JP6258237B2 - Centrifugal compressor - Google Patents

Description

  The present invention relates to a centrifugal compressor having an inlet guide vane and one suction port.

  Centrifugal compressors are used in turbo refrigerators, petrochemical plants, natural gas plants, and the like. In a centrifugal compressor, kinetic energy is given to a fluid by rotation of an impeller (impeller), and a pressure increase due to centrifugal force is obtained by blowing the fluid radially outward. In Patent Document 1, in a turbocharger (supercharger) which is one of centrifugal compressors, air flowing into the upstream side of an impeller (compressor blade) is rectified and the amount of air flowing in is adjusted. Some have an inlet guide vane (see Patent Document 1).

JP 2010-71140 A

  The inlet guide vane can adjust the amount of air flowing in by making the angle with respect to the impeller, that is, the opening, variable and changing the resistance in the flow path. In some centrifugal compressors, an inlet guide vane is fixed. Centrifugal compressors are distributed in the amount of fluid flowing into the impeller in the direction of rotation of the main shaft, and the efficiency of operation decreases as the flow rate difference increases.

  This invention solves the subject mentioned above, and it aims at providing the centrifugal compressor which can flow air into an impeller efficiently and can improve driving | operation efficiency.

  In order to achieve the above-described object, the present invention is a centrifugal compressor, in which an inlet channel provided with a suction port in one place and a connection channel connected to the inlet channel are formed. A casing, a main shaft inserted into the casing, an impeller fixed to the main shaft and disposed in the inlet flow path, and a plurality of inlet guides disposed on the upstream side of the impeller in the inlet flow path An inlet guide vane unit having a vane, wherein the inlet guide vane unit has an arrangement interval of the inlet guide vanes on the side opposite to the suction port side. It is characterized by being narrower than.

  Here, the inlet guide vane unit has an arrangement interval of 25% of the first group of the inlet guide vanes on the end side on the suction port side of all the inlet guide vanes. It is preferable that it is narrower than the arrangement interval of 25% of the second group of inlet guide vanes on the end side opposite to the suction port.

  In the inlet guide vane unit, the relationship between the maximum value dmax and the minimum value dmin of the interval between the inlet guide vanes is preferably 0.6 ≦ dmin / dmax <1.0.

  In the inlet guide vane unit, the interval between the inlet guide vanes may vary within a range of 20% or less of the amplitude of the reference line with reference to the reference line of the sin function along the rotation direction of the main shaft. preferable.

  Further, the inlet guide vane unit has a position in which the position where the interval between the inlet guide vanes is widest is moved from 0 ° to 40 ° to the upstream side in the rotation direction of the main shaft from the end opposite to the suction port. It is preferable that it exists in.

  According to the present invention, the distribution in the circumferential direction of the fluid flowing into the impeller can be averaged by changing the arrangement interval of the inlet guide vanes according to the position, and the operation efficiency can be increased.

FIG. 1 is a schematic configuration diagram of a compressor according to the present embodiment. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a partially enlarged view of the inlet guide vane unit. FIG. 4 is a graph showing an example of the flow rate distribution of the inflowing fluid. FIG. 5 is a graph showing an example of the relationship between the position and interval of the inlet guide vane. FIG. 6 is a schematic diagram illustrating an example of an inlet guide vane. FIG. 7 is a graph showing an example of the relationship between the position and interval of the inlet guide vane.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same. The compressor 1 can be used as a supply device of compressed air to a refrigerator, a petrochemical plant, or a natural gas plant, for example.

  As shown in FIG. 1, the compressor (centrifugal compressor) 1 of this embodiment is a multistage compression centrifugal compressor. In the present embodiment, the compressor 1 is described as a multi-stage compression compressor, but it may be a single-stage compression compressor. The compressor 1 includes a casing 2, a drive unit 4, a main shaft 6, and a compression unit 14.

  The casing 2 is a housing and houses the drive unit 4, the main shaft 6, and the compression unit 14. The casing 2 is formed with a flow path through which fluid to be compressed, in this embodiment, air flows. In the casing 2, the opening at the upstream end of the flow path through which the air flows becomes the suction port 12, and the opening at the downstream end of the flow path through which the air flows becomes the discharge port 16. The compressor 1 of this embodiment has one suction port 12. In the casing 2, the air flow path between the suction port 12 and the compression unit 14 becomes the suction flow path 102. In the casing 2, the air flow path between the discharge port 16 and the compression unit 14 becomes the discharge flow path 104. In the compressor 1, the suction flow path 102 is disposed in a direction inclined with respect to the axial direction of the main shaft 6, in the present embodiment, in a direction orthogonal to the axial direction of the main shaft 6.

  The drive unit 4 includes an electric motor and a power transmission unit. The drive unit 4 transmits the output of the electric motor to the main shaft 6 by the power transmission unit, and rotates the main shaft 6. The main shaft 6 is inserted into the casing 2 and is supported so as to be rotatable with respect to the casing 2. The main shaft 6 is rotated by the drive unit 4. The rotation part of the compression part 14 is being fixed to the main shaft 6.

  The compression unit 14 is disposed in the casing 2, compresses the air flowing in from the suction port 12, and discharges it from the discharge port 16. The compression unit 14 includes compression units 18a, 18b, 18c, and 18d. The compression units 18a, 18b, 18c, and 18d are arranged in this order between the suction channel 102 and the discharge channel 104. The compression unit 18 a is connected to the suction channel 102. The compression unit 18d is connected to the discharge flow path 104. Since the compression units 18a, 18b, 18c, and 18d have the same shape except for the arrangement positions, the compression unit 18a will be described as a representative.

  The compression unit 18a has a flow path formed by the casing 2 so that the fluid is sucked and compressed and then discharged. The flow path of the compression unit 18 a has an inlet flow path 33 and a return flow path 35. The inlet channel 33 has an upstream side connected to the suction channel 102 and a downstream side connected to the return channel 35. The return channel 35 is connected to the inlet channel 33 of the next-stage compression unit 18b on the downstream side. In the compression unit 18 a, an impeller (impeller) 32 is provided in the inlet flow path 33, and a return vane 34 is provided in the return flow path 35. An impeller 32 is fixed to the main shaft 6. The impeller 32 has a large number of blades 32a on its surface. The impeller 32 rotates together with the main shaft 6 to send air flowing into the inlet channel 33 toward the return channel 35. In addition, the inlet channel 33 serves as a diffuser on the downstream side of the impeller 32, and decelerates and pressurizes the fluid accelerated by the impeller 32. A return vane 34 is disposed in the return flow path 35. The return vane 34 rectifies the fluid flowing through the return flow path 35. The fluid that has passed through the return flow path 35 flows into the compression unit 18b.

  In the compressor 1, the main shaft 6 of the compression unit 14 rotates through the power transmission unit by driving the electric motor of the drive unit 4. Then, the impeller 32 rotates with the main shaft 6. As a result, the fluid is sucked from the suction port 12, flows into the suction flow path 102, flows through the inlet guide vane unit 100, flows into the inlet flow path 33 of the compression unit 18a, and is accelerated by the impeller 32. The diffuser converts kinetic energy into internal energy. Further, the fluid is folded back to the inlet channel 33 of the compression unit 18b by the return channel 35, accelerated by the impeller 32, and then converted into kinetic energy by the diffuser. The compressor 1 is similarly compressed by the compression units 18 c and 18 d and then discharged from the discharge port 16 of the discharge flow path 104.

  Next, the inlet guide vane unit (IGV, guide guide vane) 100 will be described with reference to FIGS. 2 to 3 in addition to FIG. 2 is a cross-sectional view taken along line AA in FIG. FIG. 3 is a partially enlarged view of the inlet guide vane unit.

  As described above, the inlet guide vane unit 100 is disposed in the flow path on the upstream side of the impeller 32 of the compression unit 18a disposed in the uppermost stream in the fluid flow direction in the fluid flow direction. The inlet guide vane unit 100 has a plurality of inlet guide vanes 101. As shown in FIG. 2, the plurality of inlet guide vanes 101 are arranged on the entire circumference of the main shaft 6 at a predetermined interval in the rotation direction of the main shaft 6. That is, the inlet guide vane 101 is arranged away from the inlet guide vane 101 adjacent in the rotation direction (circumferential direction) of the main shaft 6. The inlet guide vane 101 is a plate-like member extending in the radial direction of the main shaft 6. The shape of the inlet guide vane 101 differs depending on the position in the rotational direction, and the surface of the suction port 12 protrudes on the opposite side to the suction port 12 so as to guide the air flowing in from the suction port 12 to the center side of the main shaft 6. The curved surface. The air flowing in from the suction port 12 passes between the inlet guide vanes 101 and proceeds to a position where the impeller 32 of the inflow channel 33 is disposed.

  In the inlet guide vane unit 100, when the interval between the inlet guide vanes 101 is d, the interval changes depending on the position of the main shaft 6 in the rotational direction. Here, as shown in FIG. 3, the distance d is the diameter of the smallest circle connecting the ends on the center side of the main shaft 6 of the two adjacent inlet guide vanes 101. In the inlet guide vane unit 100, the interval between the inlet guide vanes 101 at the suction port side end portion 120 is narrower than the interval between the inlet guide vanes 101 at the end side end portion 122. The suction port side end 120 is a position closest to the suction port 12 in the rotation direction R of the main shaft 6. The terminal end 122 is the position closest to the terminal 112 in the rotation direction R of the main shaft 6. The end 112 is a position opposite to the suction port 12 in the air flow direction in the suction flow path 102, and is a position rotated 180 degrees from the suction port side end 120 in the rotation direction R. Here, in the present embodiment, the end side end is set to 0 degree, and the angle (circumferential position) that increases as it rotates in the rotation direction R is θ.

  FIG. 4 is a graph showing an example of the flow rate distribution of the inflowing fluid. 4 flows into the inlet flow path 33 of the compressor 1 in which the interval between the inlet guide vanes 101 at the suction port side end portion 120 of the present embodiment is narrower than the interval between the inlet guide vanes 101 at the end side end portion 122. It is a measurement result of the weight flow rate of air (air after passing through the inlet guide vane 101). The comparative example is a measurement result of the quantity flow rate when the interval between the inlet guide vanes 101 is constant in the rotation direction R. The compressor 1 adjusts the interval of the inlet guide vane 101 according to the position, and makes the interval of the inlet guide vane 101 at the suction port side end portion 120 narrower than the interval of the inlet guide vane 101 at the end side end portion 122. Even if the suction port is one place and the air flows from only a part of the circumferential direction, the weight flow rate of the air at the position in the rotational direction R (circumferential position) is averaged as shown in FIG. Can be Specifically, by adjusting the interval between the inlet guide vanes 101, the weight flow rate of air can be averaged rather than making the interval constant. The inlet guide vane unit 100 can uniformly supply air to the impeller 32.

  Here, in the inlet guide vane unit 100, the arrangement interval of the inlet guide vanes 101 of 25% of the first group 130 on the suction port side end portion 120 side of all the inlet guide vanes 101 is equal to all the inlet guide vanes 101. Among them, it is preferable that the arrangement interval of the inlet guide vanes 101 of 25% of the second group 132 on the terminal end 122 side is narrower. Here, when 25% of all the inlet guide vanes 101 include a decimal point, the numerical value is rounded up. The inlet guide vane unit 100 can average the weight flow rate of air by making the arrangement interval of the first group 130 narrower than the arrangement interval of the second group 132. The inlet guide vane unit 100 can uniformly supply air to the impeller 32.

  In the above description, the intervals of 25% of the inlet guide vanes out of the total number of sheets arranged on the suction port side end portion 120 side and the terminal end side end portion 122 side are compared, but the present invention is not limited to this. The inlet guide vane unit 100 has an inlet guide vane interval included in a range of 45 degrees in front and rear, that is, 90 ° with respect to the suction port side end portion 120 as a base point, and 45 ° in front and back with respect to the end side end portion 122 as a base point. You may make it narrower than the space | interval of the inlet guide vane included in the range of 90 degrees. As described above, even when the interval between the inlet guide vanes included in the range set on the basis of the angle satisfies the above relationship, the air can be supplied uniformly.

  Moreover, although it is preferable that the space | interval of an inlet guide vane changes gradually in a rotation direction, there may exist an inlet guide vane arrange | positioned at the same space | interval.

  In the inlet guide vane unit 100, the relationship between the maximum value dmax and the minimum value dmin of the interval between the inlet guide vanes 101 is preferably 0.6 ≦ dmin / dmax <1.0. By setting the difference in the arrangement interval in the above range, the weight flow rate of air can be more reliably averaged.

  In the inlet guide vane unit 100, the interval between the inlet guide vanes 101 is preferably gradually changed in the rotation direction R. Specifically, in one rotation of the rotation direction R, it is preferable that the half circumference (for an angle range of 180 °) is an increasing region and the half circumference (for the angle range of 180 °) is a decreasing region.

  FIG. 5 is a graph showing an example of the relationship between the position and interval of the inlet guide vane. In the inlet guide vane unit 100 shown in FIG. 5, one cycle is 360 degrees per cycle, the end side end portion θ is 180 ° and the interval is maximum, and the suction port end portion θ is 0 ° and 360 °. The interval between the inlet guide vanes 101 is increased or decreased based on the sin function that minimizes. As shown in FIG. 5, the flow rate can be made more uniform by increasing or decreasing the interval between the inlet guide vanes 101 based on the sin function. Also, when changing by the sine function, the difference between the maximum value and the minimum value is preferably in the above range.

  Here, based on the sin function, it is preferable to change the interval between the inlet guide vanes based on a point on the sin function, but the present invention is not limited to this. The inlet guide vane unit may change the interval of the inlet guide vanes within a range of 20% or less of the amplitude of the reference line with reference to the reference line of the sin function along the rotation direction of the main shaft. That is, the interval between the inlet guide vanes may be shifted within a certain range from the point on the sin function. For example, the intervals between the inlet guide vanes may be the same between a plurality of sheets, and the intervals may change stepwise. Thus, the weight flow rate of air in the rotational direction can also be averaged by changing the interval between the inlet guide vanes within a range of 20% or less of the amplitude of the reference line with reference to the reference line of the sin function. . More preferably, the inlet guide vane unit changes the interval between the inlet guide vanes within a range of 5% or less of the amplitude of the reference line with reference to the reference line of the sin function along the rotation direction of the main shaft. More preferably, the distance between the inlet guide vanes is changed within a range of 5% or less of the line amplitude.

  FIG. 6 is a schematic diagram illustrating an example of an inlet guide vane. In addition, as shown in FIG. 6, the inlet guide vane 101 is an extension line of the end portion on the center 142 side of the main shaft 6 of the pressure surface 140 which is a surface on the suction port 102 side, and a line connecting the end portion and the center 142. Is preferably 0 ° or more and 10 ° or less. Thus, the angle θa formed is positive in the direction opposite to the rotation direction with the end portion on the center side of the inlet guide vane 101 as the center. By making the pressure surface 140 of the inlet guide vane 101 into a shape that satisfies the above range, the rectifying effect can be further improved.

  FIG. 7 is a graph showing an example of the relationship between the position and interval of the inlet guide vane. In the example shown in FIG. 5, the interval between the inlet guide vanes is the maximum when θ is 0 ° and the minimum when 180 °, but is not limited thereto. In the inlet guide vane unit 100, as shown in the second pattern of FIG. 7, the position where the interval between the inlet guide vanes 101 is the widest is moved from the end side end to the upstream side in the rotation direction of the main shaft more than 0 ° and 40 ° or less. It is preferable that it exists between the positions. That is, it is preferable that the deviation 160 from the first pattern of FIG. 5 shown in FIG. 7 is larger than 0 ° and not more than 40 degrees on the upstream side in the rotation direction. In this way, by shifting the position with the widest interval between the inlet guide vanes 101 to the upstream side in the rotational direction, the weight flow rate can be adjusted in consideration of the influence of the impeller, and the weight flow rate of air in the rotational direction is averaged. Can be Here, the gap between the inlet guide vanes 101 is preferably shifted to the upstream side in the rotational direction as well as the position where the gap between the inlet guide vanes 101 is widest. It is preferable that the main shaft is located at a position moved more than 0 ° and 40 ° or less on the upstream side in the rotation direction.

DESCRIPTION OF SYMBOLS 1 Compressor 2 Casing 4 Drive part 6 Main shaft 12 Suction port 14 Compression part 16 Discharge port 18a, 18b, 18c, 18d Compression unit 32 Impeller 32a Blade 33 Inlet flow path 34 Return vane 35 Return flow path 100 Inlet guide vane unit 101 Inlet guide vane 102 Suction channel 104 Discharge channel 120 Suction port side end 122 Terminal side end 130 First group 132 Second group 160 Deviation amount

Claims (5)

A casing formed with an inlet channel provided with a suction port in one place and a connection channel connected to the inlet channel;
A main shaft inserted into the casing;
An impeller fixed to the main shaft and disposed in the inlet channel;
An inlet guide vane unit having a plurality of inlet guide vanes arranged upstream of the impeller of the inlet channel;
The inlet guide vane unit is a centrifugal compressor characterized in that an arrangement interval of the inlet guide vanes on the suction port side is narrower than an arrangement interval of the inlet guide vanes on the side opposite to the suction port side.   The inlet guide vane unit has an arrangement interval of 25% of the first group of the inlet guide vanes on the end side on the suction port side among all the inlet guide vanes. 2. The centrifugal compressor according to claim 1, wherein the centrifugal guide compressor is narrower than an arrangement interval of 25% of the second group of the inlet guide vanes on the opposite end side.   3. The inlet guide vane unit according to claim 1, wherein a relationship between a maximum value dmax and a minimum value dmin of the interval between the inlet guide vanes is 0.6 ≦ dmin / dmax <1.0. Centrifugal compressor.   The inlet guide vane unit is characterized in that the interval between the inlet guide vanes changes within a range of 20% or less of the amplitude of the reference line with reference to the reference line of the sin function along the rotation direction of the main shaft. The centrifugal compressor according to any one of claims 1 to 3.   In the inlet guide vane unit, the position where the gap between the inlet guide vanes is the widest is the position moved from 0 ° to 40 ° to the upstream side in the rotation direction of the main shaft from the end opposite to the suction port. The centrifugal compressor according to claim 4.

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