212 and the stator 213 of the driving unit is transmitted to the impellers 231a and 231b through the driving shaft 211. As the impeller rotates, the air sucked by the air rises the static pressure inside the impeller and at the same time passes through the diffusers 232a and 232b with centrifugal force, which causes the kinetic energy to rise in the pressure head and the compressed high temperature. The high pressure air is collected and discharged from the volute casings 234a and 234b.

Therefore, in the configuration disclosed in FIG. 3, heat-compression gaps 260a and 260b installed between the seal surfaces 235a and 235b and the support are formed by the heat of the compression unit that is hot due to the compressed and discharged high-temperature high-pressure air. By being blocked by), heat is prevented from being transferred into the casing 221 through the bearing housings 224a and 224b, and the casing has a double structure, thereby directly cooling the stator and the bearings, which are heat generating parts, with the air sucked in. It is possible to provide an efficient and convenient cooling structure.

However, in the embodiment shown in FIG. 3, the heat dissipation of the stator outer circumferential surface is efficient, but the air gap between the stator inner circumferential surface and the rotor outer circumferential surface does not provide smooth heat dissipation. The end ring of the end is melted, or the heat transfer by conduction occurs to the rotating shaft and the bearing portion that is integrally pushed into the rotor, and the bearing portion is pressed.

The present invention provides an efficient and convenient cooling structure that directly cools the stator and bearings, which are heat generating parts, to the intake air by using a casing in a double structure to solve the problems as described above, as well as in the rotor of the motor. The object of the present invention is to prevent the deterioration of efficiency due to heat loss and reliability of the turbomachinery by allowing the generated heat to be forced to convection through an air gap between the rotor and the stator.

In order to achieve the above object, a turbo machine according to the present invention includes a drive unit including a drive shaft, a rotor integrally pressurized with the drive shaft, and a stator having an inner circumferential surface spaced apart from the rotor outer circumferential surface by an air gap. Wow; A support comprising a casing, a drive support for supporting the drive, a bearing, and a bearing housing; A compression unit comprising an impeller connected to the drive shaft, an air circulation passage for circulating air to the front suction side of the impeller, a diffuser installed on a rear outer circumferential surface of the impeller, a shroud communicating with the diffuser, and a volute casing; And an air inlet formed at one side of the casing, an air discharge ring provided adjacent to the side end of the rotor, and air formed inside the stator such that air flows from the outer circumferential surface of the stator toward the outer circumferential surface of the rotor. And a cooling unit including an inlet hole and a heat dissipation fin formed on an outer side of the stator.

According to a preferred embodiment of the present invention, one of forming the cooling unit of the turbo machine is an air discharge ring is installed in the form surrounding the outer circumferential surface of the rotor end ring, the overall configuration is a plurality of outer circumferential surface of the air discharge ring It is manufactured by a fan provided with a spiral protrusion, or by forming a plurality of through holes in the circumferential direction of the air discharge ring to discharge the air.

Hereinafter, the configuration and operation of the turbomachine according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 4 is a view showing an embodiment of a turbomachine according to the present invention, and shows an overall configuration in which a drive unit / support unit and a compression unit are combined in separate configurations, and the drive unit 11 and the rotor 12 are shown in FIG. ) And a motor composed of a stator 13 and a support part is formed for their support and protection.

An air intake port 41 is installed on one side of the casing 21 surrounding the outside, which is an element of the support, and an air circulation passage 36a is provided on the other side after the intake air cools the inside. Through 36b).

By installing a heat dissipation fin 14 on the outer circumferential surface of the stator 13 in the turbomachine to facilitate heat exchange, the air sucked through the air inlet 41 is coiled by the heat dissipation fin 14 and the stator 13. Will be cooled directly.

In addition, the compression unit consisting of the impeller (31a, 31b), diffusers (32a, 32b), shrouds (33a, 33b) and the volute casings (34a, 34b) are formed symmetrically at both ends of the drive shaft, respectively, the air circulation The air discharged through the passages 36a and 36b is sucked up and then increased or compressed by a predetermined pressure and then discharged.

At this time, when the turbo machine is operated, power generated by the induced current of the rotor 12 and the stator 13 of the driving unit is transmitted to the impellers 31a and 31b through the drive shaft 11. As the impeller rotates, the sucked air increases the static pressure inside the impeller and at the same time passes through the diffusers 32a and 32b with the centrifugal force, the kinetic energy is led to the rise of the pressure head by the centrifugal force. Air is collected and discharged from the volute casings 34a and 34b.

In addition, the heat of the compression unit, which is high temperature due to the compressed and discharged high-temperature air, is blocked by the seal surfaces 35a and 35b, so that the heat is introduced into the casing 21 through the bearing housings 24a and 24b. This will prevent it from being delivered.

At this time, the drive shaft is press-fitted into the rotor by heat shrinkage, the air gap 15 of the rotor outer peripheral surface and the stator inner peripheral surface is a predetermined interval exists.

Therefore, the air sucked through the air inlet 41 installed on one side of the casing 21 performs heat exchange on the heat dissipation fin 14 outside the stator to cool the stator 13, and inside the turbomachine. It is also cooled by circulating air. At this time, a part of the air circulating inside the turbo machine is introduced into the air gap 15 between the rotor outer peripheral surface and the stator inner peripheral surface through an air inlet hole 42 inlet of the stator outer peripheral surface. After cooling the air gap is discharged through both ends of the rotor 12 is a heat radiation is made.

Figure 4 also shows the concept of heat dissipation through the air gap as described above, showing the air inlet 42 and the flow of air installed through the stator.

As shown in FIG. 4, the air inlet hole 42 of the stator is formed inside the stator so that air flows from the outer circumferential surface of the stator toward the outer circumferential surface of the rotor, thereby forming the air inlet 41. Part of the air sucked through it serves to directly supply to the outer peripheral surface of the rotor.

As described above, the motor cooling method by the air inlet 42 and the air discharge ring 43a, 43b of the stator is important for heat dissipation inside the motor as compared to the cooling fin that can only cool the outside of the conventional motor In particular, by installing a plurality of spiral projections on the outer circumferential surface of the air discharge ring (43a, 43b), or by forming a plurality of through holes in the circumferential direction of the air discharge ring, to discharge the air after heat exchange A greater effect can be obtained.

This is generally known, since the hourly heat transfer rate (ΔQ / Δt) of the object is proportional to the temperature change per hour (ΔT) and the mass flow rate (Δm / Δt), so for a motor having the same heat generation, the air passing through the air gap As the mass flow rate increases, the temperature change decreases, which eventually prevents the temperature rise inside the motor. That is, the desired cooling effect can be obtained without increasing the air gap.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and the scope of application of the present invention is not limited thereto, and may be appropriately changed within the scope of the same idea.

As described above, the present invention is a simple air-cooled cooling method, but sufficient cooling is achieved, and in particular, the bearings can be kept at a low temperature by direct cooling, which is particularly effective in improving the reliability of a high-speed turbomachine applying a gas bearing. The mechanical friction and heat loss can be minimized, resulting in improved efficiency.

1 is a view showing a first embodiment of a conventional general turbo mechanical cooling structure,

2 is a view showing a second embodiment of a conventional general turbomachine cooling structure,

3 is a view showing a third embodiment of a conventional general turbomachine cooling structure.

4 is a view showing an embodiment of a turbo mechanical cooling structure according to the present invention.

<Description of the code | symbol about the principal part of drawing>

11: drive shaft 12: rotor

13: stator 14: heat sink fin

15: air gap 21: casing

22: drive support 24a, 24b: bearing housing

26a, 26b: radial bearing 27: thrust bearing

31a, 31b: impeller 32a, 32b: diffuser

33a, 33b: shroud 34a, 34b: volute casing

35a, 35b: seal side 36a, 36b: air circulation passage

41: air inlet 42: air inlet

43a, 43b: air outlet ring

Claims (1)

A drive unit comprising a drive shaft, a stator having a rotor integrally pushed into the drive shaft, and an inner circumferential surface spaced apart from the rotor outer circumferential surface by an air gap; A support comprising a casing, a drive support for supporting the drive, a bearing, and a bearing housing; A compression unit comprising an impeller connected to the drive shaft, an air circulation passage for circulating air to the front suction side of the impeller, a diffuser installed on a rear outer circumferential surface of the impeller, a shroud communicating with the diffuser, and a volute casing; And An air inlet formed on one side of the casing, an air discharge ring provided adjacent to the side end of the rotor, and an air inlet formed in the stator so that air flows from the outer peripheral surface of the stator toward the outer peripheral surface of the rotor Cooling unit consisting of a ball, a heat radiation fin formed on the outside of the stator; Turbo machine comprising a.